Vaisala RVP900 - Table 103 DAFC Setup Checklist

Background
RVP900 implements an AFC based on the measurement of the burst pulse frequency. The
DAFC connects to the TRIG–A sma port of 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.
RF Transmit frequency: __________MHz
STALO Frequency: __________MHz
Test Equipment
Setup TTY
Test Procedure
1. Enter the TTY setups through dspx.
2. Use the setup terminal to set the Digital AFC span. See A.12 Checking Burst Pulse and
AFC with Setup Mb Command (page 350).
3. 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.
4. Set to MFC using the = command, and adjust the control to the lowest setting using the
D command.
Record the results in the following table.
5. Raise the control using U to within 0.1 MHz of the IF frequency.
Record the results in the following table.
6. Raise the control using U to the highest setting.
Record the results in the following table.
7. Verify that
sucient span is covered, and the power at the end points is suciently
high to run the AFC loop.
Voltage Frequency
Midpoint: ______ A/D ______ A/D
Lower limit: ______ A/D ______ A/D
Upper limit: ______ A/D ______ A/D
Checklist
Table 103 DAFC Setup Checklist
Task Checked OK/Not OK Remarks
Test procedure completed successfully.
Appendix A – Installation and Test Procedures
357