Rohde&Schwarz FSQ3, FSQ8, FSQ26, FSQ39, FSQ40 Operating Manual

R&S®FSQ

Signal Analyzer

1313.9681.12 – 02

Test & Measurement

Operating Manual

Operating Manual

The Operating Manual describes the following R&S®FSQ models and options:

● R&S FSQ3 (1313.9100K03)

● R&S FSQ8 (1313.9100K08)

● R&S FSQ26 (1313.9100K26)

● R&S FSQ39 (1313.9100K39)

● R&S FSQ40 (1313.9100K40)

● R&S FSU-B9 (1142.8994.02)

● R&S FSQ-B10 (1129.7246.03)

● R&S FSP-B16 (1129.8042.03)

● R&S FSQ-B17 (1163.0063.02)

● R&S FSU-B21 (1157.1090.03)

The contents of this manual correspond to firmware 4.75SP5 or higher.

© 2014 Rohde & Schwarz GmbH & Co. KG

Muehldorfstr. 15, 81671 Munich. Germany

Phone: [phone]

Fax: [phone]

E-mail: [e-mail]

Internet: http://www.rohde-schwarz.com

81671 Munich, Germany

Subject to change – Data without tolerance limits is not binding.

®

R&S

is a registered trademark of Rohde & Schwarz GmbH & Co. KG.

Trade names are trademarks of the owners.

The following abbreviations are used throughout this manual:

®

R&S

FSQ is abbreviated as R&S FSQ.

Basic Safety Instructions

Always read through and comply with the following safety instructions!

All plants and locations of the Rohde & Schwarz group of companies make every effort to keep the safety
standards of our products up to date and to offer our customers the highest possible degree of safety. Our
products and the auxiliary equipment they require are designed, built and tested in accordance with the
safety standards that apply in each case. Compliance with these standards is continuously monitored by
our quality assurance system. The product described here has been designed, built and tested in
accordance with the EC Certificate of Conformity and has left the manufacturer’s plant in a condition fully
complying with safety standards. To maintain this condition and to ensure safe operation, you must
observe all instructions and warnings provided in this manual. If you have any questions regarding these
safety instructions, the Rohde & Schwarz group of companies will be happy to answer them.

Furthermore, it is your responsibility to use the product in an appropriate manner. This product is designed
for use solely in industrial and laboratory environments or, if expressly permitted, also in the field and must
not be used in any way that may cause personal injury or property damage. You are responsible if the
product is used for any purpose other than its designated purpose or in disregard of the manufacturer's
instructions. The manufacturer shall assume no responsibility for such use of the product.

The product is used for its designated purpose if it is used in accordance with its product documentation
and within its performance limits (see data sheet, documentation, the following safety instructions). Using
the product requires technical skills and, in some cases, a basic knowledge of English. It is therefore
essential that only skilled and specialized staff or thoroughly trained personnel with the required skills be
allowed to use the product. If personal safety gear is required for using Rohde & Schwarz products, this
will be indicated at the appropriate place in the product documentation. Keep the basic safety instructions
and the product documentation in a safe place and pass them on to the subsequent users.

Observing the safety instructions will help prevent personal injury or damage of any kind caused by
dangerous situations. Therefore, carefully read through and adhere to the following safety instructions
before and when using the product. It is also absolutely essential to observe the additional safety
instructions on personal safety, for example, that appear in relevant parts of the product documentation. In
these safety instructions, the word "product" refers to all merchandise sold and distributed by the Rohde &
Schwarz group of companies, including instruments, systems and all accessories. For product-specific
information, see the data sheet and the product documentation.

Safety labels on products

The following safety labels are used on products to warn against risks and dangers.

Symbol Meaning Symbol Meaning

Notice, general danger location

Observe product documentation

Caution when handling heavy equipment Standby indication

Danger of electric shock Direct current (DC)

ON/OFF supply voltage

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Symbol Meaning Symbol Meaning

Warning! Hot surface Alternating current (AC)

Protective conductor terminal Direct/alternating current (DC/AC)

Ground Device fully protected by double (reinforced)

insulation

Ground terminal EU labeling for batteries and accumulators

For additional information, see section "Waste
disposal/Environmental protection", item 1.

Be careful when handling electrostatic sensitive
devices

Warning! Laser radiation

For additional information, see section
"Operation", item 7.

EU labeling for separate collection of electrical
and electronic devices

For additonal information, see section "Waste
disposal/Environmental protection", item 2.

Signal words and their meaning

The following signal words are used in the product documentation in order to warn the reader about risks
and dangers.

Indicates a hazardous situation which, if not avoided, will result in death or
serious injury.

Indicates a hazardous situation which, if not avoided, could result in death or
serious injury.

Indicates a hazardous situation which, if not avoided, could result in minor or
moderate injury.

Indicates information considered important, but not hazard-related, e.g.
messages relating to property damage.
In the product documentation, the word ATTENTION is used synonymously.

These signal words are in accordance with the standard definition for civil applications in the European
Economic Area. Definitions that deviate from the standard definition may also exist in other economic
areas or military applications. It is therefore essential to make sure that the signal words described here
are always used only in connection with the related product documentation and the related product. The
use of signal words in connection with unrelated products or documentation can result in misinterpretation
and in personal injury or material damage.

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Operating states and operating positions

The product may be operated only under the operating conditions and in the positions specified by the
manufacturer, without the product's ventilation being obstructed. If the manufacturer's specifications are
not observed, this can result in electric shock, fire and/or serious personal injury or death. Applicable local
or national safety regulations and rules for the prevention of accidents must be observed in all work
performed.

1. Unless otherwise specified, the following requirements apply to Rohde & Schwarz products:
predefined operating position is always with the housing floor facing down, IP protection 2X, use only
indoors, max. operating altitude 2000 m above sea level, max. transport altitude 4500 m above sea
level. A tolerance of ±10 % shall apply to the nominal voltage and ±5 % to the nominal frequency,
overvoltage category 2, pollution severity 2.

2. Do not place the product on surfaces, vehicles, cabinets or tables that for reasons of weight or stability
are unsuitable for this purpose. Always follow the manufacturer's installation instructions when
installing the product and fastening it to objects or structures (e.g. walls and shelves). An installation
that is not carried out as described in the product documentation could result in personal injury or
even death.

3. Do not place the product on heat-generating devices such as radiators or fan heaters. The ambient
temperature must not exceed the maximum temperature specified in the product documentation or in
the data sheet. Product overheating can cause electric shock, fire and/or serious personal injury or
even death.

Electrical safety

If the information on electrical safety is not observed either at all or to the extent necessary, electric shock,
fire and/or serious personal injury or death may occur.

1. Prior to switching on the product, always ensure that the nominal voltage setting on the product
matches the nominal voltage of the AC supply network. If a different voltage is to be set, the power
fuse of the product may have to be changed accordingly.

2. In the case of products of safety class I with movable power cord and connector, operation is
permitted only on sockets with a protective conductor contact and protective conductor.

3. Intentionally breaking the protective conductor either in the feed line or in the product itself is not
permitted. Doing so can result in the danger of an electric shock from the product. If extension cords
or connector strips are implemented, they must be checked on a regular basis to ensure that they are
safe to use.

4. If there is no power switch for disconnecting the product from the AC supply network, or if the power
switch is not suitable for this purpose, use the plug of the connecting cable to disconnect the product
from the AC supply network. In such cases, always ensure that the power plug is easily reachable and
accessible at all times. For example, if the power plug is the disconnecting device, the length of the
connecting cable must not exceed 3 m. Functional or electronic switches are not suitable for providing
disconnection from the AC supply network. If products without power switches are integrated into
racks or systems, the disconnecting device must be provided at the system level.

5. Never use the product if the power cable is damaged. Check the power cables on a regular basis to
ensure that they are in proper operating condition. By taking appropriate safety measures and
carefully laying the power cable, ensure that the cable cannot be damaged and that no one can be
hurt by, for example, tripping over the cable or suffering an electric shock.

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6. The product may be operated only from TN/TT supply networks fuse-protected with max. 16 A (higher
fuse only after consulting with the Rohde & Schwarz group of companies).

7. Do not insert the plug into sockets that are dusty or dirty. Insert the plug firmly and all the way into the
socket provided for this purpose. Otherwise, sparks that result in fire and/or injuries may occur.

8. Do not overload any sockets, extension cords or connector strips; doing so can cause fire or electric

hocks.

s

9. For measurements in circuits with voltages V

> 30 V, suitable measures (e.g. appropriate

rms

measuring equipment, fuse protection, current limiting, electrical separation, insulation) should be
taken to avoid any hazards.

10. Ensure that the connections with information technology equipment, e.g. PCs or other industrial
computers, comply with the IEC60950-1/EN60950-1 or IEC61010-1/EN 61010-1 standards that apply
in each case.

11. Unless expressly permitted, never remove the cover or any part of the housing while the product is in
operation. Doing so will expose circuits and components and can lead to injuries, fire or damage to the
product.

12. If a product is to be permanently installed, the connection between the protective conductor terminal
on site and the product's protective conductor must be made first before any other connection is
made. The product may be installed and connected only by a licensed electrician.

13. For permanently installed equipment without built-in fuses, circuit breakers or similar protective
devices, the supply circuit must be fuse-protected in such a way that anyone who has access to the
product, as well as the product itself, is adequately protected from injury or damage.

14. Use suitable overvoltage protection to ensure that no overvoltage (such as that caused by a bolt of
lightning) can reach the product. Otherwise, the person operating the product will be exposed to the
danger of an electric shock.

15. Any object that is not designed to be placed in the openings of the housing must not be used for this
purpose. Doing so can cause short circuits inside the product and/or electric shocks, fire or injuries.

16. Unless specified otherwise, products are not liquid-proof (see also section "Operating states and
operating positions", item 1). Therefore, the equipment must be protected against penetration by
liquids. If the necessary precautions are not taken, the user may suffer electric shock or the product
itself may be damaged, which can also lead to personal injury.

17. Never use the product under conditions in which condensation has formed or can form in or on the
product, e.g. if the product has been moved from a cold to a warm environment. Penetration by water
increases the risk of electric shock.

18. Prior to cleaning the product, disconnect it completely from the power supply (e.g. AC supply network
or battery). Use a soft, non-linting cloth to clean the product. Never use chemical cleaning agents such
as alcohol, acetone or diluents for cellulose lacquers.

Operation

1. Operating the products requires special training and intense concentration. Make sure that persons
who use the products are physically, mentally and emotionally fit enough to do so; otherwise, injuries
or material damage may occur. It is the responsibility of the employer/operator to select suitable
personnel for operating the products.

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Basic Safety Instructions

2. Before you move or transport the product, read and observe the section titled "Transport".

3. As with all industrially manufactured goods, the use of substances that induce an allergic reaction
(allergens) such as nickel cannot be generally excluded. If you develop an allergic reaction (such as a
skin rash, frequent sneezing, red eyes or respiratory difficulties) when using a Rohde & Schwarz
product, consult a physician immediately to determine the cause and to prevent health problems or
stress.

4. Before you start processing the product mechanically and/or thermally, or before you take it apart, be
sure to read and pay special attention to the section titled "Waste disposal/Environmental protection",
item 1.

5. Depending on the function, certain products such as RF radio equipment can produce an elevated
level of electromagnetic radiation. Considering that unborn babies require increased protection,
pregnant women must be protected by appropriate measures. Persons with pacemakers may also be
exposed to risks from electromagnetic radiation. The employer/operator must evaluate workplaces
where there is a special risk of exposure to radiation and, if necessary, take measures to avert the
potential danger.

6. Should a fire occur, the product may release hazardous substances (gases, fluids, etc.) that can
cause health problems. Therefore, suitable measures must be taken, e.g. protective masks and
protective clothing must be worn.

7. Laser products are given warning labels that are standardized according to their laser class. Lasers
can cause biological harm due to the properties of their radiation and due to their extremely
concentrated electromagnetic power. If a laser product (e.g. a CD/DVD drive) is integrated into a
Rohde & Schwarz product, absolutely no other settings or functions may be used as described in the
product documentation. The objective is to prevent personal injury (e.g. due to laser beams).

8. EMC classes (in line with EN 55011/CISPR 11,
EN 55032/CISPR 32)
 Class A equipment:

Equipment suitable for use in all environments except residential environments and environments
that are directly connected to a low-voltage supply network that supplies residential buildings
Note: Class A equipment is intended for use in an industrial environment. This equipment may
cause radio disturbances in residential environments, due to possible conducted as well as
radiated disturbances. In this case, the operator may be required to take appropriate measures to
eliminate these disturbances.

 Class B equipment:

Equipment suitable for use in residential environments and environments that are directly
connected to a low-voltage supply network that supplies residential buildings

Repair and service

1. The product may be opened only by authorized, specially trained personnel. Before any work is
performed on the product or before the product is opened, it must be disconnected from the AC supply
network. Otherwise, personnel will be exposed to the risk of an electric shock.

and analogously with EN 55022/CISPR 22,

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2. Adjustments, replacement of parts, maintenance and repair may be performed only by electrical
experts authorized by Rohde & Schwarz. Only original parts may be used for replacing parts relevant
to safety (e.g. power switches, power transformers, fuses). A safety test must always be performed
after parts relevant to safety have been replaced (visual inspection, protective conductor test,
insulation resistance measurement, leakage current measurement, functional test). This helps ensure
the continued safety of the product.

Batteries and rechargeable batteries/cells

If the information regarding batteries and rechargeable batteries/cells is not observed either at all or to the
extent necessary, product users may be exposed to the risk of explosions, fire and/or serious personal
injury, and, in some cases, death. Batteries and rechargeable batteries with alkaline electrolytes (e.g.
lithium cells) must be handled in accordance with the EN 62133 standard.

1. Cells must not be taken apart or crushed.

2. Cells or batteries must not be exposed to heat or fire. Storage in direct sunlight must be avoided.
Keep cells and batteries clean and dry. Clean soiled connectors using a dry, clean cloth.

3. Cells or batteries must not be short-circuited. Cells or batteries must not be stored in a box or in a
drawer where they can short-circuit each other, or where they can be short-circuited by other
conductive materials. Cells and batteries must not be removed from their original packaging until they
are ready to be used.

4. Cells and batteries must not be exposed to any mechanical shocks that are stronger than permitted.

5. If a cell develops a leak, the fluid must not be allowed to come into contact with the skin or eyes. If
contact occurs, wash the affected area with plenty of water and seek medical aid.

6. Improperly replacing or charging cells or batteries that contain alkaline electrolytes (e.g. lithium cells)
can cause explosions. Replace cells or batteries only with the matching Rohde & Schwarz type (see
parts list) in order to ensure the safety of the product.

7. Cells and batteries must be recycled and kept separate from residual waste. Rechargeable batteries
and normal batteries that contain lead, mercury or cadmium are hazardous waste. Observe the
national regulations regarding waste disposal and recycling.

Transport

1. The product may be very heavy. Therefore, the product must be handled with care. In some cases,
the user may require a suitable means of lifting or moving the product (e.g. with a lift-truck) to avoid
back or other physical injuries.

2. Handles on the products are designed exclusively to enable personnel to transport the product. It is
therefore not permissible to use handles to fasten the product to or on transport equipment such as
cranes, fork lifts, wagons, etc. The user is responsible for securely fastening the products to or on the
means of transport or lifting. Observe the safety regulations of the manufacturer of the means of
transport or lifting. Noncompliance can result in personal injury or material damage.

3. If you use the product in a vehicle, it is the sole responsibility of the driver to drive the vehicle safely
and properly. The manufacturer assumes no responsibility for accidents or collisions. Never use the
product in a moving vehicle if doing so could distract the driver of the vehicle. Adequately secure the
product in the vehicle to prevent injuries or other damage in the event of an accident.

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Waste disposal/Environmental protection

1. Specially marked equipment has a battery or accumulator that must not be disposed of with unsorted
municipal waste, but must be collected separately. It may only be disposed of at a suitable collection
point or via a Rohde & Schwarz customer service center.

2. Waste electrical and electronic equipment must not be disposed of with unsorted municipal waste, but

ust be collected separately.

m
Rohde & Schwarz GmbH & Co. KG has developed a disposal concept and takes full responsibility for
take-back obligations and disposal obligations for manufacturers within the EU. Contact your
Rohde & Schwarz customer service center for environmentally responsible disposal of the product.

3. If products or their components are mechanically and/or thermally processed in a manner that goes
beyond their intended use, hazardous substances (heavy-metal dust such as lead, beryllium, nickel)
may be released. For this reason, the product may only be disassembled by specially trained
personnel. Improper disassembly may be hazardous to your health. National waste disposal
regulations must be observed.

4. If handling the product releases hazardous substances or fuels that must be disposed of in a special
way, e.g. coolants or engine oils that must be replenished regularly, the safety instructions of the
manufacturer of the hazardous substances or fuels and the applicable regional waste disposal
regulations must be observed. Also observe the relevant safety instructions in the product
documentation. The improper disposal of hazardous substances or fuels can cause health problems
and lead to environmental damage.

For additional information about environmental protection, visit the Rohde & Schwarz website.

Instrucciones de seguridad elementales

¡Es imprescindible leer y cumplir las siguientes instrucciones e informaciones de seguridad!

El principio del grupo de empresas Rohde & Schwarz consiste en tener nuestros productos siempre al día
con los estándares de seguridad y de ofrecer a nuestros clientes el máximo grado de seguridad. Nuestros
productos y todos los equipos adicionales son siempre fabricados y examinados según las normas de
seguridad vigentes. Nuestro sistema de garantía de calidad controla constantemente que sean cumplidas
estas normas. El presente producto ha sido fabricado y examinado según el certificado de conformidad
de la UE y ha salido de nuestra planta en estado impecable según los estándares técnicos de seguridad.
Para poder preservar este estado y garantizar un funcionamiento libre de peligros, el usuario deberá
atenerse a todas las indicaciones, informaciones de seguridad y notas de alerta. El grupo de empresas
Rohde & Schwarz está siempre a su disposición en caso de que tengan preguntas referentes a estas
informaciones de seguridad.

Además queda en la responsabilidad del usuario utilizar el producto en la forma debida. Este producto
está destinado exclusivamente al uso en la industria y el laboratorio o, si ha sido expresamente
autorizado, para aplicaciones de campo y de ninguna manera deberá ser utilizado de modo que alguna
persona/cosa pueda sufrir daño. El uso del producto fuera de sus fines definidos o sin tener en cuenta las
instrucciones del fabricante queda en la responsabilidad del usuario. El fabricante no se hace en ninguna
forma responsable de consecuencias a causa del mal uso del producto.

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Se parte del uso correcto del producto para los fines definidos si el producto es utilizado conforme a las
indicaciones de la correspondiente documentación del producto y dentro del margen de rendimiento
definido (ver hoja de datos, documentación, informaciones de seguridad que siguen). El uso del producto
hace necesarios conocimientos técnicos y ciertos conocimientos del idioma inglés. Por eso se debe tener
en cuenta que el producto solo pueda ser operado por personal especializado o personas instruidas en
profundidad con las capacidades correspondientes. Si fuera necesaria indumentaria de seguridad para el

so de productos de Rohde & Schwarz, encontraría la información debida en la documentación del

u
producto en el capítulo correspondiente. Guarde bien las informaciones de seguridad elementales, así
como la documentación del producto, y entréguelas a usuarios posteriores.

Tener en cuenta las informaciones de seguridad sirve para evitar en lo posible lesiones o daños por
peligros de toda clase. Por eso es imprescindible leer detalladamente y comprender por completo las
siguientes informaciones de seguridad antes de usar el producto, y respetarlas durante el uso del
producto. Deberán tenerse en cuenta todas las demás informaciones de seguridad, como p. ej. las
referentes a la protección de personas, que encontrarán en el capítulo correspondiente de la
documentación del producto y que también son de obligado cumplimiento. En las presentes
informaciones de seguridad se recogen todos los objetos que distribuye el grupo de empresas
Rohde & Schwarz bajo la denominación de "producto", entre ellos también aparatos, instalaciones así
como toda clase de accesorios. Los datos específicos del producto figuran en la hoja de datos y en la
documentación del producto.

Señalización de seguridad de los productos

Las siguientes señales de seguridad se utilizan en los productos para advertir sobre riesgos y peligros.

