KR20010010280A - Method for tuning a channel of video-machine - Google Patents

Abstract

PURPOSE: A method for selecting channels of a video equipment is provided to selectively designate sky wave channels and cable channels according to regional features, so as to select every channel transmitting broadcasting to reduce a necessary time for the selection. CONSTITUTION: In selection of a channel, whether a channel setup mode is a sky wave channel selection mode, a cable channel selection mode, or a sky wave/cable channels selection mode is decided. If the channel setup mode is the sky wave channel selection mode, every channel transmitting sky wave broadcasting is sequentially selected and the selected channels are stored. If the channel setup mode is the cable channel selection mode, every channel transmitting cable broadcasting is sequentially selected and the selected channels are stored. If the channel setup mode is the sky wave/cable channels selection mode, every channel transmitting the sky wave broadcasting and the cable broadcasting is sequentially selected and the selected channels are stored.

Description

Method for tuning a channel of video-machine}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a channel tuning method in an image processing apparatus, and more particularly, to a method for selectively selecting an airwave channel and a cable channel according to a regional characteristic of watching airwave broadcasting and cable broadcasting.

In general, in order to tune a broadcasting channel transmitted from a broadcasting system, such as a video device, that is, to receive a signal of a frequency band provided by a television or cable broadcasting system in which a plurality of channels are broadcast, a carrier of a channel to be received. The tuner should be tuned to the frequency. This channel tuning function automatically determines a channel provided with a broadcast signal among all broadcast channels by the presence or absence of a synchronization signal, and stores the channel provided with the broadcast signal in a memory, so that the user can change the channel, that is, the channel. It is possible to facilitate channel switching by only up / down channels through which broadcasting is performed during up / down.

To this end, the NTSC (Frequency Synchronization) method employs an AFT (Automatic Fine Tunning) voltage to tune the tuner of the receiver to the carrier frequency of each channel. have. More specifically, when the PLL data for tuning the frequency of each channel is stored in the memory of the micom internal of the receiving apparatus, and the user selects a predetermined channel by dial or the like, the micom applies the PLL data of the selected channel to the tuner.

A phase lock loop is formed inside 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, since the carrier frequency of the signal transmitted from the broadcasting station varies slightly depending on the region or environment, it is necessary to change the oscillation frequency of the voltage controlled oscillator in order to synchronize the carrier frequency with the tuner.

To this end, the FS method outputs an AFT voltage according to the frequency of the intermediate frequency (IF) signal output from the tuner, and allows the microcomputer to finely change the PLL data according to the AFT voltage. That is, an intermediate frequency (IF) signal outputted from the tuner by finely changing the PLL data in predetermined step units so that the applied AFT voltage becomes an intermediate voltage within a predetermined window range (for example, 2.8-3.8 V). The frequency is 45.75 MHz (in case of NTSC), and the PLL data at this time is stored as the reception channel data.

An example of an apparatus for performing the above-described operation is a "automatic tuning method of an electronic system with a tuning circuit" disclosed in Korean Patent Application No. 96-77315, which is a tuning condition of a tuning system by performing automatic frequency fine tuning. Performs the optimal tuning operation accordingly.

However, due to the appearance of broadcast stations and cable broadcasts, the number of channels on which broadcasts are transmitted is quite large. Therefore, even if channels are automatically tuned by the channel auto-tuning process described above, there is a problem in that channel tuning takes much time.

That is, in the case of over-the-air broadcasting, which receives a broadcast signal wirelessly transmitted through an antenna, channels generally exist in channels 2-4, channels 5-12, and channels 21-69, and in the case of cable broadcasting, channels 1-20. Since channels exist between 21 and 41, the channel selection process usually requires searching 100 channels one by one, and this channel searching process takes a lot of time.

Therefore, the present invention has been made to solve the above-described problem, and in the present invention, in the case of wired and wireless broadcasting, the channel on which the broadcast is performed is concentrated around a predetermined channel to select a channel range for the user to tune into. It is possible to provide a channel tuning method of a video device that can shorten the time required for channel tuning by making it possible to designate.

