开云体育

Hi,

So while we are stuck at home and have nothing to do but play with all
the instruments I started a project to build a distribution amplifier
for 10MHz reference. I do have a GPSDO, but that is cumbersome to use
as I don't have a good view of the sky from my room. So Instead I
decided that I build a two-in-one distribution amplifier + OCXO
reference, as I have a spare, well aged 10544A laying around. (I'll
share the design if it ever gets done.) That would be plenty of enough
precision for what I do, the GPSDO could be used to calibrate it once
in a while. That should be plenty of enough for me, as I would be
driving signal and function generators from it, nothing extreme
time-nuttery.
So my question is: Is it worth to connect the EFC input of the OCXO?
The datasheet says it has about 1 Hz range, but then I would need to
provide the -5/+5V supply for it, preferably with some good quality
reference. I know that this input is not connected in the 5335A for
example, only the "coarse" adjustment is used.
I guess it is is good for the 5335A then it should be good for me, but
on the other hand, why not make some overly complicated thing when we
finally have time for it :-)
So basically, my question is would you recommend to simply short the
EFC input and only have the coarse adjustment or should I take the
extra effort to have this fine adjustment? Would it have any drawbacks
if I do?

Thanks.

Szabolcs

It's up to you. How close do you want to be abl to set it?

A +-5V supply an 10 Turn pot is not too hard to do. Personlly I've used a isolated 12V output DC-DC converter with lots of filtering, a 10V reference IC? a 1:1 resistive divider connected to the EFC common, and a 10k 10 tun pot.

Robert G8RPI

Hi,

Thanks, that is a good idea with the DC-DC converter. I guess I can go
with that and make it jumper configurable to enable or disable efc.

Szabolcs

Robert G8RPI via groups.io <robert8rpi@...> ezt írta
(id?pont: 2020. ápr. 1., Sze, 18:38):