Joshua Shriver wrote:

> I was thinking about writing a sound filter.  So from this lister
> perspective I'm wondering where I can get a mini-stereo jack input
> like you see radio/mp3 players have for headphones. Then from a
> programming i/o perspective what would that be considered and how do
> you interface with that? Guessing there is some form of
> analog-to-digital converter.=20
>=20
> First project is to try and create a noise filter. When listening to
> HF radio (ham) you can get a lot of noise. Thought by sampling I
> could build a nice list of what to cancel out :)

This looks like you can nicely split the project into two parts. One is
the hardware and basic firmware to interface to it (that's where you
talk about A/D and D/A converters etc.) and the other is about filter
algorithms.

The second part you can do nicely in a PC; it provides you with a
comfortable environment to play with different filters. I'm sure there
are some free programs around that allow you to play with high-level
filter descriptions. Once you found one that does what you want, you can
then implement it in firmware.

Gerhard
--=20
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