BRIEF CHECKING PROCEDURE
3 - 5
-
The Probe Adjust output square-wave voltage should be well triggered. The
waveform must be easy to read.
-
Press the ANALOG key (’DIGITAL MODE’ is displayed briefly): the
oscilloscope is now in digital mode.
-
Press the AUTOSET key again.
-
Adjust the AMPL keys to an input sensitivity of 100mV/div.
-
Adjust the MAIN TB TIME/DIV keys pair to 100
µ
s/div.
-
Verify that a square wave as indicated in Fig. 3.3 is displayed.
Input coupling and POS control:
-
Press the AC/DC/GND key so that dc input coupling (=) is obtained.
-
Verify that this results in an upward signal shift. Fig. 3.4 shows this for
channels with 100mV input sensitivity: the shift is 3 divisions. Fig. 3.6 shows
this for channels with 1.00 V input sensitivity: the shift is 0.3 divisions.
-
Turn the POS control CCW until the display of Fig. 3.3 is obtained again.
-
Press the AC/DC/GND key so that GND input coupling (
⊥
) is obtained.
-
Verify that this results in a horizontal line in the lower part of the CRT.
-
Turn the POS control CW until the line is in the middle of the screen.
-
Press the AC/DC/GND key so that ac input coupling (
) is obtained. The
waveform as indicated in Fig. 3.3 is displayed again.
Figure 3.3
CH... 100mV
MTB 100
µ
s
ST6649
Figure 3.4
CH...100mV
MTB 100
µ
s
ST6651