BSV533 L3 Harris Bit Synchronizer Module

The L3 Harris / L-3 Communications BSU532/BSV533 Bit Synchronizer Modules are 6U VME modules, manufactured in two models (BSU532 and BSV533), which create a clock synchronized to an incoming PCM data steam and make bit decisions on that stream at data rates up to 20 Mbps. They convert the input data code to NRZ-L and one other operator-selected IRIG format. The modules condition the signal through analog and digital filtering techniques that implement automatic gain, offset, frequency (tracking), and phase control.

Both Bit Sync modules use a unique digital approach to making bit decisions, increasing performance over traditional analog bit syncs and eliminating recalibration. The input can be selected from one of four single-ended inputs or from one RS-422 input. Input impedance of 10 kΩ or 75 Ω can be selected. Each input can be individually terminated so that non-selected inputs are not left unterminated.

The principal difference between the two models is the BSV533's Viterbi decoder, which decodes convolutionally encoded signals to provide an improved level of bit error rate performance.

The BSV533's Viterbi Forward Error Correction (FEC) decoder and convolutional encoder decodes rate 1/2 (or 1/3) constraint length K=7 encoded data with (8) combinations of connection vector swapping and alternate symbol inversion; and provides BER improvement of 5.2 dB @ 10^-5 (5.5 dB @ 10^-5).