In the channel tuning method of the video device according to the present invention, whether the channel setting mode when the channel is tuned to the air channel channel selection mode to watch the airwaves, the cable channel tuning mode to watch the cable broadcast or both the airwave and cable broadcast channels Determining whether to tune to an airwave / cable broadcasting channel tuning mode to be tuned; if the airwave channel tuning mode is determined according to the mode determination, sequentially tuning all channels for transmitting the airwave broadcasting and storing the tuned channel; Storing the tuned channels by sequentially tuning all channels transmitting the cable broadcast in the cable channel tuning mode according to the mode determination; and performing the airwave broadcasting and cable broadcasting in the airwave / cable channel tuning mode according to the mode determination. All channels that are transmitted are tuned in sequence A characterized in that it comprises the step of storing.

1 is a block diagram of a video device performing a channel tuning method according to the present invention.

2 is a flowchart of a channel tuning method of a video device according to the present invention;

<Explanation of symbols for main parts of drawing>

10: key input unit 20: tuner

30: synchronization detection unit 40: signal processing unit

50: OSD unit 60: control unit

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

1 is a block diagram of a video device for performing channel selection using a synchronization signal detection method according to the present invention, and includes a key input unit 10, a tuner 20, a synchronization detection unit 30, and a signal processing unit 40. As shown in FIG. , An OSD unit 50, a controller 60, and a memory 70.

The key input unit 10 may be typically implemented as a key operation unit installed in a video device or a remote control capable of key input at a remote location. The key input unit 10 may include a plurality of keys for selective channel selection according to the present invention. An air channel channel selection key 12 for tuning the air broadcasting channel, a cable channel tuning key 14 for tuning the cable broadcasting channel, an air wave / cable channel selection key 16 for tuning both the air broadcasting channel and the cable channel A plurality of keys are configured, including the like. According to the present invention, the air channel channel selection key 12 can be used in the mode of tuning the air channel in the local area where only the air broadcasting system is generalized and the cable broadcasting system is not installed, and the cable channel tuning key 14 Can be mainly used in the mode of tuning the cable broadcasting in a specific area such as a hotel depending on the cable broadcasting, and the airwave / cable channel selection key 16 is mainly used in the urban area where the cable broadcasting system is installed. It can be used in the mode of tuning both over-air and cable broadcasting. Accordingly, channel selection time can be shortened as described below by adaptively selecting a tuning mode of a broadcast channel in consideration of regional characteristics. The key signals corresponding to the operation of the airwave channel tuning key 12, the cable channel tuning key 14 and the airwave / cable channel tuning key 16 on the key input section 10 are provided to the controller 60 as infrared signals.

The tuner 20 performs a function of receiving a broadcast signal of a channel corresponding to PLL data, which is a tuning signal of the controller 60, from among a plurality of broadcast frequency signals transmitted from the broadcast system and input through the antenna. The broadcast signal received by the tuner 20 is provided to the synchronization detector 30, and the AFT voltage tuned by the tuner 20 is applied to the controller 60 to be used to control the PLL data.

The sync detector 30 separates and detects a sync signal from the broadcast signal received by the tuner 20, and provides the sync signal to the controller 60.

The signal processor 40 separates the video signal and the audio signal from the broadcast signal received by the tuner 20 under the control of the controller 60, the video signal to the OSD unit 50, and the audio signal to the speaker (not shown). Are applied separately). At this time, the OSD unit 50 is configured to display a monitor (not shown) by mixing a predetermined text signal with the image signal of the signal processing unit 40 under the control of the control unit 60.

The controller 60 may be implemented as a microcomputer that controls the overall operation of the video device according to the key signal generated from the key input unit 10, and is input through the key input unit 10 as can be seen from the description below. The synchronization detection unit outputs corresponding PLL data for tuning to the tuner 20 in response to the respective tuning signals provided from the over-the-air channel tuning key 12, the cable channel tuning key 14, and the over-the-air / cable channel tuning key 16. Channel tuning is controlled based on the presence or absence of a synchronization signal from 30 and the AFT voltage from tuner 20, and the tuned channel is stored in memory 70 in accordance with the input of the channel switching key from key input section 10. Used to automatically select a channel.

2 is a flowchart illustrating an operation for selective channel tuning performed in an image device having the above-described configuration.

