Multi-frequency detection and conversion.

Discussion in 'The Projects Forum' started by Chygoz, Apr 27, 2011.

  1. Chygoz

    Thread Starter New Member

    Apr 27, 2011
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    I'm working on a project which involves the fm detection of different frequencies and the conversion of these frequencies to voltage. Basically, i want the circuit to be able to detect a range of frequencies and produce a distinct voltage for each of the frequencies. The entire range of frequencies need not be present at the same time. Can anyone give me an idea and possibly a circuit diagram on how to achieve this? Any contribution is appreciated.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    Lots of details are missing. Are these frequencies modulations of the FM carrier? What is that carrier frequency?

    A set of filters can do the frequency detection.
     
  3. Chygoz

    Thread Starter New Member

    Apr 27, 2011
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    Yes these frequencies are modulations of the fm carrier. The carrier is 100MHz.
     
  4. CDRIVE

    Senior Member

    Jul 1, 2008
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    Why is it that most of the posts that fall into this topic arena seem to always be 100MHz, which falls into the commercial FM band?

    Anyway, what you're describing is called "PL" tones, meaning "private line". In the old days this was accomplished with resonant reed relays, which were eventually replaced by a PLL tone decoder which, in turn, was superseded by microcontrollers. Most of the commercial radios today use DPL which translates to "digital private line".

    How many tones do you want to decode? If you have more than a couple the PLL decoders will take up considerable real estate.
     
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  5. Chygoz

    Thread Starter New Member

    Apr 27, 2011
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    Thanks for the info. I'm thinking of working with 3 different tones. As for the carrier frequency, i may change it to something else once i understand the circuit .
     
  6. CDRIVE

    Senior Member

    Jul 1, 2008
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  7. Chygoz

    Thread Starter New Member

    Apr 27, 2011
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    Last edited: May 4, 2011
  8. CDRIVE

    Senior Member

    Jul 1, 2008
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    Bad or broken link.
     
  9. Chygoz

    Thread Starter New Member

    Apr 27, 2011
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    Here's the circuit diagram.
     
  10. CDRIVE

    Senior Member

    Jul 1, 2008
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    Here's the data sheet.
     
  11. Chygoz

    Thread Starter New Member

    Apr 27, 2011
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    Thanks for that. I've been trying to get it for a while now.
     
  12. Chygoz

    Thread Starter New Member

    Apr 27, 2011
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    Thanks for that. I've been looking for it's datasheet for a while now.
     
  13. CDRIVE

    Senior Member

    Jul 1, 2008
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    Your welcome but it wasn't that hard to find.;)
     
  14. Chygoz

    Thread Starter New Member

    Apr 27, 2011
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    The datasheet consists of two circuit diagrams: the test circuit and the application circuit. Which of them is to be used? Because none of them is similar to the circuit in the picture i uploaded earlier.
     
  15. CDRIVE

    Senior Member

    Jul 1, 2008
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    Fig(1) is a block diagram, while Fig(5) is a typical practical circuit.

    Where did you get the schematic that you posted?
     
  16. Audioguru

    New Member

    Dec 20, 2007
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    The Philips TEA5591 AM-FM radio IC had poor performance and is obsolete. It has not been made for many years and the newer TEA5711 also is obsolete and also has not been made for many years. Sony also used to have a few radio ICs.

    I don't know of an available simple half-decent radio IC. I have the datasheet for the TDA7513 that is used in modern car radios and it is surface-mount with 80 tiny pins.
     
  17. CDRIVE

    Senior Member

    Jul 1, 2008
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    I'm beginning to think that Chygoz would be better advised to search for kits. Even if he could obtain one of these chips the parts cost would be far greater than purchasing a board kit. The forum time, calculating all the components, would also break records for longest thread. ;)
     
  18. Chygoz

    Thread Starter New Member

    Apr 27, 2011
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    Okay. Thank you all for your contributions. I guess i'll just have to work with a different circuit then.
     
  19. CDRIVE

    Senior Member

    Jul 1, 2008
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    Is this a class project or assignment?
     
  20. Chygoz

    Thread Starter New Member

    Apr 27, 2011
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    It's a final year project.
     
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