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R&S®NRT-Z14/44
Directional Power Sensor
User Manual
(;ÝV?2)
1179381502
Version 02
Page 2
This document describes the following directional power sensor models (firmware version 03.00 and later)
and accessories:
●
R&S®NRT-Z14 (1444.0006K02)
●
R&S®NRT-Z44 (1444.0012K02)
●
R&S®NRT-Z5 (1400.6909K02)
© 2022 Rohde & Schwarz GmbH & Co. KG
Muehldorfstr. 15, 81671 Muenchen, Germany
Phone: +49 89 41 29 - 0
Email: info@rohde-schwarz.com
Internet: www.rohde-schwarz.com
Subject to change – data without tolerance limits is not binding.
R&S® is a registered trademark of Rohde & Schwarz GmbH & Co. KG.
All other trademarks are the properties of their respective owners.
1179.3815.02 | Version 02 | R&S®NRT-Z14/44
Throughout this manual, products from Rohde & Schwarz are indicated without the ® symbol, e.g. R&S®NRT-Z14 is indicated as
R&S NRT-Z14.
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1 Safety and regulatory information........................................................7
1.1 Safety instructions........................................................................................................7
1.2 Labels on the product...................................................................................................8
1.3 Warning messages in the documentation.................................................................. 9
2 Welcome................................................................................................11
2.1 Documentation overview............................................................................................11
2.1.1 Getting started manual.................................................................................................. 11
2.1.2 User manual.................................................................................................................. 11
2.1.3 Tutorials.........................................................................................................................11
2.1.4 Instrument security procedures..................................................................................... 11
Contents
Contents
2.1.5 Printed safety instructions............................................................................................. 11
2.1.6 Data sheets and brochures........................................................................................... 12
2.1.7 Application notes, application cards, white papers, etc.................................................12
2.2 Key features.................................................................................................................12
3 Getting started......................................................................................15
3.1 Preparing for use........................................................................................................ 15
3.1.1 Unpacking and checking............................................................................................... 15
3.1.2 Choosing the operating site.......................................................................................... 15
3.1.3 Considerations for test setup........................................................................................ 15
3.1.4 Connecting to source and load..................................................................................... 16
3.1.5 Connecting to a computer or base unit......................................................................... 17
3.2 Power sensor tour.......................................................................................................19
3.2.1 RF connectors...............................................................................................................20
3.2.2 Host interface................................................................................................................ 20
3.2.3 Power handling capacity............................................................................................... 20
3.2.4 R&S NRT‑Z5 USB interface adapter.............................................................................20
4 Operating concepts............................................................................. 23
4.1 Base unit...................................................................................................................... 23
4.2 R&S Virtual NRT.......................................................................................................... 23
4.3 Remote control............................................................................................................25
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4.3.1 Remote control using R&S Virtual NRT........................................................................ 26
4.3.2 Remote control using terminal program........................................................................ 26
5 Measurement basics............................................................................31
6 Firmware update.................................................................................. 33
6.1 Hardware and software requirements.......................................................................33
6.2 Updating the firmware................................................................................................ 33
6.3 R&S NRP Toolkit..........................................................................................................34
6.3.1 System requirements.................................................................................................... 35
6.3.2 Installation..................................................................................................................... 35
7 Remote control commands.................................................................37
7.1 Measurement setting commands.............................................................................. 37
7.1.1 BURS............................................................................................................................ 37
Contents
7.1.2 CCDF............................................................................................................................ 38
7.1.3 DIR................................................................................................................................ 38
7.1.4 DISP..............................................................................................................................39
7.1.5 FREQ............................................................................................................................ 41
7.1.6 FILT............................................................................................................................... 41
7.1.7 FOR...............................................................................................................................45
7.1.8 MOD..............................................................................................................................49
7.1.9 OFFS.............................................................................................................................50
7.1.10 PEP............................................................................................................................... 51
7.1.11 PORT............................................................................................................................ 51
7.1.12 RESET.......................................................................................................................... 53
7.1.13 REV...............................................................................................................................53
7.1.14 ZERO............................................................................................................................ 55
7.2 Query commands........................................................................................................56
7.2.1 FTRG............................................................................................................................ 56
7.2.2 QSTN............................................................................................................................ 56
7.2.3 RTRG............................................................................................................................ 57
7.2.4 SPEC............................................................................................................................ 57
7.2.5 STAT..............................................................................................................................60
7.3 General commands.....................................................................................................63
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7.4 Selftest......................................................................................................................... 67
8 Remote control basics.........................................................................69
8.1 Device-dependent messages.....................................................................................69
8.1.1 Structure and syntax of device-dependent messages.................................................. 69
8.1.2 Setting commands and queries.....................................................................................69
8.1.3 Device responses..........................................................................................................71
8.2 Hardware functions.....................................................................................................75
8.3 Command processing................................................................................................ 76
8.3.1 Device hardware and data record................................................................................. 77
8.3.2 Output unit.....................................................................................................................77
8.3.3 Cyclic background power and temperature measurements..........................................77
8.4 Status reporting system............................................................................................. 77
Contents
8.4.1 Device status.................................................................................................................78
8.4.2 Error status....................................................................................................................78
9 Troubleshooting................................................................................... 83
9.1 Test setup.....................................................................................................................83
9.2 Power-up selftest........................................................................................................ 83
9.3 Selftest......................................................................................................................... 83
9.4 Contacting customer support....................................................................................85
10 Testing the rated specifications......................................................... 87
10.1 Test equipment............................................................................................................87
10.2 Test setup.....................................................................................................................88
10.3 Test sequences............................................................................................................88
10.3.1 Testing the AVG measurement......................................................................................88
10.3.2 Testing the CCDF threshold..........................................................................................89
10.3.3 Testing the PEP measurement......................................................................................90
10.3.4 Testing the directivity.....................................................................................................91
10.3.5 Testing the matching..................................................................................................... 92
10.4 Performance test report............................................................................................. 92
11 Transporting......................................................................................... 95
12 Maintenance, storage and disposal................................................... 97
12.1 Checking and setting the baud rate.......................................................................... 97
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12.2 Regular checks............................................................................................................98
12.3 Cleaning....................................................................................................................... 99
12.4 Storage.........................................................................................................................99
12.5 Disposal..................................................................................................................... 100
Contents
List of commands.............................................................................. 101
Index....................................................................................................103
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1 Safety and regulatory information
Safety and regulatory information
Safety instructions
The product documentation helps you use the product safely and efficiently. Follow the
instructions provided here and in the following chapters.
Intended use
The R&S NRT‑Zxx directional power sensor is intended for power and reflection measurements in development and for monitoring and maintenance purposes. The supported base units are listed in the data sheet. Observe the operating conditions and performance limits stated in the data sheet.
Target audience
The target audience is developers and technicians. The required skills and experience
in power measurements depend on the used operating concept.
Main applications are continuous monitoring of transmitter systems and power measurements with digital modulation. A profound knowledge of the intended application
and test setup is required.
Where do I find safety information?
Safety information is part of the product documentation. It warns you of potential dangers and gives instructions on how to prevent personal injury or damage caused by
dangerous situations. Safety information is provided as follows:
●
In Chapter 1.1, "Safety instructions", on page 7. The same information is provided in many languages as printed "Safety Instructions". The printed "Safety
Instructions" are delivered with the product.
●
Throughout the documentation, safety instructions are provided when you need to
take care during setup or operation.
1.1 Safety instructions
Products from the Rohde & Schwarz group of companies are manufactured according
to the highest technical standards. To use the products safely, follow the instructions
provided here and in the product documentation. Keep the product documentation
nearby and offer it to other users.
Use the product only for its intended use and within its performance limits. Intended
use and limits are described in the product documentation such as the data sheet,
manuals and the printed "Safety Instructions". If you are unsure about the appropriate
use, contact Rohde & Schwarz customer service.
Using the product requires specialists or specially trained personnel. These users also
need sound knowledge of at least one of the languages in which the user interfaces
and the product documentation are available.
Reconfigure or adjust the product only as described in the product documentation or
the data sheet. Any other modifications can affect safety and are not permitted.
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Safety and regulatory information
Labels on the product
Never open the casing of the product. Only service personnel authorized by
Rohde & Schwarz are allowed to repair the product. If any part of the product is damaged or broken, stop using the product. Contact Rohde & Schwarz customer service at
https://www.rohde-schwarz.com/support.
Operating the product
Only use the product indoors. The product casing is not waterproof.
Observe the ambient conditions such as altitude, operating temperature and climatic
loads; see the data sheet.
Connecting directional power sensors
During the measurement, the RF power flow can be high. Connect both RF connectors
tightly to avoid power leakage. Contact with leaking RF power can cause electric shock
and severe skin burns. Take the following measures for your safety:
●
Before switching on the RF power of your test setup, make sure that both RF ports
of the power sensor are connected securely as described in the product documentation.
●
Do not touch the RF ports when the RF power is switched on.
●
Never exceed the permissible continuous power that is shown in the diagram on
the back of the power sensor.
●
Before disconnecting one or both RF ports of the power sensor, switch off the RF
power.
Meaning of safety labels
Safety labels on the product warn against potential hazards.
Potential hazard
Read the product documentation to avoid personal injury or product damage.
1.2 Labels on the product
Labels on the product inform about:
●
Personal safety
See "Meaning of safety labels" on page 8.
●
Environment safety
See Table 1-1.
●
Identification of the product
The front label of the power sensor contains the serial number that uniquely identifies the power sensor.
●
Power handling capacity
See "Signal input and output levels" on page 16.
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1.3 Warning messages in the documentation
Safety and regulatory information
Warning messages in the documentation
Table 1-1: Labels regarding environment safety
Labeling in line with EN 50419 for disposal of electrical and electronic equipment after the product has come to the end of its service life.
For more information, see "Disposing electrical and electronic equipment" on page 100.
A warning message points out a risk or danger that you need to be aware of. The signal word indicates the severity of the safety hazard and how likely it will occur if you do
not follow the safety precautions.
CAUTION
Potentially hazardous situation. Could result in minor or moderate injury if not avoided.
NOTICE
Potential risks of damage. Could result in damage to the supported product or to other
property.
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Safety and regulatory information
Warning messages in the documentation
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2 Welcome
2.1 Documentation overview
Welcome
Documentation overview
This chapter provides an overview of the user documentation and an introduction to
the R&S NRT-Zxx power sensor.
This section provides an overview of the R&S NRT-Zxx user documentation. Unless
specified otherwise, you find the documents at:
www.rohde-schwarz.com/manual/nrt-z_nap-z
Further documents are available at:
www.rohde-schwarz.com/product/nrt-z_nap-z
2.1.1 Getting started manual
Introduces the R&S NRT-Zxx and describes how to set up and start working with the
product. Includes basic operations and general information, e.g. safety instructions,
etc. A printed version is delivered with the power sensor.
2.1.2 User manual
Contains the description of all R&S NRT-Zxx functions. It also provides an introduction
to remote control, a complete description of the remote control commands with programming examples, and information on maintenance and interfaces. Includes the
contents of the getting started manual.
2.1.3 Tutorials
Tutorials offer guided examples and demonstrations on operating the R&S NRT-Zxx.
They are provided on the product page of the internet.
2.1.4 Instrument security procedures
Deals with security issues when working with the R&S NRT-Zxx in secure areas. It is
available for download on the Internet.
2.1.5 Printed safety instructions
Provides safety information in many languages. The printed document is delivered with
the product.
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2.1.6 Data sheets and brochures
2.1.7 Application notes, application cards, white papers, etc.
2.2 Key features
Welcome
Key features
The data sheet contains the technical specifications of the R&S NRT-Zxx. It also lists
the firmware applications and their order numbers, and optional accessories.
The brochure provides an overview of the instrument and deals with the specific characteristics.
www.rohde-schwarz.com/brochure-datasheet/nrt-z_nap-z
These documents deal with special applications or background information on particular topics.
www.rohde-schwarz.com/application/nrt-z_nap-z
The R&S NRT-Zxx power sensors support the following measurements:
Average power (RMS value)
Returns the average value of the power for any type of measurement signal — modulated, unmodulated or several carriers.
Peak envelope power (PEP) and crest factor
Both parameters provide information on the peak power of a modulated envelope and
describe the overdrive characteristics of transmitter output stages. The power sensor
outputs the result of the crest factor measurement as the ratio of peak envelope power
(PEP) to average power. In the graphical user interface of the base unit or the
R&S Virtual NRT, the crest factor is displayed as a logarithmic ratio in dB. Measurements are performed using a video bandwidth that is adjustable in several steps, so
that even short-time and high-power peaks can be determined.
Average burst power
Used to measure modulated and unmodulated bursts based on the average power and
the duty cycle. The duty cycle can be defined or determined automatically by the power
sensor.
Complementary cumulative distribution function (CCDF)
Measures the probability of the peak envelope power exceeding a preset threshold so
that the amplitude distribution of signals with an unknown envelope can be determined.
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Welcome
Key features
Voltage standing wave ratio (VSWR), reflection coefficient, return loss
These parameters provide information on the matching of the load. The power sensor
derives these parameters from the average power measurement in forward and
reverse direction.
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Welcome
Key features
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3 Getting started
3.1 Preparing for use
3.1.1 Unpacking and checking
Getting started
Preparing for use
Here, you can find basic information about setting up the product for the first time.
1. Unpack the product carefully.
2. Retain the original packing material. Use it when transporting or shipping the product later.
3. Using the delivery notes, check the equipment for completeness.
4. Check the equipment for damage.
If the delivery is incomplete or equipment is damaged, contact Rohde & Schwarz.
3.1.2 Choosing the operating site
Specific operating conditions ensure proper operation and avoid damage to the product and connected devices. For information on environmental conditions such as ambient temperature and humidity, see the data sheet.
Electromagnetic compatibility classes
The electromagnetic compatibility (EMC) class indicates where you can operate the
product. The EMC class of the product is given in the data sheet.
●
Class B equipment is suitable for use in:
– Residential environments
– Environments that are directly connected to a low-voltage supply network that
supplies residential buildings
●
Class A equipment is intended for use in industrial environments. It can cause
radio disturbances in residential environments due to possible conducted and radiated disturbances. It is therefore not suitable for class B environments.
If class A equipment causes radio disturbances, take appropriate measures to
eliminate them.
3.1.3 Considerations for test setup
Electromagnetic interference (EMI) can affect the measurement results.
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3.1.4 Connecting to source and load
Getting started
Preparing for use
To suppress electromagnetic radiation during operation:
●
Use high-quality shielded cables, for example, double-shielded RF and interface
cables.
●
Always terminate open cable ends.
●
Ensure that connected external devices comply with EMC regulations.
Signal input and output levels
Information on signal levels is provided in the data sheet. Keep the signal levels within
the specified ranges to avoid damage to the product and connected devices.
Information on power handling capacity is given also on the back of the power sensor.
A derating diagram shows the power handling capacity of the power sensor maximum
forward power versus frequency, under different conditions such as temperature and
VSWR of the load.
