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dsPIC and PSTN .. DTMF, Caller ID and QAM modem tons

Started by skylazart December 15, 2007
I have been working in a project to decode modem signals: DTMF tones,
Called ID and modulate signals in low rate QAM (until 14400).
I do have few knowledge in eletronics, so i decide to buy a Mikroe.com
�s development kit to help me in the basics...Although this kit doesn't
have any interface with "PSTN world".

Did anybody build anything based in PIC microcontrollers to demodulate
signals?


What would be better or easer? To use another CI or connect the phone
wires/line at dsPIC? Or use MATLAB to do all the things?

I build a circuit that isolate the phone line and record tons in the
sound card. I will try to analyse that in MATLAB...would this work?

Well, thanks to your time! Any tip will be very helpfull...

Thanks to all.

Follow the circuit  I am using to record tons in the PC�s sound card:
http://www.clubedohardware.com.br/imageview.php?image=11886

--
Felipe Cerqueira / skylazart
skylazart [at] gmail.com
"skylazart" <skylazart@gmail.com> wrote in message 
news:392779ed-5196-4d67-a09c-80c6abcc1387@d4g2000prg.googlegroups.com...
> I have been working in a project to decode modem signals: DTMF tones, > Called ID and modulate signals in low rate QAM (until 14400). > I do have few knowledge in eletronics, so i decide to buy a Mikroe.com > &#2013266100;s development kit to help me in the basics...Although this kit doesn't > have any interface with "PSTN world".
Check out dsPICDEM.net 1 and 2 boards and their demo software. Cheers, Howard
On Dec 15, 5:35 am, skylazart <skylaz...@gmail.com> wrote:
> I have been working in a project to decode modem signals: DTMF tones, > Called ID and modulate signals in low rate QAM (until 14400). > I do have few knowledge in eletronics, so i decide to buy a Mikroe.com > &#2013266100;s development kit to help me in the basics...Although this kit doesn't > have any interface with "PSTN world". > > Did anybody build anything based in PIC microcontrollers to demodulate > signals? > > What would be better or easer? To use another CI or connect the phone > wires/line at dsPIC? Or use MATLAB to do all the things? > > I build a circuit that isolate the phone line and record tons in the > sound card. I will try to analyse that in MATLAB...would this work? > > Well, thanks to your time! Any tip will be very helpfull... > > Thanks to all. > > Follow the circuit I am using to record tons in the PC&#2013266100;s sound card:http://www.clubedohardware.com.br/imageview.php?image=11886 > > -- > Felipe Cerqueira / skylazart > skylazart [at] gmail.com
Hi Felipe, I would prefer to digitize with the sound-card and import the data into Matlab. That would provide an environment for relatively rapid exploration of various processing techniques. Once you've modeled your processing in Matlab, then you can port it to your target system, whatever that may be. Darol