CCS C Software and Maintenance Offers
FAQFAQ   FAQForum Help   FAQOfficial CCS Support   SearchSearch  RegisterRegister 

ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

CCS does not monitor this forum on a regular basis.

Please do not post bug reports on this forum. Send them to CCS Technical Support

DTMF decoder

 
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion
View previous topic :: View next topic  
Author Message
Ayax Mayagoitia
Guest







DTMF decoder
PostPosted: Mon Jul 14, 2003 2:55 pm     Reply with quote

Hello does anybody knows how to decode DTMF signals
I want to do it in software not in hardware.
Thanks
___________________________
This message was ported from CCS's old forum
Original Post ID: 144515972
John Yaron
Guest







Re: DTMF decoder
PostPosted: Wed Jul 16, 2003 9:48 pm     Reply with quote

:=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.
___________________________
This message was ported from CCS's old forum
Original Post ID: 144516085
Ayax Mayagoitia
Guest







Re: DTMF decoder
PostPosted: Thu Jul 17, 2003 10:58 am     Reply with quote

:=:=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.
___________________________
This message was ported from CCS's old forum
Original Post ID: 144516103
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

View user's profile Send private message

Re: DTMF decoder
PostPosted: Thu Jul 17, 2003 2:30 pm     Reply with quote

:=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>

___________________________
This message was ported from CCS's old forum
Original Post ID: 144516109
John Yaron
Guest







Re: DTMF decoder
PostPosted: Thu Jul 17, 2003 9:26 pm     Reply with quote

:=:=:=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.
___________________________
This message was ported from CCS's old forum
Original Post ID: 144516121
Ayax Mayagoitia
Guest







Re: DTMF decoder
PostPosted: Fri Jul 25, 2003 11:19 am     Reply with quote

:=:=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 !




___________________________
This message was ported from CCS's old forum
Original Post ID: 144516362
subi



Joined: 29 Aug 2010
Posts: 24

View user's profile Send private message

Re: DTMF decoder
PostPosted: Wed Oct 19, 2011 5:42 am     Reply with quote

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
asmboy



Joined: 20 Nov 2007
Posts: 2128
Location: albany ny

View user's profile Send private message AIM Address

PostPosted: Wed Oct 19, 2011 8:07 am     Reply with quote

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
temtronic



Joined: 01 Jul 2010
Posts: 9226
Location: Greensville,Ontario

View user's profile Send private message

PostPosted: Wed Oct 19, 2011 8:26 am     Reply with quote

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.
subi



Joined: 29 Aug 2010
Posts: 24

View user's profile Send private message

DTNF detect in CCS
PostPosted: Wed Oct 19, 2011 9:37 am     Reply with quote

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
sahu77



Joined: 08 Sep 2011
Posts: 202

View user's profile Send private message

Re: DTNF detect in CCS
PostPosted: Wed Oct 19, 2011 10:51 am     Reply with quote

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
bkamen



Joined: 07 Jan 2004
Posts: 1615
Location: Central Illinois, USA

View user's profile Send private message

Re: DTMF decoder
PostPosted: Wed Oct 19, 2011 11:31 am     Reply with quote

John Yaron wrote:

It may be possible
to implement on uChip's DSP... but, never looked at it.



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
ckielstra



Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands

View user's profile Send private message

PostPosted: Wed Oct 19, 2011 11:43 am     Reply with quote

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.
temtronic



Joined: 01 Jul 2010
Posts: 9226
Location: Greensville,Ontario

View user's profile Send private message

PostPosted: Wed Oct 19, 2011 2:37 pm     Reply with quote

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.
asmboy



Joined: 20 Nov 2007
Posts: 2128
Location: albany ny

View user's profile Send private message AIM Address

PostPosted: Wed Oct 19, 2011 7:10 pm     Reply with quote

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
Display posts from previous:   
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group