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5-18
DUTY
CYCLE AND FREQUENCY ADJUSTMENTS
Frequency adjust
307M
9M
Duty Cycle
100M-10M 300M-100M
DESCRIPTION
These adjustments set up the correct duty cycle at high
and low frequencies and cal ibrate the frequency output.
An oscilloscope is used to check the duty cycle and a
counter to check the frequency.
08081-66502
BOARD A2
c:::J
R4
CJ
R8
c:J
R16
Figure 5-1. Duty Cycle Adjustment Test Setup
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R109
80SlA
S080A
MA~NFRAME
COUNTE.A
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SAMPLING
OSCILLOSCOPE
D
cI
8OS0A MAINfRAME
8081A
EQUIPMENT
Sampling Oscilloscope
HP
182C Mainframe
with 181 OA Sampl ing plug-in
Counter
HP 5345A
Figure 5-2. Frequency Adjustment Test Setup
3.
Set up the equ ipment as shown in figure 5-2 and
set the controls as follows:
PROCEDURE
80Bl A:
1.
Set up the equipment as shown in figure 5-1 and
set the controls as follows:
8081A:
RATE range
300-100MHz
Rate VERNIER
Clockwise
Operating Mode
NORM
Oscilloscope:
RATE RANGE
300-100MHz
Rate VERNIER
CCW
Operating Mode
NORM
Counter:
Frequency
350MHz
Sensitivity
200m V/d iv
Trigger
internal
Timebase mode
expanded
Timebase - direct
20ns/div
Timebase - expanded
1ns/div
4.
Adjust A2R4 to a frequency of 307MHz ± .5MHz
5.
Set the Model 8081 A RAT Eta 100-1 OMHz. and
rate VERNIER to CWo
2.
Adjust A2R16 for a duty cycle of .... 50 %
±
10 %
6.
Adjust A2R8 to a frequency of ... 9MHz
±
.1 MHz
7.
Reconnect the equipment as in figure 5-1 and set
the controls as follows:
B081A:
ton
Duty Cycle
=
x 100%
period
RAT E range
300-100MHz
Rate VERNIER
CCW
Operating Mode
NORM
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