[time-nuts] spur prediction DDS software

Chris Caudle chris at chriscaudle.org
Fri Jan 28 21:04:26 UTC 2011


On Fri, January 28, 2011 6:00 am, Luis Cupido wrote:
> p.s.(what's cooking)
> I need a relatively narrow tunning range
> but absolutely free of close in spurs,
> willing to see if a modest size DDS
> (inside an FPGA) will do so... and what parameters will
> be...


A couple of guys came up with a scheme a few years back for regenerating a
clock to feed an ADC or DAC which used fractional-N techniques along with
error spectrum shaping, such that the spurs were far enough away from the
fundamental that a following analog PLL could be used to track the
generated clock and reject the spurs.

See section 3.3 - 4 in the following:

http://www.tcelectronic.com/media/frandsen_travis_2006_clean_clocks_tc%281%29.pdf

-- 
Chris Caudle





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