Re: [Discuss-gnuradio] FM TX diagram

[Jorge Chávez]

Thanks a lot for the help.
 In a non Software Radio FM transmitter we have an integrator, local osc,
mixer, and RF filter.
In this case, I can´t find the integrator and the RF section. why? are not
necessary?.
 Thanks again.
 Jorge Chavez
Mexico

 On 11/9/05, cswiger <address@hidden> wrote:
>
> On Wed, 9 Nov 2005, [ISO-8859-1] Jorge Chávez wrote:
>
> > Hi Everyone:
> > I´m looking for a block diagram of the fm_tx4.py, the code is not
> totally
> > understandable for me, that's why i´m trying to find a diagram.
> >
>
> Hi Jorge - As far as I can make out it looks something like this:
>
>
> pipeline:
>
> (src|file_source)---->(fmtx|nbfm_tx)------>(mixer|multiply_cc)---->
> ^
> |
> (lo|sig_source_c)-----------+
>
>
>
>
>
> (t1:pipeline)--->(sum|add_cc)-->(gain|multiply_const_cc)-->(u:usrp_sink_c)
> ^ ^
> (t2:pipeline)-----+ |
> |
> ... |
> |
> (tn:pipeline)------------+
>
>
>
> First he creates a hierarchical block called 'pipeline' which takes
> filename, local osc freq, audio_rate and if_rate. Then he uses
> that in fm_tx_graph in a loop connecting them all to 'sum', then
> to 'gain' then out to the usrp hardware. There can be up to 7 'pipeline'
> channels. The 't' definition loop is pretty tricky - but he creates
> each 't' pipeline with a seperate audio-1.dat file (audio-2.dat,
> audio-3.dat, audio-4.dat and then I think it goes back to audio-1.dat)
> and a seperate local osc frequency from 'offset', 0, 25, -25, 50, -50,
> 75 and -75Khz for each 't' pipeline. Yes, (i % 4) is modulo -
> 0,1,2,3,0,1,2,3.
>
> Good luck.
>
> --Chuck
>
>