How To Set Sweep Time - HP 8642A Operating Manual

Operation
Model 8642A/B
Amplitude Sweep (cont'd)
How to Set Sweep Time
(Using Sweep Time to Set Amplitude Step Size and Number of Steps)
The operating characteristics for amplitude sweep time are as follows:
Minimum Sweep Time 20 ms
Maximum Sweep Time 999s
Sweep Time Resolution 1 ms
Minimum Amplitude Sweep Step Size 0.1 dB
Minimum Amplitude Dwell Time per Step 3 ms
Amplitude Sweep Calculations
Since the sweep step size is not directly selectable, the following calculations provide
ways to determine:
1) the number of steps automatically selected (page 3-86),
2) the amplitude step size automatically selected (page 3-87),
3) the required sweep time that will select a desired number of amplitude steps (page
3-87), and
4) the required sweep time that will select a desired step size (page 3-89).
However, these calculations do not directly apply to situations when the start
end-point is equal to the stop end-point (zero span). Refer to "Zero Span for
Amplitude Sweep" on page 3-92 for information about X-axis steps in zero span.
These calculations apply only to logarithmic amplitude sweep. Calculations for Linear
Amplitude Sweep (Special Function 1 22) are not discussed because calibration data
used during linear sweeps is different for each instrument.
Also, amplitude points are truncated to 0.1 dB. Span is always an integer in 0.1 dB
units since end-points are integers in 0.1 dB units.
The start and stop amplitude setting values must be in dBm in order to perform these
calculations. (Refer to Amplitude Units Conversion on page 3-205 for information
about changing amplitude values to dBm and back to other units.)
1) Calculate the number of steps automatically selected.
The number of steps is the minimum of:
| Start Amplitude (in dBm) — Stop Amplitude (in dBm) |
0.1 dB
or
INTEGER OF (
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\ 3 ms )
3-86