KR100317296B1 - Method and apparatus for controlling channel of a digital TV - Google Patents

Abstract

The present invention relates to a digital TV that stores a moving information according to a frequency shift when a public signal or a local signal is additionally transmitted to a digital broadcast signal, so that a corresponding channel can be set by referring to the frequency shift information when selecting the same channel. A tuner for selecting a signal, a decoder for extracting broadcast information of a channel selected by the tuner, and converting the signal into a displayable signal on a screen, and a service ID of a channel selected by a user if a corresponding broadcast signal does not exist in a channel selected by the user; A controller for searching for a channel having the same service ID, extracting channel movement information according to a channel search, and controlling the tuner so that an image of a corresponding channel is displayed with reference to the channel movement information when selecting the same channel thereafter; Including movement information memory for storing information When the public signal or local signal other than the air wave signal is received at the same time, the user can improve the confidence in the product by searching the frequency band in which the broadcasting signal set by the user exists and outputting the broadcasting signal normally. have.

Description

Channel control apparatus and method of digital TV {Method and apparatus for controlling channel of a digital TV}

The present invention relates to a TV, and more particularly, to a channel control apparatus and method for a digital TV.

In general, a digital TV is a device that receives a digital broadcast signal transmitted from a broadcasting station and provides a video and audio to a viewer. Most current digital broadcasts follow the MPEG standard. Especially, MPEG-2, which is a broadcast MPEG standard, has a system, audio, and video standard. For reference, the MPEG-2 system standard number is ISO / IEC 13818-1, the video standard number is ISDO / IEC 13818-2, and the audio standard number is ISO / IEC 13818-3.

In digital TV, service information refers to various additional information including broadcasting channel information, and service information includes various tables, and each table includes various descriptors as a means of transmitting information.

Hereinafter, a channel control apparatus and method for a digital TV according to the prior art will be described with reference to the accompanying drawings.

1 is a block diagram showing a channel control apparatus for a digital TV according to the prior art, Figures 2a to 2d is a view showing a channel change process according to the frequency, Figure 3 is a channel control method for a digital TV according to the prior art It is a flow chart shown.

As shown in FIG. 1, the apparatus for receiving a public hearing signal of a digital TV according to the related art selects an antenna 1 for receiving a broadcast signal and a channel desired by a user from the broadcast signal received from the antenna 1. A tuner 2 for receiving the output of the tuner 2, a channel decoder 3 for demodulation and error correction, and outputting a transport stream, and a transport stream output from the channel decoder 3 A system decoder (4) for receiving and demultiplexing, a source decoder (5) for receiving the output of the system decoder (4) and extending it into a displayable signal on a speaker / screen, and outputting a channel selection signal desired by a user A user interface 6 and a microcomputer 7 for controlling the tuner 2 and the channel decoder 4 such that a channel required by the user is selected through the user interface 6. .

Referring to the channel control device of the digital TV configured as described above in more detail.

First, the channel decoder 3 receives a channel signal tuned through the tuner 2 and multiplexes video, audio, and broadcast information in packet units and outputs it in the form of a transport stream.

In this case, the transport stream is described in the international standard ISO / IEC 13818, and the broadcast information is a generic term for a tuning frequency, a packet identification number (PID) of a video voice, information on a broadcast schedule, and the like. Different broadcasting methods adopt different standards.

The system decoder 4 receives the transport stream multiplexed by the channel decoder 3 and demultiplexes and extracts 'broadcast information'.

The source decoder 5 receives the demultiplexed video / audio streams from the system decoder 4 and expands them into a signal that can be displayed on a screen and a signal that can be output through a speaker.

The broadcast information extracted through the system decoder 4 is transferred to the microcomputer 7, and the microcomputer 7 receives user requirements through the user interface 6 to control the entire system, and Output a control signal to fulfill the requirement.

The frequency shift path by the public hearing facility of the digital TV will be described with reference to FIGS. 2A to 2D.

First, FIG. 2A is a diagram illustrating band allocation of analog broadcast signals, in which five analog channels (Analog CH1) (Analog CH3) (Analog CH5) (Analog CH7) (Analog CH10) are assigned to respective frequency bands (band1) (band3). (band5) (band7) (band10).

In this case, when an analog signal is received from an apartment complex or a public hearing facility in a predetermined area, a public signal must be added and retransmitted to each home, as shown in FIG. 2B. The analog channel (Analog CH1) (Analog CH3) (Analog CH5) (Analog CH7) (Analog CH10) and the public signal or local channel signal (Local CH1) (Local CH8) are continuously output on one line.

At this time, the local channel (Loach CH1) (Local CH8) is a signal for mediating satellite broadcasting, or broadcast on the premises or closed circuit camera.

In addition, when a digital broadcast is to be received, the broadcasting station transmits a digital channel (Digital CH2) (Digital CH4) (Digital CH8) allocated to each frequency domain as shown in FIG. 2C. In this case, it can be seen that the digital broadcast signal illustrated in FIG. 2C is allocated to an area that does not overlap with the analog broadcast signal illustrated in FIG. 2A.

