Rohde & Schwarz R&S SMU200A, Руководство по обслуживанию

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Test Procedures R&S SMU200A
1007.9845.82 1.44
E-12
Error Vector
Test assembly
See section "
Test Assembly for I/Q Modulation
", page 1.4 .
Measurement
Instead of a static measurement, an equivalent dynamic measurement
with a low symbol rate is carried out.
Settings on DUT:
RF On
Level 0 dBm
I/Q Settings menu:
Source Analog Wideband I/Q Input
State On
Generate a modulation signal on the ARB generator using the
controller and the simulation program:
- Modulation 16QAM
- No coding
- SQR COS filter with = 0.5
- PRBS-9 data sequence
- Pulse width and oversampling 32
- Length 100 symbols
- Symbol clock 10 kHz
Check if the channels on the ARB generator are equal and adjust if
necessary.
Make the corresponding settings on the demodulator. Result length
80 symbols.
Vary the carrier frequency from 20 MHz to RF
max
.
For recommended setting values see Table 1-4.
Measure the error vector magnitude (peak and rms) on the
demodulator.
RF Frequency Response due to Modulation
Test equipment - Spectrum analyzer (Table 1-2, item 24)
-
Signal generator (Table 1-1, item 5)
Test setup
Connect the RF output of the DUT to the spectrum analyzer,
and connect the signal generator to the
I input of the DUT.
Test method
By applying a sinewave AC voltage to the I (or Q) input, an amplitude
modulation with a suppressed carrier is generated. The modulation
frequency response is determined by measuring the sideband power as a
function of the frequency of the applied AC voltage. The difference
between the highest and the lowest sideband level, found by varying the
modulation frequency is the frequency response to be measured.