Vladimir Vassilevsky wrote:
> 
> 
> Jerry Avins wrote:
> 
>> Rafael Deliano wrote:
>>
>>>>> Goertzel is not viable on simple 8 bit controllers. 
>>>>
>>>> I don't have a link, but someone at Rice university published and 
>>>> linked to an 8-bit Goertzel implementation. I read it about 5 years 
>>>> ago.
>>>
>>>
>>> Fast 16 bit controller like the Mitsubishi M16C with 16x16 
>>> multiplier, DMA, would do it via Goertzel in 1999 like a DSP:
>>> http://www.embeddedFORTH.de/temp/dtmf1.pdf
>>> ( text in german. But there is reference to more literature at the
>>> end of the article. The code and probably a application note on it
>>> should be available at Mitsubishi )
>>>
>>> For a low end 16 bit controller MPS430 in 1997:
>>> "Generation and Recognition of DTMF Signals With the Microcontroller 
>>> MSP430"
>>> http://focus.ti.com/general/docs/techdocsabstract.tsp?abstractName=slaae16 
>>>
>>> Resonators like Goertzel, but implemented as wave digital filters.
>>>
>>> There has been a band-split variant for DTMF
>>> via wave digital filters too:
>>> http://www.embeddedFORTH.de/temp/dtmf2.pdf
>>> Hardware was a Intel 2920 then. But probably could be
>>> done on a controller.
>>>
>>> I would assume Goertzel on less then 16/32 bit registers and without
>>> a reasonable multiplier will not be much fun.
>>
>>
>> IIRC, the author of the Rice had a DTMF decoder on a 60MHz Z-80 with 
>> capacity to spare.
> 
> Z80 at 60 MHz ? What are you talking about?

Typo. 6-Mhz. One key over.

> The most non-trivial DTMF decoder I've seen was done on PIC16 and it 
> utilized about 5 MIPS (Amey A. Deosthali, Shawn R. McCaslin, Brian L. 
> Evans). They used the adaptive notch filters and frequency counters.
> 
> My compliant encoder/decoder does the accumulation into the frequency 
> bins. It takes about 6 MIPS of Atmel AVR.
> 
> The working (although not 100% compliant) decoder takes  only ~ 0.5 MIPS 
> and can be implemented using any microcontroller such as PIC, AVR, x51 
> or HC08.

Then try to find that Rice paper. I lost the URL in a computer disaster. 
You might find something helpful in it.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

Jerry Avins wrote:

> Rafael Deliano wrote:
> 
>>>> Goertzel is not viable on simple 8 bit controllers. 
>>>
>>> I don't have a link, but someone at Rice university published and 
>>> linked to an 8-bit Goertzel implementation. I read it about 5 years ago.
>>
>>
>> Fast 16 bit controller like the Mitsubishi M16C with 16x16 multiplier, 
>> DMA, would do it via Goertzel in 1999 like a DSP:
>> http://www.embeddedFORTH.de/temp/dtmf1.pdf
>> ( text in german. But there is reference to more literature at the
>> end of the article. The code and probably a application note on it
>> should be available at Mitsubishi )
>>
>> For a low end 16 bit controller MPS430 in 1997:
>> "Generation and Recognition of DTMF Signals With the Microcontroller 
>> MSP430"
>> http://focus.ti.com/general/docs/techdocsabstract.tsp?abstractName=slaae16 
>>
>> Resonators like Goertzel, but implemented as wave digital filters.
>>
>> There has been a band-split variant for DTMF
>> via wave digital filters too:
>> http://www.embeddedFORTH.de/temp/dtmf2.pdf
>> Hardware was a Intel 2920 then. But probably could be
>> done on a controller.
>>
>> I would assume Goertzel on less then 16/32 bit registers and without
>> a reasonable multiplier will not be much fun.
> 
> 
> IIRC, the author of the Rice had a DTMF decoder on a 60MHz Z-80 with 
> capacity to spare.

Z80 at 60 MHz ? What are you talking about?

The most non-trivial DTMF decoder I've seen was done on PIC16 and it 
utilized about 5 MIPS (Amey A. Deosthali, Shawn R. McCaslin, Brian L. 
Evans). They used the adaptive notch filters and frequency counters.

My compliant encoder/decoder does the accumulation into the frequency 
bins. It takes about 6 MIPS of Atmel AVR.

