On 01/06/2023 15:56, John Ackermann N8UR wrote:
Hi --
There's some fairly old data about the Octoclock here:
http://www.anderswallin.net/2016/09/ettus-octoclock-distribution-amplifier/
200ps of timing dispersion among different gates isn't that weird, when
the switching time can take up to
15nsec on the non-'F' variants of the 7404. I don't know which of
many variants of the 7404 were used on
the Octoclock. But if they're garden variety HC or LS or something,
the switching time dispersion on the
1PPS may be fairly high.
In the shameless plug department, the TADD-1 distribution amplifier
from TAPR:
https://tapr.org/product/tadd-1-rf-distribution-amplifier/
has very good additive noise, and is inexpensive. It has six channels
but two or more boards can be stacked and driven from a common input.
The downside is that it's a kit (through-hole parts).
I compared the additive phase noise of several distribution amps here:
https://www.febo.com/pages/amplifier_phase_noise/
(that data is also fairly old; currently-shipped TADD-1s use a newer
amplifier chip that seems to have a couple of dB better performance).
Best,
John
----
On 6/1/23 15:16, Eugene Grayver wrote:
Hello,
I am building a high-end testbed and trying to decide on a 10 MHz
distribution option. I've used octoclock for other systems and it
'works.' However the datasheet is pretty sparse. Does anyone have
detailed specs (that you measured or from Ettus). I am interested in
the non-GPSDO version since my 10 MHz comes from outside the system
* port-to-port delay variation
* phase noise increase if any (assuming external source)
My other option is
https://endruntechnologies.com/products/distribution/10-MHz-low-phase-noise
<https://endruntechnologies.com/products/distribution/10-MHz-low-phase-noise>,
which is about 5x more expensive.
Thanks.
________________________
Eugene Grayver, Ph.D.
Aerospace Corp., Principal Engineer
Tel: 310.336.1274
________________________
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