Operating instructions

ACCEPTANCE TESTING
5-22 46882-311D
(31) Refer to Results table 5-35 on page 5-42. Set the RF signal generator to provide a signal of
300 MHz at 6 dBm with 5 kHz deviation at 1 kHz modulation rate.
(32) On the UUT select the 0.3 to 3.4 kHz AF filter and the 30 kHz IF filter.
(33) On the UUT switch distortion measurement ON and check that the distortion reading
indicates less than 2%.
(34) Set the UUT to [Tx FREQ] 300 MHz and set the RF signal generator to provide a signal of
300 MHz with 5 kHz deviation at 1 kHz modulation rate. (The 2041 should be set to low
noise mode.)
(35) Note the voltage reading on the DVM connected to the DEMOD OUT socket of the UUT
(Reading 1).
(36) Switch the RF signal generator modulation off and note the reading on the DVM (Reading 2).
(37) Calculate the residual FM as shown below and check that it indicates 35 Hz or less
(functional check only).
(Reading 2
÷
Reading 1 )
× 5000
Modulation analyzer - AM
Specification
Frequency range: 100 kHz to 1.05 GHz.
Modulation frequency range: 10 Hz to 15 kHz.
AM depth range: 0 to 99% (manually tuned)
0 to 90% below 100 MHz
0 to 80% from 100 to 400 MHz
Resolution: 1% AM
Accuracy
(see Note 1)
±5% of reading ±1 digit at 1 kHz.
±8.5% of reading ±1 digit from 50 Hz to 10 kHz
Demodulation distortion (1): Less than 2% at 1 kHz & 30% AM (CCITT weighted).
Residual AM: Less than 1% (0.3 to 3.4 kHz)
Note 1:
(1) At low modulation levels, the residual AM/FM may become significant.
Test equipment
Description Minimum specification Example
RF signal
generator
500 kHz to 1 GHz AM depth 0 to 95% Modulation
rate 30 Hz to 15 kHz.
IFR 2041
Modulation meter RF I/P 500 kHz to 1 GHz AM Measurement
accuracy ±1% of reading ±1 least significant
changing digit at 1 kHz mod rate for depths up to
95%.
IFR 2305
Power splitter 6 dB 50 Ω 500 kHz to 1 GHz. WEINSCHEL
1870A