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Horizontal scan rate, or horizontal frequency, usually expressed in kilohertz, is the number of times per second that a raster-scan video system transmits or displays a complete horizontal line, as opposed to vertical scan rate, the number of times per second that an entire screenful of image data is transmitted or displayed.
The precise frequency was chosen so that horizontal line-rate modulation components of the chrominance signal fall exactly in between the horizontal line-rate modulation components of the luminance signal, such that the chrominance signal could easily be filtered out of the luminance signal on new television sets, and that it would be minimally ...
In the NTSC television standard, horizontal blanking occupies 10.9 μs out of every 63.6 μs scan line (17.2%). In PAL, it occupies 12 μs out of every 64 μs scan line (18.8%). Some modern monitors and video cards support reduced blanking, standardized with Coordinated Video Timings. [3]
The NTSC method implemented in the display of televisions bandwidth of the frequency requires an odd integer multiple of the horizontal frequency divided into two separate interlacing parallel line patterns. The Horizontal frequency was 15,750.
In NTSC, its frequency is exactly 315/88 = 3.579 54 [a] MHz with a phase of 180°. PAL uses a frequency of exactly 4.43361875 MHz, with its phase alternating between 135° and 225° from line to line. Since the colorburst signal has a known amplitude, it is sometimes used as a reference level when compensating for amplitude variations in the ...
The horizontal sync pulse separates the scan lines. The horizontal sync signal is a single short pulse that indicates the start of every line. The rest of the scan line follows, with the signal ranging from 0.3 V (black) to 1 V (white), until the next horizontal or vertical synchronization pulse. The format of the horizontal sync pulse varies.
In revision 1.2, released in 2013, a new "Reduced Blanking Timing Version 2" mode was added which further reduces the horizontal blanking interval from 160 to 80 pixels, increases pixel clock precision from ±0.25 MHz to ±0.001 MHz, and adds the option for a 1000/1001 modifier for ATSC/NTSC video-optimized timing modes (e.g. 59.94 Hz instead ...
Interlaced scanning: display of odd (green) and even (red) scanlines, and line return blanking periods (dotted) For analog NTSC, there are a total of 525 scanning lines per frame of which originally 483 lines were visible (241.5 visible lines per field + 21 lines of vertical blanking per field = 483 + 42 = 525 lines per frame) and later 480 (240 complete lines per field).