SIGLENT TECHNOLOGIES SNA5000A Series User Manual Download

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SNA5000A Vector Network Analyzer User Manual 128

value in the

Stim. Ampl.

textbox in the

Basic

bar of the

Setup

tab. Intrinsically, the

Volt

format

means the trace data is a product of the T parameters and the magnitude of the stimulus signal.

Click the measure parameter button in the grids on the left of the

Parameter

bar, the

measurement parameter of the current trace switches to the corresponding parameter. To
switch on or off the time domain transform of the current trace, click the pull-down menu in the
left of the

Measure

line. To switch to balance or unbalance parameters, click the pull-down

menu in the right of the

Measure

line. To change the format, click the

Format

pull-down menu.

5.6.5

Stimulus in Time Domain

The stimulus type can be set in the

Stimulus

pull-down menu in the

Parameter

bar of

the

TDR/TDT

tab. There are two stimulus types to choose: The option

Lowpass Step

means

T parameters show the unit step responses and the option

Lowpass Impulse

means T

parameters show the unit impulse responses.

The rise time or impulse width of the stimulus signal can be set in the Rise Time or

Impulse Width textbox. Intrinsically, it controls the beta value of the Kaiser window function
applied in the time domain transformation to weaken the sidelobes. Because the
transformation is based on the finite frequency domain data, the data truncation at the end of
frequency domain data leads to some problems, such as the extension of the rise time or
impulse width of the responses signal and the appearance of sidelobes, which is called
"truncation effect". Applying the Kaiser window lowers the sidelobe levels, but aggravates the
extension of the rise time or impulse width and brings down the resolution ratio of
transformation. The longer the rise time or impulse width of the stimulus signal, the larger the
beta value of the Kaiser window function, the stronger effects explained above are introduced
into the transformation.

5.6.6

Smoothing

The smoothing function makes the trace data smooth by replacing the original trace data

with the average of the data nearby. If the local change ratios of trace data are relatively
large, the smoothing leads to large data errors. Therefore, the smoothing function is available
for the traces whose measure parameters are reflection S parameters.

To switch on or off the smoothing function, click the

Smoothing

checkbox in the

Parameter

bar of the

TDR/TDT

tab.

5.6.7

Trace Allocation

The TDR option will delete all existing traces and windows, allocate all the traces and

windows automatically for the DUT topology, and set the traces to default settings if the trace
allocation function is activated. The operation deletes all original traces and their settings, but
the channel settings remain. There are three allocation methods to choose from: The option

Mixed

means that the traces in the time and frequency domain are allocated. The option

All

means that only traces in the time domain are allocated. The option

All S

means only

traces in the frequency domain. Note that in Single-ended 1 Port topology, only the option

Mixed

is available.

To use the trace allocation function, click the button of the corresponding method in the

Allocation

box in the