low density parity check (ldpc) error correction system

LDPC FORWARD ERROR CORRECTION PERFORMANCEPerformance OverviewQuasonix is the only vendor in the market offering LDPC encoding and decoding for serial streaming telemetry. This approach yieldsnearly triple the communications range, yet it does so with 22% less bandwidth than conventional PCM/FM.Synchronization ThresholdThe best coding gain in the world won’t helpif the telemetry link cannot maintainsynchronization through extremely deepfades. Only Quasonix can consistently showsynchronization at negative Eb/N0 values,and the LDPC subsystem is no exception.The ability to preserve bit count integrity atEb/N0 as low as –4 dB allows the user’scrypto devices to stay synchronized underthe most severe fading conditions, therebyeliminating the long data outages that occurwhen the crypto devices lose sync.Not only does the LDPC subsystemmaintain synchronization under highlyadverse link conditions, but under worstcaselink conditions the re-synchronizationpenalty is at most one LDPC code block. Signal plus noise,synchronized at-3 dB Eb/N0Signal plus noise,error-free at+3 dB Eb/N0Strong signal,+35 dB Eb/N0Receiver IF Output During 7 Mb/s LDPC Operation2www.instrumentation.itINSTRUMENTATION DEVICES SRLVia Acquanera 29, 22100 COMO (Italy) tel. +39.031.525391 - fax +39.031.507984 - info@instrumentation.it