Tektronix 1A5 Instruction Manual page 57

e. Switch the Square Wave Generator Hi Amplitude/Fast
Rise switch to High Amplitude.
f. CHECK — squareness of corner of 5 cm square wave for
½ mm or less rounding, overshoot or tilt in each setup given
in Table 5-3. Adjust the Square Wave Generator Amplitude
control and the Type 1A5 POSITION control as necessary
to maintain a centered 5 cm display. See Fig. 5-3 for typi ­
cal waveforms.
14. Check Overdrive Recovery Time
Shift Due
REQUIREMENT — Overdrive recovery time: within 10 mV
of DC shifted level after 1 µs; DC shift due to overdrive: 1 %
or less of ± overdrive signal, or 10 mV, whichever is smaller.
a. Switch VOLTS/CM to the 1 V position.
b. Remove the 20
path.
c. Replace the 5:1 attenuator with a 2:1 attenuator.
d. Switch the oscilloscope Time/cm to 50 µs, the Triggering
Slope to + and the Triggering Source control to Ext; connect
a 42" coaxial cable from the Square Wave Generator
ger Output to the oscilloscope Trigger Input connector.
e. Set the Square Wave Generator frequency
and the Amplitude control for a 5 cm display amplitude.
f. Switch the oscilloscope Time/cm to 1 µs and adjust the
Horizontal Position controls to place the beginning of the
Fig. 5-3. Input capacitance waveforms, step 13.
(C ) and (D ) A input capacitance improperly adjusted.
http://manoman.sqhill.com
To Overdrive
pF Input RC Normalizer from the signal
(A) В input capacitance properly adjusted;
Input Signal
Connected
to
В INPUT
and DC
A INPUT
Trig ­
leading edge of the positive square wave at the 2 cm line
as in Fig. 5-4 (A).
g. Switch the Type 1A5 VOLTS/CM control to 10 mV.
to 10 kHz
h. Adjust the Type 1A5 POSITION control to set the right
side of the visible portion of the trace to vertical center of the
graticule as in Fig. 5-4 (B).
(Sweep rate .2 ms/cm; vertical sensitivity dependent upon capacitance being checked.)
Performance Check — Type 1A5
TABLE 5-3
Trigger ­
AC-GND-DC VOLTS/ ing
A В CM Slope
GND DC 20 mV —
50 mV —
Remove 5:1 attenuator
. 5 V
Replace 50-Ω termination
with a GR-to-BNC
adapter
5V —
DC GND 5 V
+
Replace adapter with the
GR-to-BNC 50-Ω
termination
+
. 5 V
Insert 5:1 attenuator
50 mV
+
20 mV
+
(B) A input capacitance properly adjusted;
Check
Point
lower left
lower left
lower left
lower left
upper left
1 upper left
upper left
upper left
5-5