Rohde & Schwarz SME02 - FM Distortion Factor; FM Preemphasis; Residual am with FM

Test Procedure SME
1038.6002.02 5.24 E-13
5.2.23 FM Distortion Factor
Test equipment Test system 5.1.1.1
Measurement À Settings at the SME
- Carrier frequency 250 MHz
- Level 0 dBm
- Select INT in the MODULATION/FM/FM1 SOURCE menu,
- Deviation 62.5 kHz
- Modulation frequency 1 kHz.
À Read off distortion factor at the modulation analyzer.
Distortion factor ................................................................max. 0.5%
5.2.24 FM Preemphasis
Test equipment Test system 5.1.1.1
Measurement À Settings at the SME
- Carrier frequency 100 MHz
- Select LFGEN1 in the MODULATION/FM/FM1 SOURCE menu,
- Deviation 25 kHz.
À Read off the deviation at the modulation analyzer and note down as
a reference value with a modulation frequency of 100 Hz.
À Switch on preemphasis 50 µs at the SME and at the modulation
analyzer and increase the modulation frequency to 15 kHz.
Deviation of the deviation measured now from the reference value
< 5%
À Repeat measurement with a preemphasis of 75 µs.
5.2.25 Residual AM with FM
Test equipment Test system 5.1.1.1
Measurement À Settings at the SME
- Various test frequencies >10 MHz
(for recommended settings, see table 5-2)
- Level 0 dBm,
- Select LFGEN1 in the MODULATION/FM/FM1 SOURCE menu,
- Deviation 40 kHz ,
- Modulation frequency 1 kHz.
À Measure the amplitude modulation resulting by means of a 23-kHz
lowpass filter and peak weighting at the modulation analyzer.
Unwanted modulation measured......................................max. 0.1%