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I have an application where I have two square wave inputs at 300 MHz; I wish to measure the time delay between the rising edge of both signals.
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First question; why?
Clarification; if you are expecting to measure the delay between the edges of the two signals, then they must be synchronous. If the signals are synchronous, then chances are you do not need to align the clock edges, you just need to use FIFOs to move data between the common synchronous clock domains.
If you absolutely have to measure the phase delay, then one way is to use a phase-detector. A "simple" phase-detector can be constructed using high-speed (external) XOR gate followed by a low pass filter. The DC output of that filter represents the phase difference between the two clocks. Depending on your application, this may be sufficient.
Cheers,
Dave
Honored Contributor
