121 SNA5000A Vector Network Analyzer User Manual
5
Guide For The TDR Option
5.1 Overview
Measured frequency responses can be transformed to the time domain to analyze the
time-domain characteristics of the DUT. The TDR option provides the time domain
reflection/transmission analysis functions and eye diagram simulation function, which can
help users save time and money by minimizing the need for other test equipment Time
domain analysis also has some irreplaceable advantages:
1. Time-domain analysis shows the positions and properties of the impedance
discontinuities on DUT. It can be easy to acquire the impedance value at any point on
the transmission line by analyzing the time domain reflection characteristics. It's
helpful to locate the faults on transmission lines.
2. Using the time domain gating function to remove the influences of the impedance
discontinuities, it becomes possible to simulate the frequency domain characteristics
of DUT after the faults are removed.
3. The eye diagram simulation function doesn't need any external waveform generators.
The VNA uses a built-in virtual bit pattern generator to provide the input signal. It's a
very important tool for signal integrality analysis.
4. If you want to design a compensation network for high-speed digital signal
transmission by emphasis/de-emphasis or equalization, the advanced waveform
function in TDR waveform will be of vital use for you. You don't need to change the
DUT connection or any extra devices, it's easy to simulate the eye diagrams with the
different compensation methods.
5. You can directly inject jitter into the input signal for eye diagram simulations. A
statistical eye diagram is introduced to simulate the probability density of the output
signals.
When using the TDR option, there are some notes:
1. When opening the TDR option or switching the DUT topology, calibration and deskew
data will be cleared. Please finish the calibration wizard before measuring to get the
correct results. Save the calibration data and recall it when required, which can avoid
unnecessary calibration operations.
2. Please operate in the bottom toolbar of the TDR menu as far as possible. The
function in the TDR option desends on the time domain transform, so changing
settings in the right toolbars can lead to incorrect transform results.
3. Don't close the eye diagram module while the eye diagram is drawing, or an
unexpected error might occur. Unless necessary, don't switch between the TDR/TDT
module and the eye diagram module, for the last eye diagram will be drawn when it's
switched to the eye diagram module, which might take a long time.
4. It's NOT recommended to add too many traces, or the trace data update will be slow.
Summary of Contents for SNA5000A Series
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