Tektronix 516 series, Instruction Manual

Page: 48 / 132

Calibration — Type 5 1 6
TYPE 516
NORMALIZER
Fig. 6-8. Tektronix Type 106 Square-W ave G enerator connected fo r
attenua tor high frequency compensation.
Connect the output of the square-wave generator through
the 20-pF capacitance normalizer to the A VERTICAL input
connector of the Type 516. Adjust the square-wave generator
for an output frequency of 1 kHz. Fig. 6-8 shows the Tektronix
Type 106 Square-Wave Generator connected for high-fre­
quency compensation of the A Channel attenuator.
Set the A VERTICAL VOLTS/DIV. control to the .05 po­
sition and adjust the output amplitude of the square-wave
generator to produce about 4 divisions of deflection on the
crt screen. With the A VOLTS/DIV. switch set to the .05
position adjust the Output Amplitude control of the Type
106 to obtain 4 divisions of vertical deflection on the crt of
the Type 516. If the signal can't be reduced to 4 divisions
you may insert the 10XT/B52L10 attenuator. The attenuator
should be placed between the Type 106 and the 20 pF
capacitance normalizer.
Observing the top of the square wave adjust C403 for
SN range 101-569, and C420 for SN 570 and up, for the
best square wave response. For instruments with SN 570 or
higher change the POLARITY switch to the INV. AC posi­
tion. Observing the bottom of the square wave this time
adjust C421 for the best square wave response. Then set the
A VERTICAL VOLTS/DIV. control to each of its other settings,
and at each setting adjust the two capacitors exposed in
the SHUNT-SERIES opening below the A VERTICAL VOLTS/
DIV. control for best square-wave response. In each case
the SERIES capacitor (the adjustment on the right) affects the
attenuator high-frequency compensation (see Fig. 6-9), and
the SHUNT capacitor (the adjustment on the left) affects the
attenuator input capacitance (see Fig. 6-10). Maintain about
four divisions of vertical deflection on the crt screen by ad­
justing the output amplitude of the square-wave generator
as you switch the VOLTS/DIV. control from one setting to
the next. (With the Tektronix Type 106 Square-Wave Gener­
ator, the maximum vertical deflection will be less than four
divisions when the VOLTS/DIV. control is in the 20 VOLTS/
DIV. position. The square wave presentation should be
checked in the NORM and INV. positions of the POLARITY
switch. They should look the same in either position of the
switch.
Fig. 6 -9 . Compensating the atte n u a to r high-frequency response; (a ) proper compen­
sation, (b ) undercom pensation, and (c) overcompensation.
(a ) (b ) (c)
6-9
Fig. 6 -1 0 . A d ju stin g the in p u t capacitance; (a ) proper adjustm ent, (b ) and
(c) im prope r adjustm ent.