Símbolo Significado Símbolo Significado

Aviso: punto de peligro general

Observar la documentación del producto

Atención en el manejo de dispositivos de peso
elevado

Peligro de choque eléctrico Corriente continua (DC)

Advertencia: superficie caliente Corriente alterna (AC)

Conexión a conductor de protección Corriente continua / Corriente alterna (DC/AC)

Conexión a tierra El aparato está protegido en su totalidad por un

Tensión de alimentación de PUESTA EN
MARCHA / PARADA

Indicación de estado de espera (standby)

aislamiento doble (reforzado)

Conexión a masa Distintivo de la UE para baterías y

acumuladores

Más información en la sección
"Eliminación/protección del medio ambiente",
punto 1.

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Símbolo Significado Símbolo Significado

Aviso: Cuidado en el manejo de dispositivos
sensibles a la electrostática (ESD)

Advertencia: rayo láser

Más información en la sección
"Funcionamiento", punto 7.

Distintivo de la UE para la eliminación por
separado de dispositivos eléctricos y
electrónicos

Más información en la sección
"Eliminación/protección del medio ambiente",
punto 2.

Palabras de señal y su significado

En la documentación del producto se utilizan las siguientes palabras de señal con el fin de advertir contra
riesgos y peligros.

Indica una situación de peligro que, si no se evita, causa lesiones
graves o incluso la muerte.

Indica una situación de peligro que, si no se evita, puede causar
lesiones graves o incluso la muerte.

Indica una situación de peligro que, si no se evita, puede causar
lesiones leves o moderadas.

Indica información que se considera importante, pero no en relación
con situaciones de peligro; p. ej., avisos sobre posibles daños
materiales.
En la documentación del producto se emplea de forma sinónima el
término CUIDADO.

Las palabras de señal corresponden a la definición habitual para aplicaciones civiles en el área
económica europea. Pueden existir definiciones diferentes a esta definición en otras áreas económicas o
en aplicaciones militares. Por eso se deberá tener en cuenta que las palabras de señal aquí descritas
sean utilizadas siempre solamente en combinación con la correspondiente documentación del producto y
solamente en combinación con el producto correspondiente. La utilización de las palabras de señal en
combinación con productos o documentaciones que no les correspondan puede llevar a interpretaciones
equivocadas y tener por consecuencia daños en personas u objetos.

Estados operativos y posiciones de funcionamiento

El producto solamente debe ser utilizado según lo indicado por el fabricante respecto a los estados
operativos y posiciones de funcionamiento sin que se obstruya la ventilación. Si no se siguen las
indicaciones del fabricante, pueden producirse choques eléctricos, incendios y/o lesiones graves con
posible consecuencia de muerte. En todos los trabajos deberán ser tenidas en cuenta las normas
nacionales y locales de seguridad del trabajo y de prevención de accidentes.

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1. Si no se convino de otra manera, es para los productos Rohde & Schwarz válido lo que sigue:
como posición de funcionamiento se define por principio la posición con el suelo de la caja para
abajo, modo de protección IP 2X, uso solamente en estancias interiores, utilización hasta 2000 m
sobre el nivel del mar, transporte hasta 4500 m sobre el nivel del mar. Se aplicará una tolerancia de
±10 % sobre el voltaje nominal y de ±5 % sobre la frecuencia nominal. Categoría de sobrecarga
eléctrica 2, índice de suciedad 2.

2. No sitúe el producto encima de superficies, vehículos, estantes o mesas, que por sus características
de peso o de estabilidad no sean aptos para él. Siga siempre las instrucciones de instalación del
fabricante cuando instale y asegure el producto en objetos o estructuras (p. ej. paredes y estantes). Si
se realiza la instalación de modo distinto al indicado en la documentación del producto, se pueden
causar lesiones o, en determinadas circunstancias, incluso la muerte.

3. No ponga el producto sobre aparatos que generen calor (p. ej. radiadores o calefactores). La
temperatura ambiente no debe superar la temperatura máxima especificada en la documentación del
producto o en la hoja de datos. En caso de sobrecalentamiento del producto, pueden producirse
choques eléctricos, incendios y/o lesiones graves con posible consecuencia de muerte.

Seguridad eléctrica

Si no se siguen (o se siguen de modo insuficiente) las indicaciones del fabricante en cuanto a seguridad
eléctrica, pueden producirse choques eléctricos, incendios y/o lesiones graves con posible consecuencia
de muerte.

1. Antes de la puesta en marcha del producto se deberá comprobar siempre que la tensión
preseleccionada en el producto coincida con la de la red de alimentación eléctrica. Si es necesario
modificar el ajuste de tensión, también se deberán cambiar en caso dado los fusibles
correspondientes del producto.

2. Los productos de la clase de protección I con alimentación móvil y enchufe individual solamente
podrán enchufarse a tomas de corriente con contacto de seguridad y con conductor de protección
conectado.

3. Queda prohibida la interrupción intencionada del conductor de protección, tanto en la toma de
corriente como en el mismo producto. La interrupción puede tener como consecuencia el riesgo de
que el producto sea fuente de choques eléctricos. Si se utilizan cables alargadores o regletas de
enchufe, deberá garantizarse la realización de un examen regular de los mismos en cuanto a su
estado técnico de seguridad.

4. Si el producto no está equipado con un interruptor para desconectarlo de la red, o bien si el
interruptor existente no resulta apropiado para la desconexión de la red, el enchufe del cable de
conexión se deberá considerar como un dispositivo de desconexión.
El dispositivo de desconexión se debe poder alcanzar fácilmente y debe estar siempre bien accesible.
Si, p. ej., el enchufe de conexión a la red es el dispositivo de desconexión, la longitud del cable de
conexión no debe superar 3 m).
Los interruptores selectores o electrónicos no son aptos para el corte de la red eléctrica. Si se
integran productos sin interruptor en bastidores o instalaciones, se deberá colocar el interruptor en el
nivel de la instalación.

5. No utilice nunca el producto si está dañado el cable de conexión a red. Compruebe regularmente el
correcto estado de los cables de conexión a red. Asegúrese, mediante las medidas de protección y
de instalación adecuadas, de que el cable de conexión a red no pueda ser dañado o de que nadie
pueda ser dañado por él, p. ej. al tropezar o por un choque eléctrico.

1171.0000.42 - 07 Page 10

nstrucciones de seguridad elementales

I

6. Solamente está permitido el funcionamiento en redes de alimentación TN/TT aseguradas con fusibles
de 16 A como máximo (utilización de fusibles de mayor amperaje solo previa consulta con el grupo de
empresas Rohde & Schwarz).

7. Nunca conecte el enchufe en tomas de corriente sucias o llenas de polvo. Introduzca el enchufe por
completo y fuertemente en la toma de corriente. La no observación de estas medidas puede provocar
chispas, fuego y/o lesiones.

8. No sobrecargue las tomas de corriente, los cables alargadores o las regletas de enchufe ya que esto
podría causar fuego o choques eléctricos.

9. En las mediciones en circuitos de corriente con una tensión U

> 30 V se deberán tomar las medidas

eff

apropiadas para impedir cualquier peligro (p. ej. medios de medición adecuados, seguros, limitación
de tensión, corte protector, aislamiento etc.).

10. Para la conexión con dispositivos informáticos como un PC o un ordenador industrial, debe
comprobarse que éstos cumplan los estándares IEC60950-1/EN60950-1 o IEC61010-1/EN 61010-1
válidos en cada caso.

11. A menos que esté permitido expresamente, no retire nunca la tapa ni componentes de la carcasa
mientras el producto esté en servicio. Esto pone a descubierto los cables y componentes eléctricos y
puede causar lesiones, fuego o daños en el producto.

12. Si un producto se instala en un lugar fijo, se deberá primero conectar el conductor de protección fijo
con el conductor de protección del producto antes de hacer cualquier otra conexión. La instalación y
la conexión deberán ser efectuadas por un electricista especializado.

13. En el caso de dispositivos fijos que no estén provistos de fusibles, interruptor automático ni otros
mecanismos de seguridad similares, el circuito de alimentación debe estar protegido de modo que
todas las personas que puedan acceder al producto, así como el producto mismo, estén a salvo de
posibles daños.

14. Todo producto debe estar protegido contra sobretensión (debida p. ej. a una caída del rayo) mediante
los correspondientes sistemas de protección. Si no, el personal que lo utilice quedará expuesto al
peligro de choque eléctrico.

15. No debe introducirse en los orificios de la caja del aparato ningún objeto que no esté destinado a ello.
Esto puede producir cortocircuitos en el producto y/o puede causar choques eléctricos, fuego o
lesiones.

16. Salvo indicación contraria, los productos no están impermeabilizados (ver también el capítulo
"Estados operativos y posiciones de funcionamiento", punto 1). Por eso es necesario tomar las
medidas necesarias para evitar la entrada de líquidos. En caso contrario, existe peligro de choque
eléctrico para el usuario o de daños en el producto, que también pueden redundar en peligro para las
personas.

17. No utilice el producto en condiciones en las que pueda producirse o ya se hayan producido
condensaciones sobre el producto o en el interior de éste, como p. ej. al desplazarlo de un lugar frío a
otro caliente. La entrada de agua aumenta el riesgo de choque eléctrico.

18. Antes de la limpieza, desconecte por completo el producto de la alimentación de tensión (p. ej. red de
alimentación o batería). Realice la limpieza de los aparatos con un paño suave, que no se deshilache.
No utilice bajo ningún concepto productos de limpieza químicos como alcohol, acetona o diluyentes
para lacas nitrocelulósicas.

1171.0000.42 - 07 Page 11

nstrucciones de seguridad elementales

I

Funcionamiento

1. El uso del producto requiere instrucciones especiales y una alta concentración durante el manejo.
Debe asegurarse que las personas que manejen el producto estén a la altura de los requerimientos
necesarios en cuanto a aptitudes físicas, psíquicas y emocionales, ya que de otra manera no se
pueden excluir lesiones o daños de objetos. El empresario u operador es responsable de seleccionar
el personal usuario apto para el manejo del producto.

2. Antes de desplazar o transportar el producto, lea y tenga en cuenta el capítulo "Transporte".

3. Como con todo producto de fabricación industrial no puede quedar excluida en general la posibilidad
de que se produzcan alergias provocadas por algunos materiales empleados Slos llamados
alérgenos (p. ej. el níquel)S. Si durante el manejo de productos Rohde & Schwarz se producen
reacciones alérgicas, como p. ej. irritaciones cutáneas, estornudos continuos, enrojecimiento de la
conjuntiva o dificultades respiratorias, debe avisarse inmediatamente a un médico para investigar las
causas y evitar cualquier molestia o daño a la salud.

4. Antes de la manipulación mecánica y/o térmica o el desmontaje del producto, debe tenerse en cuenta
imprescindiblemente el capítulo "Eliminación/protección del medio ambiente", punto 1.

5. Ciertos productos, como p. ej. las instalaciones de radiocomunicación RF, pueden a causa de su
función natural, emitir una radiación electromagnética aumentada. Deben tomarse todas las medidas
necesarias para la protección de las mujeres embarazadas. También las personas con marcapasos
pueden correr peligro a causa de la radiación electromagnética. El empresario/operador tiene la
obligación de evaluar y señalizar las áreas de trabajo en las que exista un riesgo elevado de
exposición a radiaciones.

6. Tenga en cuenta que en caso de incendio pueden desprenderse del producto sustancias tóxicas
(gases, líquidos etc.) que pueden generar daños a la salud. Por eso, en caso de incendio deben
usarse medidas adecuadas, como p. ej. máscaras antigás e indumentaria de protección.

7. Los productos con láser están provistos de indicaciones de advertencia normalizadas en función de la
clase de láser del que se trate. Los rayos láser pueden provocar daños de tipo biológico a causa de
las propiedades de su radiación y debido a su concentración extrema de potencia electromagnética.
En caso de que un producto Rohde & Schwarz contenga un producto láser (p. ej. un lector de
CD/DVD), no debe usarse ninguna otra configuración o función aparte de las descritas en la
documentación del producto, a fin de evitar lesiones (p. ej. debidas a irradiación láser).

8. Clases de compatibilidad electromagnética (conforme a EN 55011 / CISPR 11; y en analogía con EN
55022 / CISPR 22, EN 55032 / CISPR 32)
 Aparato de clase A:

Aparato adecuado para su uso en todos los entornos excepto en los residenciales y en aquellos
conectados directamente a una red de distribución de baja tensión que suministra corriente a
edificios residenciales.
Nota: Los aparatos de clase A están destinados al uso en entornos industriales. Estos aparatos
pueden causar perturbaciones radioeléctricas en entornos residenciales debido a posibles
perturbaciones guiadas o radiadas. En este caso, se le podrá solicitar al operador que tome las
medidas adecuadas para eliminar estas perturbaciones.

 Aparato de clase B:

Aparato adecuado para su uso en entornos residenciales, así como en aquellos conectados
directamente a una red de distribución de baja tensión que suministra corriente a edificios
residenciales.

1171.0000.42 - 07 Page 12

nstrucciones de seguridad elementales

I

Reparación y mantenimiento

1. El producto solamente debe ser abierto por personal especializado con autorización para ello. Antes
de manipular el producto o abrirlo, es obligatorio desconectarlo de la tensión de alimentación, para
evitar toda posibilidad de choque eléctrico.

2. El ajuste, el cambio de partes, el mantenimiento y la reparación deberán ser efectuadas solamente

or electricistas autorizados por Rohde & Schwarz. Si se reponen partes con importancia para los

p
aspectos de seguridad (p. ej. el enchufe, los transformadores o los fusibles), solamente podrán ser
sustituidos por partes originales. Después de cada cambio de partes relevantes para la seguridad
deberá realizarse un control de seguridad (control a primera vista, control del conductor de
protección, medición de resistencia de aislamiento, medición de la corriente de fuga, control de
funcionamiento). Con esto queda garantizada la seguridad del producto.

Baterías y acumuladores o celdas

Si no se siguen (o se siguen de modo insuficiente) las indicaciones en cuanto a las baterías y
acumuladores o celdas, pueden producirse explosiones, incendios y/o lesiones graves con posible
consecuencia de muerte. El manejo de baterías y acumuladores con electrolitos alcalinos (p. ej. celdas de
litio) debe seguir el estándar EN 62133.

1. No deben desmontarse, abrirse ni triturarse las celdas.

2. Las celdas o baterías no deben someterse a calor ni fuego. Debe evitarse el almacenamiento a la luz
directa del sol. Las celdas y baterías deben mantenerse limpias y secas. Limpiar las conexiones
sucias con un paño seco y limpio.

3. Las celdas o baterías no deben cortocircuitarse. Es peligroso almacenar las celdas o baterías en
estuches o cajones en cuyo interior puedan cortocircuitarse por contacto recíproco o por contacto con
otros materiales conductores. No deben extraerse las celdas o baterías de sus embalajes originales
hasta el momento en que vayan a utilizarse.

4. Las celdas o baterías no deben someterse a impactos mecánicos fuertes indebidos.

5. En caso de falta de estanqueidad de una celda, el líquido vertido no debe entrar en contacto con la
piel ni los ojos. Si se produce contacto, lavar con agua abundante la zona afectada y avisar a un
médico.

6. En caso de cambio o recarga inadecuados, las celdas o baterías que contienen electrolitos alcalinos
(p. ej. las celdas de litio) pueden explotar. Para garantizar la seguridad del producto, las celdas o
baterías solo deben ser sustituidas por el tipo Rohde & Schwarz correspondiente (ver lista de
recambios).

7. Las baterías y celdas deben reciclarse y no deben tirarse a la basura doméstica. Las baterías o
acumuladores que contienen plomo, mercurio o cadmio deben tratarse como residuos especiales.
Respete en esta relación las normas nacionales de eliminación y reciclaje.

Transporte

1. El producto puede tener un peso elevado. Por eso es necesario desplazarlo o transportarlo con
precaución y, si es necesario, usando un sistema de elevación adecuado (p. ej. una carretilla
elevadora), a fin de evitar lesiones en la espalda u otros daños personales.

1171.0000.42 - 07 Page 13

nstrucciones de seguridad elementales

I

2. Las asas instaladas en los productos sirven solamente de ayuda para el transporte del producto por
personas. Por eso no está permitido utilizar las asas para la sujeción en o sobre medios de transporte
como p. ej. grúas, carretillas elevadoras de horquilla, carros etc. Es responsabilidad suya fijar los
productos de manera segura a los medios de transporte o elevación. Para evitar daños personales o
daños en el producto, siga las instrucciones de seguridad del fabricante del medio de transporte o
elevación utilizado.

3. Si se utiliza el producto dentro de un vehículo, recae de manera exclusiva en el conductor la
responsabilidad de conducir el vehículo de manera segura y adecuada. El fabricante no asumirá
ninguna responsabilidad por accidentes o colisiones. No utilice nunca el producto dentro de un
vehículo en movimiento si esto pudiera distraer al conductor. Asegure el producto dentro del vehículo
debidamente para evitar, en caso de un accidente, lesiones u otra clase de daños.

Eliminación/protección del medio ambiente

1. Los dispositivos marcados contienen una batería o un acumulador que no se debe desechar con los
residuos domésticos sin clasificar, sino que debe ser recogido por separado. La eliminación se debe
efectuar exclusivamente a través de un punto de recogida apropiado o del servicio de atención al
cliente de Rohde & Schwarz.

2. Los dispositivos eléctricos usados no se deben desechar con los residuos domésticos sin clasificar,
sino que deben ser recogidos por separado.
Rohde & Schwarz GmbH & Co.KG ha elaborado un concepto de eliminación de residuos y asume
plenamente los deberes de recogida y eliminación para los fabricantes dentro de la UE. Para
desechar el producto de manera respetuosa con el medio ambiente, diríjase a su servicio de atención
al cliente de Rohde & Schwarz.

3. Si se trabaja de manera mecánica y/o térmica cualquier producto o componente más allá del
funcionamiento previsto, pueden liberarse sustancias peligrosas (polvos con contenido de metales
pesados como p. ej. plomo, berilio o níquel). Por eso el producto solo debe ser desmontado por
personal especializado con formación adecuada. Un desmontaje inadecuado puede ocasionar daños
para la salud. Se deben tener en cuenta las directivas nacionales referentes a la eliminación de
residuos.

4. En caso de que durante el trato del producto se formen sustancias peligrosas o combustibles que
deban tratarse como residuos especiales (p. ej. refrigerantes o aceites de motor con intervalos de
cambio definidos), deben tenerse en cuenta las indicaciones de seguridad del fabricante de dichas
sustancias y las normas regionales de eliminación de residuos. Tenga en cuenta también en caso
necesario las indicaciones de seguridad especiales contenidas en la documentación del producto. La
eliminación incorrecta de sustancias peligrosas o combustibles puede causar daños a la salud o
daños al medio ambiente.

Se puede encontrar más información sobre la protección del medio ambiente en la página web de
Rohde & Schwarz.

1171.0000.42 - 07 Page 14

Quality management

Certied Quality System

ISO 9001

and environmental
management

Sehr geehrter Kunde,

Sie haben sich für den Kauf
eines Rohde & Schwarz Produk­tes entschieden. Sie erhalten
damit ein nach modernsten Fer­tigungsmethoden hergestelltes
Produkt. Es wurde nach den
Regeln unserer Qualitäts- und
Umweltmanagementsysteme
entwickelt, gefertigt und geprüft.
Rohde & Schwarz ist unter ande­rem nach den Managementsys­temen ISO 9001 und ISO 14001
zertifiziert.

Der Umwelt verpflichtet

❙ Energie-efziente,

RoHS-konforme Produkte

❙ Kontinuierliche

Weiterentwicklung nachhaltiger
Umweltkonzepte

❙ ISO 14001-zertiziertes

Umweltmanagementsystem

Dear customer,

You have decided to buy a
Rohde & Schwarz product. This
product has been manufactured
using the most advanced meth­ods. It was developed, manufac­tured and tested in compliance
with our quality management
and environmental manage­ment systems. Rohde & Schwarz
has been certified, for exam­ple, according to the ISO 9001
and ISO 14001 management
systems.

