Tektronix 7D14, Instruction Manual

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Calibration —7D14
Indicator Oscilloscope
Horizontal Mode A
b. Set the amplifier unit for a vertical deflection factor
of 50 mV/division and the time-base unit for a sweep rate
of 0.1 µs/division.
c. Connect the medium-frequency constant-amplitude
sine-wave generator to the amplifier unit input through the
five-nanosecond GR cable and 50-ohm in-line termination.
d. Set the medium-frequency generator for a three-
division display at three megahertz.
e. Disconnect the 50-ohm in-line termination from the
amplifier unit input and from the five-nanosecond GR
cable. Connect the five-nanosecond GR cable to the CH A
INPUT connector through the GR to BNC male adapter.
Fig. 5-3. Trigger switching points on sine-wave display.
3. Adjust Low-Frequency Compensation
f. Set the amplifier unit for AC input coupling at a
vertical deflection factor of 5 mV/division.
a. Set the time-base unit for a sweep rate of 0.2 ms/
division. Set the time-base unit to trigger at the center of
the negative-slope region.
g. Connect the 10X probe to the amplifier unit input.
h. Connect the 10X probe tip to test point 254 and
connect the probe ground to chassis ground.
i. Center the CRT display with the amplifier unit posi­
tion control.
j. CHECK— CRT display for the trigger switching points
to be centered on the sine wave as shown in Fig. 5-3.
k. ADJUST—Preset adjustment R125 to center the
trigger switching points on the sine-wave display.
l. CHECK —Digital voltmeter reading; zero volt ±0.001
volt.
m. ADJUST—Zero adjustment R225 for a voltmeter
reading of exactly zero volt.
n. Repeat parts i and j of this step.
o. Disconnect all test equipment.
b. Connect the 10X probe to the amplifier unit input.
c. Connect the probe tip to test point 254 and connect
the probe ground to chassis ground.
d. Connect the square-wave genoutput to the
CH A INPUT through the five-nanosecond GR cable and
GR to BNC male adapter.
e. Set the square-wave generator for a five-division dis­
play at one kilohertz.
f. CHECK— CRT display; overshoot on square-wave dis­
play should not exceed 0.25 division.
g. ADJUST—C132 for optimum square wave with over­
shoot not exceeding 0.25 division.
h. Disconnect all test equipment.
4. Adjust Reference Voltage
a. Change the following control settings:
7D14
MEASUREMENT INTERVAL 1 ms
5-14