Adjustments
Model
8904A
Adjustment
7
PHASE SYNCHRONIZATION (OPTION
005)
Description
When two
or
more Multifunction Synthesizers are chained together
in
a masterhlave arrangement,
the synchronization between the slave and master clock and slave and master phase-reset outputs
is
critical.
Errors in timing contribute directly
to
the
unit-to-unit
phase error. The slave and master
delays are adjusted
to
the same nominal value
to
bring the phase error
within
specification.
Delay
adjustments are made
in
discrete steps by setting switches. The duty-cycle
of
the clock is adjusted
by
a
potentiometer.
NOTE
This
adjustment has
no
effect on instruments without Option
005.
If
the
instrument has Option
005,
this adjustment should be made only
when there is strong reason
to
suspect
a
synchronization problem between
Multifunction Synthesizers. The nature of the adjustment and lack of
circuit diagrams make it difficult to understand what is happening. The
factory settings should remain valid
for
the life of the instrument euen when
the
A2 Controller Assembly has been repaired
or
replaced due to a fault
elsewhere on the assembly.
If a synchronization problem is suspected, run Performance Test 11,
Unit-to-Unit Phase Accuracy.
If the test fails, check the relatiue delay
between test points A2TPl on the two Multifunction Synthesizers. The
delay difference should be less than
15
rzs.
If
this
test passes, check
for
a
channel-to-channel or Output 1-to-Output 2 phase accuracy problem.
Equipment
Oscilloscope
..............................................................
.HP 1740A or Tektronix 2235
Power Splitter,
Four
Way
.......................................................
Mini-Circuits ZSC-4-3
Probe
(2
required)
............................................................................
HP
10434A
Procedure
Initial
Setup
1.
Remove the instrument’s
top
cover. The cover may be tightly secured in the groove
of
the bottom
cover.
If
the
top
cover does not pull
off
easily after backing out the screw on
the
rear edge, back
out the screw on the rear edge
of
the bottom cover also.
2.
Connect the equipment as follows.
a. On the Multifunction Synthesizer, connect the rear-panel
SYNC CLOCK
OUTPUT
to the
the input
of
the power splitter. Connect the rear-panel
SYNC
CLOCK
INPUT
to
one
of
the
outputs
of
the splitter. Use
short
cables. Terminate the other splitter outputs with
500
loads.
(A
6
dB
pad can be substituted
for
the splitter.)
b. Connect test point A2TP1
to
channel
A
of
the dc coupled oscilloscope using a low-
capacitance, divide-by-10 probe. (Refer
to
Figure
5-5B
for A2 assembly component
locations.)
5-14
Adjustment
7
rev.
01
JUL91
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