Environmental commitment

❙ Energy-efcient products
❙ Continuous improvement in

environmental sustainability

❙ ISO 14001-certied

environmental management
system

Certied Environmental System

ISO 14001

Cher client,

Vous avez choisi d’acheter un
produit Rohde & Schwarz. Vous
disposez donc d’un produit
fabriqué d’après les méthodes
les plus avancées. Le dévelop­pement, la fabrication et les
tests de ce produit ont été effec­tués selon nos systèmes de
management de qualité et de
management environnemental.
La société Rohde & Schwarz a
été homologuée, entre autres,
conformément aux systèmes
de management ISO 9001 et
ISO 14001.

Engagement écologique

❙ Produits à efcience

énergétique

❙ Amélioration continue de la

durabilité environnementale

❙ Système de management

environnemental certié selon

ISO 14001

1171.0200.11 V 05.01

1171020011

Customer Support

Technical support – where and when you need it

For quick, expert help with any Rohde & Schwarz equipment, contact one of our Customer Support
Centers. A team of highly qualified engineers provides telephone support and will work with you to find a
solution to your query on any aspect of the operation, programming or applications of Rohde & Schwarz
equipment.

Up-to-date information and upgrades

To keep your instrument up-to-date and to be informed about new application notes related to your
instrument, please send an e-mail to the Customer Support Center stating your instrument and your wish.
We will take care that you will get the right information.

Europe, Africa, Middle East

North America

Latin America

Asia/Pacific

China

Phone [phone]

[e-mail]

Phone 1-888-TEST-RSA (1-888-837-8772)

[e-mail]

Phone [phone]

[e-mail]

Phone [phone]

[e-mail]

Phone [phone] /
[phone]

[e-mail]

1171.0200.22-06.00

R&S FSQ Documentation Overview

Documentation Overview

The documentation of the R&S FSQ consists of base unit manuals and option man­uals. All manuals are provided in PDF format on the CD-ROM delivered with the
instrument. Each software option available for the instrument is described in a sepa­rate software manual.

The base unit documentation comprises the following manuals and documents:

• Quick Start Guide

• Operating Manual

• Service Manual

• Internet Site

• Release Notes

Apart from the base unit, these manuals describe the following models and options
of the R&S FSQ Signal Analyzer. Options that are not listed are described in sepa­rate manuals. These manuals are provided on an extra CD-ROM. For an overview
of all options available for the R&S FSQ visit the R&S FSQ Signal Analyzer Internet
site.

Base unit models:

• R&S FSQ3 (20 Hz to 3.6 GHz)

• R&S FSQ8 (20 Hz to 8 GHz)

• R&S FSQ26 (20 Hz to 26.5 GHz)

• R&S FSQ31(20 Hz to 31 GHz)

• R&S FSQ40 (20 Hz to 40 GHz)

Options described in the base unit manuals:

• R&S FSU-B9 (Tracking Generator)

• R&S FSP-B10 (External Generator Control)

• R&S FSP-B16 (LAN Interface)

• R&S FSQ-B17 (I/Q-Online input/output (LVDS))

• R&S FSU-B21 (External Mixer)

Operating Manual 1313.9681.12 - 02 0.3

R&S FSQ Documentation Overview

Quick Start Guide

This manual is delivered with the instrument in printed form and in PDF format on
the CD-ROM. It provides the information needed to set up and start working with the
instrument. Basic operations and basic measurements are described. Also a brief
introduction to remote control is given. More detailed descriptions are provided in
the Operating Manual. The Quick Start Guide includes general information (e.g.
Safety Instructions) and the following chapters:

Chapter 1 Front and Rear Panel

Chapter 2 Preparing for Use

Chapter 3 Firmware-Update and Installation of Firmware Options

Chapter 4 Basic Operation

Chapter 5 Basic Measurement Examples

Chapter 6 Brief Introduction to Remote Control

Appendix

Operating Manual

This manual is a supplement to the Quick Start Guide and is available in PDF format
on the CD-ROM delivered with the instrument. To retain the familiar structure that
applies to all operating manuals of Rohde&Schwarz Test & Measurement instru­ments, the chapters 1 and 3 exist, but only in form of references to the correspond­ing Quick Start Guide chapters. The operating manual has the following chapters:

Chapter 1 Putting into Operation

see Quick Start Guide chapters 1 and 2.

Chapter 2 Getting Started

see Quick Start Guide chapter 5.

Chapter 3 Manual Operation

see Quick Start Guide chapter 4.

Chapter 4 Instrument Functions

forms a reference for manual operation of the R&S FSQ and con­tains a description of all instrument functions and their application.

Chapter 5 Remote Control - Basics

describes the basics for programming the R&S FSQ, command pro­cessing and the status reporting system.

Chapter 6 Remote Control - Description of Commands

lists all the remote-control commands defined for the instrument.

Chapter 7 Remote Control - Programming Examples

contains program examples for a number of typical applications of
the R&S FSQ.

Chapter 8 Maintenance and Instrument Interfaces

describes preventive maintenance and the characteristics of the
instrument’s interfaces.

Chapter 9 Error Messages

gives a list of error messages that the R&S FSQ may generate.

Index contains an index for the chapters 1 to 9 of the operating manual.

0.4 Operating Manual 1313.9681.12 - 02

R&S FSQ Documentation Overview

Service Manual

This manual is available in PDF format on the CD-ROM delivered with the instru­ment. It informs on how to check compliance with rated specifications, on instrument
function, repair, troubleshooting and fault elimination. It contains all information
required for repairing the R&S FSQ by the replacement of modules. The manual
includes the following chapters:

Chapter 1 Performance Test

Chapter 2 Adjustment

Chapter 3 Repair

Chapter 4 Software Update / Installing Options

Chapter 5 Documents

Internet Site

The Internet site at: http://www.rohde-schwarz.com/product/fsq.html provides the
most up to date information on the R&S FSQ.

The current operating manual at a time is available as printable PDF file in the
download area. Also provided for download are firmware updates including the
associated release notes, instrument drivers, current data sheets and application
notes.

Release Notes

The release notes describe the installation of the firmware, new and modified func­tions, eliminated problems, and last minute changes to the documentation. The cor­responding firmware version is indicated on the title page of the release notes. The
current release notes are provided in the Internet.

Operating Manual 1313.9681.12 - 02 0.5

R&S FSQ Putting into Operation

1 Putting into Operation

For details refer to the Quick Start Guide chapter 1, “Front and Rear Panel” and
chapter 2, “ Preparing for Use”.

1.1 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

2 Getting Started

2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2

2.2 Measuring the Spectrums of Complex Signals . . . . . . . . . . . . . . . . . . . . . 2.3

2.2.1 Intermodulation Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3

2.2.1.1 Measurement Example – Measuring the R&S FSQ’s Intrinsic

Intermodulation Distance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5

2.3 Measuring Signals in the Vicinity of Noise . . . . . . . . . . . . . . . . . . . . . . . . 2.10

2.3.0.1 Measurement Example – Measuring the Level of the Internal

Reference Generator at Low S/N Ratios . . . . . . . . . . . . . . . . . . . . . . . . . . 2.13

2.4 Noise Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.18

2.4.1 Measuring Noise Power Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.18

2.4.1.1 Measurement Example – Measuring the Intrinsic Noise Power
Density of the R&S FSQ at 1 GHz and Calculating the R&S FSQ’s

Noise Figure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.18

2.4.2 Measurement of Noise Power within a Transmission Channel . . . . . . . 2.21

2.4.2.1 Measurement Example – Measuring the Intrinsic Noise of the
R&S FSQ at 1 GHz in a 1.23 MHz Channel Bandwidth with the

Channel Power Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.21

2.4.3 Measuring Phase Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.27

2.4.3.1 Measurement Example – Measuring the Phase Noise of a

Signal Generator at a Carrier Offset of 10 kHz . . . . . . . . . . . . . . . . . . . . . 2.27

2.5 Measurements on Modulated Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.29

2.5.1 Measurements on AM Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.29

2.5.1.1 Measurement Example 1 – Displaying the AF of an AM Signal

in the Time Domain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.29

2.5.1.2 Measurement Example 2 – Measuring the Modulation Depth

of an AM Carrier in the Frequency Domain . . . . . . . . . . . . . . . . . . . . . . . . 2.31

2.5.2 Measurements on FM Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.33

2.5.2.1 Measurement Example – Displaying the AF of an FM Carrier . . . 2.33

2.5.3 Measuring Channel Power and Adjacent Channel Power . . . . . . . . . . 2.36

2.5.3.1 Measurement Example 1 – ACPR Measurement on an IS95

CDMA Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.37

2.5.3.2 Measurement Example 2 – Measuring the Adjacent Channel

Power of an IS136 TDMA Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.42

2.5.3.3 Measurement Example 3 – Measuring the Modulation Spectrum

in Burst Mode with the Gated Sweep Function . . . . . . . . . . . . . . . . . . . . . 2.45

2.5.3.4 Measurement Example 4 – Measuring the Transient Spectrum

in Burst Mode with the Fast ACP function . . . . . . . . . . . . . . . . . . . . . . . . . 2.47

2.5.3.5 Measurement Example 5 – Measuring the Adjacent Channel

Power of a W-CDMA Uplink Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.50

2.5.4 Amplitude Distribution Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . 2.54

2.5.4.1 Measurement Example – Measuring the APD and CCDF of

White Noise Generated by the R&S FSQ . . . . . . . . . . . . . . . . . . . . . . . . . 2.55

Operating Manual 1313.9681.12 - 02 2.1

R&S FSQ Getting Started

Introduction

2.1 Introduction

This chapter explains how to operate the R&S FSQ using typical measurements as
examples. Additional background information on the settings is given.

All of the following examples are based on the standard settings of the R&S FSQ.
These are set with the PRESET key. A complete list of the standard settings can be
found in chapter “Instrument Functions”, section “R&S FSQ Initial Configuration –

PRESET Key” on page 4.6.

• “Measuring the Spectrums of Complex Signals” on page 2.3

• “Measuring Signals in the Vicinity of Noise” on page 2.10

• “Noise Measurements” on page 2.18

• “Measurements on Modulated Signals” on page 2.29

Examples of more basic character are described in the Quick Start Guide, chapter 5.

2.2 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measuring the Spectrums of Complex Signals

2.2 Measuring the Spectrums of Complex Signals

2.2.1 Intermodulation Measurements

If several signals are applied to a DUT with non-linear characteristics, unwanted
mixing products are generated – mostly by active components such as amplifiers or
mixers. The products created by 3
some as they have frequencies close to the useful signals and, compared with other
products, are closest in level to the useful signals. The fundamental wave of one sig­nal is mixed with the 2

f

= 2 × fu1 – fu2 (6)

s1

f

= 2 × fu2 – fu1 (7)

s2

nd

harmonic of the other signal.

rd

order intermodulation are particularly trouble-

where f

and fs2 are the frequencies of the intermodulation products and fu1 and f

s1

u2

the frequencies of the useful signals.

The following diagram shows the position of the intermodulation products in the fre­quency domain.

Level

P

u1

P

s1

∆

f

f

s1

Fig. 2.1 3rd order intermodulation products

∆

f

u1

u2

P

a

D3

P

s2

f

∆

f

f

u2

f

s2

Frequency

Example

fu1 = 100 MHz, fu2 = 100.03 MHz

= 2 × fu1 – fu2 = 2 × 100 MHz – 100.03 MHz = 99.97 MHz

f

s1

= 2 × fu2 – fu1 = 2 × 100.03 MHz – 100 MHz = 100.06 MHz

f

s2

The level of the intermodulation products depends on the level of the useful signals.
If the level of the two useful signals is increased by 1 dB, the level of the intermodu­lation products is increased by 3 dB. The intermodulation distance d

is, therefore,

3

reduced by 2 dB. Fig. 2.2 shows how the levels of the useful signals and the 3
order intermodulation products are related.

Operating Manual 1313.9681.12 - 02 2.3

rd

R&S FSQ Getting Started

Measuring the Spectrums of Complex Signals

Output

level

Intercept

point

Compression

Carrier

level

D3

a

1

1

Fig. 2.2 Level of the 3rd order intermodulation products as a function of the level of the useful

signals

1

Intermodulation

products

3

Input level

The behavior of the signals can explained using an amplifier as an example. The
change in the level of the useful signals at the output of the amplifier is proportional
to the level change at the input of the amplifier as long as the amplifier is operating
in linear range. If the level at the amplifier input is changed by 1 dB, there is a 1 dB
level change at the amplifier output. At a certain input level, the amplifier enters sat­uration. The level at the amplifier output does not increase with increasing input
level.

The level of the 3
level of the useful signals. The 3

rd

order intermodulation products increases 3 times faster than the

rd

order intercept is the virtual level at which the
level of the useful signals and the level of the spurious products are identical, i.e. the
intersection of the two straight lines. This level cannot be measured directly as the
amplifier goes into saturation or is damaged before this level is reached.

rd

The 3
intermodulation distance d

order intercept can be calculated from the known slopes of the lines, the

and the level of the useful signals.

2

TOI = a

with TOI (Third Order Intercept) being the 3rd order intercept in dBm and P

/ 2 + Pn (8)

D3

the

n

level of a carrier in dBm.

With an intermodulation distance of 60 dB and an input level, P
following 3

rd

order intercept is obtained:

, of –20 dBm, the

w

TOI = 60 dBm / 2 + (-20 dBm) = 10 dBm.

2.4 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measuring the Spectrums of Complex Signals

2.2.1.1 Measurement Example – Measuring the R&S FSQ’s Intrinsic Intermodulation
Distance

To measure the intrinsic intermodulation distance, use the test setup shown in the
figure below.

Test setup

Signal generator settings (e.g. R&S SMIQ)

Level Frequency

Signal generator 1 -10 dBm 999.9 MHz

Signal generator 2 -10 dBm 1000.1 MHz

Measurement using the R&S FSQ

1. Set the R&S FSQ to the analyzer mode.

➢ Press the SPECTRUM key.

The R&S FSQ is in the analyzer mode.

2. Set center frequency to 1 GHz and the frequency span to 1 MHz.

➢ Press the FREQ key and enter 1 GHz.
➢ Press the SPAN key and enter 1 MHz.

3. Set the reference level to –10 dBm and RF attenuation to 0 dB.

➢ Press the AMPT key and enter -10 dBm.
➢ Press the RF ATTEN MANUAL softkey and enter 0 dB.

By reducing the RF attenuation to 0 dB, the level to the R&S FSQ input mixer
is increased. Therefore, 3

rd

order intermodulation products are displayed.

4. Set the resolution bandwidth to 5 kHz.

➢ Press the BW key.
➢ Press the RES BW MANUAL softkey and enter 5 kHz.

By reducing the bandwidth, the noise is further reduced and the
intermodulation products can be clearly seen.

Operating Manual 1313.9681.12 - 02 2.5

R&S FSQ Getting Started

Measuring the Spectrums of Complex Signals

5. Measuring intermodulation by means of the 3

rd

order intercept

measurement function.

➢ Press the MEAS key.
➢ Press the TOI softkey.

The R&S FSQ activates four markers for measuring the intermodulation
distance. Two markers are positioned on the useful signals and two on the
intermodulation products. The 3

rd

order intercept is calculated from the level
difference between the useful signals and the intermodulation products. It is
then displayed on the screen:

Fig. 2.3 Result of intrinsic intermodulation measurement on the R&S FSQ. The 3rd order

intercept (TOI) is displayed at the top right corner of the grid

The level of a Signal Analyzer’s intrinsic intermodulation products depends on
the RF level of the useful signals at the input mixer. When the RF attenuation
is added, the mixer level is reduced and the intermodulation distance is
increased. With an additional RF attenuation of 10 dB, the levels of the
intermodulation products are reduced by 20 dB. The noise level is, however,
increased by 10 dB.

2.6 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measuring the Spectrums of Complex Signals

6. Increasing RF attenuation to 10 dB to reduce intermodulation products.

➢ Press the AMPT key.
➢ Press the RF ATTEN MANUAL softkey and enter 10 dB.

The R&S FSQ’s intrinsic intermodulation products disappear below the noise
floor.

Fig. 2.4 If the RF attenuation is increased, the R&S FSQ’s intrinsic intermodulation prod-

ucts disappear below the noise floor.

Calculation method

The method used by the R&S FSQ to calculate the intercept point takes the average
useful signal level P

in dBm and calculates the intermodulation d3 in dB as a func-

U

tion of the average value of the levels of the two intermodulation products. The third
order intercept (TOI) is then calculated as follows:

TOI/dBm = ½ d

+ PU

3

Operating Manual 1313.9681.12 - 02 2.7

R&S FSQ Getting Started

Measuring the Spectrums of Complex Signals

Intermodulation- free dynamic range

The Intermodulation – free dynamic range, i.e. the level range in which no inter­nal intermodulation products are generated if two-tone signals are measured, is
determined by the 3

rd

order intercept point, the phase noise and the thermal noise of
the R&S FSQ. At high signal levels, the range is determined by intermodulation
products. At low signal levels, intermodulation products disappear below the noise
floor, i.e. the noise floor and the phase noise of the R&S FSQ determine the range.
The noise floor and the phase noise depend on the resolution bandwidth that has
been selected. At the smallest resolution bandwidth, the noise floor and phase noise
are at a minimum and so the maximum range is obtained. However, a large increase
in sweep time is required for small resolution bandwidths. It is, therefore, best to
select the largest resolution bandwidth possible to obtain the range that is required.
Since phase noise decreases as the carrier-offset increases, its influence decreases
with increasing frequency offset from the useful signals.

The following diagrams illustrate the intermodulation-free dynamic range as a func­tion of the selected bandwidth and of the level at the input mixer (= signal level – set
RF attenuation) at different useful signal offsets.

Distortion free dynamic range

1MHz carrier offset

-60

-70

-80

-90

-100

Dynamic range dB

-110

-120

-60 -50 -40 -30 -20 -10

Fig. 2.5 Intermodulation-free range of the R&S FSQ as a function of level at the input mixer and

the set resolution bandwidth (useful signal offset = 1 MHz, DANL = -157 dBm /Hz, TOI =
25 dBm; typical values at 2 GHz)

RBW=10 kHz

RBW=1
kHz

RBW=100
Hz

RBW=10
Hz

T.O.I

Thermal noise

Mixer level

The optimum mixer level, i.e. the level at which the intermodulation distance is at its
maximum, depends on the bandwidth. At a resolution bandwidth of 10 Hz, it is
approx. –42 dBm and at 10 kHz increases to approx. -32 dBm.

2.8 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measuring the Spectrums of Complex Signals

Phase noise has a considerable influence on the intermodulation-free range at car­rier offsets between 10 and 100 kHz (Fig. 2.6). At greater bandwidths, the influence
of the phase noise is greater than it would be with small bandwidths. The optimum
mixer level at the bandwidths under consideration becomes almost independent of
bandwidth and is approx. –40 dBm.

Distortion free dynamic range

-60

-70

-80

-90

-100

Dynamic range dB

-110

-120

-60-50 -40-30-20 -10

10 to 100 kHz offset

RBW=10 kHz

RBW=1
kHz

RBW=100
Hz

RBW=10
Hz

Mixe r lev el

T.O.I

Thermal noise

Fig. 2.6 Intermodulation-free dynamic range of the R&S FSQ as a function of level at the input

mixer and of the selected resolution bandwidth (useful signal offset = 10 to 100 kHz,
DANL = -157 dBm /Hz, TOI = 25 dBm; typical values at 2 GHz).

If the intermodulation products of a DUT with a very high dynamic range are to be
measured and the resolution bandwidth to be used is therefore very small, it is
best to measure the levels of the useful signals and those of the intermodulation
products separately using a small span. The measurement time will be reduced–
in particular if the offset of the useful signals is large. To find signals reliably when
frequency span is small, it is best to synchronize the signal sources and the
R&S FSQ.

Operating Manual 1313.9681.12 - 02 2.9

R&S FSQ Getting Started

0

z

Measuring Signals in the Vicinity of Noise

2.3 Measuring Signals in the Vicinity of Noise

The minimum signal level a Signal Analyzer can measure is limited by its intrinsic
noise. Small signals can be swamped by noise and therefore cannot be measured.
For signals that are just above the intrinsic noise, the accuracy of the level measure­ment is influenced by the intrinsic noise of the R&S FSQ.

