IF of radio receiver

Discussion in 'Wireless & RF Design' started by Synaps3, Dec 7, 2013.

  1. Synaps3

    Thread Starter Member

    Jun 5, 2013
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    Do all radio receivers have an IF somewhere in them. Do portable radios? Is there an easy way to find where it is in the circuit without just going crazy with an oscilloscope looking for 450 khz or whatever?
     
  2. Art

    Distinguished Member

    Sep 10, 2007
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    All Supersonic Heterodyning receivers do at least.
    That's 455kHz or whatever.. usually.. for AM MW.

    Relating this to every schematic is the part I'm working on
    [​IMG]
     
  3. Papabravo

    Expert

    Feb 24, 2006
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  4. MrChips

    Moderator

    Oct 2, 2009
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    Not all radios are based on the superheterodyne receiver principle though a large percentage of commercially available radios use this method. The most common IF frequency is 455kHz.

    Many receivers use double conversion and triple conversion techniques where there
    could be two or three IF amplifiers.

    A direct-conversion receiver uses an oscillator that is set to the same frequency as the incoming RF signal resulting in a direct-to-baseband signal.

    Regenerative receivers use a prinicple of positive feedback to amplify the incoming signal directly.

    Edit: I wrote this as post #2 and was called away to answer the phone.
     
  5. Art

    Distinguished Member

    Sep 10, 2007
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    When I went to an antique radio dealer, I wanted to really turn it on, so I asked for a
    Thermonic Electron Valve for my Supersonic Heterodyning Meduim Wave Broadcast Receiver.

    You should be proud of me Papabravo, I took the time to discover the meaning of those big words individually :)
    and two months ago, I had no idea.
     
  6. MrChips

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    Oct 2, 2009
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    I don't think anyone uses that term. It was known as "superhet" but even that is almost extinct.
     
  7. Papabravo

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    Feb 24, 2006
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  8. Art

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    Sep 10, 2007
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  9. Art

    Distinguished Member

    Sep 10, 2007
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    Hmmmmmmmmmmmmmmmmm?
    ^512Hz----------------------------^16.3kHz
     
  10. bertus

    Administrator

    Apr 5, 2008
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    Last edited: Dec 8, 2013
  11. alfacliff

    Well-Known Member

    Dec 13, 2013
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    portable radios (modern ones anyway) use 455 khz for am if's, and 10.7mhz fm if's. there are some single chip radios that do away with the transformers with a lower frequency if and opamp based active filters.
    cliff
     
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