A Time-Weighted Graticule for the 2T Sine-Squared Pulse

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Publisher: SMPTE
Doc Type: Journal Article
Article Type: research-article
Abstract: Because international standards for video test signals and test methods for long-distance television circuits have recently been agreed upon by CCIR and CMTT committees, it is now important to resolve a long-standing discussion in North America on the dimensions of a time-weighted graticule for the 2T sin2 pulse. In the past in North America, either no graticule has been used to determine the subjective impact of a signal distortion or else a scaled version of a graticule designed for British 405-line monochrome television (shown recently not to conform to North American standards) was used. The various factors which must be considered in the formulation of a time-weighted graticule for the 2T sin2 pulse are examined, including the graticule truncation close to the impulse to prevent unwanted color distortions, the truncation at the extremities to meet the constraints posed by typical test signal formats, and the approximations involved in the derivation of a practical graticule with simply defined dimensions. Recent data by Lessman on echo time weighting are used to define a suitable graticule. The proposal involves straight-line approximation of the echo-weighting factors and considers the effect of the measurement errors resulting from the shape of typical distortions relative to the graticule outlines, in a time interval where, for economic reasons, the total available weighting should be obtainable. The proposed graticule is compared with the old scaled graticule, and the dimensions of a direct transformation of the echo-weighting factors are given to show the extent of the approximations used. There is sufficient difference between the scaled graticule and the one proposed to consider the new graticule as a North American standard.
Publication Date: 1976-06-01
DOI: 10.5594/J06822
Link: https://doi.org/10.5594/J06822
Author(s): Laurence C. Gooddy

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Laurence C. Gooddy; A Time-Weighted Graticule for the 2T Sine-Squared Pulse, SMPTE Journal ( Volume: 85, Issue: 6, June 1976); SMPTE, 1976. Available at https://doi.org/10.5594/J06822

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Laurence C. Gooddy; A Time-Weighted Graticule for the 2T Sine-Squared Pulse, SMPTE Journal ( Volume: 85, Issue: 6, June 1976); SMPTE, 1976. Available at https://doi.org/10.5594/J06822

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Laurence C. Gooddy; A Time-Weighted Graticule for the 2T Sine-Squared Pulse, SMPTE Journal ( Volume: 85, Issue: 6, June 1976); SMPTE, 1976. Available at https://doi.org/10.5594/J06822

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<span class="citation">Laurence C. Gooddy; <cite>A Time-Weighted Graticule for the 2T Sine-Squared Pulse</cite>, SMPTE Journal ( Volume: 85, Issue: 6, June 1976); SMPTE, 1976. Available at <a href="https://doi.org/10.5594/J06822" target="_blank" rel="noopener">https://doi.org/10.5594/J06822</a></span>

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Laurence C. Gooddy; A Time-Weighted Graticule for the 2T Sine-Squared Pulse, SMPTE Journal ( Volume: 85, Issue: 6, June 1976); SMPTE, 1976
doi: 10.5594/J06822
url: https://doi.org/10.5594/J06822

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<li>
Laurence C. Gooddy; <cite id="bib-10-5594-j06822">A Time-Weighted Graticule for the 2T Sine-Squared Pulse</cite>, SMPTE Journal ( Volume: 85, Issue: 6, June 1976); SMPTE, 1976
<span class="doi">10.5594/J06822</span>
</li>