The displayed noise level of a Signal Analyzer depends on its noise figure, the
selected RF attenuation, the selected reference level, the selected resolution and
video bandwidth and the detector. The effect of the different parameters is explained
in the following.

Impact of the RF attenuation setting

The sensitivity of a Signal Analyzer is directly influenced by the selected RF attenu­ation. The highest sensitivity is obtained at a RF attenuation of 0 dB. The
R&S FSQ’s RF attenuation can be set in 5 dB steps up to 70 dB. Each additional 5
dB step reduces the R&S FSQ’s sensitivity by 5 dB, i.e. the displayed noise is
increased by 5 dB.

14

12

10

Impact of the reference level setting

If the reference level is changed, the R&S FSQ changes the gain on the last IF so
that the voltage at the logarithmic amplifier and the A/D converter is always the
same for signal levels corresponding to the reference level. This ensures that the
dynamic range of the log amp or the A/D converter is fully utilized. Therefore, the
total gain of the signal path is low at high reference levels and the noise figure of the
IF amplifier makes a substantial contribution to the total noise figure of the
R&S FSQ. The figure below shows the change in the displayed noise depending on
the set reference level at 10 kHz and 300 kHz resolution bandwidth. With digital
bandwidths (≤100 kHz) the noise increases sharply at high reference levels because
of the dynamic range of the A/D converter.

RBW = 10 kHz

8

6

4

rel. noise level /dB

2

RBW = 300 kH

0

-2

-70 -60 -50 -40 -30 -20 -1
Reference l evel / dBm

Fig. 2.7 Change in displayed noise as a function of the selected reference level at bandwidths of

10 kHz and 300 kHz (-30 dBm reference level)

2.10 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

0

e

W

W

Measuring Signals in the Vicinity of Noise

Impact of the resolution bandwidth

The sensitivity of a Signal Analyzer also directly depends on the selected bandwidth.
The highest sensitivity is obtained at the smallest bandwidth (for the R&S FSQ: 10
Hz, for FFT filtering: 1 Hz). If the bandwidth is increased, the reduction in sensitivity
is proportional to the change in bandwidth. The R&S FSQ has bandwidth settings in
2, 3, 5, 10 sequence. Increasing the bandwidth by a factor of 3 increases the dis­played noise by approx. 5 dB (4.77 dB precisely). If the bandwidth is increased by a
factor of 10, the displayed noise increases by a factor of 10, i.e. 10 dB. Because of
the way the resolution filters are designed, the sensitivity of Signal Analyzers often
depends on the selected resolution bandwidth. In data sheets, the displayed aver­age noise level is often indicated for the smallest available bandwidth. The extra
sensitivity obtained if the bandwidth is reduced may therefore deviate from the val­ues indicated above. The following table illustrates typical deviations from the noise
figure for a resolution bandwidth of 10 kHz which is used as a reference value (= 0
dB).

Noise fi gur

offset /dB

3

digital RB

2

1

0

-1
0,01 0, 1 1 10 100 1000 1000

Fig. 2.8 Change in R&S FSQ noise figure at various bandwidths. The reference bandwidth is 10

kHz

analog RB

RBW /kHz

Impact of the video bandwidth

The displayed noise of a Signal Analyzer is also influenced by the selected video
bandwidth. If the video bandwidth is considerably smaller than the resolution band­width, noise spikes are suppressed, i.e. the trace becomes much smoother. The
level of a sinewave signal is not influenced by the video bandwidth. A sinewave sig­nal can therefore be freed from noise by using a video bandwidth that is small com­pared with the resolution bandwidth, and thus be measured more accurately.

Operating Manual 1313.9681.12 - 02 2.11

R&S FSQ Getting Started

Measuring Signals in the Vicinity of Noise

Impact of the detector

Noise is evaluated differently by the different detectors. The noise display is there­fore influenced by the choice of detector. Sinewave signals are weighted in the
same way by all detectors, i.e. the level display for a sinewave RF signal does not
depend on the selected detector, provided that the signal-to-noise ratio is high
enough. The measurement accuracy for signals in the vicinity of R&S FSQ intrinsic
noise is also influenced by the detector which has been selected. The R&S FSQ has
the following detectors:

• Maximum peak detector

If the max. peak detector s selected, the largest noise display is obtained, since
the R&S FSQ displays the highest value of the IF envelope in the frequency range
assigned to a pixel at each pixel in the trace. With longer sweep times, the trace
indicates higher noise levels since the probability of obtaining a high noise
amplitude increases with the dwell time on a pixel. For short sweep times, the
display approaches that of the sample detector since the dwell time on a pixel is
only sufficient to obtain an instantaneous value.

• Minimum peak detector

The min. peak detector indicates the minimum voltage of the IF envelope in the
frequency range assigned to a pixel at each pixel in the trace. The noise is strongly
suppressed by the minimum peak detector since the lowest noise amplitude that
occurs is displayed for each test point. If the signal-to-noise ratio is low, the
minimum of the noise overlaying the signal is displayed too low.

At longer sweep times, the trace shows smaller noise levels since the probability
of obtaining a low noise amplitude increases with the dwell time on a pixel. For
short sweep times, the display approaches that of the sample detector since the
dwell time on a pixel is only sufficient to obtain an instantaneous value.

• Autopeak detector

The Autopeak detector displays the maximum and minimum peak value at the
same time. Both values are measured and their levels are displayed on the screen
joint by a vertical line.

• Sample detector

The sample detector samples the logarithm of the IF envelope for each pixel of
the trace only once and displays the resulting value. If the frequency span of the
R&S FSQ is considerably higher than the resolution bandwidth (span/RBW >500),
there is no guarantee that useful signals will be detected. They are lost due to
undersampling. This does not happen with noise because in this case it is not the
instantaneous amplitude that is relevant but only the probability distribution.

• RMS detector

For each pixel of the trace, the RMS detector outputs the RMS value of the IF
envelope for the frequency range assigned to each test point. It therefore
measures noise power. The display for small signals is, however, the sum of
signal power and noise power. For short sweep times, i.e. if only one uncorrelated
sample value contributes to the RMS value measurement, the RMS detector is
equivalent to the sample detector. If the sweep time is longer, more and more
uncorrelated RMS values contribute to the RMS value measurement. The trace
is, therefore, smoothed. The level of sinewave signals is only displayed correctly
if the selected resolution bandwidth (RBW) is at least as wide as the frequency
range which corresponds to a pixel in the trace. At a resolution bandwidth of 1
MHz, this means that the maximum frequency display range is 625 MHz.

2.12 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measuring Signals in the Vicinity of Noise

• Average detector

For each pixel of the trace, the average detector outputs the average value of the
linear IF envelope for the frequency range assigned to each test point. It therefore
measures the linear average noise. The level of sinewave signals is only
displayed correctly if the selected resolution bandwidth (RBW) is at least as wide
as the frequency range which corresponds to a pixel in the trace. At a resolution
bandwidth of 1 MHz, this means the maximum frequency display range is 625
MHz.

• Quasipeak detector

The quasipeak detector is a peak detector for EMI measurements with defined
charge and discharge times. These times are defined in CISPR 16, the standard
for equipment used to measure EMI emissions.

2.3.0.1 Measurement Example – Measuring the Level of the Internal Reference Gener­ator at Low S/N Ratios

The example shows the different factors influencing the S/N ratio.

1. Set the R&S FSQ to the analyzer mode.

➢ Press the SPECTRUM key.

The R&S FSQ is in the analyzer mode.

2. Switch on the internal reference generator

➢ Press the SETUP key.
➢ Press the softkeys SERVICE - INPUT CAL.

The internal 128 MHz reference generator is on.
The R&S FSQ’s RF input is off.

3. Set the center frequency to 128 MHz and the frequency span to 100 MHz.

➢ Press the FREQ key and enter 128 MHz.
➢ Press the SPAN key and enter 100 MHz.

4. Set the RF attenuation to 60 dB to attenuate the input signal or to increase

the intrinsic noise.

➢ Press the AMPT key.
➢ Press the RF ATTEN MANUAL softkey and enter 60 dB.

The RF attenuation indicator is marked with an asterisk (*Att 60 dB) to show
that it is no longer coupled to the reference level. The high input attenuation
reduces the reference signal which can no longer be detected in noise.

Operating Manual 1313.9681.12 - 02 2.13

R&S FSQ Getting Started

Measuring Signals in the Vicinity of Noise

Fig. 2.9 Sinewave signal with low S/N ratio. The signal is measured with the autopeak

detector and is completely swamped by the intrinsic noise of the R&S FSQ.

5. To suppress noise spikes the trace can be averaged.

➢ Press the TRACE key.
➢ Press the AVERAGE softkey.

The traces of consecutive sweeps are averaged. To perform averaging, the
R&S FSQ automatically switches on the sample detector. The RF signal,
therefore, can be more clearly distinguished from noise.

2.14 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measuring Signals in the Vicinity of Noise

Fig. 2.10 RF sinewave signal with low S/N ratio if the trace is averaged.

6. Instead of trace averaging, a video filter that is narrower than the resolution

bandwidth can be selected.

➢ Press the CLEAR/WRITE softkey in the trace menu.
➢ Press the BW key.

Press the VIDEO BW MANUAL softkey and enter 10 kHz.
The RF signal can be more clearly distinguished from noise.

Operating Manual 1313.9681.12 - 02 2.15

R&S FSQ Getting Started

Measuring Signals in the Vicinity of Noise

Fig. 2.11 RF sinewave signal with low S/N ratio if a smaller video bandwidth is selected.

7. By reducing the resolution bandwidth by a factor of 10, the noise is reduced

by 10 dB.

➢ Press the RES BW MANUAL softkey and enter 300 kHz.

The displayed noise is reduced by approx. 10 dB. The signal, therefore,
emerges from noise by about 10 dB. Compared to the previous setting, the
video bandwidth has remained the same, i.e. it has increased relative to the
smaller resolution bandwidth. The averaging effect is, therefore, reduced by
the video bandwidth. The trace will be noisier.

2.16 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measuring Signals in the Vicinity of Noise

Fig. 2.12 Reference signal at a smaller resolution bandwidth

Operating Manual 1313.9681.12 - 02 2.17

R&S FSQ Getting Started

Noise Measurements

2.4 Noise Measurements

Noise measurements play an important role in spectrum analysis. Noise e.g. affects
the sensitivity of radio communication systems and their components.

Noise power is specified either as the total power in the transmission channel or as
the power referred to a bandwidth of 1 Hz. The sources of noise are, for example,
amplifier noise or noise generated by oscillators used for the frequency conversion
of useful signals in receivers or transmitters. The noise at the output of an amplifier
is determined by its noise figure and gain.

The noise of an oscillator is determined by phase noise near the oscillator frequency
and by thermal noise of the active elements far from the oscillator frequency. Phase
noise can mask weak signals near the oscillator frequency and make them impossi­ble to detect.

2.4.1 Measuring Noise Power Density

To measure noise power referred to a bandwidth of 1 Hz at a certain frequency, the
R&S FSQ has an easy-to-use marker function. This marker function calculates the
noise power density from the measured marker level.

2.4.1.1 Measurement Example – Measuring the Intrinsic Noise Power Density of the
R&S FSQ at 1 GHz and Calculating the R&S FSQ’s Noise Figure

1. Set the R&S FSQ to the analyzer mode.

➢ Press the SPECTRUM key.

The R&S FSQ is in the analyzer mode.

2. Set the center frequency to 1 GHz and the span to 1 MHz.

➢ Press the FREQ key and enter 1 GHz.
➢ Press the SPAN key and enter 1 MHz.

3. Switch on the marker and set the marker frequency to 1 GHz.

➢ Press the MKR key and enter 1 GHz.

4. Switch on the noise marker function.

➢ Press the MEAS key.
➢ Press the NOISE MARKER softkey.

The R&S FSQ displays the noise power at 1 GHz in dBm (1Hz).

Since noise is random, a sufficiently long measurement time has to be selected
to obtain stable measurement results. This can be achieved by averaging the
trace or by selecting a very small video bandwidth relative to the resolution
bandwidth.

5. The measurement result is stabilized by averaging the trace

➢ Press the TRACE key.
➢ Press the AVERAGE softkey.

The R&S FSQ performs sliding averaging over 10 traces from consecutive
sweeps. The measurement result becomes more stable.

2.18 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Noise Measurements

Conversion to other reference bandwidths

The result of the noise measurement can be referred to other bandwidths by simple
conversion. This is done by adding 10 · log (BW) to the measurement result, BW
being the new reference bandwidth.

Example

A noise power of –150 dBm (1 Hz) is to be referred to a bandwidth of 1 kHz.
P

= -150 + 10 · log (1000) = -150 +30 = -120 dBm(1 kHz)

[1kHz]

Calculation method

The following method is used to calculate the noise power:

If the noise marker is switched on, the R&S FSQ automatically activates the sample
detector. The video bandwidth is set to 1/10 of the selected resolution bandwidth
(RBW).

To calculate the noise, the R&S FSQ takes an average over 17 adjacent pixels (the
pixel on which the marker is positioned and 8 pixels to the left, 8 pixels to the right of
the marker). The measurement result is stabilized by video filtering and averaging
over 17 pixels.

Since both video filtering and averaging over 17 trace points is performed in the log
display mode, the result would be 2.51 dB too low (difference between logarithmic
noise average and noise power). The R&S FSQ, therefore, corrects the noise figure
by 2.51 dB.

To standardize the measurement result to a bandwidth of 1 Hz, the result is also cor­rected by –10 · log (RBW

), with RBW

noise

being the power bandwidth of the

noise

selected resolution filter (RBW).

Detector selection

The noise power density is measured in the default setting with the sample detector
and using averaging. Other detectors that can be used to perform a measurement
giving true results are the average detector or the RMS detector. If the average
detector is used, the linear video voltage is averaged and displayed as a pixel. If the
RMS detector is used, the squared video voltage is averaged and displayed as a
pixel. The averaging time depends on the selected sweep time (=SWT/625). An
increase in the sweep time gives a longer averaging time per pixel and thus stabi­lizes the measurement result. The R&S FSQ automatically corrects the measure­ment result of the noise marker display depending on the selected detector (+1.05
dB for the average detector, 0 dΒ for the RMS detector). It is assumed that the video
bandwidth is set to at least three times the resolution bandwidth. While the average
or RMS detector is being switched on, the R&S FSQ sets the video bandwidth to a
suitable value.

The Pos Peak, Neg Peak, Auto Peak and Quasipeak detectors are not suitable for
measuring noise power density.

Operating Manual 1313.9681.12 - 02 2.19

R&S FSQ Getting Started

Noise Measurements

Determining the noise figure

The noise figure of amplifiers or of the R&S FSQ alone can be obtained from the
noise power display. Based on the known thermal noise power of a 50 Ω resistor at
room temperature (-174 dBm (1Hz)) and the measured noise power P

noise

the noise

figure (NF) is obtained as follows:

NF = P

+ 174 – g,

noise

where g = gain of DUT in dB

Example:

The measured internal noise power of the R&S FSQ at an attenuation of 0 dB is
found to be –155 dBm/1 Hz. The noise figure of the R&S FSQ is obtained as follows

NF = –155 + 174 = 19 dB

If noise power is measured at the output of an amplifier, for example, the sum of
the internal noise power and the noise power at the output of the DUT is mea­sured. The noise power of the DUT can be obtained by subtracting the internal
noise power from the total power (subtraction of linear noise powers). By means
of the following diagram, the noise level of the DUT can be estimated from the
level difference between the total and the internal noise level.

Fig. 2.13 Correction factor for measured noise power as a function of the ratio of total power to

the intrinsic noise power of the R&S FSQ.

2.20 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Noise Measurements

2.4.2 Measurement of Noise Power within a Transmission Channel

Noise in any bandwidth can be measured with the channel power measurement
functions. Thus the noise power in a communication channel can be determined, for
example. If the noise spectrum within the channel bandwidth is flat, the noise marker
from “Measuring Noise Power Density” on page 2.18 can be used to determine the
noise power in the channel by considering the channel bandwidth. If, however,
phase noise and noise that normally increases towards the carrier is dominant in the
channel to be measured, or if there are discrete spurious signals in the channel, the
channel power measurement method must be used to obtain correct measurement
results.

2.4.2.1 Measurement Example – Measuring the Intrinsic Noise of the R&S FSQ at
1 GHz in a 1.23 MHz Channel Bandwidth with the Channel Power Function

Test setup

The RF input of the R&S FSQ remains open-circuited or is terminated with 50 Ω.

Measurement with the R&S FSQ

1. Set the R&S FSQ to the analyzer mode.

➢ Press the SPECTRUM key.

The R&S FSQ is in the analyzer mode.

2. Set the center frequency to 1 GHz and the span to 2 MHz.

➢ Press the FREQ key and enter 1 GHz.
➢ Press the SPAN key and enter 2 MHz.

3. To obtain maximum sensitivity, set RF attenuation on the R&S FSQ to 0 dB.

➢ Press the AMPT key.
➢ Press the RF ATTEN MANUAL softkey and enter 0 dB.

4. Switch on and configure the channel power measurement.

➢ Press the MEAS key.
➢ Press the CHAN PWR ACP softkey.

The R&S FSQ activates the channel or adjacent channel power measurement
according to the currently set configuration.

➢ Press the CP/ACP CONFIG ! softkey.

The R&S FSQ enters the submenu for configuring the channel.

➢ Press the CHANNEL BANDWIDTH softkey and enter 1.23 MHz.

The R&S FSQ displays the 1.23 MHz channel as two vertical lines which are
symmetrical to the center frequency.

➢ Press the PREV key.

The R&S FSQ returns to the main menu for channel and adjacent channel
power measurement.

➢ Press the ADJUST SETTINGS softkey.

The settings for the frequency span, the bandwidth (RBW and VBW) and the
detector are automatically set to the optimum values required for the
measurement.

Operating Manual 1313.9681.12 - 02 2.21

R&S FSQ Getting Started

Noise Measurements

Fig. 2.14 Measurement of the R&S FSQ’s intrinsic noise power in a 1.23 MHz channel

bandwidth.

5. Stabilizing the measurement result by increasing the sweep time

➢ Press the SWEEP TIME softkey and enter 1 s.

By increasing the sweep time to 1 s, the trace becomes much smoother
thanks to the RMS detector and the channel power measurement display is
much more stable.

6. Referring the measured channel power to a bandwidth of 1 Hz

➢ Press the CHAN PWR / Hz softkey.

The channel power is referred to a bandwidth of 1 Hz. The measurement is
corrected by -10 · log (ChanBW), with ChanBW being the channel bandwidth
that was selected.

2.22 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Noise Measurements

Method of calculating the channel power

When measuring the channel power, the R&S FSQ integrates the linear power
which corresponds to the levels of the pixels within the selected channel. The
R&S FSQ uses a resolution bandwidth which is far smaller than the channel band­width. When sweeping over the channel, the channel filter is formed by the pass­band characteristics of the resolution bandwidth (see Fig. 2.15).

-3 dB

Resolution filter

Sweep

Channel bandwith

Fig. 2.15 Approximating the channel filter by sweeping with a small resolution bandwidth

The following steps are performed:

• The linear power of all the trace pixels within the channel is calculated.

= 10

i

(Li/10)

P
where
P

= power of the trace pixel i

i

L

= displayed level of trace point i

i

• The powers of all trace pixels within the channel are summed up and the sum is

divided by the number of trace pixels in the channel.

• The result is multiplied by the quotient of the selected channel bandwidth and the

noise bandwidth of the resolution filter (RBW).

Since the power calculation is performed by integrating the trace within the channel
bandwidth, this method is also called the IBW method (Integration Bandwidth
method).

Bandwidth selection (RBW)

For channel power measurements, the resolution bandwidth (RBW) must be small
compared to the channel bandwidth, so that the channel bandwidth can be defined
precisely. If the resolution bandwidth which has been selected is too wide, this may
have a negative effect on the selectivity of the simulated channel filter and result in
the power in the adjacent channel being added to the power in the transmit channel.
A resolution bandwidth equal to 1% to 3% of the channel bandwidth should, there­fore, be selected. If the resolution bandwidth is too small, the required sweep time
becomes too long and the measurement time increases considerably.

