The Vector Signal Generator
¸SMU200A has been designed to
meet all requirements encountered in research and development of modern communications systems as well as in their
production. The ¸SMU200A not only
combines up to two independent signal
generators in one cabinet of only four
height units – it also offers unrivaled RF
and baseband characteristics.
Due to its modular design, the
¸SMU200A can be optimally adapted to the requirements of different applications. The first RF path can be
equipped with one of the four available
frequency options. The upper frequency limit of 2.2 GHz/3 GHz/4 GHz or 6 GHz
is user-selectable. In addition, a second
RF path can be installed with upper frequency limits of 2.2 GHz and 3 GHz. The
lower frequency limit of all frequency
options is 100 kHz.
Up to two generators can also be in
stalled in the baseband section. They
generate complex signals in realtime and
are equipped with an arbitrary waveform
generator with 64 Msample memory for
I and Q (256 Mbyte). The signals generated in the different basebands can be
added. Frequency offset of the individual
signals is possible.
The modern, intuitive concept of the
¸SMU200A ensures fast and easy
operation.
-
2Vector Signal Generator ¸SMU200A
2 Vector Signal Generator ¸SMU200A
Two signal generators in one
Frequency options from 100 kHz to
◆
2.2 GHz/3 GHz/4 GHz/6 GHz for the
first RF path
Optional second RF path up to
◆
2.2 GHz or 3 GHz
Up to two complete baseband paths
◆
Lossless combination of baseband
◆
signals in the digital domain (e.g. for
testing multistandard base stations)
(CW, f = 1 GHz, >5 MHz carrier offset, 1 Hz measurement bandwidth)
Excellent ACLR of typically +70 dB for
◆
3GPP FDD (test model 1, 64 DPCHs)
Very high level repeatability of
◆
0.05 dB
High output power up to +19 dBm
◆
(PEP), overrange +26 dBm
High-stability reference oscillator as
◆
standard
Unrivaled flexibility
Four code channels in realtime for
◆
3GPP FDD
Change of modulation from slot to
◆
slot for GSM/EDGE
Baseband generator with universal
◆
coder for realtime signal generation
Arbitrary waveform generator with
◆
64 Msamples for I and Q (256 Mbyte)
Arbitrary waveform generator sup-
◆
ported by Simulation Software
¸WinIQSIM™
Optional fading simulator with up to
◆
40 fading paths
Intuitive operation
Color display with 800 × 600 pixels
◆
(SVGA format)
Intuitive user interface with graphical
◆
display of signal flow (block diagram)
Graphical display of baseband signals
◆
through built-in transient recorder
Context-sensitive help system
◆
Ideal for production
Very short frequency setting times
◆
(<3 ms); only 450 µs in List mode
Electronic attenuator up to 6 GHz
◆
Minimum space required as two com-
◆
plete generators are accommodated in one cabinet of only four height
units
Connectivity
Can be remote-controlled via GPIB
◆
and LAN
USB connectors for keyboard, mouse
◆
and memory stick
User-selectable trigger and marker
◆
signals
Vector Signal Genera tor ¸SMU200A 3
Intuitive operation
Turn
Click
The ¸SMU200A is equipped with a
modern and intuitive user interface. The
signal flow from the baseband to the RF
output is clearly shown in the block diagram. Each block represents a functional unit of the instrument. The generated
signal can be seen at a glance, including
whether it is affected by additive white
Gaussian noise or other impairments.
The rotary knob plays a central role in
¸SMU200A operation. It allows
the instrument to be operated with one
hand. Any task – whether navigating in
the block diagram or menus, selecting of
parameters or toggling between states
– can be performed simply by turning or
pressing the rotary knob.
Active windows are indicated by a labeled button in the Winbar at the bottom of the screen. With the softkey below, the respective window can be
quickly brought to the foreground. This
allows rapid navigation between different windows. It is possible, for instance,
to simultaneously display two slots of
a GSM/EDGE system and to toggle between them. Windows can of course also be automatically arranged (REARR),
hidden (HIDE) or closed (CLOSE) by
means of hardkeys.
