Re: Fastest counter?

Hello Don,


I'm measuring the period of another wave by counting how many cycles of
a 10 MHz oscillator occur during one cycle of the measured wave. 10
MHz doesn't quite give me the desired resolution for sufficient
accuracy in my application.


There is another trick if you still have a few port pins available: Get two fast four-bit counters, a fast four-bit or wider latch and a really, really good OCXO for 160MHz (that one is going to set you back a pretty penny). Use one counter to divide the 160MHz by 16 and feed that to the uC, or whatever clock it needs, but this must be synchronous to the clock of the 2nd counter.

Use the other counter and latch its value every time the timer finishes. Run the timer input off the tail which will be 10MHz pulses. Read in the latched values through four port pins. Those will now be your new least significant bits. If you are hard pressed for port pins you could serialize that.

--
Regards, Joerg

http://www.analogconsultants.com
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