As shown, the channel tuning operation of the present invention is performed by the control unit 60 from the key input unit 10 to the air channel channel tuning key 12, the cable channel tuning key 14, or the air / cable channel tuning key 16. Beginning at step 100S of determining which key is the signal originating from.

As a result of the determination, if the key signal generated from the key input unit 10 is a signal from the air channel channel selection key 12 for air channel channel selection, the control unit 60 proceeds to step 110S of sequentially incrementing the channel and airwaves. PLL data corresponding to the lowest channel 2 of the broadcast channel is output (120S), the airwave channel where the synchronization signal is detected is searched (130S), and the window search using the AFT voltage is performed on the channel where the synchronization signal is detected ( 140S). As a result of the window search, the PLL data for the intermediate frequency of the channel on which the broadcast is performed is stored in the memory 70 (150S). The above-described process is repeatedly and sequentially executed for the channel through which the over-the-air broadcast is transmitted. When all processes up to the last channel 69 for transmitting over-the-air broadcast are terminated (160S), tuning operations for all the channels over the over-the-air broadcast are performed. Is done. In this case, the controller 60 selects a channel only for the channels of the over-the-air broadcasting, that is, channels 2-4, channels 5-12, and channels 21-69 in the channel increment step 170S.

However, as a result of the determination in step 100S, if the key signal generated from the key input unit 10 is a signal generated from the cable channel tuning key 14 for cable channel tuning, the controller 60 proceeds to step 210S. Proceeds by outputting PLL data corresponding to the lowest channel of the cable broadcasting channel, that is, channel 1 to the highest channel 41, and sequentially searching for channels in which a synchronization signal is detected, and using a window using the AFT voltage only for the channel where the synchronization signal is detected. By performing the search, only the PLL data for the intermediate frequency of the channel where the broadcast is performed is stored in the memory 70 (220S-260S).

On the other hand, as a result of the determination in step 100S, a key signal generated from the key input unit 10 is an airwave / cable channel for which both the airwave and the cable channel are attempted to be tuned, not the airwaves or the keys 12 and 14 for the cable channel tuning. If the signal is generated from the channel selection key 16, the control section 60 proceeds to step 310S.

Subsequently, the control unit 60 performs all the channels of the airwave and cable broadcast channels, that is, the lowest channel 1 of the cable broadcast channel from the airwave broadcast channel, similarly to the processes of steps 110S-160S and 210S-260S. Outputs PLL data corresponding to up to channel 69, sequentially searches for airwave and cable channels where synchronization signals are detected, and performs window searching using AFT voltage for all channels where synchronization signals are detected. Only PLL data for the intermediate frequencies of the airwaves and cable channels are stored in the memory 70 (320S-360S).

Accordingly, by selectively applying a band for channel automatic tuning, a channel for transmitting over-the-air and cable broadcasting is adaptively tuned.

Therefore, as described above, in accordance with the present invention, a frequency band for channel tuning is selectively designated for both airwave broadcasting, cable channel, or airwave and cable channel in accordance with the conditions such as a broadcasting area or a cable broadcasting application area. By tuning the channel, it is possible to reduce the time required by tuning all channels through which broadcast is transmitted.

Claims (2)

A channel tuning method of a video device that detects a broadcast channel as a presence or absence of a synchronization signal and AFT voltage at the time of channel tuning, Whether the channel setting mode is in the channel selection mode for watching over-the-air broadcasts, in the channel selection mode for cable broadcasting, or in the over-air / cable channel tuning mode for tuning both over-air and cable broadcasting channels. Judging, In the air channel channel selection mode according to the mode determination, sequentially tuning all channels for transmitting the air wave broadcasting to store the tuned channel; In the channel channel selection mode according to the mode determination, sequentially tuning all channels for transmitting the cable broadcast to store the tuned channel; And if the airwave / cable channel selecting mode is determined according to the mode determination, sequentially tuning all channels for transmitting the airwave broadcasting and cable broadcasting, and storing the tuned channel. 2. The method of claim 1, wherein the over-the-air broadcast channel tuning is performed for channels 2-4, channels 5-12 and channels 21-69, and the cable broadcast channel tuning is performed for channels 1-20, channels 21-41. And channel broadcasting is performed with respect to channels 2-4, channels 5-12 and channels 21-69, and channels 1-20 and channels 21-41.