[time-nuts] Ebay FE-5680A Rb

Chris Albertson albertson.chris at gmail.com
Thu Dec 15 14:04:03 EST 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




More information about the time-nuts mailing list