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 Network Analyzers using PXI software

In the CW time sweep mode, the Analyzer displays measured data as a function of time when the stimulus frequency is fixed. This function is automatically turned on when the Stimulus Span is set to zero.

The channel to which the function is applied must be preselected as active (See Selection of Active Trace/Channel ).

Stimulus

Span 0 Hz

To enable CW time sweep mode, set the Span value to zero using the following softkeys:

Stimulus > Span

A horizontal scale will then display the time.

Set Stimulus > Center to the frequency under test.

Other sweep settings (number of points, power level, IF bandwidth) can be set arbitrarily, depending on the measurement task.

In the CW time sweep mode, the following elements change from frequency representation to temporal representation:

stimulus axis labels

marker stimulus value

SCPI commands response:

CALC:DAT:XAX?

CALC:TRAC:DATA:XAX?

CALC:MARK:X


note

The sweep time is determined by the following formula:

,

where number of points,

 

IF bandwidth,

measurement delay,

hardware delay (depends on the Analyzer model and cannot be changed).


The Analyzer automatically calculates the sweep time value based on the current settings: number of points, IF bandwidth, measurement delay. An arbitrary value can be set for sweep time, in this case, the Analyzer corrects the measurement delay value. To set the minimum possible sweep time, set the measurement delay to zero.

Stimulus

Sweep time 87 ms

Meas Delay 1 us

To set the sweep time value, use the following softkeys:

Stimulus > Sweep Time

To set the measurement delay, use the following softkeys:

Stimulus > Meas Delay

 

The sweep time should not be confused with the measurement cycle time displayed in the Analyzer status bar (See Hide/Show Cycle Time). The table below shows the difference between sweep time and cycle time.

Sweep Time value

Cycle Time value

Method

Theoretically estimated

Actually measured

Scope

One channel

All sweeping channels

Sweep direction

One sweep direction1

All sweep directions2

Range

From the first sweep point to the last sweep point, excluding the time between sweeps

Between the start points of two consecutive measurement cycles, including the time between sweeps

1 One port is the stimulus source.

2 All ports can be used as a stimulus source.

If one channel is open and a measurement is made in one sweep direction, the sweep time and cycle time are close. The difference is that the sweep time value does not include the delay between the sweeps.

 

Rev.:  22.3