Model 8642A/B
Operation
Amplitude Sweep (cont'd)
Relative Amplitude Sweep
It is not possible to set an amplitude sweep directly in relative units. Refer to page
3-205 for amplitude units conversion information to determine amplitude sweep start
and stop end-points in absolute units.
X AXIS
A 0V to +10V stepped output is available at the X AXIS output connector on the rear
panel. The amplitude points at the output coincide with the points in the sweep time
calculations.
Z AXIS
A blanking pulse is available at the Z AXIS output. (The blanking pulse is TTL
positive true for CRT blanking during retrace.)
There is a time that occurs between the end of the sweep and the beginning of the
next sweep while the Z AXIS output is blanked and the frequency and X AXIS output
are being reset. This time is called start-of-sweep settling time. Start-of-sweep
settling time is not included in the sweep time setting. Also, start-of-sweep settling
time is not selectable.
For amplitude sweep, this settling time is approximately
1
5%
of sweep time with a
minimum of 7 ms and a maximum of 500 ms.
Related
Special
Functions 121. Sweep Up and Down On. During auto or single sweep modes, the Signal
Generator sweeps from the start end-point to the stop end-point and then sweeps
from the stop end-point to the start end-point in the same amount of time. See
Figure 3-10 below for a comparison of the normal sweep mode (Sweep Up and Down
Off; Special Function 221) and the up and down sweep mode (Sweep Up and Down On;
Special Function 121). (The waveforms are not drawn to scale.) There is no
start-of-sweep settling time when this special function is selected. Also, Z-AXIS is
always TTL low.
221.
Sweep Up and Down Off. This special function re-enables the normal sweep
that is disabled with Special Function 121. Special Function 221 sets the Signal
Generator to sweep from the start end-point to the stop end-point, and then again
from the start end-point to the stop end-point.
Figure 3-10. Sweep Waveforms
3-93
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