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Design >> Analog Design >> Clock frequency to voltage converter
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Message started by Rosh on Oct 5^th, 2015, 6:46pm

Title: Clock frequency to voltage converter
Post by Rosh on Oct 5^th, 2015, 6:46pm

Hello everyone,

I have a clock signal that varies from 10Mhz- 100Mhz and I need to generate a voltage proportional to the frequency as it varies in step size of 50kHz.

Is there any way to accomplish this? Would a simple RC high pass filter solve the problem? :(

Title: Re: Clock frequency to voltage converter
Post by DanielLam on Oct 6^th, 2015, 12:14am

How linear does it need to be?

I think you could use an XOR gate and lowpass filter the output to get an average voltage.

The two inputs of the XOR are 1) your clock signal and 2) a delayed version of your clock signal.

This delayed version would have a delay proportional to the frequency. To do this, I would stick the clock signal through a lowpass or a highpass filter. This will provide a phase shift proportional to the frequency. Note, I am assuming the voltages are large enough such that the XOR can still process the delayed version correctly.

Title: Re: Clock frequency to voltage converter
Post by loose-electron on Oct 9^th, 2015, 5:31pm

http://www.digikey.com/product-search/en/integrated-circuits-ics/pmic-v-f-and-f-v-converters/2556419?k=frequency%20voltage%20converter

Divide your signal down digitally before plugging into a FVC.

Other methods: count your signal over fixed period of time. Put numeric result into a DAC.