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Altera_Forum's avatar
Altera_Forum
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18 years ago

convert Mhz to microsecond

Hello guys,

can any one tell me the mathematical way to convert Mhz to microsecond, and microsecond to Mhz ?

for example : I have a 96Mhz clk and I want to build a new signal that every pulse is 25msec. the question is how many clk pulses of 96Mhz i need to have the 25msec?

thanks

amirster

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    18 years ago

    Hi,

    Frequency is related to time using the formula : F = 1 / T, where F is the frequency in Hertz and T, the time in seconds. Now, if you want to generate a new clock with a period of 25 mSec, then

    F = 1 / T => 1 / 25mSec => 0.04 Khz or 40 Hz; a dramatic decrease in frequency from your source clock 96 Mhz. What you're asking for is the decreasing factor that will decrease the 96 Mhz clock to a new clock of 40 Hz. Simply use :

    Ratio : 96E6 Hz / 40 Hz = 2400000. So, the 96 Mhz has to be decreased by a ratio of 2400000 in order to get a new clock of 40 Hz. A rather annusual decrease factor.

    Hope it'll help.