Re: [Discuss-gnuradio] State of HDTV 2

[Eric Blossom]

On Wed, Apr 05, 2006 at 05:27:51PM -0400, Charles Swiger wrote:
> On Wed, 2006-04-05 at 10:16 -0700, Eric Blossom wrote:
> 
> > I moved it all to a new module, gr-atsc in CVS.
> > 
> > It's already autoconfiscated and ready to go.  There's a file,
> > README.signal_flow in the top level directory that tells how the old
> > code was connected together.  There are loopback tests for the first
> > two blocks in each direction in the python directory.
> > 
> > The normal:
> > 
> >   ./bootstrap
> >   ./configure
> >   make && make check && make install
> > 
> 
> Ok, found it - If I understand correctly, it looks like the next block
> to finsh is the convolutional interleaver, and it's reverse the 
> convolutional de-interleaver.

That's right!

When you loop the deinterleaver back, you'll need to account for the
52 segment delay through it.  Using gr.skiphead is probably the
easiest solution (thanks Martin!).

> 
> Existing 2.0 layers:
> --------------------
> 
> Src (mpeg transport)                Dst
>        v                               ^
> Randomizer                          Derandomizer
>        v                               ^
> Reed-Soloman Encoder      ----->    RS Decoder
> 
> 
> 
> Yet to be done:
> ---------------
> 
>        v                                     ^
> Convolutional Interleaver     ->      De-Interleaver
>        v                                     ^
> Trellis Encoder               ->      Viterbi Decoder
>        v                                     ^
> Field Sync Multiplexor        ->      Field Sync Demux
>        v                                     ^
> Symbol Mapper                         Equalizer
>        v                                     ^
> Weaver Modulator Head                 Field Sync Checker
>        v                                     ^
> FIR Filter (lp root raised cosine)    Bit Timing Loop3
>        v                                     ^
> Weaver Modulator Tail                 Remove DC 
>                                              ^
>        |                              FIR Filter, Image Remove
>        |                                     ^
>        |                              FPLL Carrier Tracking PLL 
>        |                                 and down converter
>        |        IF                           ^
>        +----------------->            FIR Filter (lp root raised
>                                                        cosine)
> 
> 
> Actually the FIR filters already exist, as does the carrier tracking
> PLL and mixer. Since we start with a complex source already (usrp
> in place of the mc4020 'short' data source) image removal won't be
> necessary (I guess). So really all we need is the logic from 6 blocks
> repackaged for a receiver, and 6 for a transmitter to do stage-by-stage
> testing.  IIUC.

Yep, you're on the right track!

Eric