Tektronix 1705A User Manual

Page 106

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Checks and Adjustments

1705A Spectrum Monitor

5- 11

k. CHECK

-- that the marker tip is on the crt center line

±1 minor

Division (vertically).

8.

Check Video Filter

REQUIREMENT

-- Video Filter reduces noise by approximately 50%.

a.

Be sure that the VIDEO FILTER is OFF.

b.

Position the baseline on screen with the VERTICAL POSITION control.

c.

Switch between VIDEO FILTER ON and OFF.

d. CHECK

-- that the baseline noise amplitude drops approximately 50%

when the VIDEO FILTER is ON.

9.

Check Sweep Speed

REQUIREMENT

-- Typically 20 -- 200 ms.

a.

Verify that SPAN/DIV is set to FULL and that SWEEP SPEED is set
fully clockwise.

b. CHECK

-- for a solid trace with almost no flicker.

c.

Set SWEEP SPEED fully counterclockwise.

d. CHECK

-- for about 3 to 4 sweeps per second.

e.

Return SWEEP SPEED fully clockwise.

Alternate Method

a.

Connect the oscilloscope 10X probe to W2.

b.

Set the oscilloscope timebase to 5 ms/Div.

c.

Set the oscilloscope vertical to 2 Volts/Div.

d.

Set SWEEP SPEED fully clockwise.

e.

CHECK

-- for a ramp duration of 20 ms

±10 ms.

f.

Set SWEEP SPEED fully counterclockwise.

g.

Set the oscilloscope timebase to 50 ms/Div.

h. CHECK

-- for a ramp duration of 200 ms

±100 ms.

i.

Remove probe. Return SWEEP SPEED fully clockwise.

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