Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

DTMF decoding using 8051

Status
Not open for further replies.

sokrat

Full Member level 5
Joined
Sep 23, 2002
Messages
277
Helped
9
Reputation
18
Reaction score
7
Trophy points
1,298
Location
EGYPT
Activity points
2,116
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 :cry:
 

cdcll

Full Member level 3
Joined
Feb 15, 2002
Messages
163
Helped
8
Reputation
16
Reaction score
1
Trophy points
1,298
Activity points
1,199
dtmf decoder software

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

ASIC

Full Member level 3
Joined
May 18, 2001
Messages
164
Helped
2
Reputation
4
Reaction score
1
Trophy points
1,298
Activity points
1,205
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

Full Member level 5
Joined
Sep 23, 2002
Messages
277
Helped
9
Reputation
18
Reaction score
7
Trophy points
1,298
Location
EGYPT
Activity points
2,116
dtmf decoding using microcontroller

cdcll said:
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

Newbie level 5
Joined
Jul 8, 2002
Messages
9
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
36
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

Advanced Member level 4
Joined
Jul 19, 2001
Messages
1,059
Helped
90
Reputation
180
Reaction score
17
Trophy points
1,318
Activity points
10,189
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

Advanced Member level 1
Joined
Feb 27, 2002
Messages
422
Helped
13
Reputation
26
Reaction score
5
Trophy points
1,298
Location
brazil
Activity points
3,375
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
:D :wink:
 

C-Man

Advanced Member level 4
Joined
Jul 19, 2001
Messages
1,059
Helped
90
Reputation
180
Reaction score
17
Trophy points
1,318
Activity points
10,189
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

Full Member level 2
Joined
Apr 22, 2001
Messages
146
Helped
2
Reputation
4
Reaction score
2
Trophy points
1,298
Location
Ukraine
Activity points
1,101
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

Full Member level 5
Joined
Sep 23, 2002
Messages
277
Helped
9
Reputation
18
Reaction score
7
Trophy points
1,298
Location
EGYPT
Activity points
2,116
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

Full Member level 2
Joined
Apr 22, 2001
Messages
146
Helped
2
Reputation
4
Reaction score
2
Trophy points
1,298
Location
Ukraine
Activity points
1,101
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
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top