KR20000021873A - Method for tuning in broadcasting satellite receiving system - Google Patents

Abstract

PURPOSE: A method for tuning in a broadcasting satellite receiving system is provided to tune a previous channel of a currently watching channel, in the broadcasting satellite receiving system capable of receiving broadcasting channels and cable broadcasting channels. CONSTITUTION: A method for tuning in a broadcasting satellite receiving system comprises the steps of: distinguishing a broadcasting kind of a previous channel when a key signal for transiting to the previous channel is applied; deciding whether the distinguished broadcasting and broadcasting of a currently watching channel are the same broadcasting; performing automatic gain adjustment corresponding to the broadcasting kind of the previous channel, when the distinguished broadcasting and the broadcasting of the currently watching channel are not the same; transiting to the previous channel by adjusting tuning frequency, according to the automatic gain adjustment.

Description

Tuning Method of Composite Satellite Broadcasting System

The present invention relates to a composite satellite broadcast receiving system capable of receiving both a satellite broadcast channel and a cable broadcast channel, and more particularly, to a tuning method of a composite satellite broadcast receiving system for tuning a previous channel of a channel currently being viewed. It is about.

The composite satellite broadcasting reception system is designed to simultaneously view general cable broadcasting and satellite broadcasting, and has the advantage of detecting a cable broadcasting signal and a satellite broadcasting signal of multiple channels through a single tuning path.

The satellite broadcasting system is a broadcasting system capable of transmitting broadcast programs sent from ground stations using satellites located at an altitude of about tens to hundreds of kilos on the ground, and receiving them directly from the satellite receiving antennas in each home.

The satellite broadcasting system can be broadly divided into a transmitter side and a receiver side. For example, the transmitter side multiplexes M broadcast channel programs to form a packet stream, and then transmits the packet stream on a satellite broadcast carrier. After receiving the packet stream carried on the satellite broadcast carrier, the receiving side demultiplexes only a predetermined broadcast channel program in the packet stream and provides it to the viewer.

On the other hand, the cable broadcasting system is a system for transmitting a general NTSC broadcast signal via a cable, a system for transmitting each broadcast program on a predetermined cable broadcast carrier.

The composite satellite broadcasting reception system has two stages of receiving process. Each of the packet streams carried on the multiple satellite broadcasting carriers is detected, and each of the detected packet streams is modulated again by QAM (Quadrature Amplitude Modulation), and then cable broadcasting. The first process is to load the QAM modulation signal on the channels that remain in the idle state among the channels allocated for the purpose, and to transmit the cable broadcasting signal to each preset channel and then transmit it to each household through the cable. It can be called the fourth process.

The second reception process is performed in each home, and may be referred to as a process of tuning only a broadcast signal of a predetermined channel among broadcast signals transmitted through a cable and providing the same to a TV set. That is, when a broadcast signal of each channel is input through a cable, only a broadcast signal of a predetermined channel is detected. As described above, the broadcast signal provided through the cable is divided into a general cable broadcast signal and a digital satellite broadcast signal. Can be. Therefore, if the detected satellite signal is a general cable broadcast signal, the composite satellite broadcast reception system outputs the broadcast signal as a path for processing the cable broadcast signal, and if the detected signal is a digital satellite broadcast signal, the broadcast signal is satellite broadcast. It outputs to the path for signal processing.

That is, in the composite satellite broadcast reception system, when a user applies a signal for channel switching while watching a broadcast signal of a channel by the above-described detection process, the composite satellite broadcast reception system detects a broadcast signal of a channel to be switched and also provides a broadcast signal type. In addition, the satellite broadcast signal or the cable broadcast signal is discriminated and output to the broadcast signal processing circuit, and processed by the broadcast signal processing circuit to be provided on the TV screen.

In such a composite satellite broadcasting reception system, when a channel is selected, the selected channel information is stored in a memory. Therefore, when the previous channel selection key is pressed to view the previous channel of the currently viewed channel, the information of the previous channel stored in the memory is searched and the channel is switched by the retrieved channel information. At this time, if the previous channel is the same as the channel currently being watched, the channel switching can be performed by the channel switching method described above, but there is no problem in switching the channel if the previous channel is not the same as the channel currently being watched. This occurred.

