[time-nuts] DDS'ery

Javier Herrero jherrero at hvsistemas.es
Mon Jun 20 15:15:41 UTC 2011

The jitter when taking only the MSB is same as the DDS clock period. I 
don't think that squaring the filtered sinewave you will get that jitter 
(of course, if you square the sinewave with no filtering, you will get 
the same jitter that taking only the MSB). In fact, it is the reason 
that AD9850/AD9851 include a comparator instead of just an MSB output.



El 20/06/2011 17:04, Poul-Henning Kamp escribió:
> In message<4DFF5F2F.7050003 at hvsistemas.es>, Javier Herrero writes:
>> No, it is not the same. If you just use the MSB of the accumulator, it =
>> has a lot of period jitter. It can be unnoticeable if the ration between =
>> reference frequency and output frequency is very high.
> In practice, this jitter is a lot lower than you get from
> squaring the sinewave.

Javier Herrero                            EMAIL: jherrero at hvsistemas.com
Chief Technology Officer
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