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'Low freq. frecuency counter howto?'
1999\11\02@204543 by Lea

picon face
       Hi All
Can someone give me an idea about how to do a Low frequency , frecuency
counter?, I need to count between 50 Hz and 300 Hz, but not more than that,
and if it's possible avoid interference from higher frecuencies.
I need it to detect CTCSS tones from a given radio channel, so it must have
less than 2 Hz of error, it is possible to do it with a F84??.
Thanks in advance.
  Leandro J. Laporta (LU2AOQ)
  mail: spam_OUTlu2aoqTakeThisOuTspamyahoo.com
  wrk: Arg. Assoc. for Space Technology.
  ham: TCP/IP high speed group HSG

1999\11\02@222638 by Mauricio Jancic

flavicon
face
       Hi, I've developed a frecuency counter that counts from 0 to 720Hz for a motor driver. I've used, to acomplish that, the math routines from some app note from microchip.
       An important thing is that (I dont know why) it didn't work well at the
first time, so I've had to make some corrections to it in order to make it work well (I speak english realy bad, don't I)
       Well, the thing is that the frecuency I was measuring was very unstable, and I needed to "read" the frecuency for a more than a second to have an stable reading.
       I used for this a PIC16C63 (very big for such a thing but I'll add some
features to it) and the board is smaller than a credit card and it cost only U$S 15.
       If you are realy interested on this I can send you a brief explaining how this circuit and code works; the only thing you must do is be patient, cause it will take me a few days to do this job cause I dont have much time.

       Hope I've been usefull, MAURICIO JANCIC

-----Mensaje original-----
De:     Lea [SMTP:.....lu2aoqKILLspamspam@spam@YAHOO.COM]
Enviado el:     Martes, 02 de Noviembre de 1999 10:43 p.m.
Para:   PICLISTspamKILLspamMITVMA.MIT.EDU
Asunto: Low freq. frecuency counter howto?

       Hi All
Can someone give me an idea about how to do a Low frequency , frecuency
counter?, I need to count between 50 Hz and 300 Hz, but not more than that,
and if it's possible avoid interference from higher frecuencies.
I need it to detect CTCSS tones from a given radio channel, so it must have
less than 2 Hz of error, it is possible to do it with a F84??.
Thanks in advance.
  Leandro J. Laporta (LU2AOQ)
  mail: .....lu2aoqKILLspamspam.....yahoo.com
  wrk: Arg. Assoc. for Space Technology.
  ham: TCP/IP high speed group HSG

1999\11\02@223044 by paulb

flavicon
face
Lea wrote:

> I need it to detect CTCSS tones from a given radio channel, so it must
> have less than 2 Hz of error, it is possible to do it with a F84??.

 If you have a quiet signal for a whole second such that the CTCSS is
your only modulation, you could probably count zero-crossings OK.

 Otherwise, it means using DSP techniques and for that a PIC won't do.
Interestingly, Microchip *used to* make DSP chips but has dropped these!
--
 Cheers,
       Paul B.

1999\11\03@024338 by Pavel Kristek

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face
{Quote hidden}

1999\11\03@105051 by Tracy Smith

picon face
--- Lea <spamBeGonelu2aoqspamBeGonespamYAHOO.COM> wrote:
>         Hi All
> Can someone give me an idea about how to do a Low
> frequency , frecuency
> counter?, I need to count between 50 Hz and 300 Hz,
> but not more than that,
> and if it's possible avoid interference from higher
> frecuencies.
> I need it to detect CTCSS tones from a given radio
> channel, so it must have
> less than 2 Hz of error, it is possible to do it
> with a F84??.
> Thanks in advance.

Scott Dattalo has claimed to have done this sort of
thing with DTMF tones:

http://www.interstice.com/~sdattalo/technical/theory/dtmf.html

.lo

=====

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1999\11\03@113843 by Lea

picon face
At 12:24 AM 11/3/99 -0300, you wrote:
>        Hi, I've developed a frecuency counter that counts from 0 to 720Hz
for a motor driver. I've used, to acomplish that, the math routines from
some app note from microchip.

Spanish on the bottom of text....

