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14
- Set AC-DC, SK2 (SK6, SK10, SK14) to DC.
- Apply a 40 mVp_p-square-wave voltage with a
frequency of .3 Hz and a rise time of approximately
25 ns to channel A (B, C, D).
- Check that no sag is visible.
G. FREQUENCY RESPONSE CURVE
After adjusting the square-wave response of the four
channels, the -3 dB point of the amplifier should be at
a frequency over 50 MHz. The frequency response
curve can be measured with e.g. PHILIPS A.M./F.M.-
generator GM 2621 and PHILIPS H.F.-millivoltmeter
GM 6025. Check at the input of all channels that the
voltages required for the measurement of the frequency
response curve are equal.
- Set the knobs to the positions mentioned under F.
- Connect output socket HF II of the GM 2621 to the
input of channel A (B, C, D) via a terminated 50 SZ
cable. A 50 S2 terminating plug XE 101 96 can be
used.
Adjust the frequency to 4.5 MHz and adjust the
generator voltage so that a deflection of 4 cm is
obtained.
Increase the frequency to 50 MHz.
With the same value of the input voltage, the
deflection should exceed 28 mm.
H. DEFLECTION AND SHIFT
Before carrying out this measurement, check that the
dc-balance and the sensitivity of all channels have
been correctly adjusted.
- Set V/cm, SK3 (SK7, SK11, SK15) to position .01.
- Set CONT. R4 (R9, R14, R19) to position CAL.
- Apply a triangle or sine wave voltage with apeak-to-
peak value of 180 mV and a frequency of 1 kHz to
channel A (B, C, D)
- The control range of SHIFT, RS (R10, R15, R20)
should be so large, that the tops of the trace can be
brought within the measuring graticule.
- With this tripple overdriving, no distortion of the
trace should occur.
- Repeat this check at 10 MHz.
- Apply a signal with a frequency of 50 MHz and such
an amplitude that a trace height of 2 cm is obtained.
- Double the input voltage; the trace height should
then be 4 cm, + or — 2%.
J. INPUT ATTENUATORS
1. Square wave response
- Apply the calibration voltage of the basic oscil-
loscope to channel A, (B, C, D).
Adjust the calibration voltage to 40 mV. After cor-
rect adjustment of the sensitivity, the trace height
should amount to 40 mm.
- Check the trace height in all positions of V/cm, SK3
(SK7, SKlI, SK15) according to the following
table; the trace height should amount to 40 mm,
-~ or — 2%.
- At the same time adjust the trimmers mentioned in
the table so, that just no overshoot occurs.
Calibration voltage
V/cm
Channel A (B, C, D)
(SK3, 7 Il, IS)
40 mV
80 mV
.2 mV
.4 mV
.8 mV
2
V
4
V
8
V
20
V
40
V
.Ol
.02
.OS
.1
.2
.5
1
2
5
10
C28
C31
C34
C38
C42
C44
C48
CS i
C54
The trimmers are accessible through the hole next to
knob V/cm. (right hand side trimmers).
2. Input capacitance
With the aid of an input RC standardiser, (e.g. Tek-
tronix cat. no. 011.0073-00 BNC) the input capacitance
can be adjusted to 18 pF in all positions of V/cm, SK3
(SK7, SK11, SK15).
- Apply the calibration voltage of the basic oscil-
loscope to channel A (B, C, D) via the input RC
standardiser.
- Adjust the input capacitance of all channels by
means of the trimmers mentioned in the table below
so that the square-wave response is optimum.
Calibration voltage
V/cm
(SK3, 7, 11, I5J
Channel A (B, C, D)
80 mV
.O1
C27
.2
V
.02
C29
.4
V
.OS
C32
.8
V
.1
C36
2
V
.2
C39
4
V
.5
C43
8
V
1
C46
20
V
2
C49
40
V
5
C52
80
V
10
C56
The trimmers are accessible through the hole next to
knob V/cm (left hand side trimmers).
K. HUM
With this test the cabinet plates of the basic oscilloscope
should be mounted.
- Set V/cm SK3 (SK7, SKll, SK15) to .01.
- Depress CHECK ZERO SK1 (SKS, SK9, SK13).
The hum should not exceed 0.25 mm.
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