[time-nuts] HP5061B Peak to Valley Ratios

Donald E. Pauly trojancowboy at gmail.com
Mon Apr 3 21:26:36 EDT 2017


We hooked up the oscilloscope directly to the electron multiplier in
the beam tube with a 1 Meg termination.  We were operating open loop
and varying the fine crystal oscillator adjust for the different
photos. Remember that higher beam current is downward in the photo.
Currents listed in nA translate to beam current numbers on the HP5061B

First photo at http://gonascent.com/papers/hp/hp5061/waveform/centered.jpg
is the frequency swept at a 137 cps rate around the peak of the cesium
resonance.  Ground is at the top of the screen and 5 mV (also 5 nA)
per division.  Horizonal is 4 ms per division.This corresponds to a
peak beam current of -22 nA and a valley current of -17 nA.  One
valley current is below resonance and the other is above resonance.
The waveform is 274 cps.  Sequence is low to high and then high to
low.  No 137 cps is present.

The fine frequency control was adjusted to produce a slight offset
from center for the photo at
http://gonascent.com/papers/hp/hp5061/waveform/smalloff.jpg .   Note
that the peak beam current is still -22 nA but two different valley
currents exist.  One is 17 nA and the other is -18 nA.  Most of the
signal is 274 cps but some asymmetry is present at 137 cps.  One
extreme of the sweep is slightly closer to center frequency than the

Finally the frequency was adjusted to produce a severe offset with all
of the sweep below resonance in the photo of
http://gonascent.com/papers/hp/hp5061/waveform/largeoff.jpg .  The
peak is now slightly below resonance at -21 nA and the valley is far
below resonance at 5 nA.  The signal is all 137 cps with no 274 cps.
See figures 4-43 and 4-44 on page 4-31 of the manual for further

We will be finding out the effect on beam current of tests shortly on
the Zeeman coil and LF coil.  We think that the 55.53 kc Zeeman
frequency introduces some AM into the beam frequency but no FM.  What
the LF coil has is unclear at this time.


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