However, when the digital broadcasting signal is added and transmitted in a public hearing facility that uses a mixed analog broadcast signal and a public hearing signal (local signal) as shown in FIG. 2B, the additional signals are shifted in frequency. do.

That is, the signal shown in FIG. 2D represents a spectrum in which the public hearing facility retransmits the analog broadcast signal, the digital broadcast signal, and the public signal (local signal) to each home in one line. The digital signals allocated to band2, band4, and band8 are moved to bands 6, 9 and 10, respectively, in the retransmission process.

Accordingly, in the broadcast information, the frequency bands band2, band4, and band8 are designated, and the actual signal input to the tuner through the public hearing facility is present in the frequency bands band6, band9, and band10. A case where a broadcast signal is not received in a corresponding frequency band occurs.

The channel control method of the digital TV according to the prior art will be described with reference to FIG. 3 as follows.

Referring to FIG. 3, first, a tuning frequency selected by a user is read (S1).

The channel is set according to the read tuning frequency (S2).

It is determined whether the signal of the channel selected by the user is received (S3).

Subsequently, when the broadcast signal of the channel selected by the user is received (S3), the broadcast signal is displayed on the screen through decoding and a series of signal processing (S4).

On the other hand, if the broadcast signal of the channel selected by the user is not received (S3), an error message is output on the screen (S5).

As described above, when a user requests a channel change when receiving a broadcast on a digital TV, the frequency is changed by outputting a frequency of a carrier of a channel designated by the user to the tuner, and determining whether a signal of a channel specified by the tuner is received. If it is negative, an error message is output, and when a signal of a specified channel is received, the decoding is performed so that a broadcast is normally received and displayed on a screen.

As described above, the channel control apparatus and method of the digital TV according to the prior art have the following problems.

First, when a public signal or a local signal is added to a digital broadcast signal transmitted from a broadcasting station and output to each home from a public hearing facility, the user cannot receive a desired broadcast because the digital broadcast signal does not exist in a corresponding frequency band.

Second, since the user cannot receive the desired broadcast, the reliability of the product is lowered.

The present invention has been made to solve the above problems, and when the public signal or the local signal is additionally transmitted to the digital broadcast signal, the movement information according to the frequency shift is stored, and when the same channel is selected, the corresponding channel is set with reference to the frequency shift information. It is an object of the present invention to provide a channel control apparatus and method for a digital TV.

1 is a block diagram showing a digital TV according to the prior art.

2A to 2D are views illustrating a channel change process of the digital TV.

3 is a flowchart illustrating a channel control method of a digital TV according to the related art.

4 is a block diagram showing a channel control apparatus for a digital TV according to the present invention.

5 is a flow chart showing a channel control method of the digital TV according to the present invention.

Explanation of symbols for main parts of drawings

10: antenna 11: tuner

12: channel decoder 13: system decoder

14: Source Decoder 15: User Interface

16: moving information memory 17: micom

The channel control apparatus for digital TV according to the present invention for achieving the above object is a digital TV, a tuner for selecting a channel desired by the user, a signal that can be displayed on the screen by extracting the broadcast information of the channel selected by the tuner If there is no broadcast signal in the channel selected by the user and the channel is selected by the user, the decoder searches for a channel having the same service ID as the service ID of the channel selected by the user, extracts frequency shift information according to channel search, and then selects the same channel. And a control unit for controlling the tuner so that an image of a corresponding channel is displayed with reference to the frequency movement information, and a movement information memory for storing the frequency movement information.

The channel control method of the digital TV according to the present invention for achieving the above object is to set the channel by extracting the tuning frequency and frequency movement information of the channel selected by the user in the channel control method of the digital TV with a mobile information memory Determining whether a broadcast signal of the set channel is received; searching for a channel in which a broadcast signal of a channel set by a user exists if the broadcast signal of the set channel is not received; When the broadcasting signal of the channel is received, storing the frequency movement information of the set channel, and displaying the image on the screen is characterized by.

Hereinafter, a channel control apparatus and method for a digital TV according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 4 is a block diagram showing a channel control apparatus for digital TV according to the present invention, Figure 5 is a flow chart showing a channel control method of the digital TV according to the present invention.

As shown in FIG. 4, the channel control apparatus of the digital TV according to the present invention includes an antenna 10 for receiving a broadcast signal and a channel for selecting a desired channel from a broadcast signal received from the antenna 10. A tuner 11, a channel decoder 12 that receives the output of the tuner 11, performs demodulation and error correction, and outputs a transport stream, and a transport stream that is output from the channel decoder 12. A system decoder 13 for receiving and demultiplexing, a source decoder 14 for receiving the output of the system decoder 13 and extending the signal as a displayable signal on a speaker / screen, and a user interface 15 for outputting a user request signal. And a microcomputer 17 for controlling the tuner 11 and the channel decoder 12 so that a channel requested by the user is selected through the user interface 15, and a user's channel is changed. A movement information memory 16 for storing frequency movement information according to the present invention.

As described above, when the user selects a channel through the user interface 15, the micom 17 sets the frequency corresponding to the selected channel so that the tuner 11 is set. The control signal is output to.

