Displayport Backgrounder

DisplayPort is a high speed serial interface that connects next generation video drivers to digital displays with its primary target being personal computers (PCs) and laptops. The standard is also applicable to other markets such as consumer electronics and portable electronics. Developed nearly two years ago for the computer industry, the DisplayPort standard has been adopted by silicon vendors and system integrators to meet their margin goals as well as to address future display needs.

As a next-generation digital interface, DisplayPort will more than likely replace low-voltage differential signaling (LVDS), digital visual interface (DVI) and eventually video graphics array (VGA). By incorporating DisplayPort technology, laptops and displays will consume less power, require less material, and be less expensive, leading to a paradigm shift for the computer industry.

"Agilent has been involved with the development of the DisplayPort standard since its inception. Our test solutions have been designed to provide consistent results and support engineers throughout the entire development process," says Brian Fetz, DisplayPort program manager at Agilent Technologies. "We cover the complete set of physical layer testing -- from transmitter to receiver to cable testing."

The Video Electronics Standards Association (VESA) is an international consortium comprised of more than 160 companies around the globe that support industry-wide standards designed for the consumer electronics, PC and workstation industries. One of the standards VESA hosts is DisplayPort, which continues to evolve and is presently at Level CTS 1.1.

VESA has established a comprehensive compliance test program noted in the DisplayPort CTS, which features product testing for physical layer and link layer compliance. The physical layer, which encompasses sink, source and cable testing require test point access fixtures to get to and from the DisplayPort device under test. The link layer testing verifies training, link initiation and maintenance, and is considered an extensive process.

Engineers are able to design, characterize, debug and conduct compliance testing for source and sink outlined in the Compliance Test Specification (CTS) documents. By conducting these tests, engineers can speed up the development cycle of new personal computer displays without sacrificing the quality that consumers demand. Furthermore, DisplayPort facilitates a concept called direct drive, which means a display module can be directly connected to a cable input without having to go through a Transition Minimized Differential Signaling (TMDS) receiver. In doing this, the motherboard pin count and power requirements are reduced.

The DisplayPort connector supports one-to-four data pairs in a Main Link, carries audio and clock signals, each with a transfer rate of 1.62 or 2.7Gbit/s and supports six-to-16 bits per color channel. The DisplayPort's data transmission protocol, which is based on micro packets, is different than the DVI/HDMI protocols, which are serial data streams at 10x pixel clock rate. As a dynamic interface, DisplayPort will adapt as needed to optimize the link, allowing the user to choose the highest resolution and have the best viewing quality for their system.

Agilent is a leader that has actively participated in the standards committee for many years and offers a complete portfolio of DisplayPort test solutions, which feature automation, calibration and test accessories specifically developed to support the DisplayPort standard. The key competitive differentiators are: Agilent's test methodologies provide reliable and accurate results and are customized for the need of IC designers and system integrators; the automation process wraps up testing as one interface, and fully automates calibration of the setup and the testing of a device for compliance. Agilent's method of implementation (MOI) has been approved by VESA.

The test automation software was developed by the Agilent partner company BitifEye Digital Test Solutions. It controls advanced high speed digital test instruments, such as oscilloscopes, pattern and data generators, and BERTs, and configures the test devices. BitifEye's software platform addresses compliance testing of the DisplayPort standard, as well as margin testing and in-depth device characterization. The software is globally marketed, sold and supported by Agilent. BitifEye also offers complementary DisplayPort accessories, including the receptacle test fixture BIT-DP-RTF-0001 which is needed for the calibration of the receiver test setup.

Agilent's DisplayPort products are also being used by Allion Test Labs in Taiwan, an official DisplayPort test house, for compliance testing to make sure products are reliable and brought to market on time.

Agilent DisplayPort Compliance Test Solution - comprised of the Series 90000A Infiniium Oscilloscope , the J-BERT N4903A pattern generator or and E4887A TMDS signal generator, the N5990A test automation software, and the W2641A DisplayPort test point access adaptor, this solution supports the DisplayPort specification 1.1a. The complete solution features manual, automated physical layer compliance layer and debugging test capabilities. It also offers comprehensive source and sink design and characterization testing, and can conduct testing for both HDMI and DisplayPort testing.

W2642A AUX Channel Controller - enables engineers to control a device under test through the DisplayPort connector only. Separate proprietary software for back-channel control of each test device is no longer required. Productivity will improve dramatically because engineers and other test personnel no longer need to be present during the test process, which can take five hours for DisplayPort sources. Compliance test labs will also find these processes offer them increased productivity, consistency and accuracy.

J-BERT Pattern Generator N4903A/B - a high-performance serial Bit-Error Ratio Tester (BERT) with integrated and calibrated jitter injection capabilities, for data rates up to 7 and 12.5 Gb/s. The instrument allows complete jitter tolerance testing of serial bus devices, such as DisplayPort, PCI Express, SATA, FB-DIMM, Fibre Channel, CEI, Gigabit Ethernet and XFP. Together with the N4915A-006 DisplayPort cable emulator, it becomes very easy to inject exactly the required ISI and jitter amounts for DisplayPort sink compliance test.

ParBERT 81250A High-Performance Parallel Bit Error Ratio Tester - sets the standard in video test efficiency. With multiple generators a ParBERT setup can test a multi lane DisplayPort sink device with superior efficiency. Furthermore ParBERT is the ideal tool to stress inter-lane dependencies. ParBERT 81250A covers all compliance tests and is the ideal tool for sink characterization. Customers with a test need for HDMI may use the E4887A TMDS signal generator for HDMI and DisplayPort.

N5990A Test Automation Software - a test automation software addressing compliance testing and extensive product characterization. It unites all instruments under one user interface and automatically performs setup calibration and runs whole test suites without user interaction. The software saves time and labor as well as it eliminates human errors during test execution.

Agilent U7232A Compliance Test Software version 1.7 - designed for the Infiniium Series 90000A oscilloscopes, the software follows testing set by CTS, and offers three modes of physical-layer tests. In the first mode, engineers simply select the device capability and the number of tests to run only in the configuration (pre-emphasis, level, bit rate, lane) required by the CTS. The second mode makes it possible to add or delete configurations. The third mode permits characterization testing of any specific configuration, evaluates statistics or repeats analysis based on results. The software works on all previous models of Infiniium oscilloscopes with bandwidths of 4 GHz and higher.

W2641A DisplayPort Test Point Access Adaptor - breaks out the DisplayPort signals of interest for Compliance testing. These signals include the 4 high speed differential lanes that carry the main video content, the Auxiliary channel that carries bidirectional control information, and the Hot Plug Detect and Power lines necessary for standard DisplayPort connection. The fixture is used for both DisplayPort sink and source testing where the Device under test connector is a DisplayPort receptacle. The W2641A is used with the U7232A DisplayPort compliance test software which supports 1, 2 or 4 lane connection models. De-embed structures provided for removing fixture effects which is important for Motherboard and connector transmission analysis.

Agilent's measurement solutions and services development for digital applications is driven and supported by the work that Agilent's experts do in the various international standard committees. The Agilent Standards Program for digital applications comprises Double Data Rate (DDR) memory, PCI Express®, DisplayPort, Universal Serial Bus (USB), Serial ATA (SATA), High-Definition Multimedia Interface (HDMI®), DigRF and optical transceiver test. Our experts are in the Board of Directors in Joint Electronic Devices Engineering Council (JEDEC), PCI-SIG® and Video Electronics Standards Association (VESA). Agilent is contributing member in Serial ATA International Organization (SATA-IO), USB-Implementers Forum (USB-IF) and Mobile Industry Processor Interface (MIPI) Alliance.

Agilent's involvement in these standards gives Agilent and its customers, the computing and communication component vendors to the electronics consumer market, two main advantages:

• First, it enables us to bring the right products to the market when our customers need them. We aim to be first to market with our solutions so you as our customer can be first to market with your products ensuring standard compliance.
• Second, with Agilent's involvement in plug-fests, workshops and seminars we are in the unique position to develop solutions that evolve with the standards, giving you the ability to design the best products with the highest confidence.

PCI Express, PCIe and PCI-SIG are registered trademarks and trademarks respectively of the PCI-SIG.

HDMI, the HDMI logo and High-Definition Multimedia Interface are trademarks or registered trademarks of HDMI Licensing LLC.