[Discuss-gnuradio] Achilleas' Stereo script - DC on 38khz

[cswiger]

Gang - This is way over my head, but looking at Achilleas'
stereo FM script, which is fascinating, I see there is a
DC component in the 38Khz L-R carrier as it is being fed
to demod_lmr (demod L-R), with a dummy filter in between.
At least when run here I always get "Insignificant advance
required, using dummy filter." Just for the heck I put in
a 'leaky integrator' in place of the dummy, at least do
something useful there:


        # a_filter = gr.fir_filter_fff (1, a_coefs)
        diff = gr.fir_filter_fff (1, [1, -1])
        a_filter = gr.iir_filter_ffd ( [1, 0], [0, .999] )

with appropriate connections. You can see on the scope a little
extra delay between the 19 and 38Khz, but no more DC. Anyway it
seemed to help stereo separation - maybe completely subjective
illusion but they just played Pink Floyd and Smoke on the Water
and it sounded beautiful ;)   As soon as I get a stereo encoder
put together we can do some actual measurements of what tweaks
do.

Demo playing at the usual: http://musicriver.homeunix.com:8000

--Chuck