HP 120A - Certification Test Equipment; Vertical Amplifier

Sect. IA Page 2
1A-1 CERTIFICATION TEST EQUIPMENT
NOTE
The following equipment is required to complete the
performance tests:
a. ’ ’ Reference Oscillator ” such as the Model
The internal oscilloscope CALIBRATOR can be used
in place of the ’ ’ calibration generator ’ ’ . However, the
±2% accuracy of the CALIBRATOR signal must be
considered in determining the measurement accuracy.
200CD Wide Range Oscillator.
Frequency Range -
400 cps to 500 kilocycles.
1A-2 VERTICAL AMPLIFIER
Voltage Output -
rated 5 millivolts to 20 volts, adjustable.
First, check balance and calibration as described in
paragraph 4 -10a, b. _
Distortion - Less than 1%. a. Sensitivity
b. ’ ’ Reference VTVM ” such as the $ Model 400H
1) Connect the ’ ’ calibration generator ” , set for 100
millivolts peak-to-peak, to the vertical input ter mi-
Vacuum Tube Voltmeter.
nals.
Calibration -
average reading, rms calibrated.
2) Set VERT. SENSITIVITY switch to 10 MILLI-
VOLTS/CM and VERNIER to CAL.
Frequency Range -
400 cps to 500 kilocycles.
Voltage Range -
50 millivolts to 60 volts.
Accuracy -
Voltages given in this procedure are absolute
values and do not include allowances for volt 
meter accuracy.
3) Switch input coupling to DC.
4) Check the amplifier de sensitivity by turning the
’ ’ calibration generator ” function selector between
OFF and DC output. As the function selector is
switched the CRT spot should shift 10±. 5cm. Adjust
VERT. POS. control, if necessary.
5) Turn VERT. SENSITIVITY VERNIER full coun 
ter-clockwise. Repeat step 4 above, but spot should
shift 1 cm or less.
c. ’ ’ Time Interval Generator ” such as the Tektronix
Type 180 Time Mark Generator.
The frequencies required are decade steps from 10
megacycles to 1 cycle per second with an accuracy
of ±0. 3%.
d. ’ ’ Calibration Generator ” such as (^Specification
23678 Voltmeter Calibration Generator.
6) Turn VERT. SENSITIVITY VERNIER full clock 
wise to CAL. Set VERT. SENSITIVITY switch to 100
MILLIVOLTS/CM. Set ’ ’ calibration generator ” for
1 volt peak-to-peak output. Repeat step 4.
7) Set VERT. SENSITIVITY switch to 1 VOLT /CM.
Set ’ ’ calibration generator ” for 100 volte peak-to-peak
output. Repeat step 4.
Voltage Required -
100 volts de and 100 volts ac peak-to-peak at
400 cps or 1000 cps.
Voltage Accuracy - ±0. 25%.
1A-3 BANDWIDTH
1) Connect the "reference oscillator ” through an at 
tenuator to the vertical input terminals and monitor
the input signal with the "reference VTVM ” .
Attenuator -
to provide 100 volts to 20 millivolts with steps
arranged in a 1 - 2 - 5 sequence.
Attenuator Accuracy - ±0.25%.
2) Set the VERT. SENSITIVITY switch to 10 MILLI 
VOLTS/CM and adjust the output of the "reference
oscillator" to give exactly 10 cm of vertical deflec 
tion. Observe the input voltage on the "reference
VTVM".
Distortion -
Less than 0. 5%.
3) Increase the frequency of the "reference oscil 
lator" and adjust its output to maintain the input volt-