Updating your computers clock

27-Feb-2020 12:04

The first publicly announced network television broadcast of a program using the NTSC "compatible color" system was an episode of NBC's Kukla, Fran and Ollie on August 30, 1953, although it was viewable in color only at the network's headquarters.

The first nationwide viewing of NTSC color came on the following January 1 with the coast-to-coast broadcast of the Tournament of Roses Parade, viewable on prototype color receivers at special presentations across the country.

The National Television System Committee was established in 1940 by the United States Federal Communications Commission (FCC) to resolve the conflicts that were made between companies over the introduction of a nationwide analog television system in the United States.

In March 1941, the committee issued a technical standard for black-and-white television that built upon a 1936 recommendation made by the Radio Manufacturers Association (RMA).

Technical advancements of the vestigial side band technique allowed for the opportunity to increase the image resolution.

The NTSC selected 525 scan lines as a compromise between RCA's 441-scan line standard (already being used by RCA's NBC TV network) and Philco's and Du Mont's desire to increase the number of scan lines to between 605 and 800.

This blanking interval was originally designed to simply blank the receiver's CRT to allow for the simple analog circuits and slow vertical retrace of early TV receivers.

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Each frame is composed of two fields, each consisting of 262.5 scan lines, for a total of 525 scan lines. The remainder (the vertical blanking interval) allow for vertical synchronization and retrace.The precise frequency was chosen so that horizontal line-rate modulation components of the chrominance signal would fall exactly in between the horizontal line-rate modulation components of the luminance signal, thereby enabling the chrominance signal to be filtered out of the luminance signal with minor degradation of the luminance signal.Due to limitations of frequency divider circuits at the time the color standard was promulgated, the color subcarrier frequency was constructed as composite frequency assembled from small integers, in this case 5×7×9/(8×11) MHz.After nearly 70 years, the majority of over-the-air NTSC transmissions in the United States ceased on January 1, 2010, After a pilot program in 2013, most full-power analog stations in Mexico left the air on ten dates in 2015, with some 500 low-power and repeater stations allowed to remain in analog until the end of 2016.Digital broadcasting allows higher-resolution television, but digital standard definition television continues to use the frame rate and number of lines of resolution established by the analog NTSC standard.

Each frame is composed of two fields, each consisting of 262.5 scan lines, for a total of 525 scan lines. The remainder (the vertical blanking interval) allow for vertical synchronization and retrace.The precise frequency was chosen so that horizontal line-rate modulation components of the chrominance signal would fall exactly in between the horizontal line-rate modulation components of the luminance signal, thereby enabling the chrominance signal to be filtered out of the luminance signal with minor degradation of the luminance signal.Due to limitations of frequency divider circuits at the time the color standard was promulgated, the color subcarrier frequency was constructed as composite frequency assembled from small integers, in this case 5×7×9/(8×11) MHz.After nearly 70 years, the majority of over-the-air NTSC transmissions in the United States ceased on January 1, 2010, After a pilot program in 2013, most full-power analog stations in Mexico left the air on ten dates in 2015, with some 500 low-power and repeater stations allowed to remain in analog until the end of 2016.Digital broadcasting allows higher-resolution television, but digital standard definition television continues to use the frame rate and number of lines of resolution established by the analog NTSC standard.Most countries using the NTSC standard, as well as those using other analog television standards, have switched to, or are in process of switching to newer digital television standards, there being at least four different standards in use around the world.