On 30/09/11 17:46, [email protected] wrote:
Paul,
The time scale selection is to match the offset in each particular
receiver section and thus put it on frequency. Once there you can use the
chart to determine offsets from the value you use.
The synthesizer setting by virtue of how its designed does not allow one
digit changes! You have to use one of the settings from the chart in the
manual to get you within the C-field range when tuning!
Also after a synthesizer change you have to wait a long time (or remove
and replace the red wire powering the synthesizer) for the operation
light to reset.
I had one HP5065A with a totally non-standard setting. I put that
setting on paper and instead chose a standard one writen down on the
front panel. This gave me the wrong frequency, so I looked it up in the
table of the manual and tried a few others until I settled for one
giving me good frequency compared to by Thunderbolt locked to GPS. I the
trimmed the C-field up for the last piece. Once I decided to got this
route, it didn't take too much time to hit the spot. You are really lost
without the table with it's offset ordered sets of settings.
There is a few hidden aspects to the synthesizer settings. The factor m
and n which reshape 5 MHz to 5,312.. MHz using m/n*5 MHz is not listed.
The n factor is n=10000-TW where as m is about 1.6 times n. The m factor
determines the loop gain in that PLL lock. However, it is only part of
the story, but it is interesting to note that there is a loop within a
loop in this rubidium where as the 5,312... MHz synthesis is done using
other methods in most other rubidiums. Dividing by 16 and mix up with 5
is not too uncommon.
Cheers,
Magnus
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