Maker Pro
Maker Pro

phase/frequency detector



Jan 1, 1970
In a specific application I should compare the phase/frequency of two
signals and make a voltage proportional to their phase/frequency
difference. I want to connect this signal to the input of a VCSO.
I’ve XORed these signals and then connected them to the inputs of an
Op-Amp but I’m looking for a better way.


Jan 1, 1970
Do you mean VCXO?

Better how?

What are you really trying to do?


Tim Wescott
Wescott Design Services

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says..
See details at

Thanks Tim,
I’m trying to transmit STM64 over OTN using AMCC OTN wrapper. The AMCC
S19203 divides input and output stream frequency and gives them to
feed an external PLL. I should compare the phase of these signals and
make the output stream reference clock. The output frequency of
dividers is 50MHz.
I’ve opted VS751 to make the desired reference clock. The VS751 give
an input voltage (proportional to the phase difference) to control the
output frequency. Now I want to know how to make a voltage
proportional to the phase difference.