Tektronix 2445, Инструкция по эксплуатации

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Performance Check— 2445 Service
VERTICAL MODE
5. Use the VERTICAL POSITION control to set the
BW LIMIT On (button in)
bottom of the signal 2 divisions below graticule
AV On (press and release for a
center.
VOLTS/DIV
CH 1 and CH 2
AV readout)
2 mV
6. Rotate the AREF OR DLY POS control to align the
reference cursor with the bottom of the waveform.
A and B SEC/DIV
TRIGGER
1 ms (knobs locked)
7. Rotate the A control to align the
A
cursor with the
top of the signal display.
MODE AUTO
8. CHECK— Vertical Deflection Accuracy (measured
against the graticule) and AV Readout Accuracy are
within the limits listed in Table 4-2.
N O T E
T h e in s tru m e n t m u s t h a v e h a d a t le a s t 2 0 m in u te s
9
-
Set the TRIGGER LEVEL control at the most posi-
w a rm u p p rio r to p e rfo rm in g th e fo llo w in g s te p s .
five voltage that produces a barely triggered, jittering
display for each position of the SLOPE switch.
b. Press up and momentarily hold the CH 1 and CH 2
Input Coupling switches in their 1 MQ AC positions until a
moving dot display replaces the normal signal and readout
displays (for approximately 15 seconds). This performs a
DC Balance of CH 1 and CH 2.
c. When the signal and readout displays automatically
return to normal, set the CH 1 and CH 2 Input Coupling to
1 Mfi DC.
10. CHECK—The A Trigger Level readings (see Figure
2-8) are within the limits given in the +Peak column
of Table 4-2.
11. Set the TRIGGER LEVEL control at the most nega­
tive voltage that produces a barely triggered, jittering
display for each position of the SLOPE switch.
12. CHECK—The A Trigger Level readings are with­
in the limits given in the — Peak column of Table 4-2.
d. Connect the Calibration Generator to the CH 1 OR X
input connector via a 50 Q BNC cable. Do not use a
termination.
13. Set the TRIGGER LEVEL for a stable display.
14. Pull the SEC/DIV knob out and set the B TRIGGER
MODE to TRIG AFT DLY.
e. CHECK— CH 1 and CH 2 VOLTS/DIV, AV, and TRIG­
GER LEVEL readout accuracies as follows:
1. Set VOLTS/DIV control to the first position listed in
Table 4-2.
2. Set the Calibration Generator STD AMPLITUDE
output level to the corresponding Standard Ampli­
tude Input Level in Table 4-2.
NOTE
To p ro p e rly v e rify T R IG G E R L E V E L
R e a d o u t A c c u ra cy , th e C a lib ra tio n G en e r­
a to r ’s S T D A M P L IT U D E o u tp u t m u s t
h a v e ris in g a n d fa llin g tra n s itio n tim es
(1 0 % to 9 0 % ) > 1 0 n s. N o o v e rs h o o t
s h o u ld a p p e a r o n th e w a v e fo rm .
3. Verify that the generator output meets the require­
ments noted above.
4. Return the A and B SEC/DIV switch to 1 ms (knobs
locked).
15. Adjust AREF OR DLY POS control for a delay read­
out of 0.000 ms.
16. Set the TRIGGER LEVEL control to the most posi­
tive voltage that produces an intensified point on the
waveform display for each position of the SLOPE
switch.
17. CHECK—The B Trigger Level readings are with­
in the limits given in the +Peak column of Table 4-2.
18. Set the TRIGGER LEVEL control to the most nega­
tive voltage that produces an intensified point on the
waveform display for each position of the SLOPE
switch.
19. CHECK—The B Trigger Level readings are with­
in the limits given in the — Peak column of Table 4-2.
20. Push the B SEC/DIV knob in.
21. Change the VOLTS/DIV switch to the next position
listed in Table 4-2.
22. Set the Calibration Generator to the corresponding
signal amplitude setting.
4-6