Vaisala RVP900

Appendix C _____________________________________________ Installation and Test Procedures
VAISALA______________________________________________________________________ 375
C.11 Setup "Mb" Command (Burst Pulse and
AFC)
Test Goal
Verify that the TTY setups for the Burst Pulse and AFC Configuration
section are properly configured for the customer application.
Background: Magnetron vs Klystron Systems
Magnetron Systems
For magnetron systems, the phase and frequency of the burst pulse from
the transmitter is measured at IF. The phase measurement is used for
digital phase locking and 2nd trip echo filtering and recovery. The
frequency measurement is used to implement an analog (±10V) AFC
output to control the STALO frequency.
Klystron or TWT-based Systems
The COHO is measured instead of the burst pulse.
Special Test Equipment
- KVM connected
Reference
- See Section 4.2.6 Mb — Burst Pulse and AFC on page 126.
Test Procedure
1. Enter the TTY setups and type the "Mb" command.
2. Set all the values as required.
NOTE
An external AFC can be used rather than the RVP900 AFC, but is not
recommended.
NOTE
Klystron systems that use a phase shifter should input the phase shifted
COHO into the IFD, so that the RVP900 can digitally lock to the actual
transmitted phase. For Klystron systems the AFC feedback loop is not
used.

Parameters set.