Operating Manual 1313.9681.12 - 02 2.23

R&S FSQ Getting Started

Noise Measurements

Detector selection

Since the power of the trace is measured within the channel bandwidth, only the
sample detector and RMS detector can be used. These detectors provide measured
values that make it possible to calculate the real power. The peak detectors (Pos
Peak, Neg Peak and Auto Peak) are not suitable for noise power measurements as
no correlation can be established between the peak value of the video voltage and
power.

With the sample detector, a value (sample) of the IF envelope voltage is displayed
at each trace pixel. Since the frequency spans are very large compared with the res­olution bandwidth (span/RBW >500), sinewave signals present in the noise might be
lost, i.e. they are not displayed. This is not important for pure noise signals, however,
since a single sample in itself is not important - it is the probability distribution of all
measured values that counts. The number of samples for power calculation is lim­ited to the number of trace pixels (625 for the R&S FSQ).

To increase the repeatability of measurements, averaging is often carried out
over several traces (AVERAGE softkey in the TRACE menu). This gives spurious
results for channel power measurements (max. –2.51 dB for ideal averaging).
Trace averaging should, therefore, be avoided.

With the RMS detector, the whole IF envelope is used to calculate the power for
each trace pixel. The IF envelope is digitized using a sampling frequency which is at
least five times the resolution bandwidth which has been selected. Based on the
sample values, the power is calculated for each trace pixel using the following for­mula:

N

1

P

RMS

s

= linear digitized video voltage at the output of the A/D converter

i

----

N

2

×=

s

i

∑

i1=

N = number of A/D converter values per pixel of the trace

= power represented by a trace pixel

P

RMS

When the power has been calculated, the power units are converted into decibels
and the value is displayed as a trace pixel.

The number of A/D converter values, N, used to calculate the power, is defined by
the sweep time. The time per trace pixel for power measurements is directly propor­tional to the selected sweep time. The RMS detector uses far more samples for
power measurement than the sample detector, especially if the sweep time is
increased. The measurement uncertainty can be reduced considerably. In the
default setting, the R&S FSQ therefore uses the RMS detector to measure the chan­nel power.

For both detectors (sample and RMS), the video bandwidth (VBW) must at least be
three times the resolution bandwidth, so that the peak values of the video voltage
are not cut off by the video filter. At smaller video bandwidths, the video signal is
averaged and the power readout will be too small.

2.24 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Noise Measurements

Sweep time selection

If the sample detector is used, it is best to select the smallest sweep time possible
for a given span and resolution bandwidth. The minimum time is obtained if the set­ting is coupled. This means that the time per measurement is minimal. Extending
the measurement time does not have any advantages as the number of samples for
calculating the power is defined by the number of trace pixels in the channel.

When using the RMS detector, the repeatability of the measurement results can be
influenced by the selection of sweep times. Repeatability is increased at longer
sweep times.

Repeatability can be estimated from the following diagram:

max. error/dB

0

95 % Confidence

0.5

level

1

99 % Confidence

level

1.5

2

2.5

3

10

Fig. 2.16 Repeatability of channel power measurements as a function of the number of samples

used for power calculation

100

1000

10000

Number of samples

100000

The curves in Fig. 2.16 indicates the repeatability obtained with a probability of 95%
and 99% depending on the number of samples used.

The repeatability with 600 samples is ± 0.5 dB. This means that – if the sample
detector and a channel bandwidth over the whole diagram (channel bandwidth =
span) is used - the measured value lies within ± 0.5 dB of the true value with a prob­ability of 99%.

If the RMS detector is used, the number of samples can be estimated as follows:

Since only uncorrelated samples contribute to the RMS value, the number of sam­ples can be calculated from the sweep time and the resolution bandwidth.

Samples can be assumed to be uncorrelated if sampling is performed at intervals of
1/RBW. The number of uncorrelated samples (N

= SWT × RBW

N

decorr

The number of uncorrelated samples per trace pixel is obtained by dividing N

) is calculated as follows:

decorr

decorr

by 625 (= pixels per trace).

Operating Manual 1313.9681.12 - 02 2.25

R&S FSQ Getting Started

Noise Measurements

Example

At a resolution bandwidth of 30 kHz and a sweep time of 100 ms, 3000 uncorrelated
samples are obtained. If the channel bandwidth is equal to the frequency display
range, i.e. all trace pixels are used for the channel power measurement, a repeat­ability of 0.2 dB with a confidence level of 99% is the estimate that can be derived
from Fig. 2.16.

2.26 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Noise Measurements

2.4.3 Measuring Phase Noise

The R&S FSQ has an easy-to-use marker function for phase noise measurements.
This marker function indicates the phase noise of an RF oscillator at any carrier in
dBc in a bandwidth of 1 Hz.

2.4.3.1 Measurement Example – Measuring the Phase Noise of a Signal Generator at a
Carrier Offset of 10 kHz

Test setup

Settings on the signal generator (e.g. R&S SMIQ)

Frequency: 100 MHz

Level: 0 dBm

Measurement using R&S FSQ

1. Set the R&S FSQ to the analyzer mode

➢ Press the SPECTRUM key.

R&S FSQ is in the analyzer mode.

2. Set the center frequency to 100 MHz and the span to 50 kHz

➢ Press the FREQ key and enter 100 MHz.
➢ Press the SPAN key and enter 50 kHz.

3. Set the R&S FSQ’s reference level to 0 dBm (=signal generator level)

➢ Press the AMPT key and enter 0 dBm.

4. Enable phase noise measurement

➢ Press the MKR FCTN key.
➢ Press the PHASE NOISE ! softkey.

The R&S FSQ activates phase noise measurement. Marker 1 (=main marker)
and marker 2 (= delta marker) are positioned on the signal maximum. The
position of the marker is the reference (level and frequency) for the phase
noise measurement. A horizontal line represents the level of the reference
point and a vertical line the frequency of the reference point. Data entry for the
delta marker is activated so that the frequency offset at which the phase noise
is to be measured can be entered directly.

5. 10 kHz frequency offset for determining phase noise.

➢ Enter 10 kHz.

The R&S FSQ displays the phase noise at a frequency offset of 10 kHz. The
magnitude of the phase noise in dBc/Hz is displayed in the delta marker output
field at the top right of the screen (delta 2 [T1 PHN]).

Operating Manual 1313.9681.12 - 02 2.27

R&S FSQ Getting Started

Noise Measurements

6. Stabilize the measurement result by activating trace averaging.

➢ Press the TRACE key.
➢ Press the AVERAGE softkey.

Fig. 2.17 Measuring phase noise with the phase-noise marker function

The frequency offset can be varied by moving the marker with the rotary knob
or by entering a new frequency offset as a number.

2.28 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measurements on Modulated Signals

2.5 Measurements on Modulated Signals

If RF signals are used to transmit information, an RF carrier is modulated. Analog
modulation methods such as amplitude modulation, frequency modulation and
phase modulation have a long history and digital modulation methods are now used
for modern systems. Measuring the power and the spectrum of modulated signals is
an important task to assure transmission quality and to ensure the integrity of other
radio services. This task can be performed easily with a Signal Analyzer. Modern
Signal Analyzers also provide the test routines that are essential to simplify complex
measurements.

2.5.1 Measurements on AM Signals

The R&S FSQ detects the RF input signal and displays the magnitudes of its com­ponents as a spectrum. AM modulated signals are also demodulated by this pro­cess. The AF voltage can be displayed in the time domain if the modulation
sidebands are within the resolution bandwidth. In the frequency domain, the AM
sidebands can be resolved with a small bandwidth and can be measured separately.
This means that the modulation depth of a carrier modulated with a sinewave signal
can be measured. Since the dynamic range of a Signal Analyzer is very wide, even
extremely small modulation depths can be measured accurately. The R&S FSQ has
a test routine which measures the modulation depth in %.

2.5.1.1 Measurement Example 1 – Displaying the AF of an AM Signal in the Time
Domain

Test setup

Settings on the signal generator (e.g. R&S SMIQ)

Frequency: 100 MHz

Level: 0 dBm

Modulation: 50 % AM, 1 kHz AF

Measurement with the R&S FSQ

1. Set the R&S FSQ to the analyzer mode

➢ Press the SPECTRUM key.

The R&S FSQ is in the analyzer mode.

2. Set the center frequency to 100 MHz and the span to 0 kHz

➢ Press the FREQ key and enter 100 MHz.
➢ Press the SPAN key and enter 0 Hz.

Operating Manual 1313.9681.12 - 02 2.29

R&S FSQ Getting Started

Measurements on Modulated Signals

3. Set the reference level to +6 dBm and the display range to linear

➢ Press the AMPT key and enter 6 dBm.
➢ Press the RANGE LINEAR softkey.

4. Use the video trigger to trigger on the AF signal in order to obtain a

stationary display

➢ Press the TRIG key.
➢ Press the VIDEO softkey.

The video trigger level is set to 50% if the instrument is switched on for the first
time. The trigger level is displayed as a horizontal line across the graph. The
R&S FSQ displays the 1 kHz AF signal stably in the time domain.

Fig. 2.18 Measuring the AF signal from a 1 kHz AM carrier

The AM/FM demodulator in the R&S FSQ can be used to output the AF by
means of a loudspeaker.

5. Switch on the internal AM demodulator

➢ Press the MKR FCTN key.
➢ Press the MKR DEMOD softkey.

The R&S FSQ switches the AM demodulator on automatically.

➢ Turn up volume control.

A 1 kHz tone is output by the loudspeaker.

2.30 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measurements on Modulated Signals

2.5.1.2 Measurement Example 2 – Measuring the Modulation Depth of an AM Carrier
in the Frequency Domain

Test setup

Settings on the signal generator (e.g. R&S SMIQ)

Frequency: 100 MHz

Level: -30 dBm

Modulation: 50 % AM, 1 kHz AF

Measurement with the R&S FSQ

1. Set the R&S FSQ to the analyzer mode

➢ Press the SPECTRUM key.

The R&S FSQ is in the analyzer mode.

2. Set the center frequency to 100 MHz and the span to 0 kHz

➢ Press the FREQ key and enter 100 MHz.
➢ Press the SPAN key and enter 5 kHz.

3. Activate the marker function for AM depth measurement

➢ Press the MEAS key.
➢ Press the MODULATION DEPTH softkey.

The R&S FSQ automatically positions a marker on the carrier signal in the
middle of the graph and one delta marker on each of the lower and upper AM
sidebands. The R&S FSQ calculates the AM modulation depth from the ratios
of the delta marker levels to the main marker level and outputs the numerical
value in the marker info field

Operating Manual 1313.9681.12 - 02 2.31

R&S FSQ Getting Started

Measurements on Modulated Signals

Fig. 2.19 Measurement of AM modulation depth. The modulation depth is indicated by

MDEPTH = 49.345 %. The frequency of the AF signal is indicated by the delta
markers

2.32 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measurements on Modulated Signals

2.5.2 Measurements on FM Signals

Since Signal Analyzers only display the magnitude of signals by means of the enve­lope detector, the modulation of FM signals cannot be directly measured as is the
case with AM signals. With FM signals, the voltage at the output of the envelope
detector is constant as long as the frequency deviation of the signal is within the flat
part of the passband characteristic of the resolution filter which has been selected.
Amplitude variations can only occur if the current frequency lies on the falling edge
of the filter characteristic. This effect can be used to demodulate FM signals. The
center frequency of the R&S FSQ is set in a way that the nominal frequency of the
test signal is on the filter edge (below or above the center frequency). The resolution
bandwidth and the frequency offset are selected in a way that the current frequency
is on the linear part of the filter slope. The frequency variation of the FM signal is
then transformed into an amplitude variation which can be displayed in the time
domain.

The R&S FSQ's analog 5
have a good filter-slope linearity, if the frequency of the R&S FSQ is set to 1.2 times
the filter bandwidth below or above the frequency of the transmit signal. The useful
range for FM demodulation is then almost equal to the resolution bandwidth.

th

order filters with frequencies from 200 kHz to 3 MHz

2.5.2.1 Measurement Example – Displaying the AF of an FM Carrier

Test setup

Settings on the signal generator (e.g. R&S SMIQ)

Frequency: 100 MHz

Level: -30 dBm

Modulation: FM 0 kHz deviation (i.e., FM = off), 1 kHz AF

Measurement with the R&S FSQ

1. Set the R&S FSQ to the analyzer mode

➢ Press the SPECTRUM key.

The R&S FSQ is in the analyzer mode.

2. Set the center frequency to 99.64 MHz and the span to 300 kHz.

➢ Press the FREQ key and enter 99.64 MHz.
➢ Press the SPAN key and enter 300 kHz.

3. Set a resolution bandwidth of 300 kHz.

➢ Press the BW key.
➢ Press the RES BW MANUAL softkey and enter 300 kHz.

Operating Manual 1313.9681.12 - 02 2.33

R&S FSQ Getting Started

Measurements on Modulated Signals

4. Set a display range of 20 dB and shift the filter characteristics to the middle

of the display.

➢ Press the AMPT key.
➢ Press the RANGE LOG MANUAL softkey and enter 20 dB.
➢ Press the NEXT key.
➢ Set the GRID softkey to REL.
➢ Press the PREV softkey.
➢ Using the rotary knob, shift the reference level so that the filter edge intersects

the - 10 dB level line at the center frequency.

The slope of the 300 kHz filter is displayed. This corresponds to the
demodulator characteristics for FM signals with a slope of approx. 5 dB/100
kHz.

Fig. 2.20 Filter edge of a 300 kHz filter used as an FM-discriminator characteristic

5. Set an FM deviation of 100 kHz and an AF of 1 kHz on the signal generator

6. Set a frequency deviation of 0 Hz on the R&S FSQ

➢ Press the SPAN key.
➢ Press the ZERO SPAN.

The demodulated FM signal is displayed. The signal moves across the screen.

2.34 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measurements on Modulated Signals

7. Creating a stable display by video triggering

➢ Press the TRIG key.
➢ Press the VIDEO softkey.

A stationary display is obtained for the FM AF signal
Result: (-10 ±5) dB; this means that a deviation of 100 kHz is obtained if the

demodulator characteristic slope is 5 dB/100 kHz

Fig. 2.21 Demodulated FM signal

Operating Manual 1313.9681.12 - 02 2.35

R&S FSQ Getting Started

Measurements on Modulated Signals

2.5.3 Measuring Channel Power and Adjacent Channel Power

Measuring channel power and adjacent channel power is one of the most important
tasks in the field of digital transmission for a Signal Analyzer with the necessary test
routines. While, theoretically, channel power could be measured at highest accuracy
with a power meter, its low selectivity means that it is not suitable for measuring
adjacent channel power as an absolute value or relative to the transmit channel
power. The power in the adjacent channels can only be measured with a selective
power meter.

A Signal Analyzer cannot be classified as a true power meter, because it displays
the IF envelope voltage. However, it is calibrated such as to correctly display the
power of a pure sinewave signal irrespective of the selected detector. This calibra­tion is not valid for non-sinusoidal signals. Assuming that the digitally modulated sig­nal has a Gaussian amplitude distribution, the signal power within the selected
resolution bandwidth can be obtained using correction factors. These correction fac­tors are normally used by the R&S FSQ's internal power measurement routines in
order to determine the signal power from IF envelope measurements. These factors
are valid if and only if the assumption of a Gaussian amplitude distribution is correct.

Apart from this common method, the R&S FSQ also has a true power detector, i.e.
an RMS detector. It correctly displays the power of the test signal within the selected
resolution bandwidth irrespective of the amplitude distribution, without additional
correction factors being required. With an absolute measurement uncertainty of <

0.3 dB and a relative measurement uncertainty of < 0.1 dB (each with a confidence
level of 95%), the R&S FSQ comes close to being a true power meter.

There are two possible methods for measuring channel and adjacent channel power
with a Signal Analyzer:

The IBW method (Integration Bandwidth Method) in which the R&S FSQ measures
with a resolution bandwidth that is less than the channel bandwidth and integrates
the level values of the trace versus the channel bandwidth. This method is described
in section “Noise Measurements” on page 2.18

Measurement using a channel filter.

In this case, the R&S FSQ makes measurements in the time domain using an IF fil­ter that corresponds to the channel bandwidth. The power is measured at the output
of the IF filter. Until now, this method has not been used for Signal Analyzers,
because channel filters were not available and the resolution bandwidths, optimized
for the sweep, did not have a sufficient selectivity. The method was reserved for spe­cial receivers optimized for a particular transmission method.

The R&S FSQ has test routines for simple channel and adjacent channel power
measurements. These routines give quick results without any complex or tedious
setting procedures.

2.36 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measurements on Modulated Signals

2.5.3.1 Measurement Example 1 – ACPR Measurement on an IS95 CDMA Signal

Test setup

Settings on the signal generator (e.g. R&S SMIQ)

Frequency: 850 MHz

Level: 0 dBm

Modulation: CDMA IS 95

Measurement with the R&S FSQ

1. Set the R&S FSQ to the analyzer mode.

➢ Press the SPECTRUM key.

The R&S FSQ is in the analyzer mode.

2. Set the center frequency to 850 MHz and frequency deviation to 4 MHz.

➢ Press the FREQ key and enter 850 MHz.

3. Set the reference level to +10 dBm.

➢ Press the AMPT key and enter 10 dBm.

4. Configuring the adjacent channel power for the CDMA IS95 reverse link.

➢ Press the MEAS key.
➢ Press the CHAN PWR ACP ! softkey.
➢ Press the CP/ACP STANDARD softkey.

From the list of standards, select CDMA IS95A REV using the rotary knob or
the cursor down key below the rotary knob and press ENTER.

The R&S FSQ sets the channel configuration according to the IS95 standard
for mobile stations with 2 adjacent channels above and below the transmit
channel. The spectrum is displayed in the upper part of the screen, the numeric
values of the results and the channel configuration in the lower part of the
screen. The various channels are represented by vertical lines on the graph.
The frequency span, resolution bandwidth, video bandwidth and detector are
selected automatically to give correct results. To obtain stable results ­especially in the adjacent channels (30 kHz bandwidth) which are narrow in
comparison with the transmission channel bandwidth (1.23 MHz) - the RMS
detector is used.

Operating Manual 1313.9681.12 - 02 2.37

R&S FSQ Getting Started

Measurements on Modulated Signals

5. Set the optimal reference level and RF attenuation for the applied signal

level.

➢ Press the ADJUST REF LVL softkey.

The R&S FSQ sets the optimal RF attenuation and the reference level based
on the transmission channel power to obtain the maximum dynamic range.
The following figure shows the result of the measurement.

Fig. 2.22 Adjacent channel power measurement on a CDMA IS95 signal

The repeatability of the results, especially in the narrow adjacent channels,
strongly depends on the measurement time since the dwell time within the 10
kHz channels is only a fraction of the complete sweep time. A longer sweep
time may increase the probability that the measured value converges to the
true value of the adjacent channel power, but this increases measurement
time.

To avoid long measurement times, the R&S FSQ measures the adjacent
channel power in the time domain (FAST ACP). In the FAST ACP mode, the
R&S FSQ measures the power of each channel at the defined channel
bandwidth, while being tuned to the center frequency of the channel in
question. The digital implementation of the resolution bandwidths makes it
possible to select a filter characteristics that is precisely tailored to the signal.
In case of CDMA IS95, the power in the useful channel is measured with a
bandwidth of 1.23 MHz and that of the adjacent channels with a bandwidth of
30 kHz. Therefore the R&S FSQ jumps from one channel to the other and
measures the power at a bandwidth of 1.23 MHz or 30 kHz using the RMS
detector. The measurement time per channel is set with the sweep time. It is
equal to the selected measurement time divided by the selected number of
channels. The five channels from the above example and the sweep time of
100 ms give a measurement time per channel of 20 ms.

2.38 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

B

A

s

A

s

Measurements on Modulated Signals

Compared to the measurement time per channel given by the span (= 5.1
MHz) and sweep time
(= 100 ms, equal to 0.600 ms per 30 kHz channel) used in the example, this is
a far longer dwell time on the adjacent channels (factor of 12). In terms of the
number of uncorrelated samples this means 20000/33 µs = 606 samples per
channel measurement compared to 600/33µs = 12.5 samples per channel
measurement.

