The OVLBI Decoder performs three main functions; 1) reconfiguring the downlink I, Q and Clock to the form by the VLBA formatter, 2) precisely recording the time of arrival of satellite data frames, and 3) extracting the satellite telemetry data. The I, Q and Clock signals are sent down from the OVLBI Demodulator in the antenna vertex electronics rack. The output data stream is provided to the VLBA formatter and the OVLBI optical modum.

The Decoder is built on two 6U wire wrap cards. The two Decoder boards are shown above in their test fixture.

VME rack

The Decoder is installed in the VME rack containing the station computer and optical modum. The communication to the station computer is via the VME bus. The decoder also supports RS-232 communication for diagnostic purposes.

Related Web Sites

Return to the OVLBI Hardware Page or the OVLBI Home Page. VSOP/HALCA has a home page. The VLBA Correlator NRAO Socorro is developing other hardware and software for the NASA OVLBI project. There is a Space VLBA Correlator home page as well.

Return to the Station Software Guide. The National Radio Astronomy Observatory (NRAO) is a facillity of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.
Last update: 98 January 16