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Mark-Space Ratio

  1. Mar 22, 2016 #1
    Hi if I had the ratio of 4:1 and the frequency of 10Khz how would I go about finding the time?
  2. jcsd
  3. Mar 22, 2016 #2


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    Staff: Mentor

    Who which what?
  4. Mar 22, 2016 #3
    Perhaps you could cut back on other activities? It's always hard to find time, but if something is important most people manage. o_O

    Another term for the mark space ratio is duty cycle.

    At 10kHz, the entire wave is 100µs and the active part (usually the high part) is 4/5th of that, so 80µs.

    To get this I divided 1 cycle by 10,000 cycles per second and got 1/10,000 (100µs) of a second. Since the mark space ratio divides the cycle into parts, I divided the active parts of the ratio (4) by all the parts of the ratio (4+1=5) and got 0.8. I then multiplied 100µs times 0.8 and got 80µs.

    I wasn't really clear what you are asking, but this might answer your question.
  5. Mar 23, 2016 #4


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    Science Advisor

    Frequency = 10 kHz. Therefore period, T = 1 / 10k = 100 usec.

    Ratio 4:1 could mean ( 4 marks + 1 space ) = 20%
    That would give mark time = 4/5 * 100 usec = 80 usec and the space time = 20 usec.

    The “ratio of 4:1” is a bit confusable. It might mean 20%, 25%, 75% or 80%.
    A “ratio” suggests a simple division, not a relative proportion such as 4:1 = 4 / (4 + 1 ).
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