Re: What does zero-beat sound like? #ubitx

Clark Martin

You can’t discriminate down to zero Hz unless you tap off at the right point with a DC amplifier.  The AC coupling provides a high pass filter that will block the signal above some frequency.

I built a number of digital clocks, back when LSI chips came out to support it.  Most of the clocks I but used the AC line for the timing reference but I built one that was battery powered.  Initially I used an NE555 timer for the timing.  I zero beat it with the AC line using an analog VOM connected between an transformer and the NE555.  As I adjust the frequency the meter needle would start swinging back and forth at the beat frequency (once the beat frequency dropped low enough).  Then I could adjust it till the meter slowed and eventually stopped.  

The 555 provide to be a reasonably stable clock.  Later I switched to a crystal derived clock.

Clark Martin

On May 31, 2018, at 9:02 AM, Mike aka KC2WVB <rb5363@...> wrote:

Interesting, I will have to look at this at a level that is more than casual. I was thinking that one would be discriminating to the limit of zero Hz.

I do like the idea of the Nano or Uno or... serving as the measuring instrument because I am tone death too.

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