Re: i4l dtmf errors

From: Roy Sigurd Karlsbakk (
Date: Sat Dec 14 2002 - 09:54:29 EST

> Quick reading of drivers/isdn/isdn_audio.c(*) shows that it does use
> fixed-point Görtzel (Goertzel in english) algorithm for detecting
> tones, but it does _not_ do comparison of received overall signal
> power vs. detected DTMF tone powers.
> When there is signal power outside the DTMF channels, signal should
> not be detected. Also, DTMF tone powers should be roughly equal,
> and exactly two tones should be present for valid detection.
> Adding those power tests should be fairly trivial, but I leave it
> to Somebody Else...

Is there a 'somebody else' (perhaps the isdn maintainer?) that have time to
look at this?



Roy Sigurd Karlsbakk, Datavaktmester
ProntoTV AS -
Tel: +47 9801 3356

Computers are like air conditioners. They stop working when you open Windows.

- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to More majordomo info at Please read the FAQ at

This archive was generated by hypermail 2b29 : Sun Dec 15 2002 - 22:00:30 EST