DTMF decoding using 8051

[sokrat]

dtmf using 8051

Hi all

i want to decode DTMF tone by using 8051 ....
i read more paper for this object but antill now i cant writer my programe
if any one can help me

 

[cdcll]

dtmf decoder software

You can choose a DTMF chip such as MT8870, EM9270.

 

[ASIC]

dtmf decoder software goertzel

If you are good in optimizing the source code, you can try the Goertzel Algorithm. Look in Google for more information.


ASIC

 

[sokrat]

dtmf decoding using microcontroller

You can choose a DTMF chip such as MT8870, EM9270.

i want to decoding DTMF without external chip


ASIC

if you undersand this Goertzel Algorithm very good i want to know note ...ok

S 8O KRAT

 

[zb7401]

code 8051 dtmf

it is difficult to decode DTMF tone by 8051 ,you can do it with dsp!or some ic! and you can send DTMF tone using 8051!

 

[C-Man]

decoding dtmf without external chip

I once tried to decode DTMF by software and failed!

Here are the reasons:
The receiving levels are totally different (depends on telephone line quality).

There is also a so called "twist" which means higher tones have less amplitude than lower tones which also makes decoding more complicated.

It took me many hours experimenting until I gave up on this.

Since then I am using DTMF decoders from Mitel with built in AGC (interfaced via 3 wire interface) which work perfect for me ...

best regards

 

[gorkin]

detect dtmf tone avr

Hi sokratis!

In the following link, have the application note abaout decoding DTMF with the MSP430Fxxx Ti microcontroller. The code is simple and reusable for other microcontrollers!
Go in w!w!w.ti.com and search in microcontrollers application notes ok?


gorkin
:wink:

 

[C-Man]

best dtmf decoder

Ok the document gorkin describes is located here:
**broken link removed**

But I am afraid that if you do this with an 8051 there is no time left to do other things which are needed by your program ...

So my advice is use a hardware decoder.

best regards

 

[dacadc]

dtmf decoder 8051 microcontroller

There is no problems with DTMF decoding on 1-2 MIPS micro. Please look on my app note AN2107 from Cypress Micro (**broken link removed**) and you can easily to port on own CPU in hours. I test this for many weeks, so it works fine

 

[sokrat]

slaae16.pdf ( texas instruments) or goertzel.

thanks for all


i think Goertzel Algorithm is difficult to calculate in microcontroller ?
but !!! what about zero Crossing
if i make the DTMF signal to pass throgh zero crossing detector and then microcontroller and calculate number of zero crossing with fixed time
can i detect the DTMF signal :?:


THANKS

S 8O KRAT

 

[dacadc]

cpu with dtmf decoder

The Goertzel is not good for micro without hardware MAC. I recommend to use the digital quadrature signle bit correlator for CPU w/o ADC and digital quadrature correlator for CPU with 8 bit ADC. Try to test Goertzel algorithm under 8kHz sample rate with spech analysis for classic 8051