KR20000003157A - Channel automatic searching method in complex satellite broadcasting receiving system - Google Patents

Abstract

PURPOSE: A channel automatic searching method is provided to increase the convenience for a user, to automatically search channel in the condition that a user wants. CONSTITUTION: A channel automatic searching method contains the steps of: inputting a channel automatic searching key while a complex satellite broadcasting receiving system selects a ground wave broadcasting mode and displays; inputting the delayed time that a user inputs; tuning channels; delaying time and judging if the channel tuned is a valid channel; displaying the broadcasting screen of the channel before channel automatic searching.

Description

Method of searching channel automatically in a complex broadcasting satellite's set-up box

The present invention relates to a digital satellite broadcasting system, and more particularly, to a composite digital satellite broadcasting receiving system capable of receiving a satellite broadcasting signal and a terrestrial broadcasting signal.

Recently, our country has implemented digital satellite broadcasting service applying MPEG-2 technology and DVB standard. In this way, the satellite-based broadcasting system is located at an altitude of about tens to hundreds of kilos on the earth's surface. As a method of providing a broadcast signal to a wider area by using), RF signals in the frequency band of 11.7 GHz to 12.0 GHz are used for such satellite broadcasting.

The digital satellite broadcasting system is classified into a transmission system, a receiving system, a resource and a subscriber management system. The digital satellite broadcasting transmission system receives a program from a TV program provider or a data service provider and preprocesses, compresses, and multiplexes them. It performs scrambling, modulation, and amplification and then transmits it to the satellite repeater. The digital satellite broadcasting receiving system receives a satellite broadcasting signal and reproduces the TV or data program through the reverse process of the transmission system, and then outputs them to a terminal such as a TV, a VCR or a PC for display. Further, the resource and subscriber management system manages the program related information / subscriber / transmission system shape and the like.

The digital satellite broadcasting receiving system includes an antenna and an LNB, and the satellite broadcasting receiving antenna has a low noise converter (Low) for converting a radio frequency (RF) signal into an intermediate frequency (IF) signal. Noise Blockdown Converter, which is a low-frequency converter that converts ultra-high frequency RF signals into intermediate frequency (IF) signals in the hundreds to thousands of MHz bands (e.g., 950 MHz-2050 MHz), so that they can be received by satellite broadcasting receiver systems. Convert.

The intermediate frequency (IF) signal output from the low noise converter as described above is tuned through a satellite broadcast tuner, decoded, and displayed on various terminals as described above. In addition to maximizing channel utilization, improving video and audio signal quality, and facilitating additional digital service data transmission, the digital satellite broadcasting reception system can significantly improve the user interface.

Since the satellite broadcast signal and the terrestrial broadcast signal widely viewed in general homes use different frequency bands, a separate tuner must be installed to watch the two broadcast signals using one reception system. There was a problem that the hardware of the receiving system is unnecessarily large and the cost is excessively increased.

In order to solve the above problems, a composite tuner capable of simultaneously tuning a satellite broadcast signal and a terrestrial broadcast signal has been developed, and the applicant applied for such a composite tuner to the Korean Intellectual Property Office on October 31, 1994, for "satellite and cable broadcasting." Tuner "(Patent Application No. 94-28287).

The composite satellite broadcasting reception system employing the composite tuner as described above includes a mode conversion key for converting from one broadcast mode to another. For example, in the case of a receiving system that can be switched to terrestrial broadcast mode, satellite broadcast mode, and cable broadcast mode, when the user selects and watches the terrestrial broadcast mode, the mode conversion key is pressed to convert to the satellite broadcast mode. When the conversion key is pressed again, it switches to the cable broadcasting mode, and when the mode conversion key is pressed again, it switches back to the terrestrial broadcasting mode.

In addition, the composite satellite broadcasting receiving system includes a channel auto search key for automatically tuning a channel having good reception sensitivity. The user selects an arbitrary broadcast mode by operating a mode conversion key and selects a channel auto search key. When pressed, a channel automatic search operation for determining and storing a channel having good reception sensitivity as an effective channel is performed.

