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19
C. BALANCE
ADJUSTMENT
R187 (Fig. 13)
Before carrying out this measurement connect unit
PM 3332 to the basic oscilloscope with the extension
cable (see list of accessories of PM 3330).
Set "Y/cm"
(SK4) to "0,5 mY/cm".
Keeping
"CHECK ZERO" (SK3) depressed, turn "Y /cm"
(R2) quickly to and fro. If the trace is moving
vertically, adjust R 187 until the trace is stationary.
D. SQUARE WAVE
RESPONSE
Amplitude of the
Choíce resístor
I00 kHz signal
coorse
f ine
Positíon
of SK-?
Apply the rigid extension p,lug and set "V /cm" (SK4)
to "5 mV/cm". Turn potentiometers "GAIN ADJ"
(Rl) and "Y/cm" (R2) fully anticlockwise; set "AC-
DC" (SK3) to "DC".
-
Apply a square wave with a 10 Hz repetition fre-
quency and such an amplitude as to obtain a 4 cm
trace height.
Adjust R208 to that the square wave has a flat
toP.
Increase the frequency to 100 kHz with an am-
plitude of 20 ffiVn _ o. To obtain an optimum
square-wave response the gain of the H.F. ampli-
fier should be made equal to that of the DC am-
plifier. This can be obtained by changing the
value of several emitter resistors according to the
next table.
PE M 3 29 5
5
mV/cm
2
mV/cm
I
m V / cm
0.5 mV / cm
20
f f i V n _u
8 f f i V n _n
4 f f i V o_ n
2 mV p_ p
R138
R 139
R174
R 173
Rl 59
R 158
R t 44
R 143
Note: With choice resistor "coarse" adjust the display
so that some rounding off is present; with
choice resistor "fine" adjust the display so that
just no overshoot occurs.
Remove the extension plug und apply a square
wave with a 1.5 nsec. rise time.
This can be obtained by connecting a tunnel-
diode pulse shaper to the calibration voltage. If
a Tektronix TU-5 unit (cat. number 015-0038-00)
is used, it should be adapted to the 80 V cali-
bration voltage by connecting a 2700 ohm (0. I
Watt, 5Vo) resistor parallel to the 3300 ohm re-
sistor of the unit (see Fig. 15).
Connect the pulser to the input terminal of the
amplifier via a 5 : 1 and a 2rÁ: 1 attenuator (e.9.
Tektronix 011-0060-00 resp. 011-0076-00) and
a 50 ohm termination pad. (e.g. XE 101 .96).
Set the knobs of the basic oscilloscope to the
fo,llowing positions:
"TRIGG. MODE"
: "H.F."
"TRIGG. SOURCE"
: "INT"
"TIME / cm"
: 0.05 usec/cm
"MAGN"
: X 5
Set the knob of the PM 3332 "Y / cm" (SK4) to
"5 mY /cm".
With trimmer C4l6 adjust for a minimum rise
time.
27OO -o,
.1 Watt
5o o
to be added
or 5 - o3 8
T U- 5 P UL S E R
TEKïRO N IX,
Ii l C.
R208 (Fig. 13). C4l6
Rl38-R139-R143-R144
RL58-RL5g-RL73-RL74
(Fig. 13)
)
!
(Fis. 2r)'
t
'r( 41 (\l h
tO
\ír
ln
-t
\t
\t
\t
-f
É.É.(r (r
Item 16 of ÍiS. 14
Fig. 15. Pulser
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