Block diagram of the ¸SMU200A
Tool tip for permissible frequency setting range
4Vector Signal Genera tor ¸SMU200A
Rotary knob for navigation in the menus
Softkeys and hardkeys of the
¸SMU200A for windows
management
The baseband signal can be monitored
in the graphics block. For instance, the
vector or constellation diagram, the
I/Q characteristic or the output spectrum
of a signal can be displayed, making it
possible to check whether the generated signal corresponds to the required
signal. This is of great help particularly
when complex signals are produced.
Another outstanding feature of the
¸SMU200A is its context-sensitive
online help. If the exact function of a parameter is not known, simply pushing
the help key instantaneously displays a
help text with information about the selected parameter. Further information
can be obtained through navigation with
a browser-like system. The help system
also specifies the relevant remote-control commands. Full-text searching in the
help system, which contains the complete operating manual, comes in handy
when complex measurement tasks are
to be performed. Tool tips are provided
in addition. If you pause on a parameter,
the currently permissible setting range is
displayed.
Graphics block with I/Q, vector
and spectrum diagram
More information about the user interface at
http://www.smu.rohde-schwarz.com/
Help system
Vector Signal Genera tor ¸SMU200A 5
Outstanding signal quality
–40
–50
–60
–70
–80
–90
–100
–110
–120
–130
–140
–150
–160
SSB phase noise / dBc(1 Hz)
11010210310410510610
7
2,1 GHz
Frequency offset / Hz
100 MHz
850 MHz
5,7 GHz
A
Ref -9.5 dBmAtt 10 dB*
*
*
*1 RM
CLRWR
RBW 30 kHz
VBW 300 kHz
SWT 2 s
NOR
*
Center 2.16 GHzSpan 25.5 MHz2.55 MHz/
SGL
PRN
-90
-80
-70
-60
-50
-40
-30
-20
-9.45
Tx ChannelW-CDMA 3GPP FWD
Bandwidth3.84 MHz
Pow er-6. 03 dBm
Adjacent Channel
Bandwidth3.84 MHz
Low er- 70. 03 dB
Spacing5 MHz
Upp er- 70. 40 dB
Alternate Channel
Bandwidth3.84 MHz
Low er- 72. 96 dB
Spacing10 MHz
Upp er- 73. 42 dB
-100
-100-80-60-40-20020406080100
-5
-4
-3
-2
-1
0
1
2
3
4
5
Frequency offset from c arrier / MHz
Delta / dB
RF 850 MHz
RF 1900 MHz
RF 2200 MHz
Owing to the sophisticated multiloop
synthesizer concept, the ¸SMU200A
features extremely low SSB phase noise
and wideband noise. A high-stability
oven-controlled reference oscillator is installed as standard, which provides excellent aging characteristics as well as
minimum temperature drift. In addition,
the low phase noise option further enhances the performance significantly. The ¸SMU200A is ideal, for instance, for LO or VCO substitution.
Typical SSB phase noise at 100 MHz, 850 MHz, 2.1 GHz and 5.7 GHz
Amplifiers of 3GPP base stations require
very good adjacent channel leakage ratio
(ACLR) performance in order not to impair the adjacent channels of the transmission. To test this feature, the ACLR
characteristics of the signal generator
must be better than those of the amplifier. Presently, multicarrier power amplifiers are increasingly used. In this case,
not only one but several neighboring signals in the frequency range are amplified. Testing such amplifiers places even
higher demands on signal generator capabilities. The outstanding ACLR characteristics of the ¸SMU200A more
than qualify the generator for this task.
with internal reference oscillator (without low phase noise option)
Outstanding ACLR characteristics
When external I/Q signals are applied, the ¸SMU200A features an
RF bandwidth of 200 MHz. If the internal baseband is used, an RF bandwidth
of 80 MHz is available, which is ideal
for testing multicarrier amplifiers. The
¸SMU200A is thus well prepared for
future broadband systems.
