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FM transmitter (mod4)

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by bananasiong, Oct 26, 2006.

  1. audioguru

    audioguru Well-Known Member Most Helpful Member

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    You didn't learn from the schematic I posted with the anode of the varactor grounded so that a positive voltage can tune the radio frequency.
     

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  2. gauravkalra

    gauravkalra New Member

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    i am sorry audioguru but i think u misinterpreted me or I gave less of information
    actually what i am doing here

    Picture 1 of 5 from modified fm transmittor
     
  3. audioguru

    audioguru Well-Known Member Most Helpful Member

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    It is not good for a sytem to have two grounds with different voltages. Also, the capacitance between the grounds will probably stop the oscillator.
     
  4. dave

    Dave New Member

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  5. gauravkalra

    gauravkalra New Member

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    how capacitance between the grounds stop the oscillator


    how resonant frequency is calculated according to your modification in this circuit
    what will be the formula
    If L is the same how to calculate values of C,C1,C2
    Picture 1 of 7 from modified fm transmittor
     
  6. audioguru

    audioguru Well-Known Member Most Helpful Member

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    The frequency is so high that a few pF of stray capacitance changes the frequency a lot. Therefore you cannot calculate the frequency, you just make the circuit and try different pcb layouts and different capacitor values until the frequency range is what you want.
     
  7. mbarazeen

    mbarazeen Member

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    gauravkalra,

    i understood your idea, what you are trying to do is to directly use the VCO of the modulator, you may find dificulty in scaling it.
    how are you going to demodulate at the receiver side? if you use standard receiver the you may find problem in putting the bandwidth.

    its better you use some other way of transmitting your signals digitally via FM. it will be more acurate and you can use any modulator available with you.
     
  8. gauravkalra

    gauravkalra New Member

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    heartly thanks for all your support especially audioguru
     
  9. luckystar89x

    luckystar89x New Member

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