digital phase decoder

Discussion in 'The Projects Forum' started by A.KH, Jun 16, 2010.

  1. A.KH

    Thread Starter New Member

    Jun 16, 2010

    I ask you to help me with my mini project/homework in digital circuits...

    I want to design a digital phase decoder, that decode a voltage with phase "θ" (shifted) compared with the clock, to 4 bit (equal to the phase, that mean we have 16 options in the out, 2^4 = 16).
    Resolution = 180/16.
    0 <= θ <= 180, and the phase (θ) can be one of the values :
    180/(16*n), when n=1,2,3,......,16

    note: my design with moltisim-ewb.
    thank you
  2. eblc1388

    Senior Member

    Nov 28, 2008
    The easiest way is to generate a new clock frequency that is 32 times of the original clock, using a digital phase-locked-loop, like the 74HC4060.

    Then feeds this x32 frequency clock signal into a 4-bit counter and let it counts forever. Connects the "phase shifted" voltage to the clock input of a 4-bit latch and latches(captures) the output of this 4-bit counter.

    The counter will counts from 0 to 15 to 0 repeatedly within the 180° electrical degree of the clock(that's why you will need a x32 frequency). The counter output thus represents how much the "shifted" voltage is phase shifted with regard to the clock signal.

    if you get 0 as a result, that means the voltage is any where from 0 degree to 180/16 degree, or over 180 degree. A value of 15 would indicate the voltage is shifted in the range of 180*15/16 to 180 degrees.

    If you wants to be certain about the situation where the phase shift could be over 180 degree , then you have to use a counter with a higher bit count, e.g. 6-bit of eight bit.