phase detector

Discussion in 'The Projects Forum' started by franky_acc, Jan 23, 2014.

  1. franky_acc

    Thread Starter New Member

    Jan 23, 2014
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    Hi All,
    I am a beginner and my first time on this forum.
    I have a question on a particular phase detector (mC 4o44). I have a project that deals with PLL. The phase detector used is the one stated above. I am haveing trouble with the whole ckt so I tried to check out each block. First is the phase detect.

    some how I can't get the a pulse at the output. I feed in a reference freq from an oscillator and another frequency from a function geneator. Both inputs at same freq and same amplitude. I wired 13,4 together and 11,2 together. I also fed 10,5 to pin 9 with resistor in between.

    Please help.
    Frank
     
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Welcome to the forum.
    Can you post the schematic of your circuit?
     
  3. franky_acc

    Thread Starter New Member

    Jan 23, 2014
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  4. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    How are you conditioning the two signals from the RF generators before applying them to the pins on the 4044? Those inputs will not tolerate a signal that swings below ground.
     
  5. franky_acc

    Thread Starter New Member

    Jan 23, 2014
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    0
    Hi MikeML,
    The pin R is from an oscillator on the bread board. As far as the generator I don't know the answer to that. Maybe that is the culprit? I have the FG connected to a BNC cable and the other end are clips. The black clip connected to ground and the positive clip connected to pin V of the 40 44.
    Is this the correct way for the FG to send a signal. Also, I have the FG set to send square waves.

    Thanks,
    Frank
     
  6. RichardO

    Well-Known Member

    May 4, 2013
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    I know this sounds like a dumb question but, do you really have an MC4044?

    When Motorola first started making 4000 series CMOS they already had a 4000 series including the MC4044. Their solution was to create the MC14000 series for their CMOS parts. This was a very painful period for purchasing agents and production personal since many CMOS circuits got built with the phase comparator instead.
     
  7. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Ok if you crank in a DC offset to center the square wave on 1/2Vcc, meaning that the bottom is at or near 0V, and the top of the square wave is equal to Vcc (5V?)
     
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