Repeatability with a confidence level of 95% is increased from ± 1.4 dB to ±

0.38 dB as shown in Fig. 2.16. For the same repeatability, the sweep time
would have to be set to 1.2 s with the integration method. The following figure
shows the standard deviation of the results as a function of the sweep time.

ACPR Repeatability IS95

IBW Method

1,4

1,2

1

djacent channel

0,8

0,6

Standard dev / d

0,4

lter nat e channel

Tx channel

0,2

0

10 100 1000

Sweep t ime/ms

Fig. 2.23 Repeatability of adjacent channel power measurement on IS95-standard signals

if the integration bandwidth method is used

6. Switch to Fast ACP to increase the repeatability of results.

➢ Press the CP/ACP CONFIG ! softkey.
➢ Set the FAST ACP softkey to ON.
➢ Press the ADJUST REF LVL softkey.

The R&S FSQ measures the power of each channel in the time domain. The
trace represents power as a function of time for each measured channel (see

Fig. 2.24). The numerical results from consecutive measurements are much

more stable.

Operating Manual 1313.9681.12 - 02 2.39

R&S FSQ Getting Started

Measurements on Modulated Signals

Fig. 2.24 Measuring the channel power and adjacent channel power ratio for IS95 signals

in the time domain (Fast ACP)

The following figure shows the repeatability of power measurements in the
transmit channel and of relative power measurements in the adjacent channels
as a function of sweep time. The standard deviation of measurement results is
calculated from 100 consecutive measurements as shown in Fig. 2.23. Take
scaling into account if comparing power values.

ACPR IS95 Repeatability

0,35

0,3

0,25

0,2

Adjacent channels

0,15

Standard dev /dB

0,1

0,05

Tx channel

Alternate channels

0

10 100 1000

Sweep time/ms

Fig. 2.25 Repeatability of adjacent channel power measurements on IS95 signals in the

Fast ACP mode

2.40 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measurements on Modulated Signals

Note on adjacent channel power measurements on IS95 base-station sig­nals

When measuring the adjacent channel power of IS95 base-station signals, the
frequency spacing of the adjacent channel to the nominal transmit channel is
specified as ±750 kHz. The adjacent channels are, therefore, so close to the
transmit channel that the power of the transmit signal leaks across and is also
measured in the adjacent channel if the usual method using the 30 kHz resolu­tion bandwidth is applied. The reason is the low selectivity of the 30 kHz resolu­tion filter. The resolution bandwidth, therefore, must be reduced considerably,
e.g. to 3 kHz to avoid this. This causes very long measurement times (factor of
100 between a 30 kHz and 3 kHz resolution bandwidth).

This effect is avoided with the time domain method which uses steep IF filters.
The 30 kHz channel filter implemented in the R&S FSQ has a very high selectiv­ity so that even with a ±750 kHz spacing to the transmit channel the power of the
useful modulation spectrum is not measured.

The following figure shows the passband characteristics of the 30 kHz channel filter
in the R&S FSQ.

Fig. 2.26 Frequency response of the 30 kHz channel filter for measuring the power in the IS 95

adjacent channel

Operating Manual 1313.9681.12 - 02 2.41

R&S FSQ Getting Started

Measurements on Modulated Signals

2.5.3.2 Measurement Example 2 – Measuring the Adjacent Channel Power of an IS136
TDMA Signal

Test setup

As the modulation spectrum of the IS136 signal leaks into the adjacent channel, it
makes a contribution to the power in the adjacent channel. Exact tuning of the
R&S FSQ to the transmit frequency is therefore critical. If tuning is not precise,
the adjacent channel power ratios in the lower and upper adjacent channels
become asymmetrical. The R&S FSQ’s frequency and the generator frequency
are therefore synchronized.

Settings on the signal generator (e.g. R&S SMIQ)

Frequency: 850 MHz

Level: -20 dBm

Modulation: IS136/NADC

Measurement with the R&S FSQ

1. Set the R&S FSQ to the analyzer mode.

➢ Press the SPECTRUM key.

The R&S FSQ is in the analyzer mode.

2. Set up the R&S FSQ for synchronization to an external reference frequency.

➢ Press the SETUP key.
➢ Set the REFERENCE softkey to EXT.

3. Set the center frequency to 850 MHz.

➢ Press the FREQ key and enter 850 MHz.

4. Configure adjacent channel power measurement for IS136 signals.

➢ Press the MEAS key.
➢ Press the CHAN PWR ACP ! softkey.
➢ Press the CP/ACP STANDARD softkey.
➢ Select NADC IS136 from the list of standards and press ENTER.

The R&S FSQ performs the power measurement in 5 channels (in the useful
channel and in the two upper and two lower adjacent channels).

2.42 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measurements on Modulated Signals

5. Setting the optimum reference level and RF attenuation for the

measurement

➢ Press the ADJUST REF LEVEL softkey.

The R&S FSQ sets the optimum RF attenuation and the optimum reference
level on the basis of the measured channel power.

Fig. 2.27 Measuring the relative adjacent channel power of an NADC signal in each of the

two adjacent channels below and above the transmit channel.

To increase repeatability – especially in the adjacent channels – the R&S FSQ’s
Fast ACP routine is recommended.

6. Switching on the Fast ACP routine.

➢ Press the CP/ACP CONFIG ! softkey
➢ Set the FAST ACP softkey to ON.
➢ Press the ADJUST REF LEVEL softkey.

The R&S FSQ makes consecutive measurements on the 5 channels in the
zero span mode using the receive filter specified in IS 136 to define the
resolution bandwidth. The power in each channel is displayed on the graph as
a function of time.

Operating Manual 1313.9681.12 - 02 2.43

R&S FSQ Getting Started

Measurements on Modulated Signals

Fig. 2.28 Measuring adjacent channel power in time domain (Fast ACP)

As the resolution bandwidth is much wider than the one used for the integration
method, the results are much more stable when compared at the same sweep
time.

Repeatability can be influenced by the selected sweep time. The results
become much more stable if long sweep times are selected. Since the
amplitude distribution is different in different channels (part of the modulation
spectrum falls within the first adjacent channel), the repeatability depends on
the spacing of the measured channel from the transmit channel.

Fig. 2.29 shows the standard deviation of results in the different channels as a

function of the selected sweep time. The standard deviation for the various
sweep times was recorded using a signal generator as a source. With real
DUTs the amplitude distributions in adjacent channels may be different so that
the standard deviation could differ from that shown in Fig. 2.25. Standard
deviation of the results of Fast ACP measurement as a function of selected
sweep time evaluated from 100 measurements per sweep time. To evaluate
the correct measuring time for time-critical measurements at a given standard
deviation, the standard deviation of the ACP values at the output of the real
DUT must be determined.

2.44 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measurements on Modulated Signals

NADC Repeatability

1.4

1.2

1

0.8

0.6

0.4

Standar d Devi ati on / dB

0.2

0

10 100 1000

Fig. 2.29 Standard deviation of the results of Fast ACP measurement as a function of

selected sweep time evaluated from 100 measurements per sweep time

Alt 1 Channels

Tx Channel

Adj Channels

Sweep Time / ms

2.5.3.3 Measurement Example 3 – Measuring the Modulation Spectrum in Burst Mode
with the Gated Sweep Function

Since transmission systems compliant to IS136 use a TDMA method, the adjacent
channel power must also be measured in burst mode. An IS136 TDMA frame is
divided into 6 time slots. Two of these slots are assigned to a subscriber. This
means that the ratio of transmit time to off-time for IS136 mobile phones is only 1:3
(e.g. time slots 1 and 4)

The R&S FSQ supports the measurement of the adjacent channel power in the
TDMA mode with the Gated Sweep function.

Test setup with the R&S Signal Generator SMIQ

The R&S SMIQ has to be equipped with options R&S SMIQ-B10 or R&S SMIQ-B20
(modulation coder) and R&S SMIQ-B11 (data generator).

Option R&S SMIQ-Z5 is required to trigger the R&S FSQ. This option is connected
to the R&S SMIQ’s parallel output port. The BNC output Trigger 1 of the R&S SMIQ­Z5 provides a TTL trigger signal on the rising edge of the IS136 burst, which is used
to start the R&S FSQ sweep in the Gated Sweep mode.

Operating Manual 1313.9681.12 - 02 2.45

R&S FSQ Getting Started

Measurements on Modulated Signals

The R&S FSQ’s IF power trigger is not suitable for IS136. It triggers on every
level edge of the input signal. Since the modulation of the IS136 signal causes
level dips even during the transmit burst, there is no way of ensuring that the
R&S FSQ is only triggered on the burst edge.

Settings on signal generator R&S SMIQ

Switch the signal generator to the IS136 burst mode (time slots 1 and 4 are switched
on, the other time slots are switched off).

The R&S SMIQ is set as follows to generate the signal:

1. Press the PRESET key.

2. Press the FREQ key and enter 850 MHz.

3. Press the LEVEL key and enter -20 dBm.

4. Press the RETURN key.

5. Select DIGITAL STANDARD using the rotary knob and press the SELECT key.

6. Select NADC using the rotary knob and press the SELECT key.

7. Press the SELECT key.

8. Select ON using the rotary knob and press the SELECT key.

9. Press the RETURN key.

10.Keep turning the rotary knob until SAVE/RECALL FRAME appears in the list and

select the menu item SAVE/RECALL FRAME using the SELECT key.

11.The cursor is set to GET PREDEFINED FRAME.

12.Press the SELECT key.

13.Select UP1TCH using the rotary knob and press the SELECT key.

In the following operating sequence for the R&S FSQ, it is assumed that steps 1 to 6
of 2.5.3.2“Measurement Example 2 – Measuring the Adjacent Channel Power of an

IS136 TDMA Signal” on page 2.42 have already been performed.

Configuring the Gated Sweep function on the R&S FSQ

➢ Press the TRIG key.
➢ Press the GATED TRIGGER softkey.
➢ Press the EXTERN softkey.
➢ Press the GATE SETTINGS ! softkey.

The R&S FSQ switches to time domain measurement so that the setting of the
Gated Sweep parameters can be checked visually.

➢ Press the SWEEPTIME softkey and enter 10 ms.

Exactly one TDMA burst will be displayed.

➢ Press the GATE DELAY softkey and enter 2 ms or set the Gate Delay using the

rotary knob so that the burst is reliably detected.

➢ Press the GATE LENGTH softkey and enter 5 ms or set the vertical line for the

gate length using the rotary knob so that the burst is reliably detected.

2.46 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measurements on Modulated Signals

Fig. 2.30 Setting the parameters Gate Delay and Gate Length in time domain. The time

interval required to measure the spectrum is indicated by two vertical lines.

➢ Press the PREV key.

The R&S FSQ now performs the ACP measurement only during the switch-on
phase of the TDMA burst. The measurement is stopped during the switch-off
phase.

The selected sweep time is the net sweep time, i.e. the time during which the
R&S FSQ is actually measuring. The complete frame of an IS136 signal takes 40
ms. In the above example, measurement only takes place for 2 x 5 ms within a
frame. The R&S FSQ is therefore only measuring for 25 % of the frame duration.
The total measuring time is therefore four times that for the CW mode.

2.5.3.4 Measurement Example 4 – Measuring the Transient Spectrum in Burst Mode
with the Fast ACP function

In addition to the modulation spectrum or adjacent channel power from the modula­tion of the RF carrier, the spectrum or adjacent channel power generated by burst
edges is also to be measured in TDMA systems. The spectrum is a pulse spectrum
and must be measured with the peak detector. With the usual IBW method, only the
power of the continuously modulated signal can be measured properly. Even if the
modulation spectrum is transmitted in the TDMA mode, the measurement of the
modulation spectrum will work because the burst edges are blanked out for the
measurement by means of the Gated Sweep function. The R&S FSQ performs
measurements only if the modulation spectrum is continuous when the burst is on.

Operating Manual 1313.9681.12 - 02 2.47

R&S FSQ Getting Started

Measurements on Modulated Signals

However, the IBW method fails for the spectrum created by the burst edges. As the
measurement is carried out with resolution bandwidths that are very small compared
to the signal bandwidth, a spurious amplitude distribution is obtained in the defined
measurement channel because of the resolution bandwidth. The small resolution
bandwidth cannot settle to the peak amplitudes of the test signal. This problem is
avoided in the R&S FSQ by performing time domain measurements with the root
raised cosine filter specified in the IS136 standard.

If the peak detector is used instead of the default RMS detector (which is selected
when the standard is selected), the true adjacent channel power generated by the
burst edges can also be measured.

Test setup

The test setup for this example and the settings for R&S SMIQ are identical to those
described in “Measurement Example 3 – Measuring the Modulation Spectrum in

Burst Mode with the Gated Sweep Function” on page 2.45.

Measurement with the R&S FSQ

1. Set the R&S FSQ to the analyzer mode.

➢ Press the SPECTRUM key.

The R&S FSQ is in the analyzer mode.

2. Synchronize the R&S FSQ to an external reference frequency.

➢ Press the SETUP key.
➢ Set the REFERENCE softkey to EXT.

3. Set the center frequency to 850 MHz

➢ Press the FREQ key and enter 850 MHz.

4. Configure the adjacent channel power measurement for IS136 signals in

Fast ACP mode.

➢ Press the MEAS key.
➢ Press the CHAN PWR ACP ! softkey.
➢ Press the CP/ACP STANDARD softkey.
➢ Select NADC IS136 from the list of standards and press ENTER.
➢ Press the CP/ACP CONFIG ! softkey.
➢ Set the FAST ACP softkey to ON.

The R&S FSQ performs the power measurement in 5 channels (in the useful
channel and in the two upper and lower adjacent channels).

5. Set the optimum reference level and RF attenuation for the measurement.

➢ Press the ADJUST REF LEVEL softkey.

The R&S FSQ sets the optimum RF attenuation and the optimum reference
level on the basis of the measured channel power.

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R&S FSQ Getting Started

Measurements on Modulated Signals

6. Select the peak detector and increase the sweep time to 10 s.

➢ Press the TRACE key.
➢ Press the DETECTOR softkey.
➢ Press the DETECTOR MAX PEAK softkey.
➢ Press the SWEEP key.
➢ Press the SWEEP TIME softkey and enter 10 s.

The R&S FSQ measures the adjacent channel power generated by the burst
edges and the modulation.

Fig. 2.31 Adjacent channel power due to modulation spectrum and transient spectrum

The peak power display depends on the selected sweep time. The longer the
sweep time, the higher the probability of measuring the highest peak amplitude of
the signal.

With shorter sweep times, level dips can be seen in the time domain traces.
These level dips come from the burst characteristic of the signal. The numerical
results, however, indicate the peak amplitudes during the measurement in the
corresponding channel.

Operating Manual 1313.9681.12 - 02 2.49

R&S FSQ Getting Started

Measurements on Modulated Signals

2.5.3.5 Measurement Example 5 – Measuring the Adjacent Channel Power of a W­CDMA Uplink Signal

Test setup

Settings on the signal generator (e.g. R&S SMIQ)

Frequency: 1950 MHz

Level: 4 dBm

Modulation: 3 GPP W-CDMA Reverse Link

Measurement with the R&S FSQ

1. Set the R&S FSQ to the analyzer mode.

➢ Press the SPECTRUM key.

The R&S FSQ is in the analyzer mode.

2. Set the center frequency to 1950 MHz.

➢ Press the FREQ key and enter 1950 MHz.

3. Switch on the ACP measurement for W-CDMA.

➢ Press the MEAS key.
➢ Press the CHAN PWR ACP ! softkey.
➢ Press the CP/ACP STANDARD softkey.
➢ From the list of standards, select W-CDMA 3GPP REV using the rotary knob

or the cursor down key below the rotary knob and press ENTER.
The R&S FSQ sets the channel configuration to the 3GPP W-CDMA standard
for mobiles with two adjacent channels above and below the transmit channel.
The frequency span, the resolution and video bandwidth and the detector are
automatically set to the correct values. The spectrum is displayed in the upper
part of the screen and the channel power, the level ratios of the adjacent
channel powers and the channel configuration in the lower part of the screen.
The individual channels are displayed as vertical lines on the graph.

4. Set the optimum reference level and the RF attenuation for the applied

signal level.

➢ Press the ADJUST REF LEVEL softkey.

The R&S FSQ sets the optimum RF attenuation and the reference level for the
power in the transmission channel to obtain the maximum dynamic range. The
following figure shows the result of the measurement:

2.50 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

Measurements on Modulated Signals

Fig. 2.32 Measuring the relative adjacent channel power on a W-CDMA uplink signal

5. Measuring adjacent channel power with the Fast ACP method.

➢ Press the CP/ACP CONFIG ! softkey.
➢ Set FAST ACP softkey to ON.
➢ Press the ADJUST REF LVL softkey.

The R&S FSQ measures the power of the individual channels in the time
domain. A root raised cosine filter with the parameters α = 0.22 and chip rate

3.84 Mcps (= receive filter for 3GPP W-CDMA) is used as the channel filter.

Operating Manual 1313.9681.12 - 02 2.51

R&S FSQ Getting Started

Measurements on Modulated Signals

Fig. 2.33 Measuring the adjacent channel power of a W-CDMA signal with the Fast ACP

method

With W-CDMA, the R&S FSQ’s dynamic range for adjacent channel measure­ments is limited by the 14-bit A/D converter. The greatest dynamic range is,
therefore, obtained with the IBW method.

2.52 Operating Manual 1313.9681.12 - 02

R&S FSQ Getting Started

A

A

Measurements on Modulated Signals

Optimum Level Setting for ACP Measurements on W-CDMA Signals

The dynamic range for ACPR measurements is limited by the thermal noise floor,
the phase noise and the intermodulation (spectral regrowth) of the R&S FSQ. The
power values produced by the R&S FSQ due to these factors accumulate linearly.
They depend on the applied level at the input mixer. The three factors are shown in
the figure below for the adjacent channel (5 MHz carrier offset)

CLR /dBc

-50

-55

-60

-65

-70

-75

-80

-85

-90

-20 -15 -10 -5 0

Fig. 2.34 The R&S FSQ’s dynamic range for adjacent channel power measurements on W-CDMA

thermal

noise

phase

noise

uplink signals is a function of the mixer level.

total

CLR

spectral

regrowth

Mixer level / dBm

The level of the W-CDMA signal at the input mixer is shown on the horizontal axis,
i.e. the measured signal level minus the selected RF attenuation. The individual
components which contribute to the power in the adjacent channel and the resulting
relative level (total ACPR) in the adjacent channel are displayed on the vertical axis.
The optimum mixer level is –10 dBm. The relative adjacent channel power (ACPR)
at an optimum mixer level is –77,5 dBc. Since, at a given signal level, the mixer level
is set in 5 dB steps with the 5 dB RF attenuator, the optimum 5 dB range is shown in
the figure: it spreads from –13 dBm to –8 dBm. The obtainable dynamic range in this
range is 76 dB.

To set the attenuation parameter manually, the following method is recommended:

• Set the RF attenuation so that the mixer level (= measured channel power – RF

attenuation) is between -13 dBm and -8 dBm.

• Set the reference level to the largest possible value where no overload (IFOVLD)

is indicated.

This method is automated with the R&S FSQ’s ADJUST REF LEVEL function.
Especially in remote control mode, e.g. in production environments, it is best to cor­rectly set the attenuation parameters prior to the measurement, as the time required
for automatic setting can be saved.

To measure the R&S FSQ’s intrinsic dynamic range for W-CDMA adjacent chan­nel power measurements, a filter which suppresses the adjacent channel power
is required at the output of the transmitter. A SAW filter with a bandwidth of 4
MHz, for example, can be used.

Operating Manual 1313.9681.12 - 02 2.53

R&S FSQ Getting Started

Measurements on Modulated Signals

2.5.4 Amplitude Distribution Measurements

If modulation types that do not have a constant envelope in the time domain are
used, the transmitter has to handle peak amplitudes that are greater than the aver­age power. This includes all modulation types that involve amplitude modulation ­QPSK for example. CDMA transmission modes in particular may have power peaks
that are large compared to the average power.

For signals of this kind, the transmitter must provide large reserves for the peak
power to prevent signal compression and thus an increase of the bit error rate at the
receiver.

