KR0147985B1 - Multi channel auto tuning method - Google Patents

Abstract

The present invention relates to a multi-channel automatic tuning method in a video device having a plurality of tuners, and to this end, a method for automatically tuning multiple channels of general broadcasting and cable broadcasting in a video device having a plurality of tuners. The lowest channel frequency data of the general broadcast is applied to the first tuner. A first step of applying and tuning the lowest channel frequency data of the cable broadcasting to the second tuner; It is determined whether the synchronization signal is detected from the signal received by the first tuner, and when the synchronization signal is detected, the corresponding channel is stored in the memory. If the synchronization signal is not detected, the frequency data is stored when there is a channel of the next general broadcast. A second process of applying to the tuner; It is determined whether a synchronization signal is detected from a signal received by the second tuner, and when a synchronization signal is detected, the corresponding channel is stored in a memory. If the synchronization signal is not detected, frequency data is stored in the second tuner when there is a next cable broadcasting channel. By providing a multi-channel automatic channel selection method comprising a third process to apply to the second process and to the second process, it is possible to make the channel tuning more quickly.

Description

Multi channel auto tuning method

1 is a block diagram of a hardware device for implementing the multi-channel automatic channel selection method according to the present invention.

2 is a flowchart illustrating a multi-channel automatic tuning process according to a preferred embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

10: key input unit 20, 40: first and second tuner

30.50: First and second synchronous detection unit 60: Microcomputer

70: memory

The present invention relates to a channel tuning method, and in particular, when a channel is tuned in a video device having a plurality of tuners, the channel is divided into a general television broadcasting channel and a cable broadcasting channel, and multiple channels are automatically tuned in parallel. It is about a station selection method.

In general, the channel tuning function determines the channel to which the broadcast signal is input among all broadcast channels 2 to 83 as the presence or absence of a synchronization signal, and stores the channel to which the broadcast signal is input in the memory, so that when the user switches channels, It is a function that makes it possible to switch channels easily by up / down only the channel where broadcasting is performed at the time of up / down.

On the other hand, in order to receive signals of these frequency bands in a general broadcasting or cable broadcasting system of a television in which various frequency bands, ie, a plurality of channels are broadcast, a tuner must be tuned to a carrier frequency of a channel to be received.

NTSC (National Television System Committe) FS (Frequency Syncronizing) method adopts AFT (Automatic Fine Tunning) voltage in order to tune the tuner of the receiver to the carrier frequency of each channel. . That is, when the PLL data for tuning the frequency of each channel is stored in the memory of the microcomputer of the receiving apparatus and the user selects a predetermined channel by dial or the like, the microcomputer applies the PLL data of the selected channel to the tuner. A phase lock loop is formed in the tuner to control the oscillation frequency of the voltage controlled oscillator according to the PLL data to receive the frequency signal of the channel selected by the user.

However, in recent years, despite the fact that many TVs with multiple tuners have been widely distributed due to the multi-screen splitting function, general broadcasting and cable broadcasting channels are tuned to one tuner, and therefore, it is boring for users. There was a problem giving.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a multi-channel automatic tuning method that enables to perform the tuning by channel frequency band by using a plurality of tuners at the same time. .

A feature of the present invention for achieving the above object is a method for automatically tuning multiple channels of general broadcasting and cable broadcasting in a video device having a plurality of tuners, the lowest channel frequency data of the general broadcasting applied to the first tuner And a first step of tuning and applying the lowest channel frequency data of the cable broadcasting to the second tuner; It is determined whether the synchronization signal is detected from the signal received by the first tuner, and when the synchronization signal is detected, the corresponding channel is stored in the memory. If the synchronization signal is not detected, the frequency data is stored when there is a channel of the next general broadcast. A second process of applying to the tuner; It is determined whether a synchronization signal is detected from a signal received by the second tuner, and when a synchronization signal is detected, the corresponding channel is stored in a memory. If the synchronization signal is not detected, frequency data is stored in the second tuner when there is a next cable broadcasting channel. And a third process of applying to the second process.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a hardware device for implementing the multi-channel automatic channel selection method according to the present invention, the key input unit 10, the first tuner 20, the first synchronous detection unit 30, the second tuner 40, The second synchronization detector 50 includes a microcomputer 60 and a memory 70.

In the figure, the key input unit 10 includes various function keys including a channel automatic tuning key, a channel up / down key, and the like to control the operation of a video device and output a key signal corresponding to a user's key operation. do.

In the first and second tuners 20 and 40, a phase lock loop is formed therein, thereby controlling the oscillation frequency of the voltage controlled oscillator according to the PLL data from the microcomputer 60. Through receive the frequency signal of each channel selected by the user. In addition, the AFT voltage is applied to the microcomputer 60 according to the level of the signal received through the antenna ANT.

Next, the first and second synchronization detectors 30 and 50 detect whether the synchronization signal, that is, the horizontal synchronization signal or the vertical synchronization signal, is included in the signals applied from the first and second tuners 20 and 40. When the signal is detected, the synchronization detection signal is applied to the microcomputer 60.

