Tektronix 2A61 Instruction Manual page 27

|
PACHA
Tecmrnueemel
VV A
Fig. 5-7. Typical CRT display showing (A) FILTER OUT (B) FILTER IN.
12. Check Filter Insertion Loss
Requirement-Insertion loss at 1kHz less than 15%.
a. Reset the following controls:
Type 2A61
FILTER OUT
mV/DIV 20
Type 2B67
Time/div Tims
Audio Sine Wave Generator
Frequency 1 kHz
b. Set the Audio Sine Wave Generator Amplitude for 5
divisions of display on the Type 561A CRT.
c. Switch the Type 2A61 FILTER to IN.
d. Check for a display amplitude of not less than 4.25
divisions on the Type 561A CRT.
Performance Check—Type 2A61
13. Check Common Mode Rejection at 10 kHz
Requirement-Rejection ratio of 50,000:1 (2 divisions of dis-
play).
a. Reset the following controls:
Type 2A61
INPUT SELECTOR A—B
MILLIVOLTS/DIV 05
FILTER OUT
Type 2B67
Time/Div .] ms
Source Int
Audio Sine Wave Generator
Frequency 10 kHz
Amplitude 5 volts, p/p
b. Connect the 10 Probe fo the A Input of the Test
Oscilloscope Plug-in.
c. Connect the 10X Probe tip to the red terminal of
the dual binding post to BNC Adapter.
d. Connect the 10X Probe Gnd lead to the black terminal
of the dual banana to BNC adapter.
e. Adjust the Audio Sine Wave Generator Output for 5
volts, p/p, displayed on the test oscilloscope CRT.
f, Check for a 50,000:1 rejection ratio (2 divisions of dis-
play on the Type 561A CRT is a 50,000:1 rejection ratio}.
14. Check Hum and Noise
Requirement-Maximum hum and/or noise, 0.02 mV.
a. Reset the following controls:
Type 2A61
FREQ RESPONSE
FROM 06 Vv
TO .3 MHz
INPUT SELECTOR GND
MILLIVOLTS/DIV 01
Type 2B67
Time /div 10 ms
Mode Norm
Level Free run
Coupling AC Slow
b. Check for a display amplitude of not more than 2
divisions, (20 »V).
c. Switch the Type 2B67 Time/div switch to 0.5s.
d. Noise peaks should not exceed 2 divisions, 20 nV,
except occasionally (a few times per second).
5-7