The arrow on the power sensor front side shows the forward power flow.
1
2
3
4
5
6
Figure 3-1: Connecting to source and load
1 = source
2 = port 1 (RF connector)
3 = R&S NRT‑Zxx directional power sensor
4 = port 2 (RF connector)
5 = load
6 = host interface connector
Connect the R&S NRT-Zxx as shown in Figure 3-1 and described in the following stepby-step instructions to avoid damage to the power sensor and to use all measurements.
If you want to measure an average of forward power below 30 W with high accuracy
and matching measurements are of secondary importance, you can connect the R&S
NRT-Zxx the other way around.
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Getting started
Preparing for use
To connect to the DUT
1. Connect RF connector (2, port 1) to the source.
a) Insert RF connector (2) straight into the RF connector of the source. Take care
not to tilt the R&S NRT‑Zxx directional power sensor.
b) Tighten the RF connector securely by hand.
2. Connect RF connector (4, port 2) to the load.
a) Insert RF connector (4) straight into the RF connector of the load. Take care
not to tilt the R&S NRT‑Zxx directional power sensor.
b) Tighten the RF connector tightly by hand.
See "Connecting directional power sensors" on page 8.
To disconnect from the DUT
CAUTION! Risk of electric shock and severe skin burns. See "Connecting direc-
1.
tional power sensors" on page 8.
Switch off the RF power before touching the RF connectors.
2. Unscrew the RF connectors by hand.
3.1.5 Connecting to a computer or base unit
For connecting the power sensor to a computer or base unit, use the host interface.
See Chapter 3.2.2, "Host interface", on page 20.
For operating the power sensor, you can choose from various possibilities. For details,
see Chapter 4, "Operating concepts", on page 23.
3.1.5.1 Computer
As a controller, you can use a computer with a Microsoft Windows operating system,
equipped with R&S Virtual NRT or remote control software.
1
2
3
Figure 3-2: Connecting to computer
4
5
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Getting started
Preparing for use
1 = R&S NRT‑Zxx directional power sensor
2 = host interface connector → sensor interface
3 = R&S NRT‑Z5 USB interface adapter
4 = USB connector → USB port
5 = computer
To connect to a computer
1. Meet the prerequisites of the R&S NRT‑Z5 USB interface adapter described in
Chapter 3.2.4, "R&S NRT‑Z5 USB interface adapter", on page 20.
2. Connect the host interface connector of the R&S NRT‑Zxx directional power sensor, (2) in Figure 3-2, to the sensor interface of the R&S NRT‑Z5 USB interface
adapter.
3. Connect the USB connector of the R&S NRT‑Z5 USB interface adapter to a USB
port of the computer.
Further information:
●
Chapter 4.2, "R&S Virtual NRT", on page 23
●
Chapter 4.3, "Remote control", on page 25
3.1.5.2 Base unit
You can operate the R&S NRT-Zxx on an R&S NRT2 or R&S NRX base unit. The
R&S NRX base unit must be equipped with the interface for R&S NRT-Z sensors (R&S
NRX-B9).
1
Figure 3-3: Connecting to base unit
1 = R&S NRT‑Zxx directional power sensor
2 = host interface connector → sensor interface
3 = base unit
To connect to a base unit
► Connect the host interface connector of the R&S NRT‑Zxx directional power sen-
sor, (2) in Figure 3-3, to the sensor interface of the base unit.
2
3
The base unit recognizes the power sensor a few seconds after the connection is
made or after power-up and immediately starts to measure.
If the base unit does not recognize the power sensor, check the baud rate setting.
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3.1.5.3 Legacy setups
Getting started
Power sensor tour
See Chapter 12.1, "Checking and setting the baud rate", on page 97.
Further information:
●
Chapter 4.1, "Base unit", on page 23
●
User manual of the base unit
To support legacy setups, you can also connect the power sensor to the following legacy adapters and instruments:
●
R&S NRT‑Z3 interface adapter
To connect to a computer with standard RS-232 interface.
●
R&S NRT‑Z4 PCMCIA interface adapter
To connect to a computer with a PCMCIA type II slot.
●
R&S NRT
Legacy base unit
3.2 Power sensor tour
This chapter provides an overview of the available connectors of the power sensor.
The meanings of the labels on the product are described here and in Chapter 1.2,
"Labels on the product", on page 8.
1
3
Figure 3-4: R&S
NRT‑Zxx directional power sensor, front side
2
1 = port 1 (RF connector) → connect to source
2 = port 2 (RF connector) → connect to load
3 = host interface
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3.2.1 RF connectors
3.2.2 Host interface
Getting started
Power sensor tour
Always switch off the RF power before touching the RF connectors. See "Connecting
directional power sensors" on page 8.
The RF connectors are used for connecting the power sensor between source and
load. To help connecting the power sensor correctly, the RF connectors are assigned a
number, indicated on the front label, see Figure 3-4.
See Chapter 3.1.4, "Connecting to source and load", on page 16.
Used for establishing a connection between the power sensor and a computer or base
unit. The connection is used for:
●
Remote control of the power sensor via the serial interface (RS-422).
●
Supplying the power sensor with DC power.
See Chapter 3.1.5, "Connecting to a computer or base unit", on page 17.
3.2.3 Power handling capacity
Located on the back of the power sensor, there is a derating diagram that shows the
power handling capacity of the power sensor, forward power in W versus frequency. It
is also dependent on ambient temperature and the VSWR of the load. Further information on signal levels is provided in the data sheet. See also "Signal input and output
levels" on page 16.
3.2.4 R&S NRT‑Z5 USB interface adapter
This adapter connects the host interface of the R&S NRT‑Z5 USB interface adapter to
the USB port of a computer.
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Getting started
Power sensor tour
Prerequisites
●
The USB port of the computer must be capable to supply at least 500 mA. If necessary, use a self-powered USB hub.
●
The drivers for the R&S NRT‑Z5 USB interface adapter are installed on the computer.
To install the drivers for the R&S NRT‑Z5 USB interface adapter
► Proceed as described in the technical information delivered with the R&S NRT‑Z5
USB interface adapter.
For a detailed setup, see Chapter 3.1.5.1, "Computer", on page 17.
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Getting started
Power sensor tour
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4 Operating concepts
4.1 Base unit
Operating concepts
Virtual NRT
R&S
● Base unit................................................................................................................. 23
● R&S Virtual NRT..................................................................................................... 23
● Remote control........................................................................................................25
See also Chapter 3.1.5.2, "Base unit", on page 18.
Setup
1
Figure 4-1: Setup for base unit
1 = signal source
2 = R&S NRT‑Zxx directional power sensor
3 = load
4 = base unit
5 = host interface connector → sensor interface
Communication between the R&S NRT‑Zxx directional power sensor and a base unit is
only possible with a baud rate setting of 38400 Bd. This setting is the factory default
that must be restored if the setting was changed. If the R&S NRT‑Zxx directional power
sensor is not recognized by the base unit, check that the baud rate setting of the
R&S NRT‑Zxx directional power sensor is 38400 Bd.
2 3
4
5
See Chapter 12.1, "Checking and setting the baud rate", on page 97.
4.2 R&S Virtual NRT
R&S Virtual NRT is a Windows application provided by Rohde & Schwarz for controlling the R&S NRT-Zxx. R&S Virtual NRT provides a graphical user interface supporting:
●
Manual operation of the main measurements. For information on the graphical user
interface, see the R&S Virtual NRT help.
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Operating concepts
Virtual NRT
R&S
●
Remote control, see Chapter 4.3.1, "Remote control using R&S Virtual NRT",
on page 26.
Installing the program
R&S Virtual NRT is provided on the Rohde & Schwarz website as a separate standalone installation package,
https://www.rohde-schwarz.com/software/nrt-z_nap-z/.
► Save the EXE file on your computer.
Required equipment
●
R&S NRT-Zxx power sensor
●
R&S NRT‑Z5 USB interface adapter to connect the power sensor to the computer;
alternatively, you can use a legacy adapter, see Chapter 3.1.5.3, "Legacy setups",
on page 19.
●
Computer with Microsoft Windows operating system and the drivers for the
R&S NRT‑Z5 USB interface adapter installed, see "To install the drivers for the
R&S NRT‑Z5 USB interface adapter" on page 21.
Setup
1
2
3
4
5
Figure 4-2: Setup for R&S
1 = signal source
2 = R&S NRT‑Zxx directional power sensor
3 = load
4 = computer with installed R&S Virtual NRT
5 = R&S NRT‑Z5 USB interface adapter
Virtual NRT
To start a measurement
1. Connect the R&S NRT-Zxx to the computer as shown in "Setup" on page 24. For
detailed descriptions, refer to:
● Chapter 3.1.4, "Connecting to source and load", on page 16
● Chapter 3.1.5.1, "Computer", on page 17
2. Switch on the test signal of the signal source.
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Operating concepts
Remote control
3. Start R&S Virtual NRT.
A few seconds after the user interface is displayed, when the pointers of the analog
indication start wriggling, the power sensor is ready for operation. For further
instructions, see the R&S Virtual NRT help.
If communication with the power sensor could not be established, the display is
dimmed and the automatic configuration of the interface failed. Proceed with "To
establish the communication" on page 25.
To establish the communication
1. In the "Options" menu, select "RS-232".
Click "Auto Config" to start the automatic configuration again.
2. If automatic configuration does not work, configure the interface settings manually:
a) Set baud rate to 38400.
This value is the factory-set value of the R&S NRT-Zxx.
If you want to check the baud rate, proceed as described in Chapter 12.1,
"Checking and setting the baud rate", on page 97.
b) Under "COM port", select the virtual COM port that is assigned to the
R&S NRT‑Z5 USB interface adapter.
c) Click "OK".
d) Click "RUN".
4.3 Remote control
Using remote control, you can integrate the R&S NRT‑Zxx directional power sensors
into a remote-controlled measurement system or use functions that are not available in
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4.3.1 Remote control using R&S Virtual NRT
Operating concepts
Remote control
manual operation. You can monitor the power sensor and support the development of
your own test program.
Further information:
●
Chapter 7, "Remote control commands", on page 37
●
Chapter 3.1.5.1, "Computer", on page 17
In R&S Virtual NRT, remote control is called direct communication. R&S Virtual NRT
works like a terminal program, but also manages the configuration of the host (computer) and the initialization of the power sensor. For general information on R&S Virtual
NRT, see Chapter 4.2, "R&S Virtual NRT", on page 23.
To communicate directly
1. Start as described in "To start a measurement" on page 24.
2. Wait until you can see the measurement results.
3. In the "Options" menu, select "Direct Communication".
The "Direct Communication" dialog is displayed. Any running measurements are
interrupted.
4. In the "Input" field, enter a command, for example ID.
5. Click "SEND".
In the "Output" field, the response of the power sensor is displayed.
6. Click "STOP REC" to terminate the ready-to-receive state of R&S Virtual NRT
before sending a new command.
7. For each command you want to send, repeat step 4 to step 6.
8. If you want to clear the receiver protocol displayed in the "Output" field, click
"CLEAR".
9. Click "CLOSE" to return to manual operation.
4.3.2 Remote control using terminal program
You can use a terminal program of your choice.
4.3.2.1 Interface settings
To set up the connection successfully, the interface settings of power sensor and computer must match.
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Operating concepts
Remote control
Power sensor interface settings
●
Parity: none
●
Data bits: 8
●
Stop bits: 1
●
Start bits: 1
●
Protocol: XON / XOFF
You can change the baud rate, see Chapter 12.1, "Checking and setting the baud
rate", on page 97.
Computer interface configuration
●
Port connected to the power sensor
●
Interface parameters same as for power sensor, see "Power sensor interface set-
tings" on page 27.
●
ASCII configuration: end of transmitted lines with LF
Example: Using the PuTTY terminal program
This example shows the configuration of the PuTTY terminal program (https://
www.putty.org/).
1. Under "Session", configure as follows:
a) "Serial line": Must match the COM port that is assigned to the serial adapter,
usually R&S NRT‑Z5 USB interface adapter. You can look up this information in
the device manager of the operating system.
b) Speed: Must match the baud rate setting of the power sensor.
See also Chapter 12.1, "Checking and setting the baud rate", on page 97.
c) Connection type: "Serial"
2. If you want to reuse the session settings, you can save them:
a) Under "Saved Sessions", enter the name.
b) Click "Save".
c) To load a session, double-click the list entry.
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Operating concepts
Remote control
3. Recommendation for "Terminal" settings: Set both "Local echo" and "Local line
editing" to "Force on". This way, you can see your input and edit the input line.
4. Under "Connection" > "Serial", configure the parameters of the serial interface.
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Operating concepts
Remote control
4.3.2.2 Testing the connection
On power-up, the R&S NRT-Zxx responds to commands with one or several lines, if
the connection is working.
To ready the power sensor for measuring
1. Open the terminal program.
2. Send appl.
3. Wait for a response; see Chapter 4.3.2.3, "Behavior during booting", on page 30.
4. Repeat step 2 and step 3 until the power sensor responds with:
@8E oper _____________________________________________
After receiving the response, you can make settings and query results.
To test the connection
1. Open the terminal program.
2. Enter the string test.
3. Confirm with the return key.
The power sensor responds:
@17 0 - This is a test string__________________
@18 1 - This is a test string__________________
@19 2 - This is a test string__________________
...
@37 97 - This is a test string__________________
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Operating concepts
Remote control
@38 98 - This is a test string__________________
@39 99 - This is a test string__________________
See also Chapter 4.3.2.3, "Behavior during booting", on page 30.
To query the identification
► Send the id command.
The power sensor responds with its identification string.
Example: @6E Rohde&Schwarz NRT-Z14 V3.00 2021-12-01____
To query the last result
► Send rtrg.
The power sensor responds with:
@11 +2.1234E+01 +2.1530E+01 __avrl15500 ________
Interpreting the response:
+2.1234E+01
●
Result for measurement direction 1>2; in this example 21.234 W average power
●
+2.1530E+01
Result for measurement direction 2>1; in this example 21.53 dB return loss.
●
__avrl15500
Power sensor status in coded form.
Power sensor status in coded form. See also Chapter 7.2.5, "STAT", on page 60.
See also Chapter 7.2.1, "FTRG", on page 56.
4.3.2.3 Behavior during booting
On power-up, the power sensor is booting. During booting, you can load new firmware.
After booting is completed, a power-up test is performed for approx. 3 s.
Do not interrupt the power-up test. If you send the appl command during power-up
test, the power sensor responds with:
@9B busy_________________________________________
After the power-up test is completed, send the appl command again to ready the
power sensor for measuring. The power sensor responds with:
@8C boot_________________________________________
Now the power sensor is ready for operation. If you send the appl command again,
the power sensor responds with:
@8E oper_________________________________________
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5 Measurement basics
Measurement basics
The R&S NRT‑Zxx directional power sensor measures the forward and reverse power.
The forward power is the power flux from the source to the load.
The ratio of forward and reverse power is a measure of the matching of the load which
can be measured as standing wave ratio (SWR), return loss or reflection coefficient.
