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Method for searching analog television channels

A technology for simulating TV and center frequency, which is applied to TV, color TV parts, TV system parts, etc. It can solve problems such as missing channels and signal frequency deviation exceeding the tuner.

Inactive Publication Date: 2018-04-06
SICHUAN CHANGHONG ELECTRIC CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is: to propose an analog TV channel search method to solve the problem that the signal frequency deviation in the traditional analog TV channel search program exceeds the locking index of the tuner, resulting in missing channels

Method used

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  • Method for searching analog television channels

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Experimental program
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Effect test

Embodiment

[0031] In this embodiment, taking the lock range requirement of + / -2M, the tuner lock index is positive deviation 1.25M, negative deviation 0.75M as an example, the search method is as follows figure 1 described, which includes the steps of:

[0032] A. Initialization operation: clear the programs in the database, and initialize the searched channel number as the first program;

[0033] B. Start searching, obtain the original center frequency point of the corresponding channel, and write the original center frequency point into the tuner, and set the signal flag of the stored program to 0;

[0034] In this step, the original center frequency point (standard transmission frequency) of the first channel can be written into the tuner according to the channel search sequence.

[0035] C. Determine whether the tuner has locked the synchronous head for three consecutive times, if locked, then enter step D, if not locked, then enter step E;

[0036] D. Read the feedback value of AF...

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Abstract

The invention relates to an analog television technology, and discloses a method for searching analog television channels, which solves the problem of channel missing caused by the fact that the signal frequency offset exceeds a locking indicator of a high-frequency head in the conventional analog television channel search scheme. The method comprises the steps of: setting a plurality of local oscillation center frequency points near the standard transmitting frequency of each channel, so that the local oscillation center frequency is close to a signal frequency, and the difference between theboth meets a high-frequency head locking indicator; and when a channel is searched, if the high-frequency head under a local oscillation center frequency point cannot lock a synchronization head, switching the center frequency point to next center frequency point to search the channel.

Description

technical field [0001] The invention relates to analog TV technology, in particular to a method for searching channels for analog TV. Background technique [0002] The analog TV station search is to write the local oscillation center frequency point to the tuner device through I2C. Before writing, the local oscillation center frequency point needs to be converted. The conversion algorithm is: local oscillation center frequency / step size (the tuner’s There are generally three types of step size: 31.25Khz, 50Khz, and 62.5Khz, generally set to 50Khz), for example, the step size of the tuner is set to 50Khz, the local oscillation center frequency point is 55.25Mhz, and the parameters set to the tuner = 55.25*1000 / 50=1105, after setting the local oscillation center frequency point, read whether the signal sync head is locked, if the signal frequency deviation is within the range of the high frequency head lock index, you can lock the signal sync head, and then read AFC The feedb...

Claims

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Application Information

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IPC IPC(8): H04N5/38H04N5/50
Inventor 付信芳薛群波孙祖省胡雪菲
Owner SICHUAN CHANGHONG ELECTRIC CO LTD