Tektronix DTG5000 Series User Manual

Page 7

HDMI Compliance & Sink Characterization Using DTG5000 Series Data Timing Generator

Application Note

www.tektronix.com/signal_sources

Hardware Requirements: Test Equipment and

Peripherals For Sink Tests

Table 3 summarizes the measurement equipment and

accessories (probes, cables, etc.) required for the

sink tests just described. The list includes many

products recommended in the current version of the

HDMI compliance test specifications. Note that the

requirements for characterization and compliance

testing differ somewhat, necessitating a selection

of tools contingent on the task at hand

In addition to the items in Table 3, instruments such

as digital multimeters, protocol analyzers and LCR

meters are required for certain HDMI compliance tests

beyond the scope of this document.

The high bandwidths, differential signaling, and

complex stimulus requirements of the HDMI architec-

ture place rigorous demands on the instrumentation

used in compliance and characterization testing. The

following headings summarize some essential points

to consider when choosing test equipment for HDMI

test applications.

Digital Storage Oscilloscope/Digital

Phosphor Oscilloscope

HDMI jitter tolerance tests require a minimum record

length of 16 megapoints (16M) in the oscilloscope.

In addition, the instrument must offer a means for

recovering the embedded clock (the HDMI specification

prescribes software-based clock recovery) for eye

diagram measurements. The Tektronix TDS family

of digital storage oscilloscopes (DSO) and digital

phosphor oscilloscopes (DPO) can be equipped with

integrated TDSHT3 application software for automated

HDMI clock recovery, eye diagram measurements,

and more. The TDS7404B, with its four input channels,

4 GHz bandwidth, and 20 megasample-per-second

sample rate, is a good match for HDMI measurements.

Data Timing Generator

The stimulus source (generator) that provides the

TMDS signal plays a pivotal role in HDMI Sink tests.

The key challenge for a TMDS signal generator is

to provide the needed range of highly accurate

signals, and to provide precise control of the signal

parameters. For example, differential sensitivity tests

require an amplitude resolution of 20 mV. Intra-pair

skew tests require precise delay settings with

sub-picosecond resolution.

Historically, TMDS data signals have been generated

by aggregations of custom devices designed for

narrow output ranges and/or test conditions.

The Tektronix DTG5000 Series Data Timing Generator

offers a complete stimulus solution for HDMI sink

testing. The DTG5000 Series combines the power

of a data generator with the capabilities of a pulse

generator to provide a wide range and variety of

accurate test signals on multiple output channels

simultaneously. The user operates a set of simple

graphic controls to set the signal parameters

and variables.

Every DTG5000 Series instrument is configured from a

mainframe and plug-in output modules to provide the

desired number and type of signals. Channels may be

single-ended or differential, depending on the test

requirement. Output terminals of the plug-in channel

modules are SMA connectors that can easily be

converted to HDMI connectors using optional TPA test

adapter accessories.

The DTG5274 Data Timing Generator with its maximum

sample rate of 2.7 Gb/s or the DTG5334 with its

sample rate of 3.35 Gb/s maximum rate are the

mainframes of choice for HDMI applications. Both

can support the maximum resolution of a UXGA

device with the required data rate of 1.62 Gb/s; both

offer controllable voltage levels that support all TMDS,

timing, and jitter parameters.