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A free software equalizer for listening to Mix Radio International (and more!)

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redhat:
NRSC white paper outlining the response of the modified 75uS cure is here.

https://www.nrscstandards.org/standards-and-guidelines/documents/archive/nrsc-1-a.pdf

+-RH

ChrisSmolinski:
Thanks, my response was actually pretty close to that, perhaps a little more attenuation on the high end to reduce the hiss.

JimIO:
RH, what does a 'modified 75uS  NRSC pre-emphasis' circuit look like?
I have searched for it before and now and can't find one. How 'modified' is it compared to FM?

redhat:
I'll have to dig and see if I can find a good example.  Usually the pre-emphasis is built into the processing HF limiter stage so there is a lot going on and sometimes it isn't just one pole.  The standard defines it as a 75uS pre emphasis network with another pole at 8700 Hz.  In practice, there is not much difference between the responses (4dB more boost at 10 KHz), and the second pole was added to ease transmitter linearity requirements, and also reduce adjacent channel interference.

+-RH

JimIO:
RH, thanks for pointing out 8700Hz. I only skimmed through that pdf file and missed that.
I did a little more searching found that it is a 'truncated 75 us curve'. I'm not really interested in the dynamic processing part of it.

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