On Thu, 2006-04-27 at 11:57 -0700, Eric B. wrote:
Also, can you please post a brief status report about what’s the next
thing to get working? I’m not sure at this time what’s needed to get
get the next step of the loopback working.
Ok, I’ve added to gr-atsc cvs these files:
atsc_field_sync_mux
atsc_field_sync_demux
atsc_equalizer
atsc_fs_checker (field sync checker)
atsc_bit_timing_loop
which will compile, load into python and run in a flow graph
but have NOT been tested or debugged. atsc_field_sync_mux
appears to work as far as I can tell by writing to a file
and examining the hexdump (there’s a field sync inserted after
every 312 data segments, with valid segment sync, pn511, pn63,
inverted pn63 on FIELD2, another pn63, vsb mode info, 92 symbols
from pn63 and even the last 12 symbols from the previous segment,
all look ok, except there’s junk in the pad space).
It would seem the next test phase would be to loopback
atsc_field_sync_mux to atsc_field_sync_demux BUT mux does not
output a syminfo stream that demux requires so not sure how to
proceed there. Nothing else seems a logical loopback point as
the only thing left in the transmitter is a symbol mapper then
modulator and filter.
At this point we NEED:
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
HAVE but not debugged:
atsc_bit_timing_loop float float,syminfo
track symbol & segment timing and do fractional interpolation
atsc_fs_checker float,syminfo float,syminfo
look for field sync patterns
atsc_equalizer float,syminfo float,syminfo
LMS equalizer
atsc_field_sync_demux float,syminfo
atsc_soft_data_segment remove field syncs and pack into data
segments
HAVE WORKING and tested:
atsc_viterbi_decoder atsc_soft_data_segment
atsc_mpeg_packet_rs_encoded Viterbi decoder (12 seg delay)
atsc_deinterleaver atsc_mpeg_packet_rs_encoded
atsc_mpeg_packet_rs_encoded convolutional de-interleaver (52 seg delay)
atsc_rs_decoder atsc_mpeg_packet_rs_encoded
atsc_mpeg_packet_no_sync Reed-Solomon decoder
atsc_derandomizer atsc_mpeg_packet_no_sync atsc_mpeg_packet
de-whiten with LFSR