[Discuss-gnuradio] mods to gr-carriertracking

[Robert W McGwier]

I modified the gr complex pll carrier tracking.  I changed the lock 
signal from a float to a bool.  I added lock detection threshold 
setting.  I added squelch and squelch enable.

These changes were made in preparation of upgrades to the FM stereo 
receiver.  The current receiver works and the stereo separation is 
really sweet on strong stations. But on stations that are not strong or 
on stations that have no stereo signal,  or while tuning,   I am sure 
you agree the output is horrific. 

1) We will remove much of the phase noise hiss that comes from squaring 
the "fading, distorted, etc." stereo subcarrier by doing a phase locked 
loop for the stereo carrier.

2) This will have the added benefit of providing a lock threshold signal 
"for free".   You will be able to set the sensitivity of the stereo 
detection.

3) With the pll recovered clean carrier,  a filtered version of the RDS 
signal will be basebanded and sent to a gr-null-sink.  This will enable 
others to feed the gr-rds block that was recently contributed to our 
efforts.


Those are the great reasons I made the mods but did I break anyone's 
toys?  Let me know.

Bob

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