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Ayax Mayagoitia Guest
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DTMF decoder |
Posted: Mon Jul 14, 2003 2:55 pm |
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Hello does anybody knows how to decode DTMF signals
I want to do it in software not in hardware.
Thanks
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This message was ported from CCS's old forum
Original Post ID: 144515972 |
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John Yaron Guest
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Re: DTMF decoder |
Posted: Wed Jul 16, 2003 9:48 pm |
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:=Hello does anybody knows how to decode DTMF signals
:=I want to do it in software not in hardware.
:=Thanks
I always liked referencing algo's targetting the
analog devices ADSP2105.
<a href="http://www.analog.com/Analog_Root/static/library/dspManuals/pdf/Volume1/Chapter_14.pdf" TARGET="_blank">http://www.analog.com/Analog_Root/static/library/dspManuals/pdf/Volume1/Chapter_14.pdf</a>
modified Goertzel ... I implemented them and results were
superior talk-off and sensitivity. It may be possible
to implement on uChip's DSP... but, never looked at it.
DSP experience is a plus when doing these routines.
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This message was ported from CCS's old forum
Original Post ID: 144516085 |
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Ayax Mayagoitia Guest
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Re: DTMF decoder |
Posted: Thu Jul 17, 2003 10:58 am |
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:=:=Hello does anybody knows how to decode DTMF signals
:=:=I want to do it in software not in hardware.
:=:=Thanks
:=
:=I always liked referencing algo's targetting the
:= analog devices ADSP2105.
:=
:= <a href="http://www.analog.com/Analog_Root/static/library/dspManuals/pdf/Volume1/Chapter_14.pdf" TARGET="_blank"> <a href="http://www.analog.com/Analog_Root/static/library/dspManuals/pdf/Volume1/Chapter_14.pdf" TARGET="_blank">http://www.analog.com/Analog_Root/static/library/dspManuals/pdf/Volume1/Chapter_14.pdf</a></a>
:=
:=modified Goertzel ... I implemented them and results were
:= superior talk-off and sensitivity. It may be possible
:= to implement on uChip's DSP... but, never looked at it.
:=
:=DSP experience is a plus when doing these routines.
Thanks John but I mean using the PIC to decode DTMF signals
something like the DTMFIN command on basic stamp.Feeding
the DTMF tone to pic pin and decode this information.
Thanks again for the info.
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This message was ported from CCS's old forum
Original Post ID: 144516103 |
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PCM programmer
Joined: 06 Sep 2003 Posts: 21708
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Re: DTMF decoder |
Posted: Thu Jul 17, 2003 2:30 pm |
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:=Thanks John but I mean using the PIC to decode DTMF signals
:=something like the DTMFIN command on basic stamp.Feeding
:=the DTMF tone to pic pin and decode this information.
----------------------------------------------------------
I did a web search and could not find anything on a DTMFIN
command for the basic stamp.
Here is a link to the BS2 manual. It only lists DTMFOUT.
<a href="http://www.parallax.com/Downloads/Documentation/bs/BASIC_Stamp_Manual_v2-0.pdf" TARGET="_blank">http://www.parallax.com/Downloads/Documentation/bs/BASIC_Stamp_Manual_v2-0.pdf</a>
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This message was ported from CCS's old forum
Original Post ID: 144516109 |
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John Yaron Guest
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Re: DTMF decoder |
Posted: Thu Jul 17, 2003 9:26 pm |
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:=:=:=Hello does anybody knows how to decode DTMF signals
:=:=:=I want to do it in software not in hardware.
:=:=:=Thanks
:=:=
:=:=I always liked referencing algo's targetting the
:=:= analog devices ADSP2105.
:=:=
:=:= <a href="http://www.analog.com/Analog_Root/static/library/dspManuals/pdf/Volume1/Chapter_14.pdf" TARGET="_blank"> <a href="http://www.analog.com/Analog_Root/static/library/dspManuals/pdf/Volume1/Chapter_14.pdf" TARGET="_blank"> <a href="http://www.analog.com/Analog_Root/static/library/dspManuals/pdf/Volume1/Chapter_14.pdf" TARGET="_blank">http://www.analog.com/Analog_Root/static/library/dspManuals/pdf/Volume1/Chapter_14.pdf</a></a></a>
:=:=
:=:=modified Goertzel ... I implemented them and results were
:=:= superior talk-off and sensitivity. It may be possible
:=:= to implement on uChip's DSP... but, never looked at it.
:=:=
:=:=DSP experience is a plus when doing these routines.
:=
:=
:=Thanks John but I mean using the PIC to decode DTMF signals
:=something like the DTMFIN command on basic stamp.Feeding
:=the DTMF tone to pic pin and decode this information.
:=Thanks again for the info.
Running a decent decoder on a PIC would be something to see.
I'm somewhat skeptical due to it's limited horsepower.
... unless there was no voiced speech on the channel
(i.e. vowels). If not, be prepared to handle the false
digit detects while speech is occurring. I've got some
years under my belt in the telephone sector (about 10) and
have seen some pretty mickey-mouse decoders cause many
people some bad headaches. Sometimes using dedicated silicon
is worth the effort in the long run.
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This message was ported from CCS's old forum
Original Post ID: 144516121 |
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Ayax Mayagoitia Guest
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Re: DTMF decoder |
Posted: Fri Jul 25, 2003 11:19 am |
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:=:=Thanks John but I mean using the PIC to decode DTMF signals
:=:=something like the DTMFIN command on basic stamp.Feeding
:=:=the DTMF tone to pic pin and decode this information.
