![]() ![]() The resulting signals are serialized and sent to a data compressor. The luminance sampling rate is 14.3 MHz, and the chroma sampling rate is 7.15 MHz. ![]() The video from the camera consists of the R, G, and B signals that are converted to the luminance and chrominance signals. To permit this quantity of data to be transmitted over the 6-MHz channel, special encoding and modulation techniques are used.įigure shows a block diagram of an HDTV transmitter. Add to this the audio channels, and the total required bandwidth is almost 300 MHz. Multiply this by 3 to get 67.2 _ 3 = 201.6 MHz. If each sample is translated to an 8-bit word (byte) and the bytes are transmitted serially, the data stream has a rate of, or 67.2 MHz. ![]() Assume that the video to be transmitted contains frequencies up to 4.2 MHz.įor this signal to be digitized, it must be sampled at least 2 times per cycle or at a minimum sampling rate of 8.4 MHz. The FCC’s requirement is that all this information be transmitted reliably over the standard 6-MHz TV channels now defined for NTSC TV. In HDTV both the video and the audio signals must be digitized by A/D converters and transmitted serially to the receiver.īecause of the very high frequency of video signals, special techniques must be used to transmit the video signal over a standard 6-MHz-bandwidth TV channel.Īnd because both video and audio must be transmitted over the same channel, multiplexing techniques must be used.
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