Racal Instruments RA6790/GM, Техническое руководство

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Racal RA6790/GM Alignment & Tuning Manual
Page 20 of 20
(4) On the Receiver select LSB and manual AGC.
TABLE 3-3. SPECIAL FILTERS DELAY TEST PARAMETERS
FILTER
NUMBER
FILTER
SLOT
REFERENCE
FREQUENCY
START
FREQUENCY
STOP
FREQUENCY
DELAY
MICROSECONDS
4 FL1 455825 455600 457850 1000
5 FL2 454175 454400 452150 1000
6 F L 3 455000 454800 455200 2000
7 FL4 455000 454400 455600 900
8 F L 5 455000 453450 456550 1250
9 F L 6 455000 451600 458400 1000
10 F L 7 455000 447000 463000 1000
(5) Set the automatic synthesizer (part of network analyzer) as follows:
Frequency
455825 Hz
Frequency Step 5 Hz
Steps 10
Time/Step 100 millisecs
Amplitude -10 dBm
(6) Set the network analyzer controls as follows:
Amplitude Function
B-A
Max Reference Voltage 0 dB
Bandwidth 100 Hz
Phase Reference A
Delay Mode CW
Frequency Step 50 Hz
Delay Function Absolute
(7) Adjust the Receiver manual IF gain control for a 0 dB reading on the network
analyzer.
(8) Measure delay at 455825 Hz by pressing START CONT pushbutton on the
automatic synthesizer.
(9) On the automatic synthesizer, switch delay function to relative and enter
the OFFSET by pressing the appropriate pushbutton. Stop the sweep. The
required reference has now been established at +825 Hz.
(10) Set the network analyzer and automatic synthesizer controls to measure the
differential delay over the frequency range of 455600 to 457850 Hz in the
CW or sweep mode as convenient. Compare the delay reading with the
requirement set forth in Table 3-3.
(11) Repeat steps 4 through 10 for filter numbers 4 through 10. Always select the
filter to be tested and use the start and stop frequency shown in Table 3-3.