[time-nuts] AD5791 for EFC control ?

[Herbert Poetzl]

On Sat, Apr 20, 2013 at 08:14:06PM +0000, Poul-Henning Kamp wrote:

> I looked at the DAC1220 first, but in an EFC application it
> worries me to no end that it is a Sigma-Delta DAC.

> Even if I feed it a clock divided down from the OCXO you're
> EFC'ing, to avoid beatfrequency effects, I would still worry
> about harmonic effects and noise.

> Also, the noise-spec is pretty horrid, almost a
> microvolt/sqrt(Hz) all the way to one kHz.

> For comparison the AD5791 is purely static and its noise is
> below 10 nv/sqrt(Hz) from 5Hz and up.

At a price of ~100 USD (100pcs for ~50 USD each) 
it's also in a different price range as the DAC1220
which can be bought for less than 20 USD (~8 USD
when you buy 100).

best,
Herbert

> -- 
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG         | TCP/IP since RFC 956
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