Articles You May Have Missed – March 1, 2017

Engineers face a variety of new challenges in measuring 12G-SDI signals, as well as ABR streaming signals. Testing 12G-SDI requires different techniques compared to those used with SD-SDI, HD-SDI and 3G-SDI signals. And monitoring ABR content requires additional signal preparation steps before test can even be undertaken. Here are two tutorials that examine test and measurement for both SDI and streaming signals and how to best perform such tests.

With the advent of SD-SDI, HD-SDI and 3G-SDI, the measurement of Eye Diagram shape and jitter became an everyday task to ensure that signals were correct and transmission was maintained.

Until now, the Eye Diagram was basically a square wave (with harmonic distortions) that allowed the amplitude, rise time, fall time, overshoot and undershoot to be measured easily and accurately. But for 12G-SDI, the signal shape has effectively become a sine wave, which is inherently harder to measure consistently.

Here are some measurement tips in the article, “Testing 12G-SDI Interfaces.” 

Today, distributing multiple video resolutions via IP at adaptive bit rates is a major task in many control rooms. The nature of adaptive-bit-rate (ABR) services means there will be downstream deliverables in multiple profiles derived from a single HD or UHD source — all of which require test and measurement to verify their quality. The most accurate way to do that is through full-reference testing.

But, full-reference testing requires the source and processed sequences be at the same resolution and frame rate. In other words, you must start out comparing apples to apples in order to accurately measure changes in quality between the source and processed video.

With IP content, you can’t typically compare the processed video to the source, because the source will very likely be at too high a resolution. This requires the resolution/frame rate of the source material be reduced to create an acceptable reference for each delivery profile. And that is only the first step in the measurement process.

Learn more about testing ABR content signals in the article, “Demystifying ABR Testing in the IP Domain.”

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