HP 3580A Operating And Service Manual page 52

Model 3580A
Section IV
OV TO +5V
~---------------------------------~LINE~ 0
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DIGITAL
STORAGE
SECTION
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FREQUENCY
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6
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=
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FREQ
SPAN/ DIV
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Figure 4-10. Frequency and Sweep Section.
1. STOP SWEEPING AND ALLOW TIME FOR THE IF Fl LTER
TO SETTLE. SWEEP SLOW FORWARD TO POINT 2.
a. During slow sweeps the sweep time is as indicated by the
front panel SWE.EP TIME setting.
b. The instrument initially sweeps slowly to ensure that the zero
response (if present) is properly detected.
c. The distance between Points 1 and 2 is equal to 0.75 times
the Step Back distance (See Step
31.
2. IF A RESPONSE IS NOT PRESENT, SWEEP FAST FOR-
WARD.
a. The fast sweep time is 20 to 25 times faster than indicated by
the SWEEP TIME setting.
3. RESPONSE DETECTED. SWEEP FAST BACKWARD TO
POINT4.
a. The distance between Points 3 and 4 is called the "Step
Back" distance and is determined by the FREQ SPAN and
BANDWIDTH settings.
®
j
4. STOP SWEEPING AND ALLOW TIME FOR THE IF FILTER
TO SETTLE. SWEEP SLOW FORWARD TO POINT 5.
a. The distance between Points 4 and 5 is equal to 1.75 times
the Step Back distance.
b. This step ensures that the instrument sweeps slowly past the
point it stepped back from initially.
5. CONTINUE TO SWEEP SLOWLY TO POINT 6 WHERE
RESPONSE IS NO LONGER DETECTED.
6. SWEEP SLOW FORWARD TO POINT 7.
a. The distance between Points 6 and 7 is equal to 0.75 times
the Step Back distance.
b. This step ensures that the response is completely passed
before the sweep rate is increased.
7. IF RESPONSE IS NOT PRESENT, SWEEP FAST FORWARD
TO POINTS.
8. END OF SWEEP. RESET TO POINT 1.
Figure 4-11. Adaptive Sweep Routine.
4-9