[time-nuts] HP10544a Technical Info needed
Dr Bruce Griffiths
bruce.griffiths at xtra.co.nz
Sat Feb 3 02:07:20 EST 2007
Gerald Molenkamp wrote:
> Hi Bruce,
> You are right. I havn't checked my unit against the schematic at all. It is
> well secured calibrated and operating in my HP 5342 operating well within
> the specifications. The scanned schematic came from Leapsecond a few years
> ago, and I have not had to use it as yet. Lets hope it stays that way.
On closer inspection it would appear that to be consistent with the
specified output R8 in the AGC cascode amplifier should be 100 ohms as
in the output cascode amplifier that feeds the emitter follower
otherwise the AGC detector will not develop enough output.
Some modifications to the oscillator circuit were made to improve the
phase noise floor by about 15dB between the early and later versions of
Thus you will need to know if your oscillator is an early or later
I suspect the circuit schematic that Tom scanned is for the early
production unit as the ouput cascode amplifier has an RF voltage gain of
about 13.2x (22.4dB) and a corresponding RF input voltage at the base of
the input transistor of about 76mV rms which is quite low.
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