Teledyne LeCroy QPHY-HDMI - Manual (Page 21)

QPHY-HDMI Operator’s Manual
Test7-4: TMDS TRise, TFall
This test confirms that the rise times and fall times on the TMDS differential signals fall within
the limits of the specification.
R EQUIREMENT
75psec ≤ Rise Time or Fall Time
Reference: [HDMI: Table 4-16] Source AC Characteristics at TP1
M ETHODOLOGY
1. Connect TPA-P adapter to Source DUT HDMI output connector.
2. Configure Source DUT to output a video format and pixel size with highest supported
TMDS clock frequency.
3. Accumulate at least 10,000 triggered waveforms.
4. Measure TRISE as the mode of the sampled edge times from 20% to 80% of the
differential swing voltage rising edge.
5. Measure TFALL as the mode of the sampled edge times from 80% to 20% of the
differential swing voltage on the falling edge.
If (TRISE < 75ps) then FAIL.
If (TFALL < 75ps) then FAIL.
6. Repeat the test for all remaining TMDS clock and data pairs.
Test7-5: TMDS Over/Undershoot
This test confirms that the differential TMDS signals do not have overshoot or undershoot
beyond that allowed by the specified limits (HDMI 1.0 only).
922540 Rev A 17