The peak power, or the crest factor of a signal is therefore an important transmitter
design criterion. The crest factor is defined as the peak power / mean power ratio or,
logarithmically, as the peak level minus the average level of the signal.

To reduce power consumption and cut costs, transmitters are not designed for the
largest power that could ever occur, but for a power that has a specified probability
of being exceeded (e.g. 0.01%).

To measure the amplitude distribution, the R&S FSQ has simple measurement func­tions to determine both the APD = Amplitude Probability Distribution and CCDF =
Complementary Cumulative Distribution Function.

In the literature, APD is also used for the probability of amplitude violation. This is
the complimentary function to the APD function of R&S FSQ. The term PDF
(=Probability Density Function) which is frequently used in the literature corre­sponds to the APD function of R&S FSQ.

In the APD display mode, the probability of occurrence of a certain level is plotted
against the level.

In the CCDF display mode, the probability that the mean signal power will be
exceeded is shown in percent.

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R&S FSQ Getting Started

Measurements on Modulated Signals

2.5.4.1 Measurement Example – Measuring the APD and CCDF of White Noise Gener­ated by the R&S FSQ

1. Set the R&S FSQ to the analyzer mode.

➢ Press the SPECTRUM key.

The R&S FSQ is in the analyzer mode.

2. Configure the R&S FSQ for APD measurement

➢ Press the AMPT key and enter -60 dBm.

The R&S FSQ’s intrinsic noise is displayed at the top of the screen.

➢ Press the MEAS key.
➢ Press the SIGNAL STATISTIC ! softkey.
➢ Set the APD softkey to ON.

The R&S FSQ sets the frequency span to 0 Hz and measures the amplitude
probability distribution (APD). The number of uncorrelated level
measurements used for the measurement is 100000. The mean power and the
peak power are displayed in dBm. The crest factor (peak power – mean
power) is output as well (see Fig. 2.35).

Fig. 2.35 Amplitude probability distribution of white noise

Operating Manual 1313.9681.12 - 02 2.55

R&S FSQ Getting Started

Measurements on Modulated Signals

3. Switch to the CCDF display mode.

➢ Set the CCDF softkey to ON

The APD measurement is switched off and the CCDF display mode is switched
on.

Fig. 2.36 The CCDF of white noise

The CCDF trace indicates the probability that a level will exceed the mean
power. The level above the mean power is plotted along the x-axis of the
graph.The origin of the axis corresponds to the mean power level. The
probability that a level will be exceeded is plotted along the y-axis.

4. Bandwidth selection

If the amplitude distribution is measured, the resolution bandwidth must be set in
a way that the complete spectrum of the signal to be measured falls within the
bandwidth. This is the only way of ensuring that all the amplitudes will pass
through the IF filter without being distorted. If the selected resolution bandwidth is
too small for a digitally modulated signal, the amplitude distribution at the output
of the IF filter becomes a Gaussian distribution according to the central limit
theorem and so corresponds to a white noise signal. The true amplitude
distribution of the signal therefore cannot be determined.

A video bandwidth which is large in comparison to the resolution bandwidth (≥ 3 x
RBW) must be selected. This ensures that the amplitude peaks of the signal are
not smoothed by the lowpass effect of the video filter. The video bandwidth is set
automatically during statistics measurements.

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R&S FSQ Getting Started

Measurements on Modulated Signals

Since the video bandwidth of the R&S FSQ is limited to 10 MHz, lowpass filtering
occurs during measurements with a resolution bandwidth of 10 MHz. Additional
band-limiting occurs at a resolution bandwidth of 10 MHz due to the lowpass
filtering at the output of the log amplifier. The latter limits the video signal to a
bandwidth of 8 MHz in order to obtain sufficient suppression of the 20.4 MHz IF.
The level range of the signal amplitudes, e.g. during APD white-noise
measurements, is smaller. For broadband-modulated signals such as W-CDMA
signals, the effect depends on the bandwidth occupied by the signal. At a signal
bandwidth of 4 MHz, the amplitude distribution can be measured correctly with the
effective video bandwidth.

5. Selecting the number of samples

For statistics measurements with the R&S FSQ, the number of samples N

Samples

is entered for statistical evaluation instead of the sweep time. Since only
statistically independent samples contribute to statistics, the measurement or
sweep time is calculated automatically. It is indicated on the R&S FSQ display.
The samples are statistically independent if the time difference is at least 1/RBW.
The sweep time SWT is, therefore, expressed as follows:

SWT = N

Samples

/RBW

Operating Manual 1313.9681.12 - 02 2.57

R&S FSQ Manual Operation

3 Manual Operation

For details refer to the Quick Start Guide chapter 4, “Basic Operation”.

3.1 Operating Manual 1313.9681.12 - 02

R&S FSQ Instrument Functions

4 Instrument Functions

4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5

4.2 R&S FSQ Initial Configuration – PRESET Key . . . . . . . . . . . . . . . . . . . . . . 4.6

4.3 Mode Selection – Hotkey Bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8

4.4 Return to Manual Operation – LOCAL Menu . . . . . . . . . . . . . . . . . . . . . . . 4.9

4.5 Analyzer Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.10

4.5.1 Frequency and Span Selection – FREQ Key . . . . . . . . . . . . . . . . . . . . 4.11

4.5.2 Setting the Frequency Span – SPAN Key . . . . . . . . . . . . . . . . . . . . . . . 4.15

4.5.3 Level Display Setting and RF Input Configuration – AMPT Key . . . . . . 4.17

4.5.3.1 Electronic Attenuator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.21

4.5.4 Setting the Bandwidths and Sweep Time – BW Key . . . . . . . . . . . . . . . 4.23

4.5.4.1 Filter Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.28

4.5.5 Sweep Settings – SWEEP Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.34

4.5.6 Triggering the Sweep – TRIG Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.37

4.5.7 Selection and Setting of Traces – TRACE Key . . . . . . . . . . . . . . . . . . . 4.44

4.5.7.1 Selection of Trace Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.44

4.5.7.2 Selection of Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.52

4.5.7.3 Mathematical Functions for Traces . . . . . . . . . . . . . . . . . . . . . . . . 4.56

4.5.8 Recording the Correction Data – CAL Key . . . . . . . . . . . . . . . . . . . . . . 4.57

4.5.9 Markers and Delta Markers – MKR Key . . . . . . . . . . . . . . . . . . . . . . . . 4.60

4.5.9.1 Frequency Measurement with the Frequency Counter . . . . . . . . . 4.62

4.5.10 Marker Functions – MKR FCTN Key . . . . . . . . . . . . . . . . . . . . . . . . . . 4.67

4.5.10.1 Activating the Markers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.68

4.5.10.2 Measurement of Noise Density . . . . . . . . . . . . . . . . . . . . . . . . . . 4.68

4.5.10.3 Phase Noise Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.70

4.5.10.4 Measurement of the Filter or Signal Bandwidth . . . . . . . . . . . . . 4.72

4.5.10.5 Measurement of a Peak List . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.73

4.5.10.6 AF Demodulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.76

4.5.10.7 Selecting the Trace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.78

4.5.11 Change of Settings via Markers – MKR-> Key . . . . . . . . . . . . . . . . . . 4.79

Operating Manual 1313.9681.12 - 02 4.1

R&S FSQ Instrument Functions

4.5.12 Power Measurements – MEAS Key . . . . . . . . . . . . . . . . . . . . . . . . . . 4.86

4.5.12.1 Power Measurement in Time Domain . . . . . . . . . . . . . . . . . . . . . 4.87

4.5.12.2 Channel and Adjacent-Channel Power Measurements . . . . . . . 4.92

4.5.12.3 Measurement of Occupied Bandwidth . . . . . . . . . . . . . . . . . . . 4.113

4.5.12.4 Measurement of Signal Amplitude Statistics . . . . . . . . . . . . . . . 4.115

4.5.12.5 Measurement of Carrier/Noise Ratio C/N and C/No . . . . . . . . . 4.124

4.5.12.6 Measurement of the AM Modulation Depth . . . . . . . . . . . . . . . . 4.126

4.5.12.7 Capturing IQ Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.127

4.5.12.8 Measurement of the Third Order Intercept (TOI) . . . . . . . . . . . . 4.130

4.5.12.9 Harmonic Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.133

4.5.12.10 Measuring Spurious Emissions . . . . . . . . . . . . . . . . . . . . . . . . 4.135

4.5.12.11 Spectrum Emission Mask Measurement . . . . . . . . . . . . . . . . . 4.142

4.6 Basic Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.161

4.6.1 Setup of Limit Lines and Display Lines – LINES Key . . . . . . . . . . . . . 4.161

4.6.1.1 Selection of Limit Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.162

4.6.1.2 Entry and Editing of Limit Lines . . . . . . . . . . . . . . . . . . . . . . . . . . 4.165

4.6.1.3 Display Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.170

4.6.2 Configuration of Screen Display – DISP Key . . . . . . . . . . . . . . . . . . . 4.173

4.6.3 Instrument Setup and Interface Configuration – SETUP Key . . . . . . . 4.179

4.6.3.1 External Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.182

4.6.3.2 External Noise Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.183

4.6.3.3 Signal Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.183

4.6.3.4 RF Preamplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.186

4.6.3.5 Transducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.186

4.6.3.6 Programming the Interface Configuration and Time Setup . . . . . 4.192

4.6.3.7 System Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.207

4.6.3.8 Service Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.209

4.6.3.9 Firmware Update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.213

4.6.4 Saving and Recalling Data Sets – FILE Key . . . . . . . . . . . . . . . . . . . . 4.215

4.6.4.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.215

4.6.4.2 Operating Concept of File Managers . . . . . . . . . . . . . . . . . . . . . 4.220

4.6.5 Measurement Documentation – HCOPY Key . . . . . . . . . . . . . . . . . . . 4.225

4.6.5.1 Selecting Printer Colors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.228

4.7 Tracking Generator – Option R&S FSU-B9 . . . . . . . . . . . . . . . . . . . . . . . 4.232

4.7.1 Tracking Generator Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.233

4.7.2 Transmission Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.235

4.7.2.1 Calibration of Transmission Measurement . . . . . . . . . . . . . . . . . 4.235

4.7.2.2 Normalization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.237

4.7.3 Reflection Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.241

4.7.3.1 Calibration of Reflection Measurement . . . . . . . . . . . . . . . . . . . . 4.241

4.7.4 Calibration Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.242

4.7.5 Frequency-Converting Measurements . . . . . . . . . . . . . . . . . . . . . . . . 4.244

4.2 Operating Manual 1313.9681.12 - 02

R&S FSQ Instrument Functions

4.7.6 External Modulation of the Tracking Generator . . . . . . . . . . . . . . . . . . 4.245

4.7.7 Power Offset of the Tracking Generator . . . . . . . . . . . . . . . . . . . . . . . 4.247

4.8 External Generator Control – Option R&S FSP-B10 . . . . . . . . . . . . . . . 4.248

4.8.1 External Generator Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.249

4.8.2 Transmission Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.250

4.8.2.1 Calibration of Transmission Measurement . . . . . . . . . . . . . . . . . 4.250

4.8.2.2 Normalization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.252

4.8.3 Reflection Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.256

4.8.3.1 Calibration of Reflection Measurement . . . . . . . . . . . . . . . . . . . . 4.256

4.8.4 Calibration Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.257

4.8.5 Frequency-Converting Measurements . . . . . . . . . . . . . . . . . . . . . . . . 4.258

4.8.6 Configuration of an External Generator . . . . . . . . . . . . . . . . . . . . . . . . 4.259

4.8.7 List of Generator Types Supported by the R&S FSQ . . . . . . . . . . . . . 4.262

4.9 LAN Interface - Option R&S FSP-B16 . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.266

4.9.1 NOVELL Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.266

4.9.2 MICROSOFT Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.266

4.9.3 Remote Data Transfer with TCP/IP Services . . . . . . . . . . . . . . . . . . . 4.266

4.10 RSIB Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.268

4.10.1 Remote Control via RSIB Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . 4.268

4.10.1.1 Windows Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.268

4.10.1.2 UNIX Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.269

4.11 RSIB Interface Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.270

4.11.1 Overview of Interface Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.270

4.11.1.1 Variables ibsta, iberr, ibcntl . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.271

4.11.1.2 Description of Interface Functions . . . . . . . . . . . . . . . . . . . . . . . 4.272

4.11.2 Programming via the RSIB Protocol . . . . . . . . . . . . . . . . . . . . . . . . . 4.281

4.11.2.1 Visual Basic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.281

4.11.2.2 Visual Basic for Applications (Winword and Excel) . . . . . . . . . . 4.285

4.11.2.3 C / C++ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.286

4.12 Digital Baseband Interface - Option R&S FSQ-B17 . . . . . . . . . . . . . . . 4.288

4.12.1 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.288

4.12.2 Online Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.290

4.12.3 Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.291

4.12.4 Signal Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.292

4.12.4.1 Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.292

4.12.4.2 Pin description: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.292

4.12.5 Channel Link Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.294

4.12.6 Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.295

4.12.7 Remote Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.295

Operating Manual 1313.9681.12 - 02 4.3

R&S FSQ Instrument Functions

4.13 LO/IF ports for external mixers - Option R&S FSU-B21 . . . . . . . . . . . . 4.296

4.13.1 Connecting an External Mixer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.296

4.13.2 Manual Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.297

4.13.3 Conversion Loss Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.303

4.13.3.1 Editing a Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.306

4.13.4 Signal Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.310

4.13.4.1 Remarks Concerning Signal Identification with AUTO ID . . . . . 4.311

4.13.5 Introductory Example of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 4.317

4.4 Operating Manual 1313.9681.12 - 02

R&S FSQ Instrument Functions

Introduction

4.1 Introduction

All functions of the R&S FSQ and their application are explained in detail in this
chapter. The sequence of the described menu groups depends on the procedure
selected for the configuration and start of a measurement:

1. Resetting the instrument

– “R&S FSQ Initial Configuration – PRESET Key” on page 4.6

2. Setting the mode

– “Mode Selection – Hotkey Bar” on page 4.8

– “Return to Manual Operation – LOCAL Menu” on page 4.9

3. Setting the measurement parameters in analyzer mode

– “Analyzer Mode” on page 4.10

4. Basic functions for general settings, printout and data management

– “Setup of Limit Lines and Display Lines – LINES Key” on page 4.161

– “Configuration of Screen Display – DISP Key” on page 4.173

– “Instrument Setup and Interface Configuration – SETUP Key” on page 4.179

– “Saving and Recalling Data Sets – FILE Key” on page 4.215

– “Measurement Documentation – HCOPY Key” on page 4.225

5. Additional and optional functions

– “Tracking Generator – Option R&S FSU-B9” on page 4.232

– “External Generator Control – Option R&S FSP-B10” on page 4.248

– “LAN Interface - Option R&S FSP-B16” on page 4.266

– “LO/IF ports for external mixers - Option R&S FSU-B21” on page 4.296

– “Trigger Port – Option R&S FSP-B28” on page 4.309

The operating concept is described in the Quick Start Guide, chapter 4, “Basic Oper­ation”.

The remote commands (if any) are indicated for each softkey. A detailed description
of the associated remote commands is given in chapter “Remote Control – Descrip-

tion of Commands”.

Operating Manual 1313.9681.12 - 02 4.5

R&S FSQ Instrument Functions

R&S FSQ Initial Configuration – PRESET Key

4.2 R&S FSQ Initial Configuration – PRESET Key

PRESET

Using the PRESET key, the R&S FSQ can be set to a predefined initial state.

The settings are selected in a way that the RF input is always protected against
overload, provided that the applied signal levels are in the allowed range for the
instrument.

The initial instrument state set by the PRESET key can be adapted to arbitrary
applications using the STARTUP RECALL function. With this function the STAR­TUP RECALL data set is loaded upon pressing the PRESET key. For further infor­mation refer to section “Saving and Recalling Data Sets – FILE Key” on

page 4.215.

Pressing the PRESET key causes the R&S FSQ to enter its initial state according to
the following table:

4.6 Operating Manual 1313.9681.12 - 02

R&S FSQ Instrument Functions

R&S FSQ Initial Configuration – PRESET Key

Table 4-1 Initial State of R&S FSQ

Parameter Settings

Mode Spectrum

Center frequency 1,8 GHz / 4 GHz / 13,25 GHz / 20 GHz

(R&S FSQ-3/-8/-26/-31/-40)

Center frequency step size 0.1 * center frequency

Span 3,6 GHz / 8 GHz / 26,5 GHz / 40 GHz

(R&S FSQ-3/-8/-26/-31/-40)

RF attenuation auto (5 dB)

Reference level -20 dBm

Level range 100 dB log

Level unit dBm

Sweep time auto

Resolution bandwidth auto (3 MHz)

Video bandwidth auto (10 MHz)

FFT filters off

Span / RBW 50

RBW / VBW 0,33

Sweep cont

Trigger free run

Trace 1 clr write

Trace 2/3 blank

Detector auto peak

Trace math off

Frequency offset 0 Hz

Reference level offset 0 dB

Reference level position 100 %

Grid abs

Cal correction on

Noise source off

Input RF

Display Full screen, active screen A

Operating Manual 1313.9681.12 - 02 4.7

R&S FSQ Instrument Functions

Mode Selection – Hotkey Bar

4.3 Mode Selection – Hotkey Bar

For fast mode selection the R&S FSQ has keys located under the measurement
screen, the so-called hotkeys. These hotkeys are displayed depending on the
options installed on the instrument. According to the selected mode, the correspond­ing softkey menus are displayed (on the right side of the measurement screen).

In this section, only the hotkeys provided by the basic model are described. For
information on the other hotkeys refer to the corresponding option descriptions.

Fig. 4.14 Hotkey bar of the basic model

SPECTRUM

MORE

SCREEN A /
SCREEN B

The SPECTRUM hotkey sets R&S FSQ to analyzer mode. For details on the softkey
menus refer to section “Analyzer Mode” on page 4.10.

The analyzer mode is the default mode of R&S FSQ.

Remote command: INST:SEL SAN

INST:NSEL 1

The MORE hotkey switches to side hotkey bar(s) and back to the main hotkey bar.
In the side hotkey bar(s), the hotkeys for the options are located. For further infor­mation refer to the descriptions of the corresponding options.

With the SCREEN A / SCREEN B hotkey two different settings can be selected on
the R&S FSQ in the FULL SCREEN display mode.

In the SPLIT SCREEN display mode the key switches between active diagram A
and B.

The key designation indicates the diagram which has been activated by means of
the key.

The currently active window is marked by or on the right of the dia­gram.

A

B

Remote command: DISP:WIND<1|2>:SEL

4.8 Operating Manual 1313.9681.12 - 02

R&S FSQ Instrument Functions

Return to Manual Operation – LOCAL Menu

4.4 Return to Manual Operation – LOCAL Menu

LOCAL

The LOCAL menu is displayed on switching the instrument to remote control mode.

At the same time, the hotkey bar is blanked out and all keys are disabled except the
PRESET key.

The LOCAL softkey and the DISPLAY UPDATE ON/OFF softkey are displayed.

Depending on the setting of the DISPLAY UPDATE ON/OFF softkey, the diagrams,
traces and diplay fields are displayed or hidden. For further details on the DISPLAY
UPDATE ON/OFF softkey refer to Instrument Setup and Interface Configuration –

SETUP Key.

The LOCAL key switches the instrument from remote to manual operation, with the
assumption that the remote controller has not previously set the LOCAL LOCKOUT
function.

A change in the control mode consists of:

• Enabling the Front Panel Keys

Returning to manual operation enables all inactive keys and turns on the hotkey
bar. The softkey menu which is displayed is the main menu of the current mode.

• Inserting the measurement diagrams

The blanked diagrams, traces and display fields are inserted.

• Generating the message OPERATION COMPLETE

If, at the time of pressing the LOCAL softkey, the synchronization mechanism via
*OPC, *OPC? or *WAI is active, the currently running measurement procedure is
aborted and synchronization is achieved by setting the corresponding bits in the
registers of the status reporting system.

• Setting Bit 6 (User Request) of the Event Status Register

With a corresponding configuration of the status reporting system, this bit
immediately causes the generation of a service request (SRQ) which is used to
inform the control software that the user wishes to return to front-panel control.
This information can be used, e.g., to interrupt the control program so that the user
can make necessary manual corrections to instrument settings. This bit is set
each time the LOCAL softkey is pressed.

