EMRFD Message Archive 4370

Message Date From Subject
4370 2010-02-24 13:22:50 R Wall Phase detection circuit to measure frequency....
Hi all,

I have a N2PK VNA which is a great piece of equipment, it can also be used as a signal generator with two outputs. But I don't have a "Frequency Counter" and need one to determine the frequency of the DDS in my PicaStar. I could use a receiver with the VNA (in signal generator mode) and zero beat the two signals to measure frequency. But I wonder if anyone has a simple phase detection circuit that can be used to indicate when the two signals are the same frequency. A simple same frequency LED indicator would do.

Thanks,

Roderick Wall, vk3yc.


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4375 2010-02-25 00:55:19 Ashhar Farhan Re: Phase detection circuit to measure frequency....
if you can solder a phase-frequency detector with one 74LS74 and a74LS00,
you can get the null of frequencies very accurately. alternatively, you can
just use an SB-101 with it's output terminated in a 6 db pad connected to a
detector.


- farhan

4376 2010-02-25 04:11:10 Leon Heller Re: Phase detection circuit to measure frequency....