discuss-gnuradio
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Discuss-gnuradio] FM pre-emphasis and de-emphasis


From: Andy Walls
Subject: Re: [Discuss-gnuradio] FM pre-emphasis and de-emphasis
Date: Mon, 08 Jan 2018 20:10:00 -0500

> From:         Richard Lamont
> Date:         Mon, 8 Jan 2018 20:09:23 +0000
> 
> I'm new to this, so my apologies if I'm being thick. I have spent
> hours
> trying to resolve this.
> 
> The FM pre-emphasis and de-emphasis blocks do not appear to implement
> the amplitude-frequency response I would expect - equivalent to a
> simple
> analog RC filter.
> 
> Is this a known bug? (version 3.7.9)

Yes.

I implemented the pre-emphasis filter in 3.7.10 and reworked the de-
emphasis filter at the same time.

Here's the python code that does the filter generation for both
filters:

https://github.com/gnuradio/gnuradio/blob/master/gr-analog/python/analog/fm_emph.py

But you would need to fix more than just that file. The complete
changeset to fix 3.7.9 is viewable under closed pull request #777:

https://github.com/gnuradio/gnuradio/pull/777/files

They are all text files and scripts, so you could conceivably fix up
all your installed files without recompiling anything.  It would be
better to upgrade to a later version though.

Regards,
Andy




reply via email to

[Prev in Thread] Current Thread [Next in Thread]