2 is a flowchart illustrating an automatic channel search operation in a terrestrial broadcasting mode. In step S21, while the receiving system selects a terrestrial broadcasting mode and a broadcast screen of a corresponding channel is displayed, the channel automatic searching key is pressed in step S22. Detect whether it is input. If the channel automatic search key is input in step S22, the flow advances to step S23 to perform channel tuning to the initial channel for the channel automatic search operation. In step S23, the channel is tuned, and in step S24, after a time delay for a predetermined time (t _d ), it is determined in step S25 whether or not the effective channel is valid. That is, the synchronization of the broadcast signal received through the tuned channel is extracted, and if the synchronization signal is above a certain level, it is determined as an effective channel, and if the synchronization signal is below a certain level, it is determined as an invalid channel.

After determining and storing the effective channel for the tuned channel in step S25, and then detects whether the channel is the last channel in step S26. If the channel tuned in step S26 is the last channel, since there are no more channels to determine whether it is an effective channel, the process proceeds to step S28. If the channel tuned in step S26 is not the last channel, the process proceeds to the next channel in step S27 to step S23. Feedback.

Step S28 is a step of restoring a channel before automatic channel search and displaying a broadcast screen of a corresponding channel.

As described above, when the delay time is long, the effective channel can be determined more accurately. However, the channel automatic search time is too long, which is boring for users. When the delay time is short, the effective channel cannot be correctly determined. The short channel auto search time can reduce the boredom of users. However, in the related art, since the delay time is constantly set, users have no choice but to accept a predetermined channel automatic search time and determination sensitivity of an effective channel.

Accordingly, the present invention has been made to solve the above problems, and when the channel is automatically searched in the terrestrial broadcast mode, the user can directly set the delay time, thereby automatically searching the channel with the desired determination sensitivity and search time of the users. The purpose of the present invention is to provide an automatic channel searching method of a composite satellite broadcasting receiving system.

In order to achieve the above object, the present invention provides a first process of inputting a channel automatic search key while a composite satellite broadcasting reception system selects a terrestrial broadcast mode and displays a broadcast screen; A second step of displaying an OSD screen for setting a delay time and receiving a delay time input by a user; Tuning a channel and determining whether a tuned channel is an effective channel after a time delay during the delay time; And determining a valid channel for all channels, and then displaying a broadcast screen of the channel before automatic channel search.

1 is a configuration diagram of a general composite satellite broadcasting reception system;

2 is a flowchart illustrating a conventional channel automatic searching method in a composite satellite broadcasting receiving system;

3 is a flowchart illustrating a channel automatic search method according to the present invention in a composite satellite broadcasting reception system.

Explanation of symbols on the main parts of the drawings

102: tuner unit 104: MPEG video decoder unit

106: video encoding unit 108: video processing unit

110: synchronization extracting unit 112: control unit

114: memory unit 116: OSD processing unit

118: mixer 120: switching unit

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 composite satellite broadcasting reception system suitable for applying the automatic channel search method according to the present invention.

The composite satellite broadcasting reception system includes a tuner unit 102, an MPEG video decoder unit 104, a video encoding unit 106, a video processing unit 108, a synchronization extractor 110, a controller 112, and a memory unit 114. ), An OSD processing unit 116, a mixer 118, and a switching unit 120.

Referring to FIG. 1, the tuner unit 102 is selected by a user from a broadcast signal received through a satellite broadcasting antenna or a terrestrial wave receiving antenna based on a tuning control signal provided from the control unit 112 through a line L11. The broadcast channel is tuned and the tuned broadcast channel signal is demodulated to the original signal before transmission. In this case, when the satellite broadcast signal is tuned, the demodulated satellite broadcast channel signal is provided to the MPEG video decoder 104 through line L12, and when the terrestrial broadcast signal is tuned, the demodulated terrestrial broadcast channel signal is transmitted through line L14. To the video processor 108.

The MPEG video decoder 104 performs compression encoding in consideration of the spatial and spatial correlation of the compression-encoded video signal, for example, the video signal, of the satellite broadcasting channel signal provided from the tuner 102 through the line L12. The decoded video signal is restored to the original signal before encoding by using a decoding technique such as variable length decoding, inverse DCT, inverse quantization, and motion compensation, and the restored digital video signal is provided to the video encoding unit 106.

Next, the video encoding unit 106 converts the digital video signal provided from the MPEG video decoder unit 104 into an NTSC or PAL analog video signal and then provides it to the contact point b of the switching unit 120 through the line L13. do.