To observe during the power reflection measurement
CAUTION! Risk of electric shock and severe skin burns. During the measurement,
►
the RF power flow can be high.
After switching on the RF power, do not touch the RF ports.
Never exceed permissible continuous power that is shown in the diagram on the
back of the power sensor.
Further information:
●
Setup see Chapter 3.1.4, "Connecting to source and load", on page 16.
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Measurement basics
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6 Firmware update
6.1 Hardware and software requirements
Firmware update
Updating the firmware
● Hardware and software requirements.....................................................................33
● Updating the firmware.............................................................................................33
● R&S NRP Toolkit.....................................................................................................34
For performing a firmware update, the system requirements are as follows:
●
Connectors and cables for establishing a connection to the computer:
Chapter 3.1.5.1, "Computer", on page 17
●
Rohde & Schwarz update file (*.bin) for the R&S NRT-Zxx is available.
Download the most recent firmware version from the Rohde & Schwarz homepage
on the Internet, since the CD-ROM accompanying the power sensor contains the
firmware dating from the time of delivery. The latest firmware update files are available at www.rohde-schwarz.com/firmware/nrt-z
●
R&S NRP Toolkit for Windows is installed on the computer. See Chapter 6.3,
"R&S NRP Toolkit", on page 34.
6.2 Updating the firmware
Do not interrupt the firmware update because an interruption can lead to missing or
faulty firmware. Take special care not to disconnect the power supply while the update
is in progress.
To update the firmware
A firmware update can take up to 5 minutes. Ensure that the update is not interrupted.
1. Connect the power sensor to the computer as described in Chapter 3.1.5.1, "Com-
puter", on page 17.
2. Start the Firmware Update for NRP Family program:
"Start" menu > "NRP-Toolkit" > "Firmware Update".
3. Under "Hostname, IP Address or Serial", enter the COM port to which the
R&S NRT‑Z5 USB interface adapter is connected, for example "COM7". You can
look up this information in the device manager of the operating system.
The program automatically starts scanning this COM port for power sensors. When
the scan is successful, the COM port is listed under "Device".
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Firmware update
NRP Toolkit
R&S
4. Under "Firmware", enter the full path and filename of the update file or press the
browse button next to the field. New firmware for the R&S NRT-Zxx has an *.bin
extension.
5. Click "Update".
During the update process, a progress bar is displayed. The update sequence can
take a couple of minutes.
6. Check if the update was successful. The firmware version in the "Identification"
field must match the version you selected in the "Firmware" field.
Problems during a firmware update
If, for example, a power cut happened during the firmware update, problems can occur.
1. Perform the firmware update again. Sometimes, a further update fixes the problems.
2. If the power sensor is not accessible anymore, contact the service.
6.3 R&S NRP Toolkit
Firmware Update for NRP Family is part of the R&S NRP Toolkit.
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6.3.1 System requirements
6.3.2 Installation
Firmware update
R&S NRP Toolkit
Hardware requirements:
●
Desktop computer or laptop
Supported Microsoft Windows versions:
●
Microsoft Windows Vista 32/64-bit
●
Microsoft Windows 7 32/64-bit
●
Microsoft Windows 8/ 8.1 32/64-bit
●
Microsoft Windows 10 32/64-bit
1. Start the R&S NRP Toolkit installer on the Windows-based computer.
In the "NRP-Toolkit Setup" dialog, the correct R&S NRP Toolkit version for your
operating system, 32-bit or 64-bit, is already selected.
2. Accept the license terms to continue with the installation.
3. Click "Next" and complete the installation process.
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R&S NRP Toolkit
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7 Remote control commands
7.1 Measurement setting commands
Remote control commands
Measurement setting commands
Describes all commands useful for measurement tasks. An alphabetic list of all commands is provided at the end of the user manual.
Enter physical quantities in their basic unit — W, s, Hz. Enter the value without the unit.
Values with unit are not recognized.
● BURS...................................................................................................................... 37
● CCDF...................................................................................................................... 38
● DIR..........................................................................................................................38
● DISP........................................................................................................................39
● FREQ...................................................................................................................... 41
● FILT.........................................................................................................................41
● FOR.........................................................................................................................45
● MOD........................................................................................................................49
● OFFS.......................................................................................................................50
● PEP.........................................................................................................................51
● PORT...................................................................................................................... 51
● RESET.................................................................................................................... 53
● REV.........................................................................................................................53
● ZERO...................................................................................................................... 55
7.1.1 BURS
This command group sets the burst period and the burst width for the forward calculated burst average measurement, CBAV.
P
Figure 7-1: Envelope power characteristic of a burst signal
1 = burst width, see BURS:WIDT on page 38.
2 = burst period, see BURS:PER on page 38.
1
2
t
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Remote control commands
Measurement setting commands
Remote commands
BURS:PER......................................................................................................................38
BURS:WIDT.................................................................................................................... 38
BURS:PER <num>
Sets the burst period for the forward calculated burst average measurement, CBAV.
Parameters:
<num> Burst period, see Figure 7-1.
Range: <burst width> to 1.0
RESET: 1E-2
Unit: s
Example:
BURS:WIDT <parameter>
Sets the burst width for the forward calculated burst average measurement, CBAV.
Parameters:
<parameter> Burst width, see Figure 7-1.
Example:
7.1.2 CCDF
CCDF <num>
Sets the threshold for the complementary cumulative distribution function measurement, CCDF.
BURS:PER 40e-3
@5D old: 1.000000E-02 new: 4.000000E-02_________
Range: 1E-9 to <burst period>
RESET: 1E-3
Unit: s
BURS:WIDT 6.667e-3
@74 old: 1.000000E-03 new: 6.667000E-03_________
Applies to the measurement position defined by PORT and OFFS.
Parameters:
<num> Range: 1 to 300
7.1.3 DIR
DIR <parameter>
Sets the direction of the forward power relative to the power sensor ports 1 and 2.
RESET: 1
Unit: W
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Remote control commands
Measurement setting commands
See also Chapter 3.1.4, "Connecting to source and load", on page 16.
Parameters:
<parameter> AUTO
The power sensor automatically assigns the direction. The
greater of the two measured powers are interpreted as forward
power.
This setting is not advisable if the forward and the reverse powers are approximately equal (total reflection). Then the automatic
assignment can be wrong because, due to a measurement error,
a higher value is determined for the reverse than for the forward
power.
1>2
The forward power direction is fixed from port 1 to port 2.
2>1
The forward power direction is fixed from port 2 to port 1.
RESET: AUTO
7.1.4 DISP
This command group configures the responses for FTRG and RTRG.
Remote commands
DISP:FORW....................................................................................................................39
DISP:REFL......................................................................................................................40
DISP:STAT......................................................................................................................40
DISP:FORW <parameter>
If enabled, the result for the forward measurement is included in the response.
Parameters:
<parameter> ON | OFF
RESET: ON
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Remote control commands
Measurement setting commands
Example:
RESET
# Activates default settings.
@30 OK__________________________________________
DMA OFF
# Disables filling-up to 50 characters.
@39 old: ON new: OFF____________________________
RTRG
# Requests result.
@F9 +2.1234E+01 +2.1530E+01 __avrl15500
DISP:FORW OFF
# Disables the forward power display.
@D5 old: ON new: OFF
RTRG
# Requests result.
@B3 +2.1530E+01 __avrl15500
DISP:FORW ON;DISP:STAT OFF
# Enables the forward power display and
# disables the status display.
@D5 old: OFF new: ON
# For several commands separated by semicolons,
# the responses are output in consecutive order.
RTRG
# Requests result.
@6B +2.1234E+01 +2.1530E+01
DISP:REFL <parameter>
If enabled, the result for the reverse measurement is included in the response.
Parameters:
<parameter> ON | OFF
RESET: ON
DISP:STAT <parameter>
If enabled, the result for the status field is included in the response.
Parameters:
<parameter> ON | OFF
RESET: ON
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7.1.5 FREQ
Remote control commands
Measurement setting commands
FREQ <num>
Sets the carrier frequency of the test signal.
With this information, the characteristic frequency response of the power sensor can
be considered and the results corrected accordingly. Correction is made for the forward
and the reverse channel. The values between the stored correction factors are
obtained by way of linear interpolation. To achieve the measurement accuracy specified in the data sheet, enter the frequency with an accuracy of about 5 %.
Parameters:
<num> Range:
R&S NRT‑Z14: 2E6 to 1E9
R&S NRT‑Z44: 2E8 to 4E9
RESET:
R&S NRT‑Z14: 2E8
R&S NRT‑Z44: 1E9
Unit: Hz
7.1.6 FILT
This command group sets the averaging filters of the individual measurement paths,
the integration time of the A/D converters and the video filters.
Averaging
Averaging of measured values compensates for variations that occur due to unstable
test signals or low powers. In the free run mode (trigger setting FTRG), a "running average" is formed. That means a fixed number of measured values is averaged continuously, yielding a new output value with every new measured value. The oldest measured value is removed from the filtering process, see Figure 7-2.
The number of measured values that is averaged is called average count and is set
using FILT:AVER:COUN. The higher the count, the lower the noise, and the longer it
takes to obtain a measured value.
Figure 7-2: Averaging filter
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Remote control commands
Measurement setting commands
Integration time
You can select the integration time of the A/D converters in the two measurement
channels. This setting affects the stability of results at low powers (noise) and with lowfrequency modulation of the envelope. The default setting of FILT:INT:TIME results
in a suppression of low-frequency modulation, or to an integer multiple thereof as from
20 Hz and in optimum noise reduction.
●
Forward average power and forward measured burst average measurements,
AVER, MBAV:
For modulation frequencies below 20 Hz, increase the integration time to stabilize
the displayed power. Ideally, set the integration time equal to the period of the
envelope modulation. Low-frequency envelope modulation can also occur for digitally modulated radio signals, due to the so-called idle bursts which are regularly
included in the transmitted signal.
●
Triggered measurements:
You can increase the measurement speed by reducing the integration time if the
averaging count remains unchanged. For automatic averaging, FILT:AVER:MODE,
this condition is fulfilled only for sufficiently high powers. If an averaging filter is
already active with the default integration time setting, a further reduction generally
results in an automatic enhancement of the averaging count. So that on the whole,
no gain in the measurement speed is achieved.
Video bandwidth
The video bandwidth defines the passband of the forward channel for the rectified signal. Figure 7-3 shows the great influence on the time characteristic of the envelope signal and thus on the following measurements:
●
Peak envelope power, PEP
●
Crest factor, CF
●
Complementary cumulative distribution function, CCDF
●
Measured burst average, MBAV
Set the video bandwidth as small as possible to obtain stable results even at low forward powers (noise reduction). Not too small, however, because then significant distortion of the demodulated signal can result. As a rule of thumb, set the video bandwidth
about 2 to 3 times the bandwidth of the measured signal at the RF. The rule of thumb
does not apply to MBAV measurements.
Figure 7-3 shows the influence of video bandwidth. The peak envelope power (PEP) is
indicated as a dotted line.
P
1 2 3
Figure 7-3: Influence of video bandwidth on rectified signal
t
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Remote control commands
Measurement setting commands
1 = 4 MHz video bandwidth
2 = 200 kHz video bandwidth
3 = 4 kHz video bandwidth
Table 7-1 shows the bandwidth settings for several common waveforms. The settings
allow transmission of the rectified signal that is largely free from distortion.
Table 7-1: Video bandwidth settings for common waveforms
Waveform Video bandwidth setting, FILT:VID
AM Mod. frequency ≤ 1 kHz 4E3 (4 kHz)
AM Mod. frequency ≤ 50 kHz 2E5 (200 kHz)
CW burst Burst width ≥ 150 μs 4E3 (4 kHz)
CW burst Burst width ≥ 3 μs 2E5 (200 kHz)
CW burst Burst width ≥ 1.5 μs 6E5 (600 kHz)**
CW burst Burst width ≥ 200 ns 4E6 (4 MHz)***
π/4 DQPSK Symbol rate ≤ 24 k/s 2E5 (200 kHz)
π/4 DQPSK Symbol rate ≤ 72 k/s 6E5 (600 kHz)**
π/4 DQPSK Symbol rate ≤ 200 k/s 4E6 (4 MHz)***
CDMA/W-CDMA Chip rate ≤ 8.2 M/s
DAB/DVB-T ---------------
*) You can increase the accuracy for digitally modulated signals by enabling the modulation correction, see
Chapter 7.1.8, "MOD", on page 49.
**) only R&S NRT‑Z14
***) only R&S NRT‑Z44
4E6 (4 MHz) *, ***
4E6 (4 MHz) *, ***
Remote commands
FILT:AVER:COUN............................................................................................................ 43
FILT:AVER:MODE............................................................................................................ 44
FILT:INT:MODE................................................................................................................44
FILT:INT:TIME..................................................................................................................44
FILT:RES.........................................................................................................................45
FILT:VID.......................................................................................................................... 45
FILT:AVER:COUN <num>
Sets a fixed number of measured values that are averaged continuously. The setting
applies to all measurement paths — forward average power, reverse average power,
peak power and CCDF. See also "Averaging" on page 41.
If a valid value is sent, FILT:AVER:MODE is automatically set to USER.
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Remote control commands
Measurement setting commands
Parameters:
<num> A value of 1 means that no averaging takes place. Each mea-
sured value is output immediately.
Range: 1, 2, 4, 8, 16, 32, 64, 128, 256
RESET: 1
FILT:AVER:MODE <parameter>
Enables or disables automatic averaging. See also "Averaging" on page 41.
Parameters:
<parameter> AUTO
Sets the count of the averaging filters as a function of the forward power, the test function, the integration time of the A/ Dconverters and the selected resolution of results.
The resolution is set using FILT:RES. It has the following effect
on the automatically set averaging count. A small measured
power combined with a high-resolution results in a high average
count. Only a comparatively high measured power combined
with a low-resolution results in non-averaged measured values.
For further information on measurement speed, refer to data
sheet.
USER
Uses the average count set by FILT:AVER:COUN.
RESET: AUTO
FILT:INT:MODE <parameter>
Enables or disables a fixed integration time setting. See also "Integration time"
on page 42.
Parameters:
<parameter> DEF
Uses the default integration time.
USER
Uses the value set by FILT:INT:TIME.
RESET: DEF
FILT:INT:TIME <num>
Sets the integration time. See also "Integration time" on page 42.
If a valid value is sent, FILT:INT:MODE is automatically set to USER.
Parameters:
<num> Range: 5E-3 to 0.1111
RESET: 0.03667
Unit: s
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Remote control commands
Measurement setting commands
FILT:RES <parameter>
Sets the number of significant digits for automatic averaging. Also enables automatic
averaging; you do not need to send FILT:AVER:MODE AUTO in this case.
See also:
●
FILT:AVER:MODE
●
"Averaging" on page 41
Note: Measured values are output in a fixed number format that is not affected by the
resolution. Non-significant digits are truncated by the base unit or the user program
corresponding to the set resolution.
