Datasheet

Datasheet
85/100/115  plots for the 100BASE-TX Return Loss measurement.
TDSET3 – Automated Ethernet Physical Layer
Compliance Testing
Ethernet compliance testing has some unique measurement challenges:
Generating the “disturbing” signal requires tools to generate both pattern
data and noise to provide real-world noise for return loss measurements
There are many individual amplitude, timing, return loss, and template
tests required for each Ethernet variant:
The 10BASE-T standard specifies 22 tests per port plus fault
tolerance and CMRR
The 100BASE-TX standard outlines 12 tests per port plus CMRR and
more
The 1000BASE-T standard calls for 80 tests per port plus BER,
CMRR, and more
Because of the large number of individual tests, compliance testing
takes a lot of setup and measurement time, and makes repeatable
measurement results difficult to achieve quickly
Performing return loss measurements can be expensive if using a vector
network analyzer. Tektronix provides a patented, cost-effective method
using an arbitrary waveform generator (AWG) and oscilloscope
The TDSET3 provides automated compliance testing for 10, 100, and
1000BASE-T PHY verification, including:
Compliance and margin testing for accurate analysis and improved
interoperability
Time- and frequency-domain measurements made with single analysis
instrument
Jitter and timing measurements with and without filters
Amplitude, linearity, and droop testing for transmitter performance
Frequency domain measurements including return loss and power
spectral density
User-defined mode enables flexible parameter control for
characterization and margin analysis
Detailed test reports with margin and statistical information aid analysis
Wide Range of Tests
To ensure reliable information transmission over a network, industry
standards specify requirements for the network’s physical layer. The
Peak-to-peak jitter on 100BASE-TX with single voltage crossing.
TDSET3 Ethernet Compliance Test Software automates Ethernet physical
layer tests for 10BASE-T, 10BASE-Te, 100BASE-TX, and 1000BASE-T
in compliance with standards such as IEEE 802.3-2000 and ANSI
X3.263-1995. The portfolio of tests includes core PMA and MDI tests such
as Template, Distortion, Return Loss, Jitter (including the proposed alternate
jitter method), and Common Mode Voltage.
Amplitude Domain Tests
The industry standards require the signals to have amplitudes within
specified ranges to assure interoperability between devices. The amplitude
tests vary with the signal speeds, but include such parameters as peak
or peak-to-peak amplitude, overshoot, common mode voltage, and
positive/negative pulse symmetry.
Return Loss Test
The return loss of the cabling system can also affect interoperability.
The standards define the minimum amount of attenuation the reflected
signal should have relative to the incident signal. The Return Loss test
measures the impedance, typically over the range of 100  ±15%. TDSET3
ingeniously performs the Return Loss test for 85, 100, and 115 (111 for
10BASE-T) impedances as prescribed by the standards, using the same
tools such as oscilloscopes and AWG used for other tests, enabling efficient
usage of resources.
Time Domain Tests
Timing parameters of the signals are also specified by the standards.
These tests include timing measurements such as rise time, fall time, and
difference or symmetry between rise and fall times.
Jitter Tests
Jitter tests quantify the timing variations of the edges of the signal, using
specified test patterns. These jitter measurements include the contributions
from duty cycle distortion and the baseline wander. Jitter is determined by
accumulating waveforms, measuring the width of the accumulated points
at the eye crossing, and the peak-to-peak is inferred from minimum and
maximum values in the tails of the histogram. For example, the figure above
shows the jitter measurement on a 100BASE-TX signal.
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