05 | Keysight | N5399C, N5399D HDMI Electrical Performance Validation and Compliance Software - Data Sheet

To validate a transmitter (at test point 1), we must access the

signals of the transmitter with a test point adapter and analyze

with an oscilloscope. This is shown in the middle portion of the

figure. The HDMI 2.0 required processing functions are depicted

below the oscilloscope block. These functions include: fixture

de-embedding for removing the effects of the fixture; impressing

a cable model that is considered a worst-case acceptable cable

in an HDMI system (loss vs. frequency); adding worst-case

skew to either side of the differential pair (one signal at a time);

and modeling the minimum equalization an HDMI receiver will

have (the HDMI reference equalizer). The HDMI EPVC software

generates all of these transfer functions and enables any

combination of them. Further, the implementation is performed

automatically in hardware by real-time convolution subsequent

to the acquisition. The result is the fastest waveform processing

available for HDMI 2.0 electrical testing.

Figure 4. Test point 1 acquisition with test point adaptor with subsequent mathematical processing

functions available.

New HDMI Transmitter Test Requirements for HDMI 2.0

While many of the tests remain similar for HDMI 2.0, there are

many complex mathematical processes that are now required

for the test processing on the oscilloscope for the data rates

above 3.4 Gbs. These ‘complex mathematical processes’ amount

to filtering acquired data using transfer functions to obtain the

required view. Examples of such functions are finite impulse

response filters (FIRs) that can be convolved with acquisitions to

accomplish de-embedding the fixture and embedding a worst-

case cable. In the figure below, we have an idealized HDMI link

with HDMI transmitter, sink and cable between them.

HDMI

sink

HDMI

transmitter

Oscilloscope acquisition

and transfer function

application

TP1

TP1’

TP2

TP2Eq

Acquisition

Fixture

De-embedding

Worst case

cable

embedding

Worst case

skew

modeled

Measurement

Reference

equalization

TP1

TP2

Test point adapter