CFG253
Performance Verification & Adjustment Procedures
Page 13 of 19
Procedure #: CP1005 Revision: A
3.
Adjust Square Wave Duty Cycles
a.
Set-Up:
AMPLITUDE
Midrange
RANGE
1K
FUNCTION
Square Wave
FREQ/10
Button In
FREQ DIAL
3.0
b.
Test Scope Set-Up:
Volts/Div
1V
AC/GND/DC
DC
Time/Div
0.2 mSec
c.
Connect MAIN OUTPUT to test scope vertical input via coax cable and 50 ohm
terminator. Adjust Trig Level as necessary for a stable display.
d.
Use test scope variable Time/Div control to set the display for 1 complete cycle
over 10 divisions.
e.
Adjust R67 for equal positive and negative half cycles (50 % duty cycle).
Readjust the variable Time/Div as necessary to maintain 1 complete cycle over
10 divisions.
f.
Set FREQ/10 button out.
g.
Adjust R126 for 1 cycle per division on the test scope.
h.
Repeat steps d and e to set the 50 % duty cycles for the settings and adjustments
in Table 1.
Table 1
RANGE
FREQ. DIAL FREQ/10 TIME/DIV
ADJUST RESULT
1K
3.0
OUT
20uSec
R127
50 % Duty Cycle
1K
0.3
OUT
0.2mSec
R18
50 % Duty Cycle
1K
0.3
IN
2 MSec
R16
50 % Duty Cycle
100K
0.3
OUT
2 uSec
R132
50 % Duty Cycle
1M
0.3
IN
2 uSec
R128
50 % Duty Cycle