Parameters:
<parameter> The average of forward power above 1 W is displayed as fol-
lows:
HIGH
4.5 digits.
LOW
3.5 digits.
RESET: LOW
FILT:VID <num>
Sets the video bandwidth. See also "Video bandwidth" on page 42.
Parameters:
<num> Range:
7.1.7 FOR
This command sets the forward measurement. See also Chapter 7.1.4, "DISP",
on page 39.
The forward measurement set by default is AVER.
For the CCDF, CF, MBAV and PEP measurements, connect the power sensor for the
forward power in the privileged direction to ensure that the corresponding measurement paths are at sufficient power.
R&S NRT‑Z14: 4E3, 2E5, 6E5
R&S NRT‑Z44: 4E3, 2E5, 4E6
RESET: 2E5
Unit: Hz
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Remote control commands
Measurement setting commands
Peak envelope power (PEP)
Power
Burst average
Average
Burst width
Burst period
Figure 7-4: Forward power measurement parameters
Time
FOR <parameter>
AVER
Sets the forward average power measurement.
This measurement provides the lowest measurement uncertainty and the widest measurement range. To keep the measurement accuracy specified in the data sheet, it is
necessary to enter the carrier frequency using FREQ.
You can increase the accuracy for digitally modulated signals by enabling the modulation correction, see Chapter 7.1.8, "MOD", on page 49.
CBAV
Sets the forward calculated burst average (CBAV) measurement.
This measurement determines the average power of modulated or unmodulated RF
bursts, as shown in Figure 7-4. The CBAV measurement result is calculated from the
average power and the duty cycle.
Define the duty cycle using BURS:WIDT and BURS:PER on page 38.
You can increase the accuracy for digitally modulated signals by enabling the modulation correction, see Chapter 7.1.8, "MOD", on page 49.
For unmodulated bursts without envelope overshoot, the average burst power must be
equal to the peak envelope power.
CCDF
Sets the complementary cumulative distribution function (CCDF) measurement.
This measurement determines the probability of the forward envelope power exceeding a preset threshold. It thus describes the amplitude distribution of the envelope.
Set the threshold using CCDF.
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Remote control commands
Measurement setting commands
Make sure that the video bandwidth is correct using FILT:VID.
You can increase the accuracy for digitally modulated signals by enabling the modulation correction, see Chapter 7.1.8, "MOD", on page 49.
Figure 7-5 illustrates the CCDF measurement for an RF signal with a stochastic enve-
lope. The thick lines in the righthand graph indicate the time periods during which the
envelope power exceeds the threshold. The percentage of these periods relative to the
total measurement period equals the CCDF measurement result for the given threshold.
P
1
2
t
Figure 7-5: CCDF measurement shown for a test signal with stochastic envelope
1 = CCDF threshold
2 = observation period
Example:
RESET
# Default setting.
@30 OK__________________________________________
FOR CCDF
# Sets CCDF measurement.
@60 old:AVER new:CCDF___________________________
CCDF 20
# Sets CCDF threshold to 20 W.
@55 old: 1.000000E+01 new: 2.000000E+01_________
RTRG
# Triggers the result.
@14 +2.4356E+01 +2.2345E+01 _icdrl13300 ________
# The CCDF value is 24.356 %, the return loss 22.345 dB.
CF
t
Sets the crest factor (CF) measurement.
The crest factor is the ratio of peak envelope power (PEP) to average power. The crest
factor provides information on the amount of modulation distortion and can assume
high values for burst or spread-spectrum signals, e.g. approx. 5 to 10 with CDMA.
Make sure that the video bandwidth is correct using FILT:VID.
Enable the modulation correction, see Chapter 7.1.8, "MOD", on page 49.
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Remote control commands
Measurement setting commands
For further information on the correct setting of the power sensor, see also PEP.
MBAV
Sets the forward measured burst average measurement (MBAV: measured burst average).
The measured burst average is calculated from the average power and the duty cycle,
see Figure 7-4.
In contrast to the CBAV measurement, CBAV, you do not need to define the duty cycle.
The duty cycle is determined automatically by the power sensor using the CCDF measurement, CCDF, setting the CCDF threshold to half of the peak value for this process.
For modulated bursts, ensure the correct calculation of the duty cycle as follows. Set
the video bandwidth narrow enough for the suppression of the modulation signal but
still wide enough to prevent distortion of the rectangular envelope power characteristic.
For an appropriate setting, see the middle graph of Figure 7-3.
For CW bursts, select the video bandwidths as listed in Table 7-1. Ensure the required
measurement accuracy for the R&S NRT‑Z44 as follows: duty cycle ≥ 10 %, average
burst power ≥ 2 W.
You can increase the accuracy for digitally modulated signals by enabling the modulation correction, see Chapter 7.1.8, "MOD", on page 49.
PEP
Sets the continuous measurement of peak envelope power (PEP) of modulated signals
and bursts.
While the output signal follows each increase in the envelope power directly, it
responds to a decrease with a delay set by the PEP command group, see Chap-
ter 7.1.10, "PEP", on page 51.
To obtain stable results, select the hold time longer than the interval between two consecutive peaks. The default setting of 60 ms allows measurements from modulation
frequencies of about 20
Hz.
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Remote control commands
Measurement setting commands
Figure 7-6: Output signal for peak envelope power (PEP)
The output signal is smoothed by digitization and subsequent averaging so that the
actual fluctuation is much lower than shown in Figure 7-6.
If you do not want to blank unwanted components, select the video bandwidth corresponding to the highest frequency component of the envelope signal, see Table 7-1.
You can increase the accuracy for digitally modulated signals by enabling the modulation correction, see Chapter 7.1.8, "MOD", on page 49.
7.1.8 MOD
This command group is used for increasing the measurement accuracy for various digital communication standards.
The deviations that can be compensated are proportional to power for the average
power and average burst measurements. Because they are only a few percent at nominal power, 120 W for R&S NRT‑Z44, the modulation correction has practically no
effect below approx. 10 W for R&S NRT‑Z44.
To make sure that the modulation correction is enabled for the PEP, CF and CCDF
measurements, set the R&S NRT‑Z44 to full video bandwidth, using FILT:VID 4E6.
Systematic zero offsets of up to 1.5 W are normal for the PEP measurement at full
video bandwidth and with modulation correction on. These offsets do not have any
influence on the measurement accuracy in the specified power range.
Remote commands
MOD:RATE..................................................................................................................... 49
MOD:TYPE..................................................................................................................... 50
MOD:RATE <num>
Only available for the R&S NRT‑Z44.
Sets the chip rate for the WCDMA communication standard.
Only effective if MOD:TYPE WCDMA is set.
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Measurement setting commands
Parameters:
<num> Range: 0 to 8.2E6
RESET: 4.096E6
Unit: per second
MOD:TYPE <parameter>
Sets a communication standard for the modulation correction to reduce systematic
deviations occurring in power measurements.
The corrections always apply to the following measurements: forward average power
AVER, forward calculated burst average CBAV, forward measured burst average MBAV.
For the IS95, WCDMA, DVBT and DAB communication standards, the corrections also
apply to: complementary cumulative distribution function CCDF, crest factor CF, peak
envelope power PEP.
Spread-spectrum signals not available as communication standard can be treated like
WCDMA signals that are assigned a chip rate of 0.9 times the RF bandwidth.
Parameters:
<parameter> OFF
Disabled
IS95
IS-95 CDMA standard for base stations
Only available for R&S NRT‑Z44
WCDMA
WCDMA standard for base stations
Only available for R&S NRT‑Z44
DVBT
DVB-T standard for terrestrial DVB TV transmitters
Only available for R&S NRT‑Z44
DAB
DAB standard for radio transmitters.
Only available for R&S NRT‑Z44
EDGE
Mobile communication standard
TETRA
Terrestrial trunked radio standard
Only available for R&S NRT‑Z14.
RESET: OFF
7.1.9 OFFS
OFFS <num>
Considers the transmission loss in a cable that connects the desired measurement
point, set by PORT, and the power sensor.
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7.1.10 PEP
Remote control commands
Measurement setting commands
Depending on whether the cable is connected to the source or load port, the specified
attenuation value has different effects on the measurement result. See "Reference
plane" on page 51.
Parameters:
<num> Range: 0 to 100
RESET: 0
Unit: dB
This command group sets the hold time of the peak hold circuit.
Remote commands
PEP:HOLD......................................................................................................................51
PEP:TIME....................................................................................................................... 51
PEP:HOLD <parameter>
Enables or disables a fixed hold time.
Parameters:
<parameter> DEF
PEP:TIME <num>
Sets the hold time.
If a valid value is sent, PEP:HOLD is automatically set to USER.
Parameters:
<num> Range: 1E–3 to 1E–1
7.1.11 PORT
Uses the default hold time.
USER
Uses the value set by PEP:TIME.
RESET: DEF
RESET: 6E–2
Unit: s
Reference plane
The measurement results are referred to the power sensor port. This distinction is necessary to meet more stringent measurement accuracy requirements. The power sensor absorbs part of the RF power and thus the outgoing waves from the power sensor
are reduced by the insertion loss in comparison with the incoming waves, see Fig-
ure 7-7.
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Remote control commands
Measurement setting commands
Measurement point source
Offset source Offset load
Return loss
Power
Position
Figure 7-7: Definition of the test point
Measurement point load
Forward
Reverse
Depending on the desired measurement result, the measurement has to be carried out
at the source or load. See Table 7-2.
Table 7-2: Reference plane for the different measurement results
Measurement result Power sensor setting Load matching
Ref. plane Measurement
Active power provided by source
Active power absorbed by load
Forward power (source)
Forward power (load)
Load matching
Power of source into 50 Ω
SOUR
LOAD
SOUR
LOAD
LOAD
SOUR
AVER
CBAV
MBAV
PEP
* ( 1 - (REV RCO)2 )
AVER
CBAV
MBAV
PEP
RL
RCO
SWR
AVER good (SWR < 1.2)
any
The maximum difference between the two measurement points is:
●
R&S NRT‑Z14: 0.017 dB at 1 GHz
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Measurement setting commands
●
R&S NRT‑Z44: 0.048 dB at 4 GHz
At some DUTs, the test point itself is not accessible, for example an output connector
of a transmitter or an antenna input. In these cases, you can enter the attenuation of
the cable that connects the power sensor and the test point using OFFS. Using the reference plane and the attenuation, power and matching are corrected as if the measurement is carried out at the inaccessible test point.
Example: Measuring the output power of a transmitter
The power sensor is connected to the transmitter output using a cable with an insertion
loss of 0.45 dB.
The correct setting of the power sensor is reference plane SOUR with 0.45 dB attenuation. Without considering the attenuation, the measured output power of the transmitter
would be 0.45 dB or 10 % too low.
Example: Measuring the matching of an antenna
The input of an antenna is connected to the power sensor using a long cable with an
insertion loss of 1.2 dB.
The correct setting of the power sensor is reference plane LOAD with 1.2 dB attenuation. Without considering the cable loss, the measured return loss of the antenna would
be 2.4 dB too high.
PORT <parameter>
Selects the power sensor port to which the measurement results are referred, see
"Reference plane" on page 51.
Parameters:
<parameter> SOUR
7.1.12 RESET
RESET
Sets the power sensor to a defined initial state. The default settings are indicated in the
description of commands as RESET value.
The default settings are not identical with the power-up status. On power-up, the settings from the last session are loaded.
Source connector of the power sensor, see Figure 3-4.
LOAD
Load connector of the power sensor, see Figure 3-4.
RESET: LOAD
7.1.13 REV
This command sets sets the reverse measurement.
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Remote control commands
Measurement setting commands
The reverse measurement set by default is RL.
REV <parameter>
POW
The effect of this command depends on the selected forward measurement. Except for
the crest factor, peak envelope power and complementary cumulative distribution function measurements, the command measures the reverse power corresponding to the
selected forward measurement, see Table 7-3.
Table 7-3: Reverse power measurement
Forward measurement Measured in reverse power measurement
forward average power AVER reverse average power
forward calculated burst average CBAV reverse calculated burst average
complementary cumulative distribution function
crest factor CF forward average power
forward measured burst average MBAV reverse measured burst average
peak envelope power PEP reverse average power *
* R&S Virtual NRT: If the PEP measurement is selected, "PWR" displays the maximum reverse PEP.
CCDF forward average power
RCO
Sets the reflection cefficient (RCO) measurement.
The reflection coefficient is defined as the ratio of reflected to incident wave. The values range from 0 for matching to 1 for total reflection.
The power sensor calculates the reflection coefficient from the average values of the
forward and the reverse power:
Reflection coefficient =
Reverse power
Forward power
RL
Sets the return loss (RL) measurement.
The return loss indicates the attenuation in dB of the reflected wave relative to the incident wave:
Return loss =
10 x log
Forward power
Reverse power
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Measurement setting commands
SWR
Sets the standing wave ratio (SWR) measurement.
The standing wave ratio indicates the ratio of maximum to minimum voltage on an RF
line:
Standing wave ratio =
7.1.14 ZERO
Zeroing in the PEP measurement
For PEP measurement with active modulation correction, residual zero offsets of up to
approx. 1.5 W are normal for the R&S NRT‑Z44 after zeroing, see Chapter 7.1.8,
"MOD", on page 49.
Example:
After successful zeroing, the power sensor outputs the calculated offset values as follows. All values are in V, referred to detector output:
@DE pack 04____________________________________
@79 01 zero1 = +3.0047E-08, zero2 = -1.8586E-06_
Indicates the offsets for measurement of the average power in the forward (zero1) and
reverse (zero2) measurement paths.
@28 02 PEP zero for 4kHz filter : -4.2817E-07_
@48 03 PEP zero for 200kHz filter : -5.2792E-05_
@03 04 PEP zero for 4MHz filter : -1.6621E-04_
1 + Reflection coefficient
1 − Reflection coefficient
These lines indicate the offset for the PEP function in the forward measurement path
for various settings of the video filter.
ZERO <parameter>
Starts zeroing or disables the zero offset correction.
Zeroing removes offset voltages from the analog circuitry of the power sensor, so that
there are only low powers displayed when there is no power applied.
An active test signal during zeroing causes an error (Error ZERO), and the results are
ignored. Therefore switch off the RF power during zeroing.
You can perform zeroing any number of times. Each new zeroing overwrites the results
of previous zero measurement.
Parameters:
<parameter> <no parameter>
Performs zeroing.
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7.2 Query commands
7.2.1 FTRG
Remote control commands
Query commands
0
Disables the zero offset correction; active on power-up.
● FTRG...................................................................................................................... 56
● QSTN...................................................................................................................... 56
● RTRG......................................................................................................................57
● SPEC...................................................................................................................... 57
● STAT....................................................................................................................... 60
FTRG
Starts a continuous measurement at a high speed controlled by an internal timer, without any reference to an external trigger. Reads the last result.
The command has no effect on the internally controlled measurement processes. Measurements are started automatically on completion of a power-up or an external trigger,
see Chapter 7.2.3, "RTRG", on page 57. The measurement speed depends on the
measurement, but is not affected by the setting of the averaging filter, see "Averaging"
on page 41.