In general, the method of detecting satellite broadcast signals is more difficult than the method of detecting general cable broadcast signals. In other words, the broadcasting signal carried on the predetermined channel is transmitted by varying the tuning frequency little by little. When the channel is switched from the conventional cable broadcasting to the satellite broadcasting For example, when the previous channel is the satellite broadcasting and the channel to be switched is the channel of the general cable broadcasting, since the satellite broadcasting is a digital broadcasting signal, the demodulation is properly performed when the tuning frequency is changed. Therefore, there is a problem that the channel switching is not made properly, so that the screen of a clean picture quality cannot be viewed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and an object of the present invention is to tune a complex satellite broadcast reception system to accurately switch channels when a previous channel is a satellite broadcast channel and a channel to be switched is a general cable broadcast channel. To provide a way.

In order to achieve the above object, the present invention provides a tuning method of a hybrid satellite broadcasting reception system for switching from a currently viewed channel to a previous channel, wherein a type of broadcast of the previous channel is applied when a key signal for switching to the previous channel is applied. Determining a first step; A second step of determining whether the broadcast determined in the first step is identical to the broadcast of the channel currently being viewed; A third step of performing automatic gain adjustment corresponding to the broadcast type of the previous channel if the broadcast determined in the first step and the broadcast of the currently viewed channel are not the same as a result of the determination of the second step; And a fourth step of switching to the previous channel by adjusting the tuning frequency according to the automatic gain adjustment of the third step.

1 is a block diagram of a composite satellite broadcast receiving system for performing a tuning method of the present invention;

2 is a detailed flowchart for performing a tuning method of a composite satellite broadcast reception system according to the present invention.

<Description of the symbols for the main parts of the drawings>

100: satellite broadcasting receiver 110: QAM modulator

120: trans modulator 130: tuner

140: control unit 150: key input unit

160: NTSC signal processing unit 170: satellite broadcasting signal processing unit

180, 190: switching unit

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 illustrating a configuration of a composite satellite broadcast reception system according to the present invention, and includes a satellite broadcast receiver 100, a QAM modulator 110, a transmodulator 120, a tuner 130, a controller 140, The key input unit 150, the NTSC signal processor 160, the satellite broadcast signal processor 170, and the switching units 180 and 190 are configured.

The satellite broadcast receiver 100 detects packet streams carried on a plurality of satellite broadcast carriers, and provides each detected packet stream to the QAM modulator 110.

The QAM modulator 110 performs QAM modulation on each packet stream provided from the satellite broadcast receiver 100 and provides the modulated packet to the transmodulator 120. The trans modulator 120 is provided with a general cable broadcast signal and a packet stream detected from the QAM modulator 110. That is, the transmodulator 120 QAM modulates a packet stream when it is input from the QAM modulator 110, allocates a channel to a general cable broadcast signal and a QAM modulated satellite broadcast signal, and then transmits it to the tuner 130. do.

At this time, the tuner 130 detects the broadcast signal of the corresponding channel from the broadcast signal input under the control of the controller 140. That is, the control unit 140 provides the control unit 140 with the key signal according to the channel selection from the user through the key input unit 150, and the control unit 140 transmits the tuning control signal to the tuner 130. To print. Accordingly, the tuner 130 detects a broadcast signal of a channel under the control of the controller 140, and thus the channel selected through the key input unit 150 among the broadcast signals of each channel transmitted from the transmodulator 120 through a cable. It detects only the signal of and provides it to the satellite broadcast signal processor 160 and the NTSC signal processor 170.

That is, when a key signal for switching from the user to the previous channel is input through the key input unit 150, the controller 140 determines the broadcast signal type of the previous channel, and switches the corresponding automatic gain adjustment switch 190. The tuner 130 is controlled to detect a channel according to the broadcast signal type. At this time, the automatic gain adjustment switch 190 is switched to the corresponding broadcast type terminal under the control of the control unit