When the corresponding frequency is set in the tuner 11, the channel decoder 12 receives the selected channel signal through the tuner 11 and multiplexes video, audio, and broadcast information in packet units in time to transport. Output in the form of a stream.

In this case, the transport stream is described in the international standard ISO / IEC 13818, and the broadcast information is a generic term for a tuning frequency, a packet identification number (PID) of a video voice, information on a broadcast schedule, and the like. Different broadcasting methods adopt different standards.

The system decoder 13 receives the transport stream multiplexed by the channel decoder 12 and demultiplexes and extracts 'broadcast information'.

At this time, the microcomputer 17 checks whether the broadcast of the channel selected by the user is being received or not by checking a service ID or additional information parameter in the transport stream.

Subsequently, when the microcomputer 17 determines that the broadcast of the channel selected by the user is being received, the source decoder 14 receiving the demultiplexed signal from the system decoder 13 outputs the signal and the speaker which can be displayed on the screen. Extend it to a possible signal.

Referring to FIG. 5, the operation of the digital TV automatic signal receiving apparatus is as follows.

Referring to FIG. 5, first, frequency and frequency movement information of a channel selected by a user are extracted (S1). The user sets a frequency corresponding to the channel selected by the user, and changes the channel accordingly (S2).

In operation S3, it is determined whether a signal of a channel selected by the user is received.

Subsequently, when the signal of the channel selected by the user is received, the determination result (S3) stores frequency shift information (S4).

The received broadcast signal is displayed on the screen through decoding and signal processing (S5).

On the other hand, if the signal of the channel selected by the user is not received, as a result of the determination (S4), the channel is sequentially increased to search for the existence of the corresponding channel (S6) (S7).

If the corresponding channel does not exist as a result of the search, an error message is output on the screen and the process returns to the initial routine (S8).

In this case, when the user requests channel change, the frequency is read by referring to the preset table. If the channel change is performed more than once, the stored frequency shift information is known. In this case, the channel can be tuned using the frequency shift information. have.

The determining of whether the signal of the channel selected by the user is received is to detect and determine the contents of the transport stream, which is determined by checking a service ID, a broadcasting station ID, an additional information parameter, etc. present in the transport stream. Can be.

If the user-selected broadcast is not received through this checking process, channel search is started to determine whether the user has moved to another frequency band. At this time, if the designated broadcast is not received even after searching the entire frequency band (all channels), an error message is output on the screen.

In this case, the channel search process is a process of determining whether there is a signal of a channel selected by a user by sequentially increasing the channel at the currently selected tuning frequency and moving to the next band.

When the channel is searched through such a channel search process, it is possible to know whether a broadcast is received in a frequency band that differs from the initially set frequency, which is stored in the movement information memory as frequency movement information and thus there may be another channel change. If there is frequency movement information stored in the movement information memory, the frequency band is directly converted to the corresponding frequency band.

As described above, the frequency variation using the frequency shift information is expressed as follows.

Here, fo is an initial tuning frequency and fΔ is frequency shift information.

That is, when the channel is changed for the first time, f f becomes '0', so fn becomes the same frequency as fo. If the channel is changed more than once, frequency shift information (fΔ) previously stored in the movement information memory exists. The frequency is changed to a value obtained by adding the frequency moving information fΔ to the frequency fo.

In this case, the frequency shift information fΔ is determined as a difference between the original frequency fo transmitted from the broadcasting station and the frequency fn moved in the retransmission process, and is stored when a frequency variation due to channel search occurs.

As described above, in the digital TV channel control apparatus and method according to the present invention, when an external signal other than an airwave signal is received at the same time, the user searches for a frequency band in which the broadcast signal set by the user exists so that the broadcast signal is normally output. It has the effect of improving the confidence in the product.

Claims (5)

In digital TV, A tuner for selecting a channel desired by the user; A decoder configured to extract broadcast information of a channel selected by the tuner and convert the broadcast information into a displayable signal on a screen; If the corresponding broadcasting signal does not exist in the channel selected by the user, the channel having the same service ID as the service ID of the channel selected by the user is searched, and the channel movement information is extracted according to channel search. A controller for controlling the tuner to display an image of a corresponding channel with reference; And, And a movement information memory for storing the channel movement information. In the channel control method of a digital TV having a mobile information memory, Extracting tuning frequency and frequency shift information of a channel selected by a user and setting a corresponding channel; Determining whether a broadcast signal of the set channel is received; Searching for a channel in which a broadcast signal of a channel set by a user exists if the broadcast signal of the set channel is not received; And, And storing the frequency movement information of the set channel when the broadcast signal of the set channel is received, and displaying a corresponding image on the screen. The method of claim 2, The step of determining whether the broadcast signal of the channel set by the user is received And determining whether the service ID of the set broadcast signal is the same as a preset service ID. The method of claim 2, Searching for a channel in which a broadcast signal of a channel set by the user exists And sequentially searching for a channel having a service ID identical to a service ID of a channel set by a user by sequentially increasing channels throughout the entire channel area. The method of claim 2, Searching for a channel having a broadcast signal of a channel set by the user; And outputting an error message on a screen when a channel in which a broadcast signal of a channel set by a user exists does not exist.