6Vector Signal Genera tor ¸SMU200A
Frequency response (mode: external wideband I/Q)
The ¸SMU200A offers highly ac-
30
28
26
24
22
20
18
16
14
12
10
Level / dBm
00.5
Frequency / GHz
Available Power, Attenuator Mode Normal (lower trace) and High Power (upper trace)
1.01.52.02.53.0
0123456
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
Time/hours
Level deviati on/dB
Level repeatability (2 GHz, 0dB m, ALC=ON)
CW
Internalbas eband I/Q
External wideband I/Q
curate output power of up to +13 dBm
(PEP). A wear-and-tear-free electronic
attenuator is used in the full level range.
With the aid of the high-power output option, the output power can be increased to +26 dBm (PEP) in the overrange.
Digital ALC implemented in the
¸SMU200A together with a detector
operating at constant temperature ensures high level linearity and repeatability. ALC may be on for most kinds of complex signal scenarios.
Typical maximum output power versus frequency (with and without high-power output
option)
High level repeatability
of the ¸SMU200A
Amplifier test with the ¸SMU200A
Vector Signal Generator ¸SMU200A 7
Unrivaled flexibility
011010101…
Bit error
1011…
Block error
0
Information data
CRC attachment
Tail bit attachment
Conv. coding R=1/3
Rate matching
1st interleaving
804
686
686
24416 8
DATACRC
244
DTCH
CRC16
360
308
308
100128
10012
100
DCCH
CRC12
Tail8Tail8
Transmission
1
The standards of the third mobile radio
generation set considerably higher demands on signal generator functionality. Because of their good RF characteristics and their flexibility, signal generators are the instrument of choice particularly when base stations are tested. The
universal coder in the baseband generator of the ¸SMU200A has been designed for easy implementation of new
standards. The ¸SMU200A is therefore well prepared for present and future
mobile radio standards.
In the case of 3GPP FDD, the
¸SMU200A can generate up to four
code channels in realtime. Up to four
base stations with 128 code channels
each or four mobile stations can be simulated. This allows any configuration
to be set, from reference measurement
channels in line with 3GPP TS 25.141 or
TS 25.101 up to complex code channel
scenarios for traffic simulation in the mobile radio network.
Realtime
channels
Four code channels in realtime with additional background channels
The mobile phone changes its output power in compliance with TPC information from the
¸SMU200A
For the control channels, the transmit
power control (TPC) field of the individual slots of a frame can be read from a
data list. This allows long TPC profiles to
be generated for power-level control in
the DUT. With this feature, output power ramping or the maximum output power of a mobile phone can be measured,
for instance. The TPC information can also be used for power-level control in the
respective code channel of the signal to
be output by the ¸SMU200A. This
allows simulation of complex power scenarios as may occur for a mobile phone
in motion.
The ¸SMU200A is capable of inserting bit errors and block errors in the
generated signal. This allows the internal bit error ratio (BER) and block error
ratio (BLER) calculations of a base sta-
8Vector Signal Genera tor ¸SMU200A
The ¸SMU200A changes the code channel output power on the basis of the TPC field
Insertion of bit errors and block errors into the output signal
tion to be checked in line with TS 25.141.
The number of required bit and block errors can be set in the ¸SMU200A.
Because of generation in realtime, continuous measurements of BER and BLER
can be carried out without wrap-around
problems.
The receiver of a mobile phone must of
course also function under real operating conditions. To check this, orthogonal background and interfering channels
of a base station can be simulated in
line with TS 25.101. The power of these
channels is automatically configured so
that the total output power of the base
station remains unchanged. This allows
measurements of the maximum input
level in line with TS 25.101, for instance.
The base station must also be tested under real conditions. In this case, up to 64
mobile phones can be configured in addition to the four user-configurable ones.
The 64 mobile phones use different
scrambling codes.
