TB 9-4931-503-24
20. Aberrations and Risetime
a. Performance Check
(1) Position controls as listed in (a) through (c) below:
(a) CH 1 and CH 2 VOLTS/DIV switches to 10 m.
(b) MODE CH 1 pushbutton pressed.
(c) TRIGGER CH 1 pushbutton pressed.
(2) Press delaying time base SWP MAG pushbutton and set MAIN SEC/DIV
switch to 10 n.
(3) Connect oscilloscope calibrator SOURCE/MEASURE CHAN 1 to CH 1 input
using 50 feedthrough termination.
(4) Set oscilloscope calibrator EDGE output for 50 mV, 1 MHz.
(5) Adjust delaying time base MAIN TRIG LEVEL and POSITION controls and
TI CH 1 POSITION control as necessary to view leading edge of waveform near
center of display.
(6) Adjust oscilloscope calibrator EDIT FIELD knob for 5 divisions of vertical
deflection on oscilloscope.
(7) If aberrations are not within 4%, adjust C199 (C399 for CH 2) (fig. 4) for best
square corner on waveform (R).
(8) Measure risetime using standard risetime technique. Risetime will be 5.8 ns or
less for SN B068140 and below (7 ns or less for SN B068140 and above).
(9) Set oscilloscope calibrator EDGE output for 5 mV, 1 MHz and TI CH 1 VOLTS/
DIV switch to 1 m.
(10) Adjust delaying time base MAIN TRIG LEVEL and POSITION controls and
TI CH 1 POSITION control as necessary to view leading edge of waveform near the center
of display.
(11) Adjust oscilloscope calibrator EDIT FIELD knob for 5 divisions of vertical
deflection on oscilloscope.
(12) Measure risetime using standard risetime technique. Risetime will be 14 ns
or less.
(13) Press MODE CH 2 and TRIGGER CH 2 pushbuttons.
(14) Repeat technique of (3) through (12) above for CH 2.
b. Adjustments. No further adjustments can be made.
21. Final Procedure
a. Deenergize and disconnect all equipment.
b. Annotate and affix DA label/form in accordance with TB 750-25.
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