How to calculate R and C for AM Demodulation envelope detection?

Discussion in 'Homework Help' started by Bilal12, Oct 22, 2015.

  1. Bilal12

    Thread Starter New Member

    Oct 22, 2015
    1
    0
    Hello , one question if posible .

    How can I calculate the value of R and C for an Am envelope detection circuit.

    Knowing that the carrier wave is 20KHz, 1Vpp, and the message signal is a 32Hz, 2Vpp, with a 5V DC offset:

    [​IMG]


    and thank you .
     
  2. GS3

    Senior Member

    Sep 21, 2007
    408
    35
    So you have a 20 KHz carrier. That is a period T = 20 uS.

    How does the circuit work. Think about it. How do you want it to respond to each carrier cycle. What happens if it reacts to slow or too fast. Think about it.

    BTW, it seems to me this should go into the homework forum.
     
  3. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,386
    1,605
    I would think about this in the frequency domain. You need to pass 32hz but block the 20khz.

    So what frequency would you pick for the cutoff?

    Unless you have additional information from your instructor there are a wide range of values that work.
     
  4. GS3

    Senior Member

    Sep 21, 2007
    408
    35
    I suspect he hasn't done the frequency domain yet.
     
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