The working (although not 100% compliant) decoder takes  only ~ 0.5 MIPS 
and can be implemented using any microcontroller such as PIC, AVR, x51 
or HC08.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

Rafael Deliano wrote:
>>> Goertzel is not viable on simple 8 bit controllers. 
>> I don't have a link, but someone at Rice university published and 
>> linked to an 8-bit Goertzel implementation. I read it about 5 years ago.
> 
> Fast 16 bit controller like the Mitsubishi M16C with 16x16 multiplier, 
> DMA, would do it via Goertzel in 1999 like a DSP:
> http://www.embeddedFORTH.de/temp/dtmf1.pdf
> ( text in german. But there is reference to more literature at the
> end of the article. The code and probably a application note on it
> should be available at Mitsubishi )
> 
> For a low end 16 bit controller MPS430 in 1997:
> "Generation and Recognition of DTMF Signals With the Microcontroller 
> MSP430"
> http://focus.ti.com/general/docs/techdocsabstract.tsp?abstractName=slaae16
> Resonators like Goertzel, but implemented as wave digital filters.
> 
> There has been a band-split variant for DTMF
> via wave digital filters too:
> http://www.embeddedFORTH.de/temp/dtmf2.pdf
> Hardware was a Intel 2920 then. But probably could be
> done on a controller.
> 
> I would assume Goertzel on less then 16/32 bit registers and without
> a reasonable multiplier will not be much fun.

IIRC, the author of the Rice had a DTMF decoder on a 60MHz Z-80 with 
capacity to spare.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

>> Goertzel is not viable on simple 8 bit controllers. 
> I don't have a link, but someone at Rice university published and linked 
> to an 8-bit Goertzel implementation. I read it about 5 years ago.

Fast 16 bit controller like the Mitsubishi M16C with 16x16 multiplier, 
DMA, would do it via Goertzel in 1999 like a DSP:
http://www.embeddedFORTH.de/temp/dtmf1.pdf
( text in german. But there is reference to more literature at the
end of the article. The code and probably a application note on it
should be available at Mitsubishi )

For a low end 16 bit controller MPS430 in 1997:
"Generation and Recognition of DTMF Signals With the Microcontroller MSP430"
http://focus.ti.com/general/docs/techdocsabstract.tsp?abstractName=slaae16
Resonators like Goertzel, but implemented as wave digital filters.

There has been a band-split variant for DTMF
via wave digital filters too:
http://www.embeddedFORTH.de/temp/dtmf2.pdf
Hardware was a Intel 2920 then. But probably could be
done on a controller.

I would assume Goertzel on less then 16/32 bit registers and without
a reasonable multiplier will not be much fun.

MfG JRD

Rafael Deliano wrote:
>  > should I detect the energy of incoming signal
> Dial-tone in a lower frequency band and all
> sort of background noise from the microphone
> may prevent that.
> 
>> I have to scale by 8 bits to implement Goertzel
> What sort of hardware do you intend to use ?
> Goertzel is not viable on simple 8 bit controllers.

I don't have a link, but someone at Rice university published and linked 
to an 8-bit Goertzel implementation. I read it about 5 years ago.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

Mannai_Murali wrote:
> Hello,
> 
> I am implementing DTMF detection using Goertzel Algorithm.

Don't use Goertzel.

http://www.abvolt.com/research/Multitone%20detect-IEEE.pdf



Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

 > should I detect the energy of incoming signal
Dial-tone in a lower frequency band and all
sort of background noise from the microphone
may prevent that.

> I have to scale by 8 bits to implement Goertzel
What sort of hardware do you intend to use ?
Goertzel is not viable on simple 8 bit controllers.

MfG  JRD

Hello,

I am implementing DTMF detection using Goertzel Algorithm.I have two
questions

1.Since the duration of DTMF signal present is 40 msec and Goertzel takes
25msec should I detect the energy of incoming signal (at 3Khz) and then
start Goertzel.(If I start my Goertzel after 20msec of actual signal I need
another 5 msec more DTMF signal presence.But valid DTMF is available only
for 20 msec.I started my Goertzel late by 20 msec).To avoid this can I
check the signal energy in the entire 3 KHz band for say 5 msec compare
with a threshold and then based on this start Goertzel.I will have 35 msec
signal left.


2.I have to scale by 8 bits to implement Goertzel (I need 201 and 205
samples at 8KHz) to avoid overflow.Since the signal itself may at low level
(not at 0dBm) should I have an AGC before Goertzel.Or else the entire
signal could be lost due to a) siganl being low level and may not occupy
entire 16 bits precision.b)Scaling of 8 bits for Goertzel

Kindly give feedback on 1 and 2.

Thanks,

V.Muralidharan