[Discuss-gnuradio] Stereo FM receiver: wfm_rcv_pll.py and usrp_wfm_rcv_pll.py

[Robert W McGwier]

The functional stereo squlech with a slider controlling the level has 
been added to usrp_wfm_rcv_pll.py.  All of the activity on 
wfm_rcv_pll.py in the last 24 hours has been getting gains,  loop 
parameters,  etc. all to work correctly to reduce hiss, and allow this 
squelch to work.  This was also accompanied by setting the usrp default 
gain so match the loop expectations.

As you slide the squelch threshold from its default value (0) to the 
right,  somewhere around 1/3 scale the stereo will disappear and mono 
will replace it.  As you move it slowly up and down you can hear the 
stereo additive pop in and out.  This code is functional.  Not all is 
perfect here and more work remains but there is so much detritus in 
wfm_rcv_pll.py  and it is formatted so poorly that even I have trouble 
reading my mess.

The RDS signal is also picked off.   For now while we await a couple of 
logistical necessities to be handled,  this signal is sent to a complex 
null sink.

Now that all of this is together,  I will go through and clean up 
namespaces and all sorts of scuzz.  I want to add a check box for stereo 
disable, etc. but I want to clean my mess up while I look for  
optimizations.

Enjoy,
Bob

--
Robert W. McGwier, Ph.D.
Center for Communications Research
805 Bunn Drive
Princeton, NJ 08540
(609)-924-4600