Method and device for automatically detecting analog television PAL (Phase Alternating Line) system

Abstract

The invention discloses a method and a device for automatically detecting an analog television PAL (Phase Alternating Line) system. The method comprises the following steps: selecting f from audio frequency FM (Frequency Modulation) carriers f corresponding to different PAL systems; setting the FM demodulation carrier at an f-delta f position; during FM demodulation, estimating an audio frequencysignal to be detected to obtain carrier frequency offset marked as a negative-phase carrier frequency offset a; setting the FM demodulation carrier at an f+delta f position; estimating the audio frequency signal to be detected in the FM demodulation to obtain a carrier frequency offset marked as a positive-phase carrier frequency offset b; if a and b satisfy the PAL system judgment condition, determining the PAL system of the analog television signal corresponding to the audio frequency to be detected according to f; otherwise, selecting f again from f corresponding to different PAL systems and not selected before; and then performing estimation. The invention also discloses a device for detecting an analog television PAL system. After the embodiment disclosed by the invention is applied,various PAL systems can be automatically recognized.

Description

technical field [0001] The present invention relates to the technical field of analog television, more specifically, to a method and device for automatically detecting the PAL system of analog television. Background technique [0002] PAL is one of the three major analog TV systems in the world (PAL, NTSC, SECAM), widely used in China, Europe, Australia and many other countries. The PAL standard can be divided into PAL-D / K, PAL-B / G, PAL-I, PAL-M, PAL-N, PAL-Nc and other standards. The important parameters are shown in Table 1: [0003] Table 1 [0004] PAL-B / G PAL-D / K PAL-I PAL-M PAL-N PAL-Nc lines per frame 625 625 625 525 625 625 Field frequency (Hz) 50 50 50 60 50 50 Bandwidth (MHz) 7 / 8 7 / 8 8 6 6 6 Chroma Subcarrier (MHz) 4.43 4.43 4.43 3.58 3.58 3.58 audio subcarrier (MHz) 5.5 6....

AI Technical Summary

Problems solved by technology

For example, when going abroad with a handheld analog TV receiver, the country needs to be found from this list, and if the PAL system of the country is not in the list, it will be difficult to receive the TV signal correctly

[0014] It can be seen that in the analog TV receiver, various PAL systems including PAL-D / K, PAL-B / G, and PAL-I cannot be automatically recognized

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