Additional mobile stations for testing a base station receiver
(green: background, red: user)
Since the universal coder in the
¸SMU200A is extremely flexible,
signals for high-speed downlink packet access (HSDPA) are generated without problems. Test model 5 with all its
versions, as defined in TS 25.141 of the
3GPP specification, is also supported.
The test case wizard of the
¸SMU200A allows one-button
base station testing. By simply choosing the required test case as defined in
TS 25.141, the complete generator will
be set up in accordance with the specification. All specific parameters, such as
noise level, fading profile, and interfering signal are set without having to look
them up in the standard document. The
automatic setup includes the wanted
signal, frequency offset and power level
as well as interfering signals, noise and
fading conditions. To test beyond the
specifications, the parameters can also
be adjusted.
Display of 3GPP FDD menu and code domain with two HSDPA data channels
Test case wizard: intermodulation characteristics with display of signal setup
Vector Signal Genera tor ¸SMU200A 9
Slot0123456701
Frame
P1
P2
P3
P4
P5
P6
P7
For receiver power measurements, the
¸SMU200A generates access, control and traffic channels of the various
radio configurations in the 1× mode.
Since channel coding is fully implemented in the ¸SMU200A, no additional bit error ratio testers are necessary. By
evaluating the CRC fields, the base station is able to perform the frame error ratio (FER) measurement specified in the
standard directly on the received signal.
In the forward link mode, the
¸SMU200A supports a total of four
user-selectable base stations for each carrier frequency. Each simulated base station provides all control channels of the
standard and up to eight independently configurable traffic channels. Any radio
configuration can be selected for these
channels. The channel coding can be set
for each fundamental, supplemental and
dedicated control subchannel of a traffic
channel in any manner within the parameters defined by the standard. Thus, complex test scenarios can be set up that far
exceed the mobile station tests defined in
the 3GPP2 C.S00011-B specification.
CDMA2000® channel table
1)
The ¸SMU200A supports receiver
tests by providing a fully channel-coded F-PDCH. The F-PDCCHs, which are
indispensable for demodulation, are provided in duplicate. In addition to the
packet channels, all regular control and
user channels can also be activated.
When the GSM/EDGE option is used,
even the modulation can be changed between GMSK and 8PSK EDGE in realtime as may be the case in GSM/EDGE
base stations. All burst types defined by
the standard can be generated. In addition, up to eight different levels can
be defined for the timeslots. A separate level can thus be assigned to each
slot of a GSM frame. Furthermore, the
¸SMU200A permits two frames to
be defined. The frame repetition rate can
be set by the user as required.
10Vector Signal Generator ¸SMU20 0A
Change of modulation and different power levels in each slot for GSM/EDGE
The change from GMSK to 8PSK EDGE
modulation in a timeslot over time can
thus be simulated, for instance.
1)
CDM A2000® is a registered trademark o f the Telecom-
munications Industr y Associa tion (TI A -USA).
When receivers are tested, it must be
Waveform 2
Waveform 1
Waveform 3
Resulting waveform in output RAM
Segment 1Segment 2Segment 3
Output signal
Segment switching by
¸SMU user interface,
IEC/IEEE bus,
external trigger line
Automatic repetition of partial
waveform within segment
possible to simulate real receive conditions. In the ¸SMU200A, additive white Gaussian noise (AWGN) can
be superimposed on the wanted signal.
The signal-to-noise ratio can be set in a
wide range. Thus, highly accurate sensitivity measurements can be performed
on receivers with a defined S/N ratio,
in compliance with 3GPP specifications
TS 25.141 and TS 25.101.
The internal arbitrary waveform generator (ARB) with its large 56 Msample
memory for I and Q (and 4 marker bits per sample) and a clock rate of
100 Msample/s offers ideal conditions
for generating complex signal scenarios.
Due to the implemented hardware resampling, lower oversampling rates can
be used so that less memory is required
for storing waveforms. Therefore longer
sequences are possible.
