Subject: [linux-audio-dev] Amateur Radio Repeater - Audio control via soundcard
From: Howard, Chris (HowardC_AT_prpa.org)
Date: Fri Apr 06 2001 - 18:09:27 EEST
Hi,
I am not subscribed to this list, but I have a quick
question if you all will indulge me.
I am looking at building an amateur radio repeater for use
in my area. And since I am a software guy, I thought I would
approach it from a software perspective. I am investigating using
a soundcard in a Linux machine to do the job.
A repeater is a radio system where the input and the output
are on different frequencies. The receiver is set up with
a squelch, and it's output audio is sent to the transmitter
via a control circuit. The control circuit senses activity and
keys up the transmitter and sends it the audio for output.
There are also other tasks the controller can do, like injecting
some audio of it's own for station identification, handling timers
to limit long conversations, and detecting DTMF tones and subaudible
tones on the input for doing control functions like shutting the thing
off.
I have read the information about full duplex and low latency. I think
those things are within my ability. The part I am particularly stumped
about is tone detection. This is not a signal modification DSP kind of
effort, just detecting whether a particular tone pair (DTMF) or subaudible
tone is part of the audio input.
I would appreciate any leads or advice you all might have for me.
chris_AT_yipyap.com
Chris Howard
Estes Park, Colorado
This archive was generated by hypermail 2b28 : Fri Apr 06 2001 - 18:36:42 EEST