Example:
7.2.2 QSTN
QSTN
Queries the stock number.
Example:
RESET
# Resets the power sensor.
FTRG
@2A +7.0392E-04 +1.2667E+01 __avrl15500 ________
# Response:
# <forward power in W> <return loss in dB> <status field>
QSTN
@2E 1444.0012.02________________________________
The stocknumber is also included in the response of SPEC.
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7.2.3 RTRG
7.2.4 SPEC
Remote control commands
Query commands
RTRG
Triggers a remote-controlled measurement.
The command interrupts the current, internally controlled measurement, starts a new
measurement and outputs the result.
If averaging is enabled, a result is output only when averaging is completed, i.e. when
the required number of measurements has been performed.
The results are read when the measured quantity remains constant after the command
has been sent.
The measurement time depends on the measurement, the setting of the averaging filter, and the integration time of the A/D converters, see the data sheet. The output format corresponds to that of FTRG.
Table 7-4 explains the meaning of the data read out from the power sensor by SPEC.
Table 7-4: Specifications
Line Parameter Meaning
1
2
3
4
5
6
7
8
9
10
11
12
13
ID:ID
ID:SER
ID:CAL:REV
ID:CAL:LAB
ID:CAL:DAT
ID:CAL:SIGN
ID:STOCK
TYPE
FREQ:RANG:LOW
FREQ:RANG:UPP
FREQ:RANG:DEF
POW
IMP
Identification string, see ID on page 66.
Serial number
Version number of calibration program
Calibration lab
Calibration date
Name of person in charge
Stock no. of the power sensor
Power sensor type
Lower frequency limit
Upper frequency limit
Default frequency
Nominal power
Characteristic impedance
14
15
FORW:AVER:RANG:LOW
FORW:AVER:RANG:UPP
Lower measurement limit for average forward power in W,
direction 1>2
Upper measurement limit for average forward power in W,
direction 1>2
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Query commands
Line Parameter Meaning
16
17 - 20
21
22 - 25
26 - 29
30 - 38
39
40
41
FORW:AVER:RANG:LSD
FORW:MBAV:RANG:LOWn
FORW:MBAV:RANG:UPP
FORW:MBAV:RANG:LSDn
FORW:CF:RANG:LSDn
FORW:PEP:RANG: to
FORW:PEP:TIME:LOW
FORW:PEP:TIME:UPP
FORW:PEP:TIME:DEF
Least significant digit of measured value with decimal notation in W
Example: -3 means that results are represented including the
mW position.
Lower measurement limit for forward measured burst average
n: coding of video bandwidth, see lines 60 to 64.
Upper measurement limit for forward measured burst average
Least significant digit of measured value with decimal notation in W
n: coding of video bandwidth, see lines 60 to 64.
Least significant digit of measured value with decimal notation in dB
n: coding of video bandwidth, see lines 60 to 64.
PEP measurement limit; definition analog to
FORW:MBAV:RANG
Minimum selectable hold time for PEP measurement
Maximum selectable hold time PEP measurement
Default hold time for PEP measurement
42 - 50
51 - 53
54
55
56
57
58
59
60
61 - 64
65
FORW:CCDF:RANG to
REFL:AVER:RANG to
FILT:AVER:AUTO
FILT:AVER:COUN:UPP
FILT:AVER:COUN:DEF
FILT:INT:TIME:LOW
FILT:INT:TIME:UPP
FILT:INT:TIME:DEF
FILT:VID:NRBW
FILT:VID:BWn
MOD:TYPE:NRST
CCDF measurement limits; definition analog to
FORW:MBAV:RANG
Measurement limits for reverse power; definition analog to
FORW:AVER:RANG
Automatic averaging available
Maximum count of averaging filter
Default count of averaging filter
Minimum integration time for A/D converters
Maximum integration time for A/D converters
Default integration time for A/D converters
Number of video filter settings
Video bandwidth for nth setting
Number of communication standards with modulation correction, incl. OFF
SPEC
Reads all relevant data of the power sensor. These data are used by the basic unit to
perform sensor-specific scaling and to recognize the limit values of input parameters.
See Table 7-4.
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Query commands
Example:
SPEC
# Response: Multiple lines with the following structure:
@28 pack 72
@A4 01 ID:ID:Rohde & Schwarz NRT-Z43V1.40
@53 02 ID:SER
@61 03 ID:CAL:REV
@44 04 ID:CAL:LAB
@4F 05 ID:CAL:DAT
@A8 06 ID:CAL:SIGN
@4A 07 ID:STOCK 1081.2905.02
@C5 08 TYPE POWER DIRECTIONAL
@74 09 FREQ:RANG:LOW 400E6
@12 10 FREQ:RANG:UPP 4E9
@EA 11 FREQ:RANG:DEF 1E9
@FC 12 POW 30
@EF 13 IMP 50
@CE 14 FORW:AVER:RANG:LOW 0.007
@49 15 FORW:AVER:RANG:UPP 75
@2D 16 FORW:AVER:RANG:LSD -4
@98 17 FORW:MBAV:RANG:LOW1 0.5
@9A 18 FORW:MBAV:RANG:LOW2 0.5
@CF 19 FORW:MBAV:RANG:LOW3 1.25
@C8 20 FORW:MBAV:RANG:LOW4 1.25
@3E 21 FORW:MBAV:RANG:UPP 75
@52 22 FORW:MBAV:RANG:LSD1 -3
@54 23 FORW:MBAV:RANG:LSD2 -3
@56 24 FORW:MBAV:RANG:LSD3 -3
@58 25 FORW:MBAV:RANG:LSD4 -3
@B8 26 FORW:CF:RANG:LSD1 -2
@BA 27 FORW:CF:RANG:LSD2 -2
@BC 28 FORW:CF:RANG:LSD3 -2
@BE 29 FORW:CF:RANG:LSD4 -2
@4E 30 FORW:PEP:RANG:LOW1 0.1
@86 31 FORW:PEP:RANG:LOW2 0.25
@56 32 FORW:PEP:RANG:LOW3 0.5
@54 33 FORW:PEP:RANG:LOW4 1.0
@01 34 FORW:PEP:RANG:UPP 75
@15 35 FORW:PEP:RANG:LSD1 -3
@16 36 FORW:PEP:RANG:LSD2 -2
@18 37 FORW:PEP:RANG:LSD3 -2
@1A 38 FORW:PEP:RANG:LSD4 -2
@74 39 FORW:PEP:TIME:LOW 1E-3
@CF 40 FORW:PEP:TIME:UPP 100E-3
@7F 41 FORW:PEP:TIME:DEF 60E-3
@B2 42 FORW:CCDF:RANG:LOW1 0.25
@B4 43 FORW:CCDF:RANG:LOW2 0.25
@B6 44 FORW:CCDF:RANG:LOW3 0.25
@B8 45 FORW:CCDF:RANG:LOW4 0.25
@2F 46 FORW:CCDF:RANG:UPP 75
@42 47 FORW:CCDF:RANG:LSD1 -2
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Query commands
@44 48 FORW:CCDF:RANG:LSD2 -2
@46 49 FORW:CCDF:RANG:LSD3 -2
@3F 50 FORW:CCDF:RANG:LSD4 -2
@EA 51 REFL:AVER:RANG:LOW 0.0007
@35 52 REFL:AVER:RANG:UPP 75
@1A 53 REFL:AVER:RANG:LSD -5
@93 54 FILT:AVER:AUTO
@7C 55 FILT:AVER:COUN:UPP 256
@EB 56 FILT:AVER:COUN:DEF 1
@FF 57 FILT:INT:TIME:LOW 1.06E-3
@D1 58 FILT:INT:TIME:UPP 111E-3
@1D 59 FILT:INT:TIME:DEF 36.67E-3
@99 60 FILT:VID:NRBW 4
@58 61 FILT:VID:BW1 4kHz
@B8 62 FILT:VID:BW2 200kHz
@3E 63 FILT:VID:BW3 4MHz
@43 64 FILT:VID:BW4 SPSP
@BC 65 MOD:TYPE:NRST 4
@8E 66 MOD:TYPE:ST IS95, WCDMA, DVB-T,DAB, OFF
@4F 67 MOD:RATE:LOW 0
@36 68 MOD:RATE:UPP 8.2E6
@7A 69 MOD:RATE:DEF 4.096E6
@93 70 OFFS:RANG:LOW 0
@F8 71 OFFS:RANG:UPP 100
@72 72 OFFS:RANG:DEF 0
7.2.5 STAT
This command group represents the status reporting system, see Chapter 8.4, "Status
reporting system", on page 77. It gives information about the power sensor status
including all current settings and all occurred errors.
After querying the errors, all temporary errors — mainly operating errors — are
cleared, all permanent errors remain.
Remote commands
STAT:MEAS.....................................................................................................................60
STAT:ERR:TEXT.............................................................................................................. 61
STAT:ERR:CODE.............................................................................................................62
STAT:ERR:VALS.............................................................................................................. 63
STAT:MEAS
Returns the power sensor status. For each setting, the current value is output.
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Query commands
Example:
STAT:MEAS
# Response: Multiple lines with the following structure:
@26 pack 34
@04 01 Cal.mode lock: ON
@CE 02 DMA mode: OFF
@EE 03 Forward meas. func.: AVER
@AC 04 Reverse meas. func.: RCO
@84 05 Burst period: 1.0000E-01
@43 06 Burst width: 1.0000E-02
@01 07 PEP hold mode: DEF
@35 08 PEP hold time: 6.0000E-02
@93 09 CCDF threshold: 4.0000E+01
@C3 10 Average filt mode: AUTO
@C3 10 Average filt mode: AUTO
@DD 12 ADC integ. time mode: USER
@47 13 ADC integration time: 3.6667E-02
@20 14 Video Bandwidth: 2.0000E+05
@75 15 Spread spectr.weight. OFF
@A9 16 Correction Frequency 1.0000E+09
@F0 17 Forward display ON
@C7 18 Reflection display ON
@5E 19 State display ON
@DE 20 Sign. chan. assignmnt 1>2
@40 21 Reference port SOUR
@40 22 Display resolution LOW
@3E 23 Modulation type OFF
@54 24 Modulation rate 4.0960E+05
@62 25 Attenuation 1.0000E+00
@40 26 C eff1 1.0000E-11
@48 27 C eff2 7.0000E-11
@4E 28 Measured parameters:
@50 29 Average zero value ADC1: -3.3953E-06
@47 30 Average zero value ADC2: -2.5194E-06
@3A 31 PEP zero value for 4kHz: +6.4601E-06
@56 32 PEP zero value for 200kHz: -3.2413E-05
@27 33 PEP zero value for 4MHz: -1.5866E-04
@E2 34 Current temperature: 27.045
STAT:ERR:TEXT
Returns the error status as a plain-text list. The following information is included:
●
Status of the analog hardware (HW PARAMETERS)
●
Results of other checks (PERMANENT ERRORS)
●
Operating errors (OPERATION ERRORS)
Each check is evaluated as OK or ERROR.
See also Chapter 8.4.2, "Error status", on page 78.
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Remote control commands
Query commands
Example:
STAT:ERR:TEXT
# Response: Multiple lines with the following structure.
# Example (DMA OFF):
@27 pack 26
@6E 01 HW PARAMETERS:
@07 02 SUPPLY VOLTAGE + (ANA) OK
@0C 03 SUPPLY VOLTAGE + (DIG) OK
@0B 04 SUPPLY VOLTAGE - (ANA) OK
@10 05 SUPPLY VOLTAGE - (DIG) OK
@1B 06 LOGIC SUPPLY OK
@68 07 SENSOR SUPPLY OK
@61 08 FORW. CONTROL VOLTAGE OK
@4D 09 REFL. CONTROL VOLTAGE OK
@6E 10 CCDF OUTPUT LOW OK
@7D 11 CCDF OUTPUT HIGH OK
@3B 12 CCDF MEDIUM THRESHOLD OK
@0C 13 TEMPERATURE OK
@66 14 PERMANENT ERRORS:
@CF 15 COMMUNICATION ADC 1 OK
@D1 16 COMMUNICATION ADC 2 OK
@6B 17 PEP CIRCUIT OPERATION OK
@8D 18 FLASH READ OK
@DD 19 FLASH WRITE OK
@FD 20 CAL. VALUES CHECKSUM OK
@F5 21 CALIBRATION VALUES OK
@6C 22 OPERATION ERRORS:
@D9 23 CALIBRATION LOCKED OK
@37 24 SYNTAX ERROR
@DE 25 RANGE ERROR
@E2 26 ZERO OK
STAT:ERR:CODE
Returns the error status as a single-line error code for fast evaluation.
Each error condition in Table 8-1 is assigned 1 flag. The code starts with the highest
flag no. on the left:
<flag no. 23>...<flag no. 1>
Erroneous parameters are indicated by 1, correct parameters by 0.
Example:
STAT:ERR:CODE
# For the example in STAT:ERR:TEXT, the response looks
# as follows:
@52 00000000000000000000110
# For the flags with number 3 and 2, an error is present.
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Remote control commands
General commands
STAT:ERR:VALS
Gives details on the status of the analog hardware, listed in STAT:ERR:TEXT under
HW PARAMETERS. Returns the internal test voltages together with their limit values.
Example:
STAT:ERR:VALS
@DD pack 12_____________________________________
@3D 01 SUPPLY VOLTAGE + (ANA): +4.7500E+00 +5.0191E+00 +5.2500E+00
@47 02 SUPPLY VOLTAGE + (DIG): +4.7500E+00 +5.0394E+00 +5.2500E+00
@45 03 SUPPLY VOLTAGE - (ANA): -5.2500E+00 -5.0333E+00 -4.7500E+00
@53 04 SUPPLY VOLTAGE - (DIG): -5.2500E+00 -5.0639E+00 -4.7500E+00
@4D 05 LOGIC SUPPLY : +3.1350E+00 +3.3130E+00 +3.4650E+00
@9E 06 SENSOR SUPPLY : +6.0000E+00 +1.1937E+01 +2.8500E+01
@A9 07 FORW. CONTROL VOLTAGE : -4.2500E+00 -6.9953E-02 +4.2500E+00
@89 08 REFL. CONTROL VOLTAGE : -4.2500E+00 -2.1738E-01 +4.2500E+00
@0E 09 CCDF OUTPUT LOW : -9.9987E-04 +9.6858E-05 +9.9987E-04
@C5 10 CCDF OUTPUT HIGH : +6.8000E-01 +7.5665E-01 +8.2000E-01
@6B 11 CCDF MEDIUM THRESHOLD : -1.3500E+00 -1.2364E+00 -1.1500E+00
@4B 12 TEMPERATURE : -1.5000E+01 +2.9497E+01 +6.5000E+01
7.3 General commands
APPL..............................................................................................................................63
BOOT............................................................................................................................. 64
DMA............................................................................................................................... 64
HELP..............................................................................................................................64
ID................................................................................................................................... 66
PURGE...........................................................................................................................67
SETUP:SAVE..................................................................................................................67
SETUP:RCL.................................................................................................................... 67
APPL
Enables the measurement mode.
