The recently released HDMI 48G 8K/10K resolution offerings introduce the highest level of image quality ever in the history of consumer television. The latest initiative from DPL Labs to validate cabling claims, the company has announced its True Image Testing.
DPL Labs explains that testing along with these high resolutions comes a litany of features that provide for a wide variety of picture attributes never before available to the viewer. It improves color depth, color space, and frame rates just to name a few. However, along with these benefits also comes new challenges of which many in the consumer electronics industry have little knowledge or understanding. One, in particular, is a new feature that was added to neutralize cable interoperability issues but has a cost to image quality. Known as “Link Training” it determines if cable throughput can support high data rates that carry the extended image enhancements that make up 8K/10K video. If the cable cannot support the incoming data rate requested by the display Link Training will reduce the data rate and image quality to a point where the system can function reliably.
For over 10 years DPL Labs‘ Digital High-Speed testing has circumvented many of these interoperability problems within the cable interface stemming from its video and other supporting functions. This was achieved by new and improved test and measurement fundamentals designed and engineered by using scores of interoperability case studies and debugging under different system environments.
Most recently DPL Labs new 48G Reference Standard has been updated taking all aspects of the new 48G offering into consideration including an Image Quality Assessment (IQA) to study Link Training’s quantitative effect on image quality and system reliability. An entirely new test methodology needed to be developed that pushes cables beyond their normal limits to verify they have the necessary dynamic headroom to guarantee the delivery of its True Image expected by each system.
According to DPL Labs, before True Image Testing, there were no traditional test procedures available to provide such data. New testing protocols had to be designed to interrogate each device at multiple data rates while considering noise and symmetry in the Time Domain of digital testing. A series of calculations must be repeated over and over to challenge the cabling under a host of adverse conditions to guarantee the delivery of each cable’s published claims. The purpose for this level of interrogation lies within the unpredictable performance of the interconnected components in each system environment. Losses are common with all systems like this. Some worse than others depending on a number of factors; how many devices are used, workmanship, manufacturing tolerances both in cables and hardware, installation variables as well as the anomalies of atmospheric conditions. All of these have to be taken into consideration when determining the amount of headroom required to prevent these systems from even entering into Link Training.
Losses are typically found deep in the bowels of each system. DPL Labs has experimented with many different display devices to uncover just how much loss there is between a display’s input and the first input pin of the HDMI electronics positioned inside each display. One display for example had three inputs with the best being Input 2. The other two inputs had losses as great as 2dB. This was due to printed circuit board (PCB) material, trace artwork, and layout. These are natural occurrences in any high-speed PCB. This is the reason why in past cases some systems would favor one particular input over others. Only now, if Link Training has to come in to save the day, this very same loss can introduce picture degradation.