Automatic mode detector for TV broadcasting system

Abstract

An automatic-discriminating apparatus. The switch connects one of crystal oscillators to a VCO of the APC circuit by a control signal from the automatic discrimination control circuit. The automatic discrimination control circuit divides one vertical scanning period into predetermined sections. When receiving a killer signal indicating the OFF state from the killer circuit at the predetermined sections even one time, it outputs a control signal holding the connection state thereof to the switch, and holds the APC circuit in the locking state. When receiving a killer signal indicating the ON state at the divided predetermined sections a predetermined number of times, it outputs a control signal connecting the other crystal oscillator through the VCO to the switch. As a result, the time for discriminating the TV broadcast systems can be shortened, a malfunction can be avoided, and a stable discrimination can be achieved.

Description

technical field [0001] The invention relates to an automatic mode detector (automatic identification device for broadcasting standards) of a television broadcasting system in a multi-standards television receiver, which can automatically identify and receive television signals (TV signals) of different systems. Background technique [0002] Multi-system TV reception can be used for different TV broadcasting systems, such as NTSC system adopted in Japan, PAL system adopted in Germany and South America, SECAM system adopted in France, etc. It must use some kind of device to identify its broadcasting system, and press each format to operate video reception. [0003] Especially in areas where multiple TV standard signals can be received, in order to allow viewers to watch TV programs regardless of the broadcast standard, it is necessary to provide an automatic broadcast standard identification device that can automatically identify the standard on the TV receiver side, automatic...

AI Technical Summary

Problems solved by technology

Moreover, in the above description, the automatic recognition operation starts from the PAL system, but in actual situations, it is possible to start from the process figure 2 The recognition operation starts anywhere

[0027] exist figure 2 In the above-mentioned device for automatic identification of traditional standards shown above, the automatic identification of all standards is performed in a state where the respective oscillators of the crystal oscillator OSC1 or OSC2 are selected, so it takes a long time from the beginning to the end of the identification, The problem that arises is the inconvenience that occurs in the television receiver screen display

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