On 24 Apr 2005 at 20:22, Russell McMahon wrote:

> > Last year I did a 1200bps BELL-202 modem for a client using the
> > Atmel ATMEGA8 processor running at 6.144MHz.
> > TX audio generated via PWM and RX demodulation using fixed-point
> > 16bit math as explained on the link below:
> 
> Work OK?

	The RX performed equal to or better than the MX614P.

> 
> > http://www.baycom.org/~tom/ham/da95/d_dspmod.pdf
> 
> Gives basic principles well - being able to read German would make it 
> even more helpful. No doubt babelfish can help.

	The more important in that article are the C routines, easy to write 
in assembly. I used one timer interrupt reading the ADC 9600 times/sec.
	The ATMega8 has an 8x8 multiply instruction eating just two clock 
cylcles. That saves a lot of time!

	Mark Jordan, PY3SS


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