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    clock ppm

    anyone tell me "clock frequency is 50MHz+/-50ppm?" what is really frequency?


    (50M+ 50/1,000,000)Hz? or (50M - 50/1,000,000)Hz?

    50/1,000,000 is very small ,almost can be ignored . I think.

    •   Alt26th December 2008, 09:26

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    ppm clock

    You are right but this small time when accumulated over years then it creates an error of second per say.
    Some people may not interested in this error too.

    For the above calculation the frequency will lie between the two possible frequencies.



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    clock ppm calculation

    50 ppm at 50 MHz means a deviation of 2.5 kHz, an amount that isn't really small for a lot of applications.
    For a watch, 50 ppm implies an error of 26 minutes per year, for an UHF small band radio device, it would be considerably above tolerated error limits.



    •   Alt26th December 2008, 09:48

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    clock ppm calculator

    if the samle frequency and different ppm in write clock and read clock ,Anyone can tell me how to calculate fifo depth ?



    •   Alt2nd January 2009, 03:21

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    clock frequency ppm

    hi feel_on_on

    i think if you meet case that different ppm in write clock and read clock, u have to consider worse case to calculate fifo depth.

    littlebu



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    how to compute ppm in clocks

    if read clock is 50Mhz+/-50ppm,write clock is 50Mhz+/-50ppm ,but they is the different clock . please tell me how to think about the fifo depth?

    Added after 1 hours 57 minutes:

    forget to speak ,the MAX transmit Unit is 1500 bytes



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    what is clock ppm

    Quote Originally Posted by FvM
    50 ppm at 50 MHz means a deviation of 2.5 kHz, an amount that isn't really small for a lot of applications.
    For a watch, 50 ppm implies an error of 26 minutes per year, for an UHF small band radio device, it would be considerably above tolerated error limits.
    Sir u have told deviation of 2.5 kHz, can i know with what formula u have calculated that......thanq u



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    50ppm

    50e-6*50e6=2500



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    Re: clock frequency is 50MHz+/-50ppm?

    Here is how to calculate

    Convert ppm to Hz
    50 MHz nominal +/-50 ppm

    (50000000 / 1000000)*50 = +/- 2500 Hz which define the frequency bound of
    the oscillator to 49.9975 MHz <= f <= 50.0025 MHz

    Hope this will help



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    Re: clock frequency is 50MHz+/-50ppm?

    Friends check this link for PPM to Hz and vice - versa conversion:

    http://www.jittertime.com/resources/ppmcalc.shtml



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