Re: [Discuss-gnuradio] Stereo gain "hacked"

[al davis]

On Tuesday 14 February 2006 00:13, Robert McGwier wrote:
> But the COMPOSITE signal is what is
> FM modulated but I bet they do not preemphasize the composite
> signal. They might do preemphasis on the L+R baseband signal
> as Matt suggests but I just don't know about the others.  I
> am trying to understand what about that would make sense.  It
> would be very interesting to read a real spec.  I have
> googled and not really found one a  useful one.

Preemphasis is done separately on left and right, before 
encoding, with a 75 microsecond time constant, which gives a 
corner at 2 KHz.   A simple RC network does the job.  Then in 
the receiver, it is deemphasized after decoding, again with a 
simple RC network, low pass with 75 microsecond time constant.