:=----------------------------------------------------------
:=
:=I did a web search and could not find anything on a DTMFIN
:=command for the basic stamp.
:=
:=Here is a link to the BS2 manual. It only lists DTMFOUT.
:= <a href="http://www.parallax.com/Downloads/Documentation/bs/BASIC_Stamp_Manual_v2-0.pdf" TARGET="_blank"> <a href="http://www.parallax.com/Downloads/Documentation/bs/BASIC_Stamp_Manual_v2-0.pdf" TARGET="_blank">http://www.parallax.com/Downloads/Documentation/bs/BASIC_Stamp_Manual_v2-0.pdf</a></a>
Thanks guys
I appreciate your replies... Great !
Probably I got confussed somehow as John said this task might not be easy for the PIC. I think I should use a hardware solution instead. I did that many years back ..I should brouse
my files and remember how I did it.
Thanks again !
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This message was ported from CCS's old forum
Original Post ID: 144516362 |
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subi
Joined: 29 Aug 2010 Posts: 24
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Re: DTMF decoder |
Posted: Wed Oct 19, 2011 5:42 am |
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Hello everybody,
I would like to ask, that somebody has a good CCS program to detect DTMF please share it and to do upload it.
Sorry for my English.
Thank you for you help and kindness.
Subi |
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asmboy
Joined: 20 Nov 2007 Posts: 2128 Location: albany ny
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Posted: Wed Oct 19, 2011 8:07 am |
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i'll make this simple:
there Are ways to count squared up input frequencies - ONE AT A TIME
but DTMF is TWO frequencies blended together.
That is a DSP operation - NOT a pic coding undertaking that you
will find already done for you -
enjoy yourself thinking of how to do it - but i personally would use one of several external very nice chips to do the heavy lifting - and
then harvest the results on your pic.
best o luck 2 U |
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temtronic
Joined: 01 Jul 2010 Posts: 9226 Location: Greensville,Ontario
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Posted: Wed Oct 19, 2011 8:26 am |
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You could try 'Google' !
the very first hit(of a few hundred) found a complete article using a 16F877 as a 'remote DTMF' decoder....tones in---->LCD of the keys pressed.
sorry I didn't save the link, but then Google is easy to use. |
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subi
Joined: 29 Aug 2010 Posts: 24
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DTNF detect in CCS |
Posted: Wed Oct 19, 2011 9:37 am |
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Dear Everybody,
Thank you for your advice and I have really found DTMF decoder program code in the WEB but unfortunately it is in asm. So I would like to get it in CCS if it is possible. My English knowledge is not to good so I have not understood the Goetzer description. This was the reason what I ask it for you.
Sorry for my trouble....
Thank you
Subi |
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sahu77
Joined: 08 Sep 2011 Posts: 202
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Re: DTNF detect in CCS |
Posted: Wed Oct 19, 2011 10:51 am |
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subi wrote: | Dear Everybody,
Thank you for your advice and I have really found DTMF decoder program code in the WEB but unfortunately it is in asm. So I would like to get it in CCS if it is possible. My English knowledge is not to good so I have not understood the Goetzer description. This was the reason what I ask it for you.
Sorry for my trouble....
Thank you
Subi |
can post here DTMF decoder program code (asm or ccs c) _________________ sahu |
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bkamen
Joined: 07 Jan 2004 Posts: 1615 Location: Central Illinois, USA
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Re: DTMF decoder |
Posted: Wed Oct 19, 2011 11:31 am |
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John Yaron wrote: |
It may be possible
to implement on uChip's DSP... but, never looked at it.
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I think I saw a library to do this in MCHP's App Library. (free) for the dsPIC series.
-Ben _________________ Dazed and confused? I don't think so. Just "plain lost" will do. :D |
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ckielstra
Joined: 18 Mar 2004 Posts: 3680 Location: The Netherlands
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Posted: Wed Oct 19, 2011 11:43 am |
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Techniques for DTMF decoding can be band-pass filters or Discrete Fourier Transformation, but using Google I just stumbled upon a third method that is very lightweight to implement in software: read chapter 10.10 from EMBEDDED SYSTEMS PROGRAMMING WITH THE PIC16F877
It uses the fact that DTMF is specified with very tight 2% tolerances. By sampling at clever chosen time intervals and some simple arithmetic the frequencies can be determined.
The example code is in PIC assembly but using the #asm/#endasm directives you can mix assembly and C code in your program. |
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temtronic
Joined: 01 Jul 2010 Posts: 9226 Location: Greensville,Ontario
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Posted: Wed Oct 19, 2011 2:37 pm |
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Another option, though I haven't read the entire site....I have my own battles today...
http://www.romanblack.com/DTMF/DTMF_alg.htm
Has C code for DTMF decoding, very impressive what a small PIC can do !
You'll have to convert to CCS C but it can be done.
The other option is to use the ASM program as a 'subroutine' from your C program. Again, it can be done, though might be harder depending on what level you cut code at. |
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asmboy
Joined: 20 Nov 2007 Posts: 2128 Location: albany ny
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Posted: Wed Oct 19, 2011 7:10 pm |
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well now i'm very interested to hear how you do with this.
I wonder is your DTMF for "in" or "out" - of band signaling ?
if "in band" please share your experience with issues like:
baseband noise rejection
talk-up
false detection
amplitude susceptibility |
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