The video processor 108 processes the terrestrial broadcast signal provided from the tuner 102 through line L14, and performs various signal processes such as level amplification, noise reduction, and gain control, for example, to obtain a synchronization extractor ( 110 and the contact point c of the switching unit 120.

Meanwhile, the sync extractor 110 extracts a sync signal, that is, a horizontal sync signal, included in the tuned terrestrial broadcast signal provided through the line L15 from the video processor 108, and the horizontal sync signal extracted in this way is a line L16. It is provided to the control unit 112 through. At this time, the horizontal synchronization signal extracted here is used to determine whether the tuned broadcast signal is an effective channel, and the existence of the horizontal synchronization signal is checked for each channel so that only the channel with good viewing can be automatically tuned. It is performed for a predetermined time.

The control unit 112 is a microprocessor that performs overall operation control of the reception system. When the user broadcast channel selection signal is input from the outside, the control unit 112 generates a corresponding tuning control signal to the tuner unit 102 through the line L11. do. When the channel is automatically searched in the terrestrial broadcasting mode, the effective channel (that is, the channel on which the broadcast signal can be viewed) is determined based on the horizontal synchronization signal provided from the synchronization extracting unit 110 through the line L16, and the channel being tuned is determined. When the channel is valid, the channel number is stored in the area A of the memory unit 114. That is, the number information of the effective channels automatically tuned for each broadcasting mode is stored in the area A of the memory unit 114.

In addition, the control unit 112 generates and switches a switching control signal on the line L17 for output switching of a broadcasting signal corresponding to a broadcasting mode currently being viewed or a broadcasting mode that the user wants to switch based on a user manipulation signal from the outside. Provided to section 120. The control unit 112 checks whether the user operation signal for channel switching is a channel switching signal by a channel up / down key or a channel switching signal by a channel number designation key (numerical key for channel switching). In case of a switching signal by the / down key, the effective channel stored in the current broadcasting mode is switched only, and the channel switching to any broadcasting mode is performed regardless of the current broadcasting mode by the channel number designation key. In other words, the channel up / down key allows channel switching only within the same broadcast mode, and the channel number designation key enables channel switching to another broadcast mode.

In the area B of the memory unit 114, various OSD data, for example, a message for guiding broadcast mode and a message for inquiring about automatic tuning, are stored. When the controller 112 needs to send a message to the monitor For example, when it is necessary to send a message for guiding the broadcast mode, the message is extracted from the area B of the memory unit 114 and provided to the OSD processing unit 116 through the line L18.

Next, the OSD processing unit 116 configures the OSD screen data based on the vertical and horizontal synchronization signals generated for the positioning of the OSD message to be sent when the message data is provided from the control unit 112 through the line L18. The OSD screen data configured here is provided to the mixer 118 through line L19. At this time, the generated vertical and horizontal synchronization signals are signals for positioning the OSD data in a predetermined fixed position (for example, a portion of the upper side of the screen, a portion of the lower side of the screen, etc.) or the OSD at a variable position according to a user's request. It may be a signal for locating data.

Therefore, the mixer 118 properly mixes the terrestrial broadcast signal on the line L15 and the OSD screen data on the line L19 when the OSD screen data including the message (ie, the guidance message, the inquiry message, etc.) is provided through the line L19. It is provided to the contact point c of the switching unit 120 through the line L20. In addition, the mixer 118 bypasses the terrestrial broadcast signal on the line L15 to the contact point c of the switching unit 120 when there is no OSD screen data on the line L19.

Meanwhile, the switching unit 120 selectively switches the video signal output of the tuned terrestrial broadcast signal (or the mixed video signal mixed with the OSD data) and the video signal output of the tuned satellite broadcast channel signal. That is, when the satellite broadcasting mode is selected by the user based on the switching control signal provided from the controller 112 through the line L17, the video signal of the satellite broadcasting channel provided through the line L13 is provided to the display side by connecting the contacts ab. When the terrestrial broadcast mode is selected by the user, the contact ac is connected to provide a video signal (or a mixed video signal mixed with OSD data) provided through the line L20 to the display side.

