Frequency Modulation

Discussion in 'Wireless & RF Design' started by mghg13, Mar 22, 2014.

  1. mghg13

    Thread Starter Member

    Jul 17, 2013

    Can any one explain to me briefly what is meat by 'the time response of frequency modulation'?

    I am not able to find explanation on this in any textbook I have.

  2. WBahn


    Mar 31, 2012
    What's the context in which this phrase is being used?
  3. mghg13

    Thread Starter Member

    Jul 17, 2013

    I am to perform an experiment on frequency modulation. And one of the objectives of the experiment is 'to investigate the time response of FM'.

    In the experiment, a variable amplitude constant frequency sinusoid (modulating signal) is applied to an FM modulator and the output of the modulator is observed with the help of an oscilloscope and a frequency counter. Then the expt is repeated with a constant amplitude but variable frequency sinusoid and the results are compared.

    The whole expt is repeated with square waves.

    Where in this expt is 'time response' concerned?
  4. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    There are only two 'time response' actions of interest in this type circuit.

    Time delays in modulator output with response to input change. delay when change starts and 'settle' time when changing input becomes constant again. There are many ways to measure the errors and their rate of occurance depending on what you are investigating and how it pertains to your problem.

    (Slew rate measurements when used with square wave inputs could be considered as well.)

    Is there anything else it could be? anyone?
  5. radiohead

    Senior Member

    May 28, 2009
    Look up pre-emphasis and de-emphasis instead. That should point you in the right direction for the 'time response' issue.