Constellation diagram of a noisy signal
Test systems often switch back and forth
between various test signals. The time
necessary to switch between these signals can be minimized by combining individual waveforms into a multisegment
waveform. The complete multisegment
waveform is loaded into the ARB memory, and each segment then represents a
separate waveform. This eliminates the
loading time that would otherwise be
necessary when switching between segments.
The internal arbitrary waveform generator of the ¸SMU200A is supported by
Simulation Software ¸WinIQSIM™.
With ¸WinIQSIM™, signals can be
easily generated for WLAN systems such
as IEEE 802.11a/b/g, TDMA systems such
as GSM/EDGE and even complex CDMA
systems such as TD-SCDMA. Multicarrier
signals can also be generated.
How the multisegment waveform operates
For more information, refer to the data
sheet for Simulation Software
¸WinIQSIM™ (PD 0757.6940).
Simulation Software ¸WinIQSIM™
Vector Signal Genera tor ¸SMU200A 11
When signals are sent from the transmitter to the mobile receiver, various
fading effects occur. Thus, multiple propagation paths may be superimposed on
each other either constructively or destructively. In addition, the movement
of the receiver relative to the transmitter creates a frequency shift. The
¸SMU200A fading simulator makes
it easy to simulate these conditions in
the lab. This is the only way to optimize
receiver performance.
A total of 40 fading paths at 80 MHz
bandwidth and 10 ns time resolution are
available for simulating multipath propagation. If higher time resolution is needed (10 ps), the bandwidth (30 MHz and
50 MHz) and the number of fading paths
(24 and 16) can be modified. Since up to
two baseband generators and RF paths
can be installed on the ¸SMU200A,
it is easy to simulate the receive conditions of a receiver that has two antennas
(e.g. a UMTS base station). This eliminates the problems usually associated
with cabling and synchronization since
the entire scenario is created in a single
¸SMU200A.
Rician fading of a squarewave-filtered QPSK signal (change in amplitude and phase)
The user interface was designed for
easy and straightforward operation.
Thus, it includes fading profiles for the
most common mobile radio standards
(e.g. GSM/EDGE, 3GPP, CDMA, TETRA,
WLAN). To handle special test requirements, the fading profiles can also be
configured as needed. The graphical display of the fading paths provides an
overview of the situation at all times. It
shows the number of paths, timing, relative power and the fading profile that
is used.
Setup for simulating transmit diversity with fading
Simplest setting of the preferred fading
12Vector Signal Generator ¸SMU20 0A
The ¸SMU200A supports multipath
Profile for frequency f
2
Profile for frequency f1
Time
Power
Continued profile for frequency f
1
Internal calculation of profile f
1
Frequency
hopping
f2 to f
1
Internal calculation
of profile f
2
Frequency hopping
f1 to f
2
fading with the following profiles:
Static path
◆
Pure Doppler
◆
Rayleigh
◆
Rician
◆
Constant phase
◆
Lognormal
◆
Suzuki
◆
Furthermore, it supports scenarios introduced by 3GPP such as birth-death propagation (testing of receiver performance
for disappearance and reappearance of
a signal, such as when a caller walks
around the corner of a building while on
the phone) and moving delay propagation (testing of receiver performance for
slow changes in delay).
A frequency hopping technique that resumes the preceding fading process following a frequency hop-back allows realistic simulation of frequency hopping
conditions. In this case, the calculation
of the preceding fading process is resumed in the background. The profile
is continued as if the fading at this frequency had not been interrupted.
Demonstration of moving delay fading with ASK modulation: the second path
moves relative to the first path
Fading Simulator
Signal paths
Fading paths
RF bandwidth
Time resolution
Fading Simulator with Fading Simulator Extension
Signal paths
Fading paths
RF bandwidth
Time resolution
Relation between the number of fading paths, bandwidth and time resolution
All the strengths of the two-path concept of the ¸SMU200A become especially evident in the field of mobile radio. Since the baseband section of the
¸SMU200A is fully digital, the signals of the two baseband generators can
be easily added without synchronization
problems and without an external coupler or additional equipment being required. A frequency offset and the relative power of each signal can be accurately set.
