[time-nuts] 1 pps sync'ing

[jimlux]

On 6/29/18 6:13 AM, Martyn Smith wrote:
> Hello,
> 
>   
> 
> My colleague Steve asked a question about wanting to generate a 10 MHz and
> 100 MHz squarewaves with both rising edges aligned to a reference 1 pps
> input (to within 5ns).
> 
>   

Your 1pps to 10MHz sync is complex and you want to avoid it?

Otherwise, a x10 multiplier will generate a 100MHz from 10 MHz that is 
coherent (leaving aside issues of squaring up sine waves, etc.).  There 
will be some time offset between the zero crossing of 100 and zero 
crossing of 10, but that should be "adjustable" by any of a variety of 
means (10ns is a couple meters of coax).  It will vary with temperature 
somewhat.

The x10 is usually done as a x5 and a x2. I guess a PLL multiplier would 
also work.

Other than that, some scheme where you generate your 100, divide to get 
10, and adjust the 100 a bit to line it up with the 1pps. (unless your 
tolerance spec is +/- 5ns, in which case you just use the 100 to latch 
the 1pps).