akachyan wrote:

...

> I use DFT filters to track frequency. FFT doesn't work in my case because
> I need precise frequency tracking.

FFT is an efficient way to do DFT. If different ways to do DFT give
different results, at least one of them is wrong.

> Furthermore, the off signal may have different frquency, i.e on freq is
> 15.65 Mhz and off freq is 16.59 Mhz. In this case, I have to track 15.65
> Mhz freq. of course it has on/off switches.

If the off freq is 16.59 MHz, what does "off" really mean? Do you have a
form of FSK?

...

Jerry
--
Engineering is the art of making what you want from things you can get.
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