The Model 421 Digital Receiver is an integrated solution consisting of an IF Signal Processor, two Demodulators and Bit Synchronizers contained on a single slot 2U Chassis. This state-of-the-art receiver provides a compact, cost competitive, flexible solution to a wide variety of communications link scenarios.

Up to two IF input signals may be applied to the input selector of the Model 421. The input signal selector multiplexer provides 45 dB (typical) of channel isolation thus insuring that only the signal of interest is applied to the IF signal processor. Depending upon specific user requirements, a band-pass or low-pass filter may be installed on the module. Optional an L, S or X-band RF input is also available. The RF signal is then down converted to a 70MHz IF prior to demodulation.

The demodulation process as well as baseband bit synchronization process is totally performed in the digital domain. Signal acquisition is performed by scanning the IF within the programmed acquisition band centered about the selected IF. PM / PSK waveforms are additionally scanned for acquisition at the subcarrier frequency. PSK sub-carrier or direct demodulation supported. Once signal acquisition is complete, synchronized signal tracking is performed whereby continuous validation of the lock state is maintained.