USER’S MANUAL__________________________________________________________________
382 _________________________________________________________________ M211322EN-D
C.17 Digital AFC (DAFC) Alignment (Optional)
Test Goal
Verify that the RVP900 DAFC output controls the STALO over the correct
span.
Special Test Equipment
- Setup TTY
Reference
- See Section 3.4 Digital AFC Module (DAFC) on page 84
Background
The RVP900 implements an AFC based on the measurement of the burst
pulse frequency. The DAFC connects to the TRIG–A sma port of the
RVP901. It translates the AFC requests from the RVP900 main chassis
into digital output requests supporting up to 25 bits. A frequency control
span of approximately ±7 MHz is expected.
Document the STALO frequency that is desired. This is typically the RF
frequency minus 30 or 60 MHz depending on the IF of your system.
Test Procedure
1. Use the setup terminal to set the Digital AFC span as required in
Section C.11 Setup "Mb" Command (Burst Pulse and AFC) on page
369.
2. Use the setup terminal and display scope in the Pb (plot burst) mode
to verify that the burst pulse is properly centered. Any pulse width can
be used.
3. Set to MFC using the "=" command, and adjust the control to the
lowest setting using the "D" command. Record the results in the chart
below.
4. Raise the control using “U” to within 0.1 MHz of the IF frequency.
Record the results in the chart below.
5. Raise the control using “U” to the highest setting. Record the results
in the chart below.
RF Transmit frequency ______________________MHz
STALO Frequency ______________________MHz
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