3.6 Digital AFC (DAFC)
The optional Digital AFC Module (DAFC) is a small, self-contained circuit board that
passively listens to RVP900 serial uplink transmissions. Its generates a set of digital AFC
control lines that could be applied, for example, to a custom STALO frequency synthesizer.
Vaisala recommends using the DAFC board in systems that require an AFC because it oers
advantages over other methods of frequency control:
• The stability of a synthesized STALO can be made much greater than that of a tunable
cavity oscillator. Noise on the AFC control voltage directly contributes to phase noise in
the received weather targets in analog AFC systems, so cabling of the control signal
can be
dicult.
• The board can be physically located very close to the STALO. The length of the control
cable and its susceptibility to noise and ground loops are therefore reduced. The DAFC
board can supply up to 24 output control lines.
More Information
‣
Automatic Frequency Control (AFC) (page 176)
‣
Installing DAFC (page 74)
‣
Mb — Burst Pulse and AFC (page 93)
‣
RVP900 Product Architecture (page 15)
3.7
Expansion Panels
Expansion panels allow the signal processor to interface with other radar sub-systems.
RVP901 is designed with generic I/O capability to interface with these expansion panels.
3.8
Utilities and Applications
RVP900 includes applications and utilities for the calibration, alignment, and configuration.
These can be run locally on RVP900 or over the network from a central maintenance facility.
For more information, see IRIS and RDA Utilities Guide.
Table 11 RVP Utilities
Utility Description
Ascope Used to control the signal processor manually and to display moments, times series, and
Doppler spectra.
Includes a signal simulator able to produce first and second trip targets.
Can record and playback of time series and moments.
dspx An ASCII, text-based program for accessing and controlling the signal processor,
including accessing local setup menus
RVP900 User Guide M211322EN-J
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