[time-nuts] Ebay FE-5680A Rb
Chris Albertson
albertson.chris at gmail.com
Thu Dec 15 19:04:03 UTC 2011
On Wed, Dec 14, 2011 at 10:52 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
>
> albertson.chris at gmail.com said:
>> The prime factors are 13, 3, 2, 2, 2, and lots more 2s
>
> There are also a couple of 5s in there.
>
> [~]$ factor 63897600
> 63897600: 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 3 5 5 13
Not fair. You added two zeros on the end and then got to add two more
2s and 5s. How about this:
63897600000000: 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 3 5 5 5 5
5 5 5 5 13
>> There really is no reason to clock a DDS with a nice even number frequency.
>> OK the even freq. makes the math easier but it's all done in software so
>> "easier" does not matter.
>
> I'll bet there are some second order considerations in there. How about
> spurs? If your starting frequency is "nice" relative to your target
> frequency
What is the "target frequency"? If you are building a radio or a
signal generator you will tune around all over the band.
Chris Albertson
Redondo Beach, California
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