KR20000034370A - Method for automatically searching for channel of digital television system - Google Patents

Abstract

PURPOSE: A method for automatically searching for a channel of a digital television system is provided to store analog channel information and digital channel information so as to search for the channel with more accuracy. CONSTITUTION: A method for automatically searching for a channel of a digital television system includes first thru forth steps. The digital television system searches for NTSC broadcasting channels and ATV broadcasting channels automatically. At the first step, whether a channel search key signal is applied is determined. At the second step, the broadcasting mode is acknowledged using the SD information on NTSC broadcasting and the ID information of ATV broadcasting. At the third step, AFT is performed by tuning the channel and the tuned data is stored when the broadcasting mode is NTSC broadcasting. At the forth step, ATV is performed by tuning the channel and the tuned data is stored when the broadcasting mode is ATV broadcasting.

Description

How to automatically detect channels in digital television systems

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital television system, and more particularly, to an automatic channel search method of a digital television system for automatically searching analog channels and digital channels.

ATV (Advanced Television) system, a digital television system in the United States, compresses and transmits digital video and audio data using a predetermined compression algorithm, for example, a hybrid encoding algorithm, and compresses the video and audio data that is compressed and transmitted. In this ATV system, program information, data information, and control information are multiplexed to form a predetermined packet stream, for example, a packet stream in units of 188 bytes, and then a carrier wave. It is sent on.

The program information indicates, for example, TV programs provided by each broadcaster for the purpose of being broadcast to subscribers. The program information includes video information, user information such as subtitle data and audio information, and the data information is defined according to a service provider. Includes information that becomes

The control information is program specification information such as program ID, channel ID, program name, caption service presence, and program grade necessary for demultiplexing and reconstructing program information or data information of a selected channel from a packet stream carried on a carrier. PSI: Program Specific Information). That is, the PSI carried in a packet stream of 188 byte units is PAT (Program), which is a program combination table having N-bit packet ID (PID) indicating a program number of each channel provided by a transmitter. Association Table) and Program Map Table (PMT), which is a program map table of packet ID (PID) information of N bits for actual data of each received channel, that is, video, audio, and subtitles.

Therefore, based on the control information included in the packet stream, the receiving side of the ATV automatically tunes to the carrier including the program of the selected channel, and then demultiplexes only the program information of the channel selected from the multiplexed and transmitted packet stream. By reconstructing, program information is provided to the viewer.

Since the digital television broadcasting system is a mixture of existing analog channels and digital channels, channel hopping or miss tunning occurs during channel detection, and thus, accurate tuning is not performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to provide an automatic channel search method of a digital television system for accurate channel search by storing analog channel information and digital channel information.

In order to achieve the above object, the present invention provides a channel automatic search method of a digital television system for automatically searching for an NTSC broadcast channel and an ATV broadcast channel, wherein a signal for a channel auto search key for searching for the channels is applied. Determining a first step; A second step of determining a broadcasting mode based on SD information of NTSC broadcasting and ID information of ATV broadcasting when a signal for the channel automatic search key is applied; A third step of tuning the channel by storing the tuned data by performing an AFT operation when the broadcast mode is determined as an NTSC broadcast mode; And a fourth step of storing the tuned data by tuning the ATV broadcast channel when the broadcast mode is determined as the ATV broadcast mode. Here, in the broadcast mode determination of the second step, if the SD information is detected and the ID information is not detected, it is determined as an NTSC broadcast mode, and both the SD information and the TD information are detected or the SD is not detected. If ID information is detected, it is determined that the ATV broadcast mode.

1 is a block diagram showing the configuration of a typical digital television system suitable for performing channel auto search according to the present invention;

2 is a flowchart illustrating a process for performing a channel automatic search method of a digital television system according to the present invention.

<Description of the code | symbol about the principal part of drawing>

110: tuner and demodulator 120: MPEG decoder

130: video encoder 140: video output unit

150 control unit 160 menu generation unit

170: memory

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

1 is a block diagram showing the configuration of a digital television system for performing a channel automatic search method according to the present invention. The tuner and demodulator 110, the MPEG decoder 120, the video encoder 130, the image synthesizer ( 140, the controller 150, the menu generator 160, and the memory 170.

The tuner and demodulator 110 tunes the corresponding broadcast channel according to the tuning control of the control unit 150 as described below in the broadcast signal received through the antenna, that is, the broadcast signal of NTSC broadcast and ATV broadcast. The broadcast signal of the tuned channel is restored to a transport stream through a process of conversion to IF, demodulation, and error correction. At this time, the reconstructed transport stream includes broadcast signals for each channel, that is, video signal, audio signal, and PSI information. The tuner and demodulator 110 controls the reconstructed transport stream under the control of the controller 150. The demultiplexer is provided to the MPEG decoder 120 and the PSI information is provided to the controller 150.

That is, the controller 150 provides a tuning control signal for tuning a channel according to channel selection from a user to the tuner and demodulator 110, and provides PSI information provided from the tuner and demodulator 110 to a third memory ( 173).

In this case, the tuner and the demodulator 110 are tuners corresponding to each broadcast, that is, the NTSC broadcast tuner and the ATV broadcast tuner so that they can tune to each broadcast signal having a different frequency band, that is, an NTSC broadcast signal and an ATV broadcast signal. It also has a built-in tuner that can be tuned for each broadcast mode.

