This describes the signal flow through the ATSC Transmitter and Receiver programs. ATSC Transmitter ================ module input output notes -------------------- ---------------- ------------------- -------- VrFileSource "MPEG transport stream" atsc_mpeg_packet GrAtscRandomizer atsc_mpeg_packet atsc_mpeg_packet_no_sync whiten data with LFSR GrAtscRSEncoder atsc_mpeg_packet_no_sync atsc_mpeg_packet_rs_encoded Reed-Soloman encoder GrAtscInterleaver atsc_mpeg_packet_rs_encoded atsc_mpeg_packet_rs_encoded convolutional interleaver GrAtscTrellisEncoder atsc_mpeg_packet_rs_encoded atsc_data_segment trellis encoder GrAtscFieldSyncMux atsc_data_segment atsc_data_segment add in field syncs GrAtscSymbolMapper atsc_data_segment float map [0,7] to +/- {1,3,5,7} and add pilot GrWeaverModHead float float,float front half of Weaver VSB modulator GrFIRfilterFFF (2x) float float low pass root raised cosine (matched filter) GrWeaverModTail float,float short back half of Weaver VSB modulator VrFileSink short "16-bit passband data" ATSC Receiver ============= module input output notes -------------------- ---------------- ------------------- ------- VrFileSource "16-bit passband data" short GrConvertSF short float convert short to float GrFIRfilterFFF float float band pass root raised cosine centered at IF freq (matched filter) GrAtscFPLL float float carrier tracking freq and phase lock loop with down converting mixer GrFIRfilterFFF float float low pass to kill unwanted mixer image GrRemoveDcFFF float float remove DC offset prior to symbol timing module GrAtscBitTimingLoop3 float float,syminfo track symbol & segment timing and do fractional interpolation GrAtscFieldSyncChecker float,syminfo float,syminfo look for field sync patterns GrAtscEqualizer float,syminfo float,syminfo LMS equalizer GrAtscFieldSyncDemux float,syminfo atsc_soft_data_segment remove field syncs and pack into data segments GrAtscViterbiDecoder atsc_soft_data_segment atsc_mpeg_packet_rs_encoded Viterbi decoder (12 seg delay) GrAtscDeinterleaver atsc_mpeg_packet_rs_encoded atsc_mpeg_packet_rs_encoded convolutional de-interleaver (52 seg delay) GrAtscRSDecoder atsc_mpeg_packet_rs_encoded atsc_mpeg_packet_no_sync Reed-Solomon decoder GrAtscDerandomizer atsc_mpeg_packet_no_sync atsc_mpeg_packet de-whiten with LFSR VrFileSink atsc_mpeg_packet "MPEG transport stream"