Hi Mauricio Thanks for U reply, I'm interesting in understand how to do it,
one of
the mails that I recently readed says that I should use DSP or at least FFT math
to make it works!, this scared me!, I thought that it will be less
complicated :).
I saw in the embebbed handbook from microchip, an application of an frecuency
counter using the RTCC input (A4) and another pin that forces rtcc to zero in
some specific moment, but I don't get the idea of how it works (yet :-).
If you can send me something I will really appreciate it!,no problem with the
time :).
thanks!.


Hola Mauricio!, muchas gracias por su contestaci—n, estoy muy interesado en como
hacer esto, en uno de los mails que me han mandado comentaban que deberia usar
FFT o incluso algun DSP!!, eso realmente me asusto, realmente pense que seria
menos complejo lograr algo asi, estuve leyendo una nota de aplicacion que dice
como hacerlo con un pic (creo que era 16c58) usando el RTCC y una salida para
mandar a masa la entrada , no recuerdo el numero de AN, es del libro
embebbed solutions
de microchip, pero no comprendo bien como funciona, si ud. me pudiera enviar
alguna informacion se lo agradeceria mucho, me sacaria de un aprieto :),
no hay problema con el tiempo, muchas gracias.
  Leandro J. Laporta (LU2AOQ)
  mail: TakeThisOuTlu2aoqEraseMEspamspam_OUTyahoo.com
  wrk: Arg. Assoc. for Space Technology.
  ham: TCP/IP high speed group HSG

1999\11\03@215625 by Mauricio Jancic

flavicon
face
Creo que ya le respondi este mail, pero ante la duda lo hago (nuevamente?). Gracias por escribir en castellano. De donde es Ud.??
       Bien, alrededor de este Jueves o Viernes le voy a enviar un peque–o resumen de lo que yo hice. Por cierto me gustaria sabar todo hacerca de la se–al que quiere Ud. medir, asi podre evaluar si es posible o no medirla con el sistema que le envio. En el primer mail que Ud. me envio vi una sigla que identificaba la fuente de la se–al a medir, Que significa?
       Por ultimo me interesaria saber, si no es una molestia, que tipos de trabajos realizan en el lugar donde Ud. trabaja.

       Sin mas, me despido saludandolo a Ud. muy atentamente.


                               MAURICIO JANCIC

-----Mensaje original-----
De:     Lea [SMTP:RemoveMElu2aoqspamTakeThisOuTYAHOO.COM]
Enviado el:     MiŽrcoles, 03 de Noviembre de 1999 01:37 p.m.
Para:   PICLISTEraseMEspam.....MITVMA.MIT.EDU
Asunto: Re: Low freq. frecuency counter howto?

At 12:24 AM 11/3/99 -0300, you wrote:
>        Hi, I've developed a frecuency counter that counts from 0 to 720Hz
for a motor driver. I've used, to acomplish that, the math routines from
some app note from microchip.

Spanish on the bottom of text....

Hi Mauricio Thanks for U reply, I'm interesting in understand how to do it,
one of
the mails that I recently readed says that I should use DSP or at least FFT math
to make it works!, this scared me!, I thought that it will be less
complicated :).
I saw in the embebbed handbook from microchip, an application of an frecuency
counter using the RTCC input (A4) and another pin that forces rtcc to zero in
some specific moment, but I don't get the idea of how it works (yet :-).
If you can send me something I will really appreciate it!,no problem with the
time :).
thanks!.


Hola Mauricio!, muchas gracias por su contestaci—n, estoy muy interesado en como
hacer esto, en uno de los mails que me han mandado comentaban que deberia usar
FFT o incluso algun DSP!!, eso realmente me asusto, realmente pense que seria
menos complejo lograr algo asi, estuve leyendo una nota de aplicacion que dice
como hacerlo con un pic (creo que era 16c58) usando el RTCC y una salida para
mandar a masa la entrada , no recuerdo el numero de AN, es del libro
embebbed solutions
de microchip, pero no comprendo bien como funciona, si ud. me pudiera enviar
alguna informacion se lo agradeceria mucho, me sacaria de un aprieto :),
no hay problema con el tiempo, muchas gracias.
  Leandro J. Laporta (LU2AOQ)
  mail: EraseMElu2aoqspamyahoo.com
  wrk: Arg. Assoc. for Space Technology.
  ham: TCP/IP high speed group HSG

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