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Problem occured during TDM experiment

  1. Aug 23, 2007 #1
    The experiment is that asynchronus i/p results jitter at o/p for synchronus TDM channel.

    In a experiment ,where We gave i/p as square wave (0 to 5 volt) in frequency range 500Hz to 4000 Hz. This square wave is sampled at a rate of 8000 samples/sec. & quantized in 8 bits data , thus resulting in a 64Kbps channel. Such 12 Channels were time division multiplexed (other channels may or may not have the i/p). This multiplexed data is transferred through 850nm optical fibre channel. When signal is received , demultiplexed & o/p is observed. It is seen that in square wave there is overlap in 0(0v) & 1(5v) bit for 125micro seconds, whatever may be frequency in the given range. What is reason for this overlap? :confused:

    It was also said that i/p signal is asynchronus for this system, because their frequency differs from the rate at which they are sampled.

    As a hint it was given that input is initially sampled at every 125 micro sec(at the rate 8Khz) and it might lead to some conclusion.
  2. jcsd
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