The reason for detecting the synchronization signal as described above is that the video signal transmitted from the broadcast station includes horizontal and vertical sync signals, and thus it is possible to determine whether the received frequency band is the frequency band for transmitting the video signal from the broadcast station. Because there is.

On the other hand, the microcomputer 60 controls the operation of the video device in response to the key signal input from the key input unit 10, and when the channel automatic channel selection key is pressed, as can be seen from the name described below, the lowest channel of general broadcasting The PLL data and the lowest channel PLL data of the cable broadcasting are sequentially applied to the first and second tuners 20 and 40, respectively, and the channels are finely adjusted by the AFT voltages applied from the first and second tuners 20 and 40, respectively. It is configured to perform tuning.

In addition, the first and second synchronous detection units 30 and 50 are connected to the microcomputer 60, and the microcomputer 60 is a predetermined video signal according to the synchronization detection signal applied from the first and second synchronous detection units 30 and 50. Determines that the signal is received, and stores the corresponding channel to which the synchronization detection signal is applied to the memory 70.

Next, a video apparatus including the above-described configuration unit will be described in detail with reference to the flowchart of FIG. 2 attached to the multi-channel automatic tuning process according to the present invention.

First, when the channel automatic tuning key of the key input unit 10 is pressed and the corresponding key signal is applied, the microcomputer 60 performs the following channel search and storage operation.

In step 200, the microcomputer 60 sets the lowest channel among the channels of the broadcasting frequency band where the television broadcast is being performed, reads PLL data corresponding to the lowest channel set in the memory 70, and then reads the first tuner 20. ) Is applied.

Next, the lowest channel among the channels of the cable broadcasting frequency band is set, and PLL data corresponding to the lowest channel is read from the memory 70 and applied to the second tuner 40 (step 202).

Next, the first tuner 20 will receive the frequency band signal of the lowest channel according to the PLL data of the microcomputer 60. In this case, the channel frequency band received by the first tuner 20 may be a frequency band in which a broadcast station is transmitting video broadcast, or may be a frequency band not being transmitted. To determine this, the microcomputer 60 determines whether a synchronization signal is included in the signal received by the first tuner 20.

That is, the microcomputer 60 determines whether the synchronization detection signal detected from the first synchronization detector 30 is applied in step 204. When the synchronization detection signal is applied, the microcomputer 60 stores the channel tuned to the first tuner 20 in memory ( 70 is stored (step 206), and if the synchronization detection signal is not applied, it is determined whether the general broadcast channel tuned to the first tuner 20 is the last channel (step 208). ), The next general broadcast channel PLL data is applied (step 210), and if it is the last channel, step 212 is performed.

From step 212, a process of tuning a cable broadcasting channel using the second tuner 40 is similar to the steps 204 to 210 described above. In step 220, it is determined whether the channel tuning of the general broadcasting and the cable broadcasting is finally terminated in step 220, if the end is completed, the routine ends, and if not, the process returns to the step 204 and the first tuner 20 ) And the second tuner 40 alternately perform a process of tuning all channels of general broadcasting and cable broadcasting.

Meanwhile, in the present invention, the microcomputer 60 skips the automatic fine tuning (AFT) process in order to make the channel tuning more quickly, and when the synchronization signal is detected, the microcomputer 60 stores the channel in which the synchronization signal is detected and tunes. 10), the channel up / down key is applied to the tuner while applying the PLL data of the tuned channel stored in the memory 70 to the tuner, thereby facilitating channel switching while sequentially up / down the channels. will be.

On the other hand, in the channel where the synchronization signal is detected, the tuner outputs an AFT voltage synchronized with the frequency band being received, so the microcomputer repeatedly determines that the tuner is synchronized with the center frequency of the channel when the highest AFT voltage is applied. In addition, the present invention can be modified by storing changed PLL data for receiving the center frequency band of the current channel during channel tuning. The reason for this is that it takes more time for channel selection, but it can shorten the time for channel switching.

As described above, according to the present invention, channel selection time is alternately divided by frequency bands of channels to be tuned by a plurality of tuners provided in the video device, so that channel tuning time can be shortened.

Claims (1)

A method for automatically tuning multiple channels of general broadcasting and cable broadcasting in a video device having a plurality of tuners, wherein the lowest channel frequency data of general broadcasting is applied to the first tuner, and the lowest channel frequency of cable broadcasting is provided to the second tuner. A first step of applying data and tuning each data; It is determined whether the synchronization signal is detected from the signal received by the first tuner, and when the synchronization signal is detected, the corresponding channel is stored in the memory. If the synchronization signal is not detected, the frequency data is stored when there is a channel of the next general broadcast. A second process of applying to the tuner; It is determined whether a synchronization signal is detected from a signal received by the second tuner, and when a synchronization signal is detected, the corresponding channel is stored in a memory. If the synchronization signal is not detected, frequency data is stored in the second tuner when there is a next cable broadcasting channel. And a third process of applying to the second process.