The controller 150 controls the tuning operation of the tuner and the demodulator 110 when a key manipulation signal for channel automatic search is applied. The controller 150 performs a tuning operation for each of an NTSC broadcast channel and an ATV broadcast channel, and then performs a corresponding broadcast. Mode, that is, the NTSC broadcasting mode or ATV broadcasting mode information and the tuned channel data are controlled to store the memory, that is, the NTSC broadcasting channel information in the first memory 171, and the ATV broadcasting channel information is stored in the second memory 172. To control. That is, the controller 150 determines whether the NTSC broadcast or the ATV broadcast is received from the broadcast signals received by the tuner and the demodulator 110, and performs channel tuning according thereto, thereby storing the tuned data and each broadcast mode information. To store it.

Accordingly, the first memory 171 stores NTSC broadcast mode and channel information under the control of the controller 150, and the second memory 170 stores ATV broadcast mode and channel information under the control of the controller 150. do. At this time, the memory 170 is composed of an EEPROM.

Meanwhile, the MPEG decoder 120 MEPG decodes the broadcast signal tuned by the tuner and the demodulator 110 to provide audio data to an audio signal processing stage (not shown) and to provide video data to the video encoder 130. Accordingly, the video encoder 130 converts the MPEG decoded video signal provided from the MPEG decoder 120 into an NTSC broadcast signal and provides the converted video signal to the image output unit 140.

In addition, the menu generator 160 has a preset format for configuring a menu screen, and configures a menu screen under the control of the controller 150 to provide the menu screen to the image output unit 140, and the image output unit 150. The NTSC broadcast signal provided by the video encoder 130 and the menu screen provided by the menu generator 160 are synthesized and provided to the display side.

FIG. 2 is a flowchart for performing a channel automatic search method according to the present invention, which will be described in detail with reference to the block diagram shown in FIG.

The controller 150 determines whether the operation signal for the channel auto search key is applied from the user in step S100. When the operation signal for the channel auto search key is applied, the controller 150 proceeds to step S101 to indicate that the signal is an NTSC broadcast signal. It is determined whether the synchronization (Synchronous Detection) information is detected. In other words, if the SD information of the NTSC broadcast is detected in step S101, the controller 150 proceeds to step S102 to determine whether the ID of the ATV broadcast is detected.

As a result of determination, when the ID of the ATV broadcast is detected, that is, when the SD information of the NTSC broadcast and the ID information of the ATV broadcast are detected, it is determined that the ATV broadcast mode is stored, and the ATV broadcast mode information is stored in the second memory 172 (step S108). If the ID of the ATV broadcast is not detected, i.e., if the SD information of the NTSC broadcast is detected and the ID information of the ATV broadcast is not detected, it is determined that the NTSC broadcast mode is selected. Store in

Next, the controller 150 proceeds to step S104 to perform AFT (Automatic Fine Tunning) pupil. This AFT operation uses the AFT voltage to tune the tuner of the receiver to the carrier frequency of each channel to receive signals of various frequency bands of multiple channels of broadcast. That is, the phase detection of the deviation of the image IF due to the change of the local oscillation frequency of the tuner is made, and the DC voltage according to the phase change is made. Perform the action to make it work.

Then, the controller 150 proceeds to step S105 to determine whether the AFT operation as described above is completed. When the AFT operation is completed, the controller 150 stores the tuned data in the first memory 171 and proceeds to step S107 to increase one channel. To repeat the process as described above.

On the other hand, if the ID information of the ATV broadcast is detected in step S102, the controller 150 proceeds to step S108 to store the ATV broadcast mode information in the second memory 172.

When the ATV tuning operation is completed (step S110) and the ATV tuning operation is completed (step S110), the controller 150 proceeds to step S111 to store the tuned data and PSI information in the second memory 172. Next, the process proceeds to step S107.

If the NT information of the NTSC broadcast is not detected in step S101, the controller 150 determines whether the ID information of the ATV broadcast is detected in step S112, and if the ID information of the ATV broadcast is detected, that is, the SD information of the NTSC broadcast is detected. If the ID information of the ATV broadcast is detected, it is determined that it is the ATV broadcast mode, and the flow proceeds to step S108 to store the ATV broadcast mode information in the second memory 172, and then repeats the above process (step S108 and later).

In step S112, if the ID information of the ATV broadcast is not detected, that is, if the SD information of the NTSC broadcast and the ID information of the ATV broadcast are not detected, the controller 150 determines that the channel has no broadcast signal and proceeds to step S107.

As described above, the method of the present invention determines, tunes, and tunes an NTSC broadcast mode and an ATV broadcast mode according to detection of SD information and ID information of a currently received channel when an operation signal for a channel auto search key is applied. By storing one data, the channel can be switched accurately when switching channels.

Claims (2)

In the channel automatic search method of a digital television system that automatically searches for NTSC broadcast channels and ATV broadcast channels, Determining whether a signal for a channel auto search key for searching the channels is applied; A second step of determining a broadcasting mode based on SD information of NTSC broadcasting and ID information of ATV broadcasting when a signal for the channel automatic search key is applied; A third step of tuning the channel by storing the tuned data by performing an AFT operation when the broadcast mode is determined as an NTSC broadcast mode; And a fourth step of storing the tuned data by tuning the ATV broadcast channel when the broadcast mode is determined as the ATV broadcast mode. The broadcast mode determination of the second step further comprises: determining that the SD information is detected and the ID information is not an NTSC broadcast mode, and both the SD information and the TD information are detected or the SD is detected. Is not detected, and if the ID information is detected, it is determined that the ATV broadcast mode is selected.