The composite satellite broadcasting reception system constructed and operated as described above performs the channel automatic search operation according to the flowchart shown in FIG. 3. In step S31, while the reception system displays the broadcast in the terrestrial broadcasting mode, the broadcast processing is performed through step S32. When the channel auto search key is input, an OSD screen for setting a delay time is output in step S33.

An embodiment of the OSD screen is shown in FIG. 4, where a slide bar for setting determination sensitivity and delay time is provided, in which case the delay time is changed analogously. When the OSD screen as shown in FIG. 4 is provided, the user can adjust the size of the judgment sensitivity using the arrow keys. When the judgment sensitivity is set to the minimum, the delay time t _d is equal to the minimum delay time t _d0 . When the determination sensitivity is set to the maximum, the delay time t _d is equal to the maximum delay time t _d0 + α. When the determination sensitivity is set to an intermediate level as shown in FIG. 4, the delay time ( t _d )

Here, t _d is the delay time, t _d0 is the minimum delay time, and t _d0 + α is the maximum delay time.

Another embodiment of the OSD screen is shown in FIG. 5, where a number of buttons are provided to adjust the delay time. For example, the OSD screen is provided with a button indicating a LOW level, a button indicating a MEDIUM level, and a button indicating a HIGH level, respectively. When the LOW button is selected by the user, the delay time t _d is the minimum delay time t _d0. If the MEDIUM button is selected, the delay time (t _d ) is the sum of the minimum delay time (t _d0 ) and the additional delay time (α) .If the HIGH button is selected, the delay time (t _d ) is the minimum delay time. It is the sum of (t _d0 ) and the double additional delay time 2α.

If the delay time is set by the user in step S34 after the OSD screen for selecting the delay time t _d is displayed as described above, channel tuning starts from the initial channel in step S35. The tuned channel is time-delayed by a delay time t _d in step S36, because the synchronization extractor 110 must be delayed by a predetermined time in order to operate normally. It is possible to determine whether the effective channel of.

In step S37, it is stored whether the tuned channel is an effective channel, and in step S38 it is detected whether the channel is the last channel. In step S38, if the channel is the last channel to determine whether it is an effective channel, the process proceeds to step S40. If the channel is not the last channel, the channel is fed back to the step S35 through step 39 to determine whether the channel is valid and stores the next channel. .

Step S40 is a step of restoring a channel before automatic channel search and displaying a broadcast screen of the corresponding channel.

For example, if a channel auto search key is input while the user is watching a channel in the terrestrial broadcasting mode, an OSD screen for setting a delay time is displayed, and the user operates a slide bar as shown in FIG. The delay time may be adjusted analogously, or the delay time may be adjusted discretely by operating a button with a switch key as shown in FIG.

When the delay time is set by the above operation, the channel is sequentially delayed for the delay time t _d while the channels are tuned in sequence so that the synchronization extractor 110 is in a normal state. The synchronization extractor 110 outputs a low level determination signal for a channel that can be viewed with good reception sensitivity, indicating that it is an effective channel, and outputs a high level determination signal for a channel for which viewing is impossible due to poor reception sensitivity. Is displayed.

At this time, when determining whether or not the effective channel for each channel in this way, the delay time (t _d ) is set by the user, if the delay time is long, the whole channel automatic search time is long and the effective channel determination sensitivity is good, but delay If the time is short, the effective channel determination sensitivity is deteriorated while the entire channel automatic search time is short.

As described above, the present invention enables the user to directly set the delay time for determining the determination sensitivity of the effective channel, so that the user can perform the channel automatic search operation with the determination sensitivity and the search time desired by the user. Convenience is increased and discomfort is eliminated.

Claims (3)

A first step of inputting a channel automatic search key while the composite satellite broadcasting receiving system selects a terrestrial broadcasting mode and displays a broadcasting screen; A second step of displaying an OSD screen for setting a delay time and receiving a delay time input by a user; Tuning a channel and determining whether a tuned channel is an effective channel after a time delay during the delay time; And determining a valid channel for all channels and displaying a broadcast screen of the channel before channel automatic search. The method of claim 1, wherein the OSD screen is represented by a slide bar, and a delay time is changed analogously by a user's manipulation. The method of claim 1, wherein the OSD screen is represented by a plurality of buttons, and a delay time is changed discretely by a user's manipulation.