I am relatively new to gnuradio block-level development and am working with the gr-atsc module. I am specifically interested in the transmit portion and have a few [likely elementary] questions:
1) From what I can see the transmit functionality is only implemented up to the atsc_field_sync_mux(), I don't see the symbol mapping or VSB modulation though I have read a few other posts that suggest it is there. The gnuradio 0.9 has GrAtscWeaverModHead and GrAtscWeaverModTail header files but maybe these did not get modified into gr 3.x.
2) The atsc_field_sync_mux block is derived from gr_sync_block however it outputs more data fields than it consumes (by a factor of 313/312). Even though this seems to work, for my own benefit I re-did this as a gr_block but I am not sure if that is necessary; could someone shed some light on why gr_sync_block works (or appears to but doesn't)?