If the LOCAL LOCKOUT function is active in the remote control mode, the front­panel PRESET key is also disabled. The LOCAL LOCKOUT state is left as soon
as the process controller de-activates the REN line or the GPIB cable is discon­nected from the instrument.

Operating Manual 1313.9681.12 - 02 4.9

R&S FSQ Instrument Functions

Analyzer Mode

4.5 Analyzer Mode

The analyzer mode is activated by pressing the SPECTRUM hotkey (see also sec­tion “Mode Selection – Hotkey Bar” on page 4.8)

SPECTRUM

The SPECTRUM hotkey selects the mode for spectrum analysis, the so-called ana­lyzer mode.

This mode is the default mode of the R&S FSQ.

The functions provided correspond to those of a conventional spectrum analyzer.
The R&S FSQ measures the frequency spectrum of the test signal over the selected
frequency range with the selected resolution and sweep time, or, for a fixed fre­quency, displays the waveform of the video signal.

If two displays (screen A and screen B) are opened after switch-on of signal analy­sis, the analyzer mode is only set for the display activated for entry (marked at the
top right corner of diagram). For the other display, the previous settings remain
valid.

Data acquisition and display of measured values is sequential: first in the upper
and then in the lower display.

4.10 Operating Manual 1313.9681.12 - 02

R&S FSQ Instrument Functions

Analyzer Mode

4.5.1 Frequency and Span Selection – FREQ Key

The FREQ key is used to specify the frequency axis of the active display window.
The frequency axis can be defined either by the start and stop frequency or by the
center frequency and bwthe span (SPAN key). With two windows (SPLIT SCREEN)
displayed at the same time, the input data always refer to the window selected in the
SYSTEM - DISPLAY menu.

The softkeys in the CF STEPSIZE menu depend on the selected domain: frequency
domain or time domain.

FREQ

CENTER

CF STEPSIZE ! 0.1 * SPAN / 0.1 * RBW

0.5 * SPAN / 0.5 * RBW

X * SPAN / X * RBW

= CENTER

= MARKER

MANUAL

START

STOP

FREQUENCY OFFSET

SIGNAL TRACK

EXTERNAL MIXER

(option B21)

! TRACK (ON OFF)

TRACK BW

TRACK THRESHOLD

SELECT TRACE

CENTER

The CENTER softkey opens the window for manually entering the center frequency.

The allowed range of values for the center frequency is:

• for the frequency domain (span >0):

minspan / 2 ≤ f

center

≤ f

max

– minspan / 2

• and for the time domain (span = 0):

0 Hz ≤ f

f

center frequency

center

minspan smallest selectable span > 0 Hz (10 Hz)

max. frequency

f

max

center

≤ f

max

Remote command: FREQ:CENT 100MHz

CF STEPSIZE

The CF STEPSIZE softkey opens a submenu for setting the step size of the center
frequency. The step size can be coupled to the span (frequency domain) or the res­olution bandwidth (time domain) or it can be manually set to a fixed value. The soft­keys are mutually exclusive selection keys.

The softkeys are presented according to the selected domain (frequency or time).

Operating Manual 1313.9681.12 - 02 4.11

R&S FSQ Instrument Functions

Analyzer Mode

Softkeys in frequency domain:

0.1 * SPAN The 0.1 * SPAN softkey sets the step size for the center frequency entry to 10% of
the span.

Remote command: FREQ:CENT:STEP:LINK SPAN

FREQ:CENT:STEP:LINK:FACT 10PCT

0.5 * SPAN The 0.5 * SPAN softkey sets the step size for the center frequency entry to 50% of
the span.

Remote command: FREQ:CENT:STEP:LINK SPAN

FREQ:CENT:STEP:LINK:FACT 50PCT

X * SPAN The X * SPAN softkey allows the factor defining the center frequency step size to be

entered as % of the span.

Remote command: FREQ:CENT:STEP:LINK SPAN

FREQ:CENT:STEP:LINK:FACT 20PCT

= CENTER The = CENTER softkey sets the step size coupling to MANUAL and the step size to

the value of the center frequency. This function is especially useful during measure­ments of the signal harmonic content because by entering the center frequency
each stroke of the STEP key selects the center frequency of another harmonic.

Remote command: --

= MARKER The = MARKER softkey sets the step size coupling to MANUAL and the step size to

the value of the marker. This function is especially useful during measurements of
the signal harmonic content at the marker position because by entering the center
frequency each stroke of the STEP key selects the center frequency of another har­monic.

Remote command: --

MANUAL The MANUAL softkey activates the window for entering a fixed step size.

Remote command: FREQ:CENT:STEP 120MHz

Softkeys in time domain:

0.1 * RBW The 0.1 * RBW softkey sets the step size for the center frequency entry to 10% of
the resolution bandwidth.

AUTO 0.1 * RBW corresponds to the default setting.

Remote command: FREQ:CENT:STEP:LINK RBW

FREQ:CENT:STEP:LINK:FACT 10PCT

0.5 * RBW The 0.5 * RBW softkey sets the step size for the center frequency entry to 50% of
the resolution bandwidth.

Remote command: FREQ:CENT:STEP:LINK RBW

FREQ:CENT:STEP:LINK:FACT 50PCT

4.12 Operating Manual 1313.9681.12 - 02

R&S FSQ Instrument Functions

Analyzer Mode

X * RBW The X * RBW softkey allows the factor defining the center frequency step size to be

entered as % of the resolution bandwidth.

Values between 1 % and 100 % in steps of 1 % are allowed. The default setting is 10
%.

Remote command: FREQ:CENT:STEP:LINK RBW

FREQ:CENT:STEP:LINK:FACT 20PCT

= CENTER The = CENTER softkey sets the step size coupling to MANUAL and the step size to

the value of the center frequency. This function is especially useful during measure­ments of the signal harmonic content because by entering the center frequency
each stroke of the STEP key selects the center frequency of another harmonic.

Remote command: --

= MARKER The = MARKER softkey sets the step size coupling to MANUAL and the step size to

the value of the marker. This function is especially useful during measurements of
the signal harmonic content at the marker position because by entering the center
frequency each stroke of the STEP key selects the center frequency of another har­monic.

START

STOP

Remote command: --

MANUAL The MANUAL softkey activates the window for entering a fixed step size.

Remote command: FREQ:CENT:STEP 120MHz

The START softkey activates the window for manually entering the start frequency.

The allowed range of values for the start frequency is:
0 Hz ≤ f

f

start frequency

start

minspan smallest selectable span (10 Hz)

max. frequency

f

max

start

≤ f

- minspan

max

Available for measurements in the frequency domain.

Remote command: FREQ:STAR 20MHz

The STOP softkey activates the window for entering the stop frequency.

The allowed range of values for the stop frequency is:
minspan ≤ f

f

stop frequency

stop

minspan smallest selectable span (10 Hz)

max. frequency

f

max

stop

≤ f

max

Available for measurements in the frequency domain.

Remote command: FREQ:STOP 2000MHz

Operating Manual 1313.9681.12 - 02 4.13

R&S FSQ Instrument Functions

Analyzer Mode

FREQUENCY
OFFSET

SIGNAL
TRACK

The FREQUENCY OFFSET softkey activates the window for entering an arithmeti­cal frequency offset which is added to the frequency axis labelling. The allowed
range of values for the offset is -100 GHz to 100 GHz. The default setting is 0 Hz.

Remote command: FREQ:OFFS 10 MHz

The SIGNAL TRACK softkey switches on the tracking of a signal near the center fre­quency. The signal is tracked as long it is in the search bandwidth around the center
frequency defined with TRACK BW and above the level threshold defined with
TRACK THRESHOLD.

For that purpose, the maximum signal is determined (PEAK SEARCH) on the
screen and the center frequency is set to this signal (MARKER ->CENTER) after
each frequency sweep within the search bandwidth.

If the signal falls below the level threshold or jumps out of the search bandwidth
around the center frequency, the center frequency is not varied until a signal is in the
search bandwidth above the level threshold. This can be achieved by manually
modifying the center frequency, for example.

On switching on, the softkey is highlighted and the search bandwidth and the thresh­old value are marked on the diagram by two vertical lines and one horizontal line. All
these lines are provided with the designation TRK.

At the same time a submenu is opened in which the search bandwidth, the threshold
value and the trace can be modified for the maximum search.

The softkey is only available in the frequency domain (span >0).

Remote command: CALC:MARK:FUNC:STR OFF

TRACK (ON

OFF)

TRACK BW The TRACK BW softkey defines the bandwidth around the center frequency within

TRACK

THRESHOLD

SELECT TRACE The SELECT TRACE softkey selects the trace on which signal tracking is to be per-

The TRACK (ON OFF) softkey switches on and off signal tracking.

Remote command: CALC:MARK:FUNC:STR OFF

which the largest signal is searched. The frequency range is symmetrical with
respect to the center frequency.

Remote command: CALC:MARK:FUNC:STR:BAND 10KHZ

The TRACK THRESHOLD softkey defines the threshold value for signal detection.
The value is always entered as an absolute level value.

Remote command: CALC:MARK:FUNC:STR:THR -70DBM

formed.

Remote command: CALC:MARK:FUNC:STR:TRAC 1

4.14 Operating Manual 1313.9681.12 - 02

R&S FSQ Instrument Functions

Analyzer Mode

4.5.2 Setting the Frequency Span – SPAN Key

The SPAN key opens a menu which offers various options for setting the span.

The entry of the span (SPAN MANUAL softkey) is automatically active for span > 0
Hz.

For span = 0 Hz the entry for sweep time (SWEEPTIME MANUAL) is automatically
active.

With two windows (SPLIT SCREEN) displayed at the same time, the input data
always refer to the window selected with the SCREEN A/B hotkey.

SPAN

SPAN
MANUAL

SWEEPTIME
MANUAL

SPAN MANUAL

SWEEPTIME MANUAL

FULL SPAN

ZERO SPAN

LAST SPAN

FREQ AXIS (LIN LOG)

The SPAN MANUAL softkey activates the window for manually entering the fre­quency span. The center frequency is kept constant.

Allowed range of span values:

• for the time domain (span = 0): 0 Hz

• and for the frequency domain (span >0): minspan ≤ f

f

frequency span

span

minspan smallest selectable span (10 Hz)

max. frequency

f

max

span

≤ f

max

Remote command: FREQ:SPAN 2GHz

The SWEEPTIME MANUAL softkey activates the window for entering the sweep
time manually with Span = 0 Hz.

Remote command: SWE:TIME 10s

FULL SPAN

The FULL SPAN softkey sets the span to the full frequency range of R&S FSQ.

Remote command: FREQ:SPAN:FULL

ZERO SPAN

The ZERO SPAN softkey sets the span to 0 Hz. The x-axis becomes the time axis
with the grid lines corresponding to 1/10 of the current sweep time (SWT).

Remote command: FREQ:SPAN 0Hz

LAST SPAN

After changing the span setting the LAST SPAN softkey activates the previous set-
ting. With this function a fast change between overview measurement (FULL SPAN)
and detailed measurement (manually set center frequency and span) is possible.

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R&S FSQ Instrument Functions

Analyzer Mode

Only values > 0 Hz are restored, i.e. a transition between time and frequency
domain is not possible.

Remote command: --

FREQ AXIS
(LIN LOG)

The FREQ AXIS (LIN LOG) softkey switches between linear and logarithmic scaling
of the frequency axis. Switch over is only possible if the stop/start frequency ratio is
≥1.4.

The default state is LIN.

The logarithmic frequency axis is only available in analyzer mode and it is not avail­able in zero span mode, in external mixer mode, with frequency offset or if the ratio
stop frequency / start frequency is below 1.4.

Remote command: DISP:WIND<1|2>:TRAC:X:SPAC LIN

4.16 Operating Manual 1313.9681.12 - 02

R&S FSQ Instrument Functions

Analyzer Mode

4.5.3 Level Display Setting and RF Input Configuration – AMPT Key

The AMPT key is used to set the reference level, the maximum level and the display
range of the active window as well as the input impedance and the input attenuation
of the RF input.

The AMPT key opens a menu for setting the reference level and the input attenua­tion of the active window. The data entry for the reference level (REF LEVEL soft­key) is opened automatically.

Further settings regarding level display and attenuation can be made in this menu.

AMPT

REF LEVEL

RANGE LOG 100 dB

RANGE LOG MANUAL

RANGE LINEAR

UNIT

! dBm / dBmV / dBµV/

RF INPUT (AC DC)

RF ATTEN MANUAL

RF ATTEN AUTO

NOISE CORR (ON OFF)

Side menu

REF LEVEL POSITION

REF LEVEL OFFSET

PHASE SETTINGS (option B71)

! RANGE LINEAR %

RANGE LINEAR dB

dBµΑ / dBµW / VOLT /
AMPERE / WATT

! AUTOSCALE

Y-AXIS/DIV

Y-AXIS REF-VALUE

Y-AXIS REF-POS

PHASE OFFSET

PHASE (RAD DEG)

PHASEWRAP
(ON OFF)

GRID (ABS REL)

EL ATTEN AUTO (option B25)

EL ATTEN MANUAL (option B25)

EL ATTEN OFF (option B25)

RF INPUT (50W 75W)

MIXER

! MIXER LVL AUTO

MIXER LVL MANUAL

Operating Manual 1313.9681.12 - 02 4.17

R&S FSQ Instrument Functions

Analyzer Mode

REF LEVEL

RANGE LOG
100 dB

RANGE LOG
MANUAL

RANGE
LINEAR

The REF LEVEL softkey allows the reference level to be input in the currently active
unit (dBm, dBµV, etc.)

Remote command: DISP:WIND:TRAC:Y:RLEV -60dBm

The RANGE LOG 100 dB softkey sets the level display range to 100 dB.

Remote command: DISP:WIND:TRAC:Y:SPAC LOG

DISP:WIND:TRAC:Y 100DB

The RANGE LOG MANUAL softkey activates the manual entry of the level display
range. Display ranges from 1 to 200 dB are available. Inputs which are not allowed
are rounded to the next valid value.

The default setting is 100 dB.

Remote command: DISP:WIND:TRAC:Y:SPAC LOG

DISP:WIND:TRAC:Y 120DB

The RANGE LINEAR softkey selects linear scaling for the level display range of the
R&S FSQ. In addition, it opens a submenu for selecting % or dB for the scaling.

When linear scaling is selected, the % scaling is first activated (see also RANGE
LINEAR dB softkey).

Remote command: DISP:WIND:TRAC:Y:SPAC LIN

UNIT

RANGE

LINEAR %

RANGE

LINEAR dB

The RANGE LINEAR % softkey selects linear scaling in % for the level display
range, i.e. the horizontal lines are labelled in %. The grid is divided in decadic steps.
Markers are displayed in the selected unit; delta markers are displayed in % refer­enced to the voltage value at the position of marker 1.

Remote command: DISP:WIND:TRAC:Y:SPAC LIN

The RANGE LINEAR dB softkey selects linear scaling in dB for the level display
range, i.e. the horizontal lines are labelled in dB.

Markers are displayed in the selected unit; delta markers are displayed in dB refer­enced to the power value at the position of marker 1.

Remote command: DISP:WIND:TRAC:Y:SPAC LDB

dBm

dBmV

dBµV

dBµΑ

dBµW

VOLT

AMPERE

WATT

The UNIT softkey opens a submenu to select the unit for the level axis.

The default setting is dBm.

4.18 Operating Manual 1313.9681.12 - 02

R&S FSQ Instrument Functions

Analyzer Mode

In general, the R&S FSQ measures the signal voltage at the RF input. The level dis­play is calibrated in rms values of an unmodulated sinewave signal. In the default
state, the level is displayed at a power of 1 mW (= dBm). Via the known input resis­tance of 50 Ω or 75 Ω, conversion to other units is possible. The units dBm, dBmV,
dBµV, dBµA, dBpW, V, A and W are directly convertible.

Remote command: CALC:UNIT:POW DBM

RF INPUT
(AC DC)

RF ATTEN
MANUAL

The RF INPUT (AC DC) softkey toggles the RF input of the R&S FSQ between AC
and DC coupling.

The softkey is only available for models 3, 8 and 26.

Remote command: INP:COUP AC

The RF ATTEN MANUAL softkey allows the attenuation to be entered irrespective of
the reference level.

The attenuation can be set in 5 dB steps between 0 and 75 dB.

Other entries will be rounded to the next higher integer value.

If the defined reference level cannot be set for the given RF attenuation, the refer­ence level will be adjusted accordingly and the warning "Limit reached" will be out­put.

The 0 dB value can be entered only via the numeric keypad in order to protect the
input mixer against accidental overload.

RF ATTEN
AUTO

NOISE CORR
(ON OFF)

Remote command: INP:ATT 40 DB

The RF ATTEN AUTO softkey sets the RF attenuation automatically as a function of
the selected reference level.

This ensures that the optimum RF attenuation desired by the user is always used.

RF ATTEN AUTO is the default setting.

Remote command: INP:ATT:AUTO ON

If active, the R&S FSQ corrects the results by its inherent noise. Noise correction
increases the dynamic range.

After you activate noise correction, the R&S FSQ performs a reference measure­ment of its inherent noise. In the actual measurement, the R&S FSQ then substracts
the noise power from the power in the channel that is measured.

The inherent noise depends on the center frequency, resolution bandwidth and level
setting. Therefore, the R&S FSQ deactivates noise correction if you change one
these parameters. The R&S FSQ shows a message that noise correction is inactive.

The R&S FSQ also deactivates noise correction after you select another measure­ment (e.g. channel power, spectrum emission mask etc.).

Operating Manual 1313.9681.12 - 02 4.19

R&S FSQ Instrument Functions

Analyzer Mode

After the R&S FSQ deactivates noise correction, you have to activate it again manu­ally. The R&S FSQ performs a new reference measurement.

Remote command: POW:NCOR ON

REF LEVEL
POSITION

REF LEVEL
OFFSET

PHASE
SETTINGS

AUTOSCALE The AUTOSCALE softkey performs one-off scaling of the phase diagram so that the

The REF LEVEL POSITION softkey allows the reference level position to be
entered.

The setting range is from -200 to +200%, 0% corresponding to the lower and 100%
to the upper limit of the diagram.

Remote command: DISP:WIND:TRAC:Y:RPOS 100PCT

The REF LEVEL OFFSET softkey allows the arithmetic level offset to be entered.
This offset is added to the measured level irrespective of the selected unit. The scal­ing of the y-axis is changed accordingly.

The setting range is ±200 dB in 0.1 dB steps.

Remote command: DISP:WIND:TRAC:RLEV:OFFS -10dB

The PHASE SETTINGS softkey opens a submenu in which the scaling of the phase
diagram can be configured.

The PHASE SETTINGS softkey and the submenu are only available if option
R&S FSQ-B71 or R&S FSQ-B17 is installed.

current trace fully utilizes the value range.

Remote command: DISP:WIND2:TRAC:Y:SCAL:AUTO ONCE

Y-AXIS/DIV The Y-AXIS/DIV softkey is used to determine the value range which is to correspond

to the distance between two horizontal gridlines. The entire displayed value range is
therefore equivalent to 10 times the selected value. With manual entry, the unit
selected using the PHASE RAD/DEG softkey applies (only for the phase diagram).

Remote command: DISP:WIND2:TRAC:Y:PDIV 10DEG

Y-AXIS REF-

VALU E

Y-AXIS REF-

POS

PHASE

OFFSET

The Y-AXIS REF-VALUE softkey determines the reference value of the diagram at
the reference position. The gridlines are arranged on the basis of this reference
value. The unit selected using the PHASE RAD/DEG softkey applies (only for the
phase diagram).

Remote command: DISP:WIND2:TRAC:Y:RVAL 20DEG

The Y-AXIS REF-POS softkey is used to control the location of the reference posi­tion within the grid from 0% to 100%. The default value is 50%.

Remote command: DISP:WIND2:TRAC:Y:RPOS 50

The PHASE OFFSET softkey determines a constant phase value which is added to
the overall phase trace. This allows a test point to be assigned to a desired phase
value.

The unit selected using the PHASE RAD/DEG softkey applies.

Remote command: SENS:CORR:OFFS:PHAS 10DEG

4.20 Operating Manual 1313.9681.12 - 02