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Application Example: GSM AM Suppression Test

R&S

®

SMW-K550

15

User Manual 1178.3263.02 ─ 01

Within the available BS RF bandwidth, the up to 4 wanted signals are allocated sym-
metrically around the center frequency. The interfering signal is sent on the center fre-
quency. The inner two wanted signals are spaced at 6 MHz away form the interferer.
The remaining wanted signals are located at the edges of the maximum supported
bandwidth and at least at 600 Hz away form the inner two.

The frequency distribution is illustrated on 

Figure 4-2

.

Figure 4-2: Frequency allocation of the wanted and the interfering signals

GSM frequency bands and channels

According to 

TS 51.021

, a GSM band contains a set of adjacent channels, each with a

bandwidth of 200 kHz. The channel numbers and the assignment between channel
numbers and frequencies are band-specific.

In all frequency bands, the downlink frequencies are higher than the corresponding
uplink frequencies. The difference between downlink and uplink frequencies is termed
the duplex spacing; it is also band-specific.

For an overview the GSM bands with their channel numbers and the downlink and
uplink center frequencies, see 

TS 51.021

.

Cabling and synchronization issues

As a rule, always use short RF cables of equal length. If a trigger signal is required,
feed the BS signal to the R&S

 

SMW.

In test setups with more than one instrument, all instruments usually use the same ref-
erence clock. While testing BS receivers, the clock signal is provided by the DUT.
Additional reference frequency is not required.

4.3 How to Generate Signals for GSM AM Suppression

Tests

The following is an example on how to select the correct system configuration and con-
figure the instrument in general. Not all GSM-related settings configurations are shown.
The example uses predefined settings and PN sequences as data source; channel
coding is not used.

 

How to Generate Signals for GSM AM Suppression Tests

Summary of Contents for SMW-K550

Page 1: ...R S SMW K550 Stream Extender User Manual User Manual 1178 3263 02 01 P 2 Test Measurement...

Page 2: ...any Phone 49 89 41 29 0 Fax 49 89 41 29 12 164 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...

Page 3: ...3 Notes on Screenshots 8 2 Welcome to the R S SMW K550 Option 9 2 1 Accessing the Settings 9 2 2 Scope 10 3 Stream Extender Related Settings 11 4 Application Example GSM AM Suppression Test 13 4 1 Re...

Page 4: ...Contents R S SMW K550 4 User Manual 1178 3263 02 01...

Page 5: ...c procedure to perform signal generation tasks and step by step instruc tions for more complex tasks or alternative methods As well as detailed examples to guide you through typical signal generation...

Page 6: ...re options The tutorials offer guided examples and demonstrations on operating the R S SMW User Manual and Online Manual Separate manuals are provided for the base unit and the software options Base u...

Page 7: ...pplication Notes Application Cards White Papers etc These documents deal with special applications or background information on particu lar topics see www rohde schwarz com appnotes 1 3 Conventions Us...

Page 8: ...ting procedures The term select may refer to any of the described methods i e using a finger on the touchscreen a mouse pointer in the display or a key on the instrument or on a key board 1 3 3 Notes...

Page 9: ...8 streams out of 4 baseband signals Generation of 4 signals with real time data source for example to ensure non trun cated PN sequences Generation of wanted and interfering signals as required for th...

Page 10: ...ttings and data lists like storing and loading settings creating and accessing data lists or accessing files in a particular directory Information on regular trigger marker and clock signals and filte...

Page 11: ...ion System Configura tion 2 In the Fading Baseband Configuration dialog select Mode Advanced 3 Enable a 3x1x1 or a 4x1x1 configuration 4 Select Duplicate Streams On Confirm with Apply With the selecte...

Page 12: ...per default 3 basebands and 3 streams The first two basebands can generate signals with real time data sources If Duplicate Streams On created is a copy of each stream after baseband fading block Gene...

Page 13: ...ed signals The following example shows the configuration principle in general Not all required settings are shown The used settings do not comply with the specifi cation 4 1 Required Options The equip...

Page 14: ...terfering signal and the wanted signals are routed to two separate RF outputs because of the difference in their power levels Both RF signals are connected to a combiner The sum signal is fed to the R...

Page 15: ...ands the downlink frequencies are higher than the corresponding uplink frequencies The difference between downlink and uplink frequencies is termed the duplex spacing it is also band specific For an o...

Page 16: ...MHz offset and the outer two at 12 MHz GSM transmission in timeslot 1 for both the 4 wanted and the interfering signals The interfering signal is a GSMK modulated PN9 sequence of 511 bits length The...

Page 17: ...f the interfering signal as listed in TS 51 021 table 7 8 2 In this example the power levels of the wanted signals are 94 dBm and 98 dBm The interfering signal level is 31 dBm 5 In the baseband domain...

Page 18: ...s are transmitted in timeslot 1 1 Select Baseband C GSM 2 Select Framed Single Configuration Per default the first timeslot 0 is active 3 To disable timeslot 0 and activate timeslot 1 In the frame gra...

Page 19: ...for example Trigger Delay 70 Symbols 6 Configure the wanted signals in baseband A and B Load you own data lists as data source Configure the GSM bursts and frames according to the specification TS 51...

Page 20: ...ion of the wanted and the interfering signals Note that the streams generated form the same baseband are not transmitted on nearby carriers Figure 4 3 Block diagram understanding the displayed informa...

Page 21: ...m2 STATe 0 SCONfiguration OUTPut MAPPing IQOutput1 STReam3 STATe 0 SCONfiguration OUTPut MAPPing IQOutput2 STReam4 STATe 0 SCONfiguration OUTPut MAPPing BBMM1 STReam3 STATe 0 SCONfiguration OUTPut MAP...

Page 22: ...3 SOURce1 BB GSM TRIGger EXTernal1 DELay 70 SOURce1 FREQuency CW 947200000 SOURce2 FREQuency CW 947200000 SOURce2 POWer POWer 31 SOURce1 POWer POWer 89 53 ENTity2 SOURce1 BB PGAin 4 SOURce1 ROSCillato...

Page 23: ...nforma tion R S SMW K550 23 User Manual 1178 3263 02 01 Glossary 3GPP Specifications References Documents with Further Information T TS 51 021 Technical Specification Group GSM EDGE Radio Access Netwo...

Page 24: ...List of Commands R S SMW K550 24 User Manual 1178 3263 02 01 List of Commands SCONfiguration DUPLicate STReam 22...

Page 25: ...s 7 Application notes 7 B Brochures 7 BS receiver testing Introduction 13 D Data sheets 7 Documentation overview 5 Duplicate streams Access settings 11 Application example 13 Fading and baseband confi...

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