[time-nuts] Modern signal generators

[Richard (Rick) Karlquist]

On 12/11/2018 11:30 AM, jimlux wrote:

> 
> Most of the Silabs parts are available in an  I2C programmable version 
> rather than the factory programmed flavor.
> 

That's for clarifying that.  The web site is hard
to navigate.  I see that the phase noise is not
even close to an HP 8662 and the VCXO versions
(not surprisingly) are noisier.  The phase noise
of the XO is worse than the worst Crystek XO,
and the VCXO is worse than the worst Crystek VCXO.
The modulation BW is only 10 kHz, and you can't lock
them to an external reference frequency.  I suspect
the chip has an onboard oven providing both fine tuning
and temperature correction.  Nothing especially profound
about this architecture.  It is not clear from the block
diagram if the "DCO" refers to a DDS, or whether there
is some frac-N mechanism.

The performance is in the general ballpark of the one chip
synthesizers with on board VCOs when those are locked to
a clean reference.

Rick