One baseband generator may be used
for generating the 3GPP signal in realtime. The second baseband generator produces a realtime GSM/EDGE signal. The signals can then be added in
the digital domain with a frequency offset, if desired. This allows modern multistandard base stations to be tested, for
instance.
Generation of 3GPP and GSM/EDGE signals in realtime
For receiver tests in multicarrier base
stations with complex interfering signals, one baseband generator can produce the test signal to be evaluated.
The second baseband generator produces a suitable multicarrier signal to
be used as the background signal. Two
transmit antennas (the transmit diversity) of a base station can also be simulated. Up to now, two signal generators
have been required in this case, but only one instrument is needed when the
¸SMU200A is used.
If the RF section is furthermore equipped
with two paths, any requirement can be
met. For instance, the wanted signal and
the interfering signal needed for receiver
tests can be generated with one instrument – even if the signals greatly differ
in power and frequency offset as is the
case when out-of-band blocking measurements are to be performed.
Adding a realtime signal and a multicarrier signal
Generation of wanted signal and interfering signal
14Vector Signal Generator ¸SMU20 0A
An ¸SMU200A equipped with fading and noise options contains all components required for the performance
tests specified in 3GPP TS 25.141. Since
all components are integrated in a single
instrument, the effort that would otherwise be necessary for cabling and timeconsuming synchronization is eliminated. The ¸SMU200A 3GPP FDD Test
Case Wizard makes it possible to set
complex scenarios even such as these at
the press of a button.
Since signal paths can be switched as
needed, even after the fading simulator, complex signal scenarios that were
previously either not possible or possible
only at great effort can now be implemented. This makes it possible, for example, to simulate a GSM/EDGE frame
in which only one timeslot is faded while
the others remain unchanged. The appropriate frames are generated in the
baseband generators and then routed
through the fading simulator. Only one
baseband signal is faded and then added to the signal of the other baseband
generator.
Generation of a 3GPP signal followed by fading and noise as specified in
3GPP TS 25.141
Generation of a GSM/EDGE frame with faded and unfaded timeslots
The ¸SMU200A BBIN option makes
it possible to feed external analog I/
Q signals into the ¸SMU200A and then
apply fading, noise and impairments to
them. In addition, the external signal can
be added to the internal baseband signals, thus making it possible to simulate
even highly complex signal scenarios.
Addition of external I/Q signals to internal baseband signals
Vector Signal Genera tor ¸SMU200A 15
Connectivity
Front panel
An external keyboard and a mouse or
memory stick can be plugged into the
USB connectors on the front panel.
Two marker outputs that can be used
as required and a trigger input are
available in addition.
Rear panel
Additional marker and trigger connectors , a LAN (100BaseT) and a GPIB
interface as well as a USB slave connector are available at the rear. Using
the slave connector, the ¸SMU200A
can be directly connected to a PC. An external monitor or a video beamer can be
connected to the VGA connector .
Remote control
The ¸SMU200A is remote-controlled
via GPIB or LAN. When Windows Remote Desktop is used, the instrument
can be remote-operated from a PC.
Remote control of the ¸SMU200A via GPIB or LAN
16Vector Signal Generator ¸SMU20 0A
Modular design
Future-oriented
Owing to its modular design, the
¸SMU200A is a safe investment.
Options can be added any time. This
concept allows the ¸SMU200A to be
tailored to specific applications.
Convenient service
“Low cost of ownership” is more than
just a motto – it is a comprehensive concept. The three-year calibration cycle
considerably reduces costs.
A thermal management system with
oversized fans combined with large-scale
integration ensures high reliability even
under adverse environmental conditions.
Synthesizer module of the ¸SMU200A
Rohde & Schwarz Service Centers all
over the world reduce transit times in
the case of repair and ensure short turnaround times.