Operating instructions

ACCEPTANCE TESTING
5-12
Frequency modulation
Specification
Carrier range
400 kHz to 1.05 GHz
Accuracy
†
±7% ± 10 Hz at 1 kHz modulating frequency
† At low modulation levels the residual AM/FM may become significant
Test equipment
Description Minimum specification Example
Modulation meter RF I/P 500 kHz to 1.05 Ghz. FM measurement
accuracy ±0.5% of reading ±1 least significant digit at
1 kHz mod rate for deviation > 5 kHz.
IFR 2305
UUT
C2587
RF INPUT
BNC
OUTPUT
Modulation meter
Fig. 5-8 Internal FM accuracy checks
(1) Refer to Results table 5-10 on page 5-34. Connect the test equipment as shown in Fig. 5-8
(B
NC output on UUT).
(2) Set the UUT to [Rx TEST], RF IN/OUT [SELECT] BNC output, [RF Gen],
[LEVEL] 0 dBm, [FREQ] 0.5 MHz, [Mod Gen], [Gen 2], [LEVEL] 10 kHz, [FREQ] 1 kHz.
All other modulation generators and noise measurements should be switched OFF.
(3) Set the Modulation meter to monitor FM in a 50 Hz to 15 kHz bandwidth, Noise averaging
on.
(4) Check the Modulation meter indicates a reading within ±7% ± 10 Hz of the deviation set.
Repeat with the UUT set to each of the remaining carrier frequencies shown in the Results
t
abl
e 5-10.
(5) Refer to Results table 5-11 on page 5-35. Set th
e UUT to [RF Gen], [FR
EQ] 600 MHz,
[Mod Gen], [Gen 2], [LEVEL] 75 kHz.
(6) Check the modulation meter indicates a reading within ±7% ± 10 Hz of the deviation set.
Repeat with the UUT set to provide deviations of 50 kHz, 25 kHz and 5 kHz.