Tektronix 1A1, Инструкция по эксплуатации

Страница: 93 / 137

Calibration— Type 1A1
( A t R t f m n c i a m p litu d e a t 5 0 k H i.
i
t i g . 7 -3 5 . T y p ic a l CUT d lt p l o y t o b ta in e d w h e n ch e c k in g th e u p p e r
b a n d w id th lim it. S w ee p ta t e i 0 .5 m ie c /c m (te e ru n n in g .
f. Without changing the Type 191 output amplitude, in­
crease the output frequency until tho vertical deflection is
reduced to 2.8 cm (see Fig. 7-35B). This is the 30% down
voltage point (equivalent to —3dB). Use the Channel 1
POSITION control to position tho display to permit accurate
measurement of amplitude.
g. CHECK—Channel 1 upper bandwidth limit at a verti­
cal deflection factor of 0.05 volts/cm should be 50 MHz or
higher.
k. CHECK— Using steps 24d through 24g os a guide,
check Channel 2 upper bandwidth for a limit of 50 MHz
or higher.
l
. Set the Type 191 Frequency dial to 25 MHz, the Fre­
quency Range switch to 50 kHz Only, and the Amplitude
Range switch to 5-50 mV.
m. Set the Channel 2 VOLTS/CM switch to .005.
n. If necessary, adjust the Type 191 Amplitude controls
so the display is exactly 4 cm in amplitude. This is the ref­
erence amplitude (see Fig. 7-35A).
o. Set the Type 191 Frequency Range switch to 18-42.
p. Without changing the Typo 191 output amplitude, in­
crease the output frequency until the vertical deflection is
reduced to 2.8 cm (see Fig. 7-35B|. Use the Channel 2 PO­
SITION control to position the display to permit accurate
measurement of amplitude.
q. CHECK—Channel 2 upper bandwidth limit at a ver­
tical deflection factor of 0.005 volts/cm should be 28 MHz
or higher.
r. Disconnect the signal from the Channel 2 INPUT con­
nector and connect it to the Channel 1 INPUT connector.
s. Set the MODE switch to CH 1 and the Channel 1
VOLTS/CM switch to .005.
t. Set the Type 191 Frequency dial to 25 MHz and the
Frequency Range switch to 50 kHz ONLY.
u. CHECK—Using steps 24n through 24q as a guide,
check Channel 1 upper bandwidth for a limit of 28 MHz
or higher.
25. Check Upper Bandwidth Limit of Channel
1 Signal Out Amplifier
a. Test equipment setup is similar to that shown in Fig.
7-34.
b. Place the oscilloscope in tho upright position.
NOTE
If the 3-dB down point is slightly less than 50
MHz consider that the accuracy of the Type 191
is within ± 2 % of the selected frequency, within
± 4 % of indicated amplitude using the 50-500
mV range and ± 5 % of indicated amplitude using
the 5-50 mV range into a 50-ohm ± 1 % termina­
tion. In addition, consider that the high-frequency
response of the oscilloscope vertical amplifier must
meet its requirements. Risetime may be calculated
using the formula given in the characteristics sec­
tion.
h. Set the Type 191 Frequency diol to 45 MHz and the
Frequency Range switch to 50 kHz Only.
i. Disconnect the signal from the Channel 1 INPUT con­
nector.
j. Set the MODE switch to CH 2.
c. Set the controls as follows:
Type 1A1
MODE
CH 2
VOLTS/CM
(both channels)
.05
INPUT SELECTOR
(Channel 2)
AC
Frequency dial
Type 191
35 MHz
Frequency Range
50 kHz ONLY
Amplitude 20
Amplitude Range
50-500 mV
d. Connect an 18-inch 50-ohm cable from the CH 1 SIG­
NAL OUT connector to the Channel 2 INPUT connector.
7 -30
http://manoman.sqhill.com