[time-nuts] Synths for FMT

Bob Camp kb8tq at n1k.org
Fri May 15 09:19:48 EDT 2015


Hi

One practical trick is to do the divide by N shown below and simply let the 
normal harmonic process do the multiply by M. If both the M / N *and* the
off the air signal are inside the passband of the radio, the data reduction simply
becomes the relation between the two audio tones. Yes there is some messing
around to keep the relative signal levels in the same ballpark….

If you use a PIC to do the divide, the whole process is pretty cheap ….

Bob

> On May 15, 2015, at 4:29 AM, Hal Murray <hmurray at megapathdsl.net> wrote:
> 
> 
> tshoppa at gmail.com said:
>> Don't have any good ideas for 14121 kHz.
>> Any thoughts?
> 
> I threw together a quick hack to scan for all PLL coefficients less than 50.  
> Here are the answers closer than 50 kHz.  (I didn't remove lines with a 
> common factor.)
> 
> 17 12  14166666.67   45667
> 24 17  14117647.06    3353
> 31 22  14090909.09   30091
> 34 24  14166666.67   45667
> 38 27  14074074.07   46926
> 41 29  14137931.03   16931
> 48 34  14117647.06    3353
> 
> So multiply by 24 and divide by 17 gets you a reasonable offset.
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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