Teledyne LeCroy QPHY-10GBase-T - Manual (Page 18)

QPHY-10GBASE-T Tx Test Descriptions
These are the standard 10GBASE-T transmitter compliance tests.
Test 1 - Maximum Output Droop
The purpose of this test is to verify that the magnitude of the transmitter output droop is within
the conformance limits as defined in section 55.5.3.1 of the IEEE 802.3-2008 specification. This
test uses Test Mode 6.
W HAT I S M EASURED
The voltage level of differential signal C1-C2 (averaged) is measured at 10ns and 90ns after the
rising and falling edge of the transmitter droop test pattern in order to measure the average
droop percentage:
% Droop = 100 * (Lvl90ns-Lvl10ns) / Lvl10ns.
T EST M ETHODOLOGY
The oscilloscope is setup to acquire 20 kS waveforms, with channels C1 and C2 pre-processing
configured to average the inputs. After the scope finds the scale to use, it triggers in "normal"
mode, acquiring at least 500 acquisitions. When the averaged waveforms are acquired, the
scope determines the "X" values to use for the Level@X measurements ("X" corresponds to a
time value, with respect to the trigger position). The Level@X measurements are assigned to
the P1 and P2 parameters (with the names aliased in the measurement table: Lvl10ns and
Lvl90ns), and the % Droop calculated on P3 using the processing web. The Droop
measurement is determined for levels after both rising and falling edges. The measured value is
compared to the Droop value in the limits table to determine if the test passes.
D EFAULT P ASS C ONDITION :
The test passes when average %Droop is less than 10% after both rising and falling edges.
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