Sets the total number of measurement points per sweep. The minimum number of points is 1 (measurement at a single frequenc/power/time value).
Together with the sweep range defined with the Stimulus settings, this parameter defines the grid of sweep points. The sweep points are equidistantly distributed over the entire sweep range: The step width between two consecutive sweep points is constant on a linear scale (sweep types Lin. Frequency, Time and CW Mode) or on a logarithmic scale (sweep types Log. Frequency and Power).
In Segmented Frequency sweeps, the number of points can be set independently for each segment; see Define Segments.
As an alternative to the Number of Points, the Stimulus Step Size can be set.
Measurement time and screen resolution
A large number of points improves the resolution of the trace but increases the measurement time.
The overall measurement time is composed of a hardware settling time at the beginning of the sweep plus the sum of the measurement times at each individual sweep point. This implies that the measurement time increases roughly linearly with the number of points.
After
changing the channel settings or selecting another measured quantity,
the analyzer needs some time to initialize the new sweep. This preparation
period increases with the number of points and the number of partial measurements
involved. It is visualized by a Preparing
Sweep symbol in the status
bar:
All analyzer settings can still be changed during sweep initialization.
If necessary, the analyzer terminates the current initialization and starts
a new preparation period.
Optimizing
the measurement speed
|
Remote control: |
Sets the distance between two consecutive frequency sweep points.
The step size is an alternative to the Number of Points setting:
If the sweep range is defined by means of the Start and Stop variables, both the Stop value and the Number of Points can vary as the Frequency Step Size is changed. The Stop value is changed as little as possible so that the condition Frequency Step Size = (Stop – Start) / (Number of Points – 1) can be fulfilled. Changing the Start and Stop values modifies the Frequency Step Size.
If the sweep range is defined by means of the Center and Span variables, both the Span value and the Number of Points can vary as the Stimulus Step Size is changed. The Span is reduced as little as possible so that the condition Frequency Step Size = (Stop – Start) / (Number of Points – 1) can be fulfilled. Changing the Span modifies the Frequency Step Size.
This setting is valid for linear frequency
sweeps only. It does not apply to logarithmic and segmented sweeps, power,
time or CW Mode sweeps. Increasing the Frequency
Step Size generally increases the measurement time.
Optimizing
the measurement speed
|
Remote control: |
Opens a dialog to vary the measurement time for a sweep or delay the start of each sweep.
Auto minimizes the sweep time. If this option is checked, the input fields Sweep Time and Meas. Delay can not be edited. Sweep Time indicates the estimated sweep time, taking into account the current measurement settings, the Meas. Delay is 0 s. The Sweep Time and Meas. Delay values are maintained until changed explicitly if Auto is switched off.
Sweep Time is the total measurement time for the sweep. The minimum sweep time to be set is equal to the estimated value in the Auto mode. Setting a larger sweep time is equivalent to defining a Meas. Delay before each partial measurement.
Meas. Delay sets a delay time allowing the DUT to settle before the hardware settings of the analyzer are changed and a new partial measurement is started.
A delay time before the start of each partial measurement increases the accuracy, in particular in measurements on DUTs with long settling times (e.g. quartz oscillators, SAW filters). As an alternative to increasing the delay (and thus the total sweep time), it is possible to select Alternate sweep.
The Auto and Sweep Time settings are not active in the Time and CW Mode sweep types. The Meas. Delay is taken into account for all sweep types.
In Segmented Frequency sweeps, the sweep time parameters can be set independently for each segment; see Define Segments. Sweep Time opens a message box indicating to total sweep time, i.e. the sum of the individual sweep segment times.
In general, the
system error correction is no longer valid after a change of the sweep
time. The message Cal? appears
in the trace list.
Optimizing
the measurement speed
|
Remote control: |
[SENSe<Ch>:]SWEep:TIME:AUTO |