The response indicates the operating status of the power sensor before the command
was sent:
boot
●
The power sensor is in boot mode.
Active on power-up or on sending BOOT. Prepares the power sensor for loading
new firmware.
busy
●
The power sensor is not ready to accept commands, e.g. during the power-up test.
oper
●
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Remote control commands
General commands
The power sensor is in its normal operating mode, the measurement mode. Enable
the power sensor by sending APPL at least once. See Chapter 4.3.2.2, "Testing the
connection", on page 29.
BOOT
Enables the boot mode. No response is given.
The command has the same effect as switching off and on the supply voltage.
DMA <parameter>
Enables or disables filling up all response lines.
Parameters:
<parameter> ON
Allows DMA-supported transfer to the controller.
All response lines have a uniform length of 50 characters,
including the end-of-line characters CR and LF.
Shorter response lines are filled with '_' (ASCII 95/0x5F)
between the message content and the end of the line.
OFF
The filling-up function is disabled, resulting in variable line
length. This setting can be useful for time-critical applications
(without DMA).
RESET: ON
HELP <parameter>
Returns a brief description of the specified commands.
Response: lists all specified commands.
Parameters:
<parameter> <no parameter>
All root commands are listed.
<first letter of a command>
All commands starting with the letter are listed.
<root command>:HELP
All commands of this subsystem are listed.
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Remote control commands
General commands
Example:
HELP
# Lists all commands of the highest command level:
@DE pack 31_____________________________________
@E9 01 appl - operation mode ('boot' or 'oper')
@93 02 basever - base unit version control comm.
@4C 03 boot - soft reset_______________________
@37 04 burs - burst settings (burs:help)_______
@36 05 calib - calibration commands (calib:help)
@40 06 ccdf - CCDF threshold in W______________
@29 07 dir - meas. direction (1>2|2>1|AUTO)___
@77 08 disp - meas. display config. (disp:help)
@F3 09 dma - padding to 50 char. (ON|OFF)_____
@11 10 filt - filter settings (filt:help)______
@80 11 for - forward meas. function (for:help)
@E0 12 freq - correction freq. in Hz___________
@3E 13 ftrg - free run trigger_________________
@82 14 fwup - firmware update__________________
@3E 15 help - this command_____________________
@7C 16 id - return firmware ID_______________
@C0 17 mod - modulation type (mod:help)_______
@DD 18 offs - attenuation correction___________
@70 19 pep - PEP function settings (pep:help)_
@28 20 port - reference port (SOUR|LOAD|NONE)__
@A6 21 purge - purge receive buffer_____________
@96 22 qstn - return stock number______________
@FE 23 reset - initialization of all parameters_
@97 24 rev - reverse meas. function (rev:help)
@80 25 rtrg - remote trigger___________________
@27 26 serv - service commands (serv:help)_____
@A3 27 setup - sensor setups (setup:help)_______
@DA 28 spec - output parameter boundaries______
@EC 29 stat - device state (stat:help)_________
@75 30 test - serial interface test____________
@B7 31 zero - initiate zero correction_________
Example:
HELP F
# Lists all root commands starting with an "F".
@DF pack 05_____________________________________
@11 01 filt - filter settings (filt:help)______
@80 02 for - forward meas. function (for:help)
@E0 03 freq - correction freq. in Hz___________
@3E 04 ftrg - free run trigger_________________
@82 05 fwup - firmware update__________________
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Remote control commands
General commands
Example:
Example:
CALIB:HELP
# Lists all calibration commands.
@DF pack 05_____________________________________
@11 01 filt - filter settings (filt:help)______
@80 02 for - forward meas. function (for:help)
@E0 03 freq - correction freq. in Hz___________
@3E 04 ftrg - free run trigger_________________
@82 05 fwup - firmware update__________________
CALIB:HELP
@E4 pack 28_____________________________________
@A7 01 acal - auto calibration of ADCs_________
@D5 02 calc - initiate calculation of cal. data
@A7 03 ccdf - CCDF calibration_________________
@CC 04 err - calibration errors (calib:help)__
@96 05 fcorr1 - freq. correction constant_______
@98 06 fcorr2 - freq. correction constant_______
@76 07 freq1 - forward freq. cal. (# pow. freq.)
@7F 08 freq2 - reverse freq. cal. (# pow. freq.)
@41 09 help - this command_____________________
@BA 10 init - set all cal. values to default___
@BA 11 kappa1 - constant in correction formula__
@BC 12 kappa2 - constant in correction formula__
@5A 13 lin1 - forward lin. cal. (# pow.)_______
@63 14 lin2 - reverse lin. cal. (# pow.)_______
@D1 15 lnfreq1 - index of forward ref. freq.____
@DA 16 lnfreq2 - index of reverse ref. freq.____
@37 17 load - load binary calibration data_____
@49 18 lock - lock calibration mode____________
@77 19 offs - internal offset__________________
@C7 20 rcal - read ADC calibration values______
@FF 21 read - read calibration data as text____
@A7 22 rvid - measurement of video resistance__
@52 23 save - save binary calibration data_____
@7E 24 show - output calibration data as text__
@52 25 tcorr1 - forward temp. corr. constant____
@5B 26 tcorr2 - reverse temp. corr. constant____
@FD 27 trg - trigger for cal. measurement_____
@02 28 unlock - unlock cal. mode (keyword)______
ID
Returns the identification string that is composed of the following items, separated by
spaces:
●
Name of the manufacturer, i.e. "Rohde&Schwarz"
●
Power sensor type
●
Firmware version
●
Firmware build date in ISO format (YYYY-MM-DD)
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Remote control commands
Selftest
PURGE
Deletes the contents of the input buffer, thus preventing the execution of waiting commands. Useful to prepare the power sensor quickly for a new measurement task.
No response is given.
SETUP:SAVE <num>
Saves the current power sensor status in the specified intermediate memory.
Response: OK
Parameters:
<num> The status saved in memory no. 0 corresponds to the switch-on
status.
Range: 0 to 4
SETUP:RCL <num>
Recalls the power sensor status from the specified intermediate memory.
Parameters:
<num> The status saved in memory no. 0 corresponds to the switch-on
7.4 Selftest
See also Chapter 9.3, "Selftest", on page 83.
SERV:TEST
Performs a selftest and updates the error status.
You can read the error status using with the commands of the STAT:ERR group, see
Chapter 7.2.5, "STAT", on page 60. An error is output only if a hardware error has
occurred. Temporary errors, e.g. syntax or other input errors, are not considered.
Response: OK or ERROR
status.
Range: 0 to 4
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Remote control commands
Selftest
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8 Remote control basics
8.1 Device-dependent messages
Remote control basics
Device-dependent messages
● Device-dependent messages..................................................................................69
● Hardware functions................................................................................................. 75
● Command processing............................................................................................. 76
● Status reporting system.......................................................................................... 77
Messages from the power sensor are called device-dependent messages. These messages are transmitted on the TXD and RXD pair of lines of the serial RS-422 interface.
The ASCII code (ISO 7-bit code) is used. All device-dependent messages are line-oriented. A message line consists of several ASCII characters terminated by at least one
end-of-line character.
A message sent to the power sensor can be max. 255 characters long. Accepted endof-line characters are all characters in the ASCII code range 1 to 13 (0x0D). The power
sensor terminates its responses with the character combination 13 (0x0D) + 10 (0x0A).
8.1.1 Structure and syntax of device-dependent messages
The command syntax was designed with a view to maximum speed rather than complete compliance with the SCPI standard. Device-dependent messages are divided as
follows:
●
Setting and query commands, see Chapter 8.1.1, "Structure and syntax of device-
dependent messages", on page 69
●
Device responses, see Chapter 8.1.3, "Device responses", on page 71
Messages belonging to commands are sent by the controller to the power sensor.
Device responses are sent from the power sensor to the controller.
8.1.2 Setting commands and queries
The syntax has a tree structure with several hierarchical levels. Commands have different hierarchical levels depending on the expected frequency of application, the logic
group assignment and the required speed of execution.
The number of mnemonics (keywords) that make up a command corresponds to the
number of its hierarchical levels. The mnemonics of a command must be separated
from one another by colons. Examples for typical structures of hierarchical commands:
●
<system>:<subsystem>:<function>
●
<system>:<function>
Each hierarchical level consists of two to five characters. Refer to the alphabetical list
of all commands at the end of the user manual.
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8.1.2.1 Parameters
Remote control basics
Device-dependent messages
If an input parameter is added to a command, separate it from the command by at
least one blank. Terminate a command with an end-of-line character. You can send
several commands in a command line, but they must be separated by commas.
If a command is not understood, an error message is returned: Error SYNTAX
(xxxx). xxxx is the command or part of command that was not understood.
Example: Syntax errors
The setting command FR:AVER causes the following response:
@6C Error SYNTAX (fr:aver)______________________
The command as a whole is not understood because the system mnemonic is erroneous, FR instead of FOR.
The setting command FOR:AVR causes the following response:
@71 Error SYNTAX (avr)__________________________
The function mnemonic is erroneous, AVR instead of AVER.
Parameters can be floating-point numbers, integers and text. In the description of
remote commands, numeric input parameters are represented by <num>, text parameters by <parameter>.
Floating-point numbers
Understood by the power sensor in all common representations. You can omit leading
zeros, positive signs of mantissas or exponents, and a decimal point at the rightmost
digit of the mantissa.
Take the number 53 as an example. You can enter it in the following ways:
●
53
●
0.53e+2
●
.5300e+02
●
+005.3E01
●
5300e-002
An exponent has to start with the "E" or "e" character. The range of numbers is from
−32000 to +32000. Exponents without mantissa are not allowed.
Integers
Depending on the range of values, they can have a positive or negative sign. You can
omit the positive sign. If an integer parameter contains a character that does not
belong to the character set [0 to 9, +, -], the character in question and all subsequent
characters are ignored. No error message is output.
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8.1.3 Device responses
Remote control basics
Device-dependent messages
Input limits
Exist for all number parameters. If you try to enter a parameter outside the defined
range of values, it is rejected with an error message: Error RANGE. Correct entries
are acknowledged with:
old: <old parameter> new: <new parameter>
Except for FOR and REV. Here, correct entries are acknowledged with:
old:<old parameter> new:<new parameter>
Text parameters
Restricted to a few words like USER, DEF, LOW, HIGH. You can use upper-case or
lower-case characters, but otherwise, you have to enter the text parameters exactly as
they are specified in the command description.
The power sensor returns at least one line in response to each message. No response
indicates a communication problem between the controller and the power sensor.
Device responses are floating-point numbers, integers and text. The structure of device
responses is explained in detail for each query command. All device responses have a
header with a checksum, but single-line and multiple-line responses have different
structures. The length of response lines is explained in DMA on page 64.
8.1.3.1 Checksum header
Placed at the beginning of each response line to enable the detection of transmission
errors. The header starts with @, followed by the last two digits of the hexadecimal
checksum and a blank:
@51 +8.1234E-02 +3.4567E-03_____________________
The checksum is formed from the sum of all ASCII codes from the fifth character, modulo 256.
8.1.3.2 Status information
Consists of 11 characters and holds information on the validity of measured values.
You can add the status field to the relevant device responses, see DISP:STAT
on page 40.
CR
LF
First character
Indicates whether a hardware error is present.
●
No error:
_
●
Error:
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Remote control basics
Device-dependent messages
e for error
Hardware errors are also detected in the selftest, see Chapter 9.3, "Selftest",
on page 83.
Second character
Indicates whether the defined measurement limits are complied with.
●
Values below the specified power range or outside the allowed temperature range:
i for invalid
●
Values above the specified power range:
o for overrange
●
All conditions are met:
_
Third and fourth characters
The third and fourth character of the status field
Indicate the test function of the forward channel, see Chapter 7.1.7, "FOR",
on page 45.
●
Average power (AVER):
av
●
Distribution function (CCDF)
cd
●
Crest factor (CF)
cf
●
Calculated burst average (CBAV)
cb
●
Measured burst average (MBAV)
mb
●
Peak envelope power (PEP)
pp
Fifth and the sixth characters
Indicate the test function of the reverse channel, see Chapter 7.1.13, "REV",
on page 53.
●
Average power (POW)
pw
●
Reflection coefficient (RCO)
rc
●
Return loss (RL)
rl
●
Standing wave ratio (SWR)
sw
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Remote control basics
Device-dependent messages
Seventh character
Indicates the forward power direction, see Chapter 7.1.3, "DIR", on page 38.
●
Privileged direction, source at port 1
1
●
Inverse direction, source at port 2
2
Last four characters
Indicate the settings of the averaging filters for the physical measurement channel, see
Chapter 7.1.6, "FILT", on page 41.
Possible values are 0 to 8, standing for the averaging counts from 20 (= 1) to 28 (=
256).
●
Average power (forward):
7th character
●
Average power (reverse):
8th character
●
Peak envelope power:
9th character
●
Distribution function:
10th character
Averaging is made over 2N values. The exponent N (0 to 8) is output as an ASCII character for each measurement channel.
Example:
Device responses with status field upon triggering a measured value:
DISP:STAT ON;FTRG
@2E +2.1234E+01 +3.4567E-03 __avpw15511 ________
The response is valid: no hardware error, no overrange or underrange. The returned
values are the average powers in the forward and reverse channels. Averaging was
made over 25 = 32 values in each channel.
@32 +9.4823E+03 +5.9999E-03 e_mbrc12200 ________
The response is invalid since a hardware error is signaled.
@3C +3.5277E-04 +3.4567E-04 _ipprc22211 ________
The response is questionable since the peak envelope power specified in data sheet is
smaller than the returned value.
@15 +3.3244E+02 +1.2110E-01 _oavrc13300 ________
Overrange: The forward power exceeds the measurement range permitted in the data
sheet.
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8.1.3.3 Multiple-line responses
Remote control basics
Device-dependent messages
Some device responses take up several lines, e.g. the response to SPEC. To detect
transmission errors reliably and to make interpretation easier, multiple-line responses
are output together with additional information.
In the first line of a multiple-line response, the keyword pack xy follows the checksum
header. xy indicates the number of lines to be expected.
All subsequent response lines are numbered consecutively. The number follows the
checksum header. The consecutive numbers help you to detect missing lines easily if
transmission is disturbed.
Below is an example of multiple-line response with 'HH' standing for the checksum
header and 'xxxxxx' representing the useful information:
Example:
"HH" stands for the checksum header, and "xxxxxx" for the delivered information.
@25 pack 06
@HH 01 xxxxxx
@HH 02 xxxxxx
@HH 03 xxxxxx
@HH 04 xxxxxx
@HH 05 xxxxxx
@HH 06 xxxxxx
8.1.3.4 Status messages
busy
If you send a command while the last command is still executed, the power sensor
ignores the new command and sends the following message:
@9B busy________________________________________
This issue can occur with commands that require a long execution time. Wait and send
the new command again.
Querying the power sensor status
Send the ? command.
The response depends on the operating mode of the power sensor:
@A8 occupied____________________________________
A measurement is running.
@76 idle________________________________________
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F-AVG
amplifier
Broadband
amplifier
Lowpass
filter
Highpass
filter
Video filter
Peak hold
circuit
F-ADC
R-AVG
amplifier
Temperature
sensor
R-detector
F-detector
CCDF
DAC
CCDF
Circuit
Multiplexer
R-ADC
µP
C1
C1
C2
C2
HW test points
Forward
Power
Reverse
Power
Directional coupler
1
2
8.2 Hardware functions
Remote control basics
Hardware functions
The power sensor is waiting for new commands. If a new command is sent, the power
sensor executes it immediately.
Figure 8-1: Hardware functions
The power sensor is connected between the source and the load, see Figure 3-1. Two
RF signals are available at the outputs of the directional coupler. One RF signal is proportional to the forward wave, from the source to the load. The other RF signal is proportional to the reflected wave, from the load to the source. The output voltages of the
two detectors follow the forward and reverse envelope powers. To measure the average powers, the output voltages undergo narrowband amplification, F-AVG and R-AVG
amplifiers, digitization and error compensation in the microprocessor. The error compensation is made with stored correction values, considering the temperature, frequency and linearity of the power sensor. From the ratio of the two average powers,
the load matching can be determined in terms of return loss, SWR or reflection coefficient.
To measure the peak envelope power (PEP), the measured burst average (MBAV) and
the complementary cumulative distribution function (CCDF), the output signal of the
forward detector must undergo broadband processing. To this end, the outputs of the
F-AVG amplifier and an AC-coupled broadband amplifier are combined using a frequency filter. Unwanted signal components such as broadband noise or high-frequency
modulation components are eliminated by a switchable video lowpass filter before further processing, see FILT:VID.
The peak hold circuit delivers an output voltage corresponding to the peak envelope
power of the forward signal. The CCDF circuit outputs a pulsed signal whose average
value is proportional to the probability of the envelope power exceeding a given reference level, the CCDF threshold. The CCDF circuit is also used for measuring the average burst power, see MBAV.
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Input buffer
Input unit
Command
detection
Command
execution
Data record
(represents
hardware
settings)
Device
hardware
Status
reporting
system
Error handling
Output buffer
Output unit
RS 422
RS 422
Cyclic background
measurements /
Calibration selftests
Time control
8.3 Command processing
Remote control basics
Command processing
Digitization is performed by two highly linear ΣΔ A/D converters, F-ADC and R-ADC,
with two measurement channels each. The preset measurement time of the two converters is 36.667 ms. You can change this time using FILT:INT:TIME. Further
parameters such as temperature and various test voltages are measured during normal operation or in the selftests by the multiplexer connected ahead of the reverse A/D
converter.
Figure 8-1 illustrates the physical and logic function blocks used for command process-
ing. Commands are processed and executed from top to bottom.
Figure 8-2: Command processing
The input unit receives the commands character by character via the serial interface
and saves them in the input buffer. The input unit sends a message to the command
detection circuit if the input buffer is full or a delimiter is received.
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8.3.1 Device hardware and data record
Remote control basics
Status reporting system
If the input buffer is full, bus traffic is stopped using the XON/XOFF protocol, and the
data received up to this time are processed. Then, data traffic is resumed. If the buffer
is not full, the input unit can receive the next command while the previous command is
detected and executed.
The command detection circuit analyzes the data received from the input unit in the
sequence of the data received. Each detected command is immediately passed on to
command execution.
Syntax errors are passed on from the command detection circuit to the error handling
unit. The rest of the command line is analyzed and processed as far as possible.
Device hardware is the analog circuitry used for measuring. The controller is not part of
the device hardware. The hardware settings are represented by the data record of the
measurement program.
Setting commands generally cause a change of the data record and the device hardware. The data record management does not pass on any new values to the hardware
until it is requested to do so by the command detection circuit.
8.3.2 Output unit
The output unit collects the information from the data record management, processes it
in accordance with the rules described in Chapter 8.1.3, "Device responses",
on page 71, and saves them in the output buffer. The output buffer has a capacity of
256 characters. If the requested information is longer than 256 characters, it is divided
into several lines, see Chapter 8.1.3.3, "Multiple-line responses", on page 74.
8.3.3 Cyclic background power and temperature measurements
The cyclic background power and temperature measurements are performed independently from the interface data traffic. In the freerun trigger mode, FTRG, the background measurement continuously supplies measured power values and thus ensures
a high refresh rate of the display. The background temperature measurement is performed once per second. The results are used for correcting the temperature response
of the detectors.
8.4 Status reporting system
The status reporting system provides information on the power sensor status. Two different statuses are distinguished.
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8.4.1 Device status
8.4.2 Error status
Remote control basics
Status reporting system
The device status covers all parameters relating to measurements. It is output as a
multiple-line response by STAT:MEAS. You can reset all these parameters to a defined
initial status by RESET.
The error status is a report of occurred errors. You can output the error status either as
a plain-text multiple-line response or as code, see Chapter 7.2.5, "STAT", on page 60.
The errors are divided in two categories.
Temporary errors
For example a syntax error or a wrong range, see OPERATION ERRORS in Table 8-1.
Buffer the temporary errors if you want to evaluate them.
Permanent errors
Hardware errors or errors that have occurred during calibration, see HW PARAMETERS
and PERMANENT ERRORS in Table 8-1.
Permanent errors remain until their cause is eliminated and can only be fixed by service personnel authorized by Rohde & Schwarz. See Chapter 9.4, "Contacting cus-
tomer support", on page 85.
Error status overview
Table 8-1 gives an overview of all errors that can occur. The flag number indicates the
position of an error within the code, see STAT:ERR:CODE. The error description is
identical with the multiple-line response obtained as response to STAT:ERR:TEXT.
Table 8-1: Error status overview
Position
(from
right)
HW PARAMETERS, see also Chapter 8.4.2.1, "Hardware parameter errors", on page 79.
23 SUPPLY VOLTAGE + (ANA) ERROR +5 V on analog board not present or out of tolerance
22 SUPPLY VOLTAGE + (DIG) ERROR +5 V on digital board not present or out of tolerance
Error description Cause
21 SUPPLY VOLTAGE − (ANA) ERROR −5 V on analog board not present or out of tolerance
20 SUPPLY VOLTAGE − (DIG) ERROR −5 V on digital board not present or out of tolerance
19 LOGIC SUPPLY ERROR +3.3 V on analog board not present or out of tolerance
18 SENSOR SUPPLY ERROR Sensor supply out of tolerance
17 FORW. CONTROL VOLTAGE ERROR Offset control voltage for forward amplifier (test point K603:13)
out of tolerance
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Remote control basics
Status reporting system
Position
(from
right)
16 REFL. CONTROL VOLTAGE ERROR Offset control voltage for reflection amplifier (test point K603:14)
15 CCDF OUTPUT LOW ERROR Min. settable CCDF threshold voltage out of tolerance
14 CCDF OUTPUT HIGH ERROR Max. settable CCDF threshold voltage out of tolerance
13 CCDF MEDIUM THRESHOLD ERROR Average CCDF threshold voltage (test point K603:12) out of tol-
12 TEMPERATURE ERROR Temperature reading out of tolerance
PERMANENT ERRORS, see also Chapter 8.4.2.2, "Permanent errors", on page 80.
11 COMMUNICATION ADC 1 ERROR Communication error between A/D converter in forward channel
10 COMMUNICATION ADC 2 ERROR Communication error between A/D converter in reverse channel
9 PEP CIRCUIT OPERATION ERROR Fault in peak-hold circuit (T609, V606, T608)
8 FLASH READ ERROR Fault when reading calibration data from Flash memory
7 FLASH WRITE ERROR Fault when writing calibration data to Flash memory
6 CAL. VALUES CHECKSUM ERROR Checksum test of calibration data set failed.
Error description Cause
out of tolerance
erance
(T604) and processor
(T605) and processor
5 CALIBRATION VALUES ERROR Calibration fault or calibration value out of tolerance. For further
information, use CALIB:ERR:TEXT or CALIB:ERR:CODE.
OPERATION ERRORS
4 CALIBRATION LOCKED ERROR A calibration function has been called without unlocking calibra-
tion mode using CALIB:UNLOCK PASSWORD.
3 SYNTAX ERROR Faulty input
2 RANGE ERROR A numerical parameter exceeds its limits.
1 ZERO ERROR Zeroing failed due RF power applied.
8.4.2.1 Hardware parameter errors
Information for service personnel authorized by Rohde & Schwarz.
Error flags no. 12 to 23
All hardware parameters are measured upon power-up of the power sensor and upon
starting a selftest, see SERV:TEST. These errors can be output as voltage values
together with their tolerances, see STAT:ERR:VALS.
Possible causes:
●
The power sensor hardware is faulty.
●
The supply voltage of the power sensor is low.
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8.4.2.2 Permanent errors
Remote control basics
Status reporting system
Information for service personnel authorized by Rohde & Schwarz.
Error flags no. 10 and 11
Occurrence: At any time. The errors are immediately written into the error status report.
Error cause: The power sensor hardware is faulty.
Error flag no. 9
Occurrence: Only during a triggered measurement in the PEP, MBAV and CF measurements.
Error cause: The power sensor hardware is faulty.
Error flag no. 8
Occurrence: Only upon power-up and together with error flag no. 6 or a loss of calibration data.
Error cause: Flash memory is defective.
Error flag no. 7
Occurrence: Only when leaving the calibration mode. With successful calibration, the
calibration data are written into Flash memory upon leaving the calibration mode.
Possible causes:
●
Flash memory is defective.
●
A power supply fault has occurred while data were being written into Flash memory.
Error flag no. 6
Occurrence: Only upon power-up.
Possible causes:
●
The power sensor is not calibrated yet.
●
Flash memory is defective.
●
A power supply fault has occurred while data were being written into Flash memory.
Error flag no. 5
Represents the sum of all faults that can occur in calibration. Error flag no. 5 is set if at
least one calibration parameter is out of tolerance.
To make troubleshooting easier, saving erroneous calibration data into Flash memory
is not disabled.
Error flag no. 5 remains set until the supply voltage is switched off.
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Further information
●
Chapter 9, "Troubleshooting", on page 83
Remote control basics
Status reporting system
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Remote control basics
Status reporting system
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9 Troubleshooting
9.1 Test setup
9.2 Power-up selftest
Troubleshooting
Selftest
Before starting measurement operation, wait until the instruments have warmed up.
See Chapter 3.1.5, "Connecting to a computer or base unit", on page 17.
The R&S NRT‑Zxx directional power sensors perform an automatic test of several
hardware parameters after power-up.
Using remote control
The result of the power-up test is recorded as error status, see Chapter 8.4.2, "Error
status", on page 78.
► Send one of the following commands:
● STAT:ERR:CODE
● STAT:ERR:TEXT
The error status is also coded in the status field of a device response, see Chap-
ter 8.1.3, "Device responses", on page 71.
If you use R&S Virtual NRT, you can display the status field permanently: "Options" >
"State Indicator".
Using a base unit
Errors in the power-up test are indicated in the notification center of the base unit. See
the user manual of the base unit for details.
If the errors are grave, the R&S NRT-Zxx is not recognized by the base unit.
9.3 Selftest
The selftest gives you detailed information that you can use for troubleshooting. For
example, it helps you to detect hardware problems. If a hardware problem occurs, contact Rohde & Schwarz customer service, see Chapter 9.4, "Contacting customer sup-
port", on page 85.
Using the user interface of R&S Virtual NRT
► Select "Sensor" > "Selftest".
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Troubleshooting
Selftest
If all error state parameters are marked as "OK", the selftest is passed successfully.
Using a base unit
You can perform a selftest of a connected power sensor using manual operation or
remote control. See the user manual of the base unit for details.
Using remote control
1. Send SERV:TEST.
2. Read the error status using STAT:ERR:CODE or STAT:ERR:TEXT.
Using a terminal program
► Send SERV:TEST to start a selftest.
Responses (examples):
@30 OK__________________________________________
●
Selftest passed.
@03 ERROR_______________________________________
●
Selftest failed.
► Send STAT:ERR:CODE to query the error code.
Responses (examples):
@1B 00000000000000000000000_____________________
●
No error.
@1D 01100000000000000000000_____________________
●
Error: The negative supply voltage is faulty.
For a reference on the error codes and error texts, see Table 8-1.
► Send STAT:ERR:TEXT to query the error text.
Example: The negative supply voltage is faulty. The following text is returned:
@E2 pack 26_____________________________________
@73 01 HW PARAMETERS:___________________________
@98 02 SUPPLY VOLTAGE + (ANA) OK_______________
@9D 03 SUPPLY VOLTAGE + (DIG) OK_______________
@6F 04 SUPPLY VOLTAGE - (ANA) ERROR____________
@74 05 SUPPLY VOLTAGE - (DIG) ERROR____________
@AC 06 LOGIC SUPPLY OK_______________
@F9 07 SENSOR SUPPLY OK_______________
@F2 08 FORW. CONTROL VOLTAGE OK_______________
@DE 09 REFL. CONTROL VOLTAGE OK_______________
@FF 10 CCDF OUTPUT LOW OK_______________
@0E 11 CCDF OUTPUT HIGH OK_______________
@CC 12 CCDF MEDIUM THRESHOLD OK_______________
@9D 13 TEMPERATURE OK_______________
@4E 14 PERMANENT ERRORS:________________________
@60 15 COMMUNICATION ADC 1 OK_______________
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9.4 Contacting customer support
Troubleshooting
Contacting customer support
@62 16 COMMUNICATION ADC 2 OK_______________
@FC 17 PEP CIRCUIT OPERATION OK_______________
@1E 18 FLASH READ OK_______________
@6E 19 FLASH WRITE OK_______________
@8E 20 CAL. VALUES CHECKSUM OK_______________
@86 21 CALIBRATION VALUES OK_______________
@54 22 OPERATION ERRORS:________________________
@6A 23 CALIBRATION LOCKED OK_______________
@D8 24 SYNTAX OK_______________
@7F 25 RANGE OK_______________
@73 26 ZERO OK_______________
If you need to transport or ship the product, see Chapter 11, "Transporting",
on page 95.
Technical support – where and when you need it
For quick, expert help with any Rohde & Schwarz product, contact our customer support center. A team of highly qualified engineers provides support and works with you
to find a solution to your query on any aspect of the operation, programming or applications of Rohde & Schwarz products.
Contact information
Contact our customer support center at www.rohde-schwarz.com/support, or follow this
QR code:
Figure 9-1: QR code to the Rohde
&
Schwarz support page
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Contacting customer support
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10 Testing the rated specifications
10.1 Test equipment
Testing the rated specifications
Test equipment
Checking the specifications for the measurement uncertainties given in the data sheet
requires an extensive test equipment. The more simple test setups described here are
suitable replacements for troubleshooting but have higher measurement uncertainties.
Table 10-1: Required test equipment
Item no. Instrument characteristics R&S type Stock No.
1 Power reflection meter R&S NRT2 1424.7005.02
Computer with R&S Virtual NRT installed and
R&S NRT‑Z5 USB interface adapter installed (discontinued R&S NRT‑Z3 interface adapter and
R&S NRT‑Z4 PCMCIA interface adapter are still
supported)
2 Signal generator
R&S NRT‑Z44: 400 MHz to 4 GHz
R&S NRT‑Z14: 25 MHz to 1 GHz
3 Power amplifier
R&S NRT‑Z44: 400 MHz to 4 GHz
R&S NRT‑Z14: 25 MHz to 1 GHz
Output power > 5 W
Gain > 25 dB
Harmonic suppression > 25 dB
4 Reference power sensor
R&S NRT‑Z44: 0.4 GHz to 4 GHz
R&S NRT‑Z14: 25 MHz to 1 GHz
15 W or 30 W
5 Reference power meter R&S NRX 1424.7005.02
R&S Virtual NRT
R&S NRP18S-20
R&S NRP18S-25
R&S NRP‑ZK6
cable
R&S NRP‑ZK8
cable
1424.6738.02
1424.6744.02
1419.0664.02
1424.9408.02
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10.2 Test setup
Testing the rated specifications
Test sequences
G
1 2 3 4 5 6
Figure 10-1: Test setup
1 = signal generator, see (2) in Table 10-1
2 = power amplifier, see (3) in Table 10-1
3 = harmonic filter
4 = DUT
5 = reference power sensor, see (4) in Table 10-1
6 = reference power meter, see (5) in Table 10-1
7 = power reflection meter, see (1) in Table 10-1
10.3 Test sequences
Wait with the test power switched off until the instruments have warmed up.
DUT
P
fwd
7
P
ref
Connect the device under test (DUT) and the reference power meter directly, because
connection cables produce errors in measurement due to their attenuation and reflection. If adapters are required between RF connectors, use precision adapters with low
attenuation and reflection.
The power measured in the following tests using one of the R&S NRT‑Zxx directional
power sensors is the power coming out of the power sensor. Therefore, set the offset
reference plane of the power reflection meter to load.
Checking the specifications for the measurement uncertainties given in the data sheet
requires an extensive test equipment. The test setups described here are simpler and
have higher measurement uncertainties. The limit values specified in Chapter 10.4,
"Performance test report", on page 92 consider these additional measurement uncer-
tainties.
10.3.1 Testing the AVG measurement
Test setup see Figure 10-1. Use a harmonic filter if the harmonic suppression of the
amplifier is < 25 dB.
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Testing the rated specifications
Test sequences
To perform the test
Perform the test sequence for both directions of the power sensor.
1. Signal generator:
a) Switch off the output power.
b) Set the test frequency according to Chapter 10.4, "Performance test report",
on page 92.
2. Power reflection meter:
a) Select the forward average measurement.
b) Set the offset reference plane to load.
c) Select automatic determination of the power flow direction.
d) Enter the test frequency.
e) Perform zeroing.
3. Reference power meter:
a) Enter the test frequency.
b) Activate frequency response correction.
c) Perform zeroing.
4. Signal generator:
a) Switch on the output power (test signal not modulated).
b) Set the level so that the reference power meter measures approx. 4 W power.
5. Calculate the power deviation of the DUT according to the following formula:
FP = 100 % · [( P
fwd
/ P
) − 1]
ref
6. Repeat the test sequence in a reverse measurement. In step 2, select the reverse
average measurement.
7. Calculate the power deviation for the reverse direction.
Compare the result with Chapter 10.4, "Performance test report", on page 92.
10.3.2 Testing the CCDF threshold
Test setup see Figure 10-1.
To perform the test
1. Signal generator: Switch off the output power.
2. Perform zeroing of:
a) Power sensor using the R&S NRT2 or R&S Virtual NRT.
b) Reference power meter
3. Enter the test frequency of 1 GHz on:
a) Signal generator
b) Power reflection meter
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Testing the rated specifications
Test sequences
c) Reference power meter
4. Reference power meter: Activate frequency response correction.
5. Signal generator:
a) Switch on the output power (test signal not modulated).
b) Set the level so that the reference power meter measures 3.8 W to 4.2 W
power.
6. Select at the power reflection meter:
a) CCDF measurement
b) CCDF threshold 3 W
c) Video bandwidth 4 kHz
7. Read the CCDF value.
8. Compare the result with Chapter 10.4, "Performance test report", on page 92.
9. Select at the power reflection meter:
a) CCDF measurement
b) CCDF threshold 5 W
c) Video bandwidth 4 kHz
10. Read the CCDF value.
11. Compare the result with Chapter 10.4, "Performance test report", on page 92.
10.3.3 Testing the PEP measurement
Test setup see Figure 10-1.
The PEP function is checked with the CF power indication.
To perform the test
1. Signal generator: Switch off the output power.
2. Perform zeroing of:
a) Power sensor using the R&S NRT2 or R&S Virtual NRT.
b) Reference power meter
3. Enter the test frequency of 1 GHz on:
a) Signal generator
b) Power reflection meter
c) Reference power meter
4. Reference power meter: Activate frequency response correction.
5. Select at the power reflection meter:
a) Crest factor (CF) measurement.
b) Video bandwidth 4 kHz
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10.3.4 Testing the directivity
Testing the rated specifications
Test sequences
6. Signal generator:
a) Switch on the output power (test signal not modulated).
b) Set the level so that the reference power meter measures 0.975 W to 1.025 W
power.
c) Set 80 % AM modulation.
d) Modulation frequency 0.4
kHz.
7. Read the CF value.
8. Compare the result with Chapter 10.4, "Performance test report", on page 92.
Test setup see Figure 10-1.
The directivity is calculated from the ratio of forward and reverse power with 50 V termination of the DUT. The return loss measurement of the power reflection meter provides this value.
To perform the test
1. Select at the power reflection meter:
a) Forward average measurement
b) Reflection return loss
c) High resolution
2. Connect the signal generator to port 1 of the DUT and the reference power sensor
to port 2.
3. Power reflection meter:
a) Set the offset reference plane to load.
b) Select automatic determination of the power flow direction.
4. Signal generator:
a) Switch off the output power.
b) Set the test frequency according to Chapter 10.4, "Performance test report",
on page 92.
5. Perform zeroing of the power sensor using the power reflection meter.
6. Signal generator: Switch on the output power (test signal not modulated).
7. Record the directivity (return loss).
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10.3.5 Testing the matching
Testing the rated specifications
Performance test report
DUT
1 2 3
Figure 10-2: Test setup for testing the matching
1 = reflection test system
2 = device under test
3 = precision 50 Ω termination
To perform the test
Perform the test sequence for both directions of the power sensor.
1. Measure the reflection coefficients s11 and s22 of the power sensor.
2. Frequency range depends on the power sensor:
● R&S NRT‑Z44: 400 MHz to 4 GHz
● R&S NRT‑Z14: 25 MHz to 1 GHz
3. Record the maximum values for the specified frequency ranges.
4. Repeat the sequence for the other direction.
10.4 Performance test report
You can print the performance test reports and fill in your test results.
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Testing the rated specifications
Performance test report
Table 10-2: R&S NRT‑Z14 test report
No. Characteristic Min. Act. 1 → 2 Act. 2 → 1 Max. Unit
1 AVG measurement, see 10.3.1
27.5 MHz −4.6 (−0.20)
32.5 MHz −4.6 (−0.20)
37.5 MHz −4.6 (−0.20)
45 MHz −3.9 (−0.17)
60 MHz −3.9 (−0.17)
85 MHz −3.9 (−0.17)
150 MHz −3.9 (−0.17)
250 MHz −3.9 (−0.17)
350 MHz −3.9 (−0.17)
450 MHz −3.9 (−0.17)
550 MHz −3.9 (−0.17)
650 MHz −3.9 (−0.17)
750 MHz −3.9 (−0.17)
850 MHz −3.9 (−0.17)
950 MHz −3.9 (−0.17)
+4.6 (+0.20) % (dB)
+4.6 (+0.20) % (dB)
+4.6 (+0.20) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
1000 MHz −3.9 (−0.17)
2 CCDF ratio with 3 W, see 10.3.2 100
CCDF ratio with 5 W, see 10.3.2
3 Peak-power measurement (CF value), see 10.3.3 3.53
4 Directivity, see 10.3.4
25 MHz 21.5
50 MHz 21.5
100 MHz 21.5
200 MHz 21.5
400 MHz 21.5
600 MHz 21.5
800 MHz 21.5
1000 MHz 21.5
5 Matching (Reflection coeff. s11, s22), see 10.3.5
25 MHz to 1000 MHz
--- 4.27 dB
+3.9 (+0.17) % (dB)
%
0 %
dB
dB
dB
dB
dB
dB
dB
dB
0.05
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Testing the rated specifications
Performance test report
Table 10-3: R&S NRT‑Z44 test report
No. Characteristic Min. Act. 1 → 2 Act. 2 → 1 Max. Unit
1 AVG measurement, see 10.3.1
0.22 GHz −4.6 (−0.20)
0.32 GHz −3.9 (−0.17)
0.39 GHz −3.9 (−0.17)
0.50 GHz −3.9 (−0.17)
0.63 GHz −3.9 (−0.17)
0.83 GHz −3.9 (−0.17)
1.00 GHz −3.9 (−0.17)
1.25 GHz −3.9 (−0.17)
1.75 GHz −3.9 (−0.17)
2.15 GHz −4.2 (−0.18)
2.50 GHz −4.2 (−0.18)
2.85 GHz −4.2 (−0.18)
3.15 GHz −4.3 (−0.19)
3.50 GHz −4.3 (−0.19)
3.85 GHz −4.3 (−0.19)
+4.6 (+0.20) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+3.9 (+0.17) % (dB)
+4.2 (+0.18) % (dB)
+4.2 (+0.18) % (dB)
+4.2 (+0.18) % (dB)
+4.3 (+0.19) % (dB)
+4.3 (+0.19) % (dB)
+4.3 (+0.19) % (dB)
4.00 GHz −4.3 (−0.19)
2 CCDF ratio with 3 W, see 10.3.2 100
CCDF ratio with 5 W, see 10.3.2
3 Peak-power measurement (CF value), see 10.3.3 3.53
4 Directivity, see 10.3.4
0.4 GHz 21.5
0.9 GHz 21.5
1.3 GHz 21.5
1.8 GHz 21.5
2.4 GHz 17.7
3.0 GHz 17.7
3.5 GHz 16.5
4.0 GHz 16.5
5 Matching (Reflection coeff. s11, s22), see 10.3.5
0.4 GHz to 3 GHz
> 3 GHz to 4 GHz
--- 4.27 dB
+4.3 (+0.19) % (dB)
%
0 %
dB
dB
dB
dB
dB
dB
dB
dB
0.06
0.08
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11 Transporting
Transporting
Packing
Use the original packaging material. It consists of antistatic wrap for electrostatic protection and packing material designed for the product.
If you do not have the original packaging, use similar materials that provide the same
level of protection.
Securing
When moving the product in a vehicle or using transporting equipment, make sure that
the product is properly secured. Only use items intended for securing objects.
Transport altitude
Unless otherwise specified in the data sheet, the maximum transport altitude without
pressure compensation is 4500 m above sea level.
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Transporting
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12 Maintenance, storage and disposal
12.1 Checking and setting the baud rate
Maintenance, storage and disposal
Checking and setting the baud rate
The product does not require regular maintenance. It only requires occasional cleaning. It is however advisable to check the nominal data from time to time.
This task requires the removal of the plastic housing. Proceed exactly as described
and leave the sealed metal casing closed. If you open the casing, the calibration is void
and you have to send the R&S NRT-Zxx to the R&S service.
The factory-set value is 38400 Bd. This setting is compatible with the basic units. If
necessary, you can change the baud rate. For available settings, see to Table 12-1.
To change the baud rate
1. Disconnect the power sensor from the computer or base unit, load and source. See
"To disconnect from the DUT" on page 17.
2. Place the power sensor on its front side with the power handling capacity diagram
(1) facing upwards.
2
1
3. Remove both screws indicated by position (2).
4. Remove the upper part of the plastic housing:
a) Lift it at the rear where you have removed the screws.
b) Remove it.
5. Set the baud rate by changing the dip switch positions. See Table 12-1.
The baud rate setting shown as an example is 19200 Bd.
6. Close the upper part of the plastic housing.
7. Screw the two screws back on.
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Maintenance, storage and disposal
Regular checks
Table 12-1: Baud rate settings
Baud rate DIP switch position
Left Right
38400 Bd Off Off
19200 Bd On Off
9600 Bd Off On
4800 Bd On On
12.2 Regular checks
If the power sensor is used frequently, check the RF connectors for visible damage bent inner conductors, broken contact springs and so on. If the RF connectors are
damaged, stop using the power sensor. Contact Rohde & Schwarz customer service,
see Chapter 9.4, "Contacting customer support", on page 85.
Checking the integrity of the RF connector
1 2 3
= Perfectly formed contacts
1
2 = Normal wear
3 = Damaged contacts
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12.3 Cleaning
Maintenance, storage and disposal
Storage
Checking the concentricity of the RF connector
1 2 3
1 = Perfectly concentric
2 = Slightly off-center
3 = Excessively off-center
1. Disconnect the R&S NRT-Zxx:
a) From source and load.
b) From the computer or base unit.
2. Clean the outside of the R&S NRT-Zxx using a lint-free cloth. You can dampen the
cloth with water but keep in mind that the casing is not waterproof. If you use isopropyl alcohol or ethanol instead of water, be careful not to damage the labeling.
Do not use cleaning agents that can damage the instrument such as solvents,
acids or alkalis.
3. Clean the RF connectors as follows:
a) Dislodge any particles using compressed air.
b) Clean the inside and the connector threads using a foam swab or lint free cloth
dampened with isopropyl alcohol or ethanol.
Further information:
●
"To disconnect from the DUT" on page 17
12.4 Storage
Put plastic end caps on the RF connectors to protect them from damage. Protect the
power sensor against dust.
Ensure that the environmental conditions, e.g. temperature range and climatic load,
meet the values specified in the data sheet.
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12.5 Disposal
Maintenance, storage and disposal
Disposal
Rohde & Schwarz is committed to making careful, ecologically sound use of natural
resources and minimizing the environmental footprint of our products. Help us by disposing of waste in a way that causes minimum environmental impact.
Disposing electrical and electronic equipment
A product that is labeled as follows cannot be disposed of in normal household waste
after it has come to the end of its service life. Even disposal via the municipal collection
points for waste electrical and electronic equipment is not permitted.
Figure 12-1: Labeling in line with EU directive WEEE
Rohde & Schwarz has developed a disposal concept for the eco-friendly disposal or
recycling of waste material. As a manufacturer, Rohde & Schwarz completely fulfills its
obligation to take back and dispose of electrical and electronic waste. Contact your
local service representative to dispose of the product.
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