HP 8642A Operating Manual page 93

Operation
Model 8642A/B
RF Frequency Sweep (cont'd)
Related Special
Functions 119. Disable Settling. This special function allows the Signal Generator's
microprocessor to respond to new commands without waiting for the internal circuitry tc
settle. When using this special function, it's possible to select a function before the
previous function has finished settling. When settling is disabled, response time is
improved by up to 40 ms. Special Function 119 disables out-of-lock messages.
219. Re-enable Settling. This special function re-enables the settling that is disablec
when Special Function 119 is selected.
121. Sweep Up and Down On. During auto or single sweep modes, the Signa'
Generator sweeps from the start end-point to the stop end-point and then sweeps froix
the stop end-point to the start end-point in the same amount of time. See Figure 3-1
below for a comparison of the normal sweep mode (Sweep Up and Down Off; Specia
Function 221) and the up and down sweep mode (Sweep Up and Down On; Specia
Function 121). (The waveforms are not drawn to scale). There is no start-of-sweet
settling time when this special function is selected. Also, Z AXIS is always a TTL low.
221. Sweep Up and Down Off. This special function re-enables the normal sweej
disabled with Special Function 121. Special Function 221 sets the Signal Generator tc
sweep from the start end-point to the stop end-point, and then again from the stan
end-point to the stop end-point.
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Q.
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W
M
X
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X
TIME
Figure 3-7. Sweep Waveforms
Related
Operating
Instructions Refer to RF Frequency (page 3-39) for additional information that also applies to Rl
frequency sweep.
Refer to Knob (page 3-141) and Step, Increment Set (page 3-149) for information oi
using these to modify settings.
Refer to Operating Messages (page 3-177) if the instrument displays a message you wan
clarified.
Refer to Special Functions (page 3-165) for information about the way these ar
accessed.
NORMAL SWEEP MODE UP AND DOWN SWEEP MODE
3-66