ACCEPTANCE TESTING
5-1-17
EXTERNAL AM
SPECIFICATION
Accuracy: With ALC OFF the modulation is calibrated for an input level of
1.0 V PD RMS sine wave.
Bandwidth: ±1 dB, DC to 30 kHz relative to 1 kHz
Typically ±1 dB DC to 50 kHz, relative to 1 kHz.
TEST EQUIPMENT
Description Minimum specification Example
Modulation meter Modulation frequencies from 30 Hz to
50 kHz.
IFR 2305
Function generator DC to 50 kHz. HP3325B
Power meter Capable of measuring levels at 400 MHz. IFR 6960B
and 6912 sensor
TEST PROCEDURES
Fig. 5-1-10 External AM test set-up
(1) Connect the test equipment as shown in Fig. 5-1-10.
(2) Set the UUT to [RF Level] +7 dBm (+4 dBm for instruments fitted with
Option 012) [Carrier Freq.] 400 MHz [AM] 80%. Then select EXT MOD 1
INPUT, DC coupled as follows:
[Select Source] [Select External] [Ext1 DC Coupling]
[SIG GEN]
(3) Set the function generator to give 1 V RMS at 1 kHz sine wave.
(4) With the modulation meter set to measure AM, set a reference using the relative
function.
(5) Set the function generator to the frequencies shown in Table 5-1-12 and measure
the change in external AM response which should be less than 1 dB with respect
to 1 kHz.
Table 5-1-12 External AM test frequencies
Modulation frequency
100 Hz 1 kHz 30 kHz
300 Hz 10 kHz 50 kHz
C0433
UUT
50Ω
Load
EXT MOD 1
INPUT
RF
OUTPUT
➤
➤
Function Generator
OUTPUT
➤
Modulation Meter
RF
INPUT
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