[time-nuts] Zero-Crossing Detector Design?

[Al Wolfe]

Chris,
    The simplest zero crossing detector would be to feed your 1 volt, 10 mHz 
from the XL-DC into the input of an IC with schmidt trigger inputs. You 
would need to provide a series coupling cap and probably some DC bias from a 
pot to adjust symmetry of the output. I would also think that if you ran the 
four or six inverters of a schmidt trigger inverter chip in series that you 
would get a pretty good square wave out the end.

    I have an XL-DC with four 10 mHz sine outputs but have not had the need 
yet for a square wave. For that matter, it may be posible to find a 10 mHz 
square wave somewhere inside the box before it is converted to a sine wave 
that could be used for your application.

Al



> Subject: [time-nuts] Zero-Crossing Detector Design?
>
> Can anyone suggest a good reference design for a zero-crossing detector? I 
> am trying to home an ADC sampler trigger to the 1VRMS (50ohm) 10MHz sin 
> from my XL-DC... And now I'm thinking that I should just home the uC clock 
> to it, as well.
>
> Essentially, I believe that I'm looking for an efficient, stable, and 
> accurate sine-to-square converter... and I'll welcome any advice in this 
> area.
>
> This may also be used in a 1KHz 5Vpp IRIG-B decoder... I don't feel like 
> rectifying the signal, to be honest. I want to try to keep a smaller BOM, 
> sense the waveform primarily, and crunch numbers inside the uC.
>
>
> -CH
>
> Chris Hoffman
> cq.kg6o at gmail.com
> http://ar.ctur.us