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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
- Re: [Discuss-gnuradio] FM pre-emphasis and de-emphasis,
Andy Walls <=