Operating instructions

ACCEPTANCE TESTING
5-20
Splitter
Signal generator
C2592
RF INPUT
ANTENNA
INPUT
RF OUTPUT
Modulation meter
UUT
Fig. 5-13 Modulation meter FM
(5) Check that the deviation level indicated on the UUT is within ±5% ± resolution of the
deviation indicated on the external Modulation meter.
(6) Repeat steps 4 and 5 for RF carrier frequencies of 500 MHz and 1000 MHz.
(7) Refer to Results table 5-22 on page 5-39. On
the UUT select an AF filter of 0.3 to 3.4 kHz
an
d an IF filter of 3 kHz.
(8) Set the external Modulation meter bandwidth to 50 Hz to 15 kHz.
(9) Set the RF signal generator modulation rate to 1 kHz and set 250 Hz deviation.
(10) Check that the deviation level indicated on the UUT is within ±5% ± UUT resolution of the
deviation indicated on the Modulation meter.
(11) On the UUT select an IF filter of 30 kHz. Set the RF signal generator to provide a deviation
of 10 kHz and check that the deviation level indicated on the UUT is within ±5% ± UUT
resolution of the deviation indicated on the Modulation meter.
(12) On the UUT select an IF filter of 300 kHz. Set the RF signal generator to provide a
deviation of 50 kHz and check that the deviation level indicated on the UUT is within ±5% ±
UUT resolution of the deviation indicated on the Modulation meter. Repeat at 75 kHz.
(13) Refer to Results table 5-23 on page 5-39. Select the UUT demodulation oscilloscope by
pressi
ng
[Return], [Scope/Bar], [Scope]. Using the oscilloscope horizontal and vertical soft
keys select a vertical scale of 25 kHz/div and a horizontal scale of 200 μs/div.
(14) Adjust the deviation level from the RF signal generator until the 1 kHz trace on the
oscilloscope occupies the full six deviations.
(15) Check that the deviation indicated on the external Modulation meter is between 67.5 and
82.5 kHz.
(16) Adjust the deviation level from the RF signal generator until the external Modulation meter
reads 75.0 kHz deviation. Leave all settings unaltered while carrying out step 17.
(17) Refer to Results table 5-24 on page 5-39. Connect the DEMOD OUT socket on the rear of
th
e UUT to
the DVM. Set the DVM to monitor Volts AC and check that the level indicated
is between 4.77 V and 5.83 V.
(18) Set the RF signal generator modulation rate to 2 kHz.
(19) On the UUT press [Return], [Mod Meter], [Deemph] to switch de-emphasis on.