Teledyne LeCroy QPHY-10GBase-T - Manual (Page 20)

Test 2 - Transmitter Linearity
The purpose of this test is to verify that the SFDR is within the conformance limits as defined in
section 55.5.3.2 of the IEEE 802.3-2008 specification. This test uses Test Mode 4.
W HAT I S M EASURED
For each of the dual-tone options in Test Mode 4, the averaged spectrum of the differential
signal C1-C2 is measured in order to determine the spurious-free dynamic range (SFDR).
QualiPHY will instruct you to setup each dual-tone setting.
T EST M ETHODOLOGY
The oscilloscope is configured to calculate and display the averaged FFT of C1-C2. At least 20
sweeps are acquired in order to have sufficient averaging of the spectrum. The worst-case peak
is compared to the limit equation defined in the specification to determine if the test passes.
D EFAULT P ASS C ONDITION :
The limit equation for passing the test is:
Figure 7 – Transmitter Linearity Test Results
Shown on this screen:
• F3 = Avg(F2)
• F2 = FFT(F1)
• F1 = C1-C2
• P1 = fpeak(F3)
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