When was television invented and popularized?

British electrical engineer John Logie Baird invented television. From 1930 to 1940, television was formed.

The sequential sampling, transmission and reproduction of TV signals from point to surface are completed by scanning. Television scanning systems vary from country to country. In China, there are 25 frames per second with 625 lines per frame.

Each line is scanned from left to right, and each frame is divided into odd lines and even lines from top to bottom according to interlacing, so as to reduce flicker. Image information is transmitted during scanning. When the scanning electron beam returns to the line retrace line before the start of the next line from the end of the previous line, and the field retrace line after each field is scanned from top to bottom, it should be blanked. During the blanking period of the line field, the line field synchronization signal is transmitted to synchronize the received and transmitted scanning, thus accurately reproducing the original image.

Extended data:

The function of the high-frequency amplifier is to select and amplify the high-frequency TV program signal received by the high-frequency tuner, and get the image intermediate frequency signal and the audio intermediate frequency signal through mixing processing.

The function of the intermediate frequency (first intermediate frequency) signal acoustic surface is to form the amplitude-frequency characteristics of the amplifier in the image.

The function of the pre-IF amplifier is to amplify the large and small signal (20 dB amplification) and compensate the signal loss caused by the acoustic surface filter. Surface filter realizes impedance matching between high-cost tuner and mirror amplifier.

ACC (Automatic Gain Control) circuit: By controlling the gain of intermediate amplifier and high amplifier, the voltage amplitude of AGC and ANC video signals output by the detector is basically stable;

Reference source: Baidu Encyclopedia-TV