The HD-SDI TPG is a high definition SDI digital test pattern generator.
Powered by a 9 volt battery makes it a convenient portable tool for field work and installations.

HD-SDI TPG Specifications

In digital video systems, it is desirable to have an equal number of ones and zeros. Scramblers are used to optimize the video data as much as possible. There are cases where the scrambler does not optimize effectively resulting in an offset ratio of ones to zeros. The special cases which cause offset ones to zeros ratios are called pathologicals. The equalizer test (EQ), and the Phase-Locked Loop (PLL) test are commonly used for these pathologicals.

Equalizer Test Pattern: One of the pathologicals occurs when there is a continuous pattern of 19 HIGHs and 1 LOW or 1 LOW and 19 HIGHs.This pattern appears as a flat magenta-like color. The scrambler used in SMPTE 292 video systems does not optimize for this pattern, and the ratio of ones to zeros becomes 1 to 19 or 19 to 1. This results in a large amount of low-frequency energy, and stresses the equalizer. As a result, this pattern is referred to as the Equalizer Test.

PLL Test Pattern: To generate the PLL test, a continuous pattern of 20 HIGHs and 20 LOWs, or vice versa, is generated. This pattern has a low transition density of ones and zeros. For better performance, the PLL requires high transition density. Therefore, this test is referred to as the PLL test and is displayed as gray in the video picture. The PLL Test pattern is generated by continuously transmitting 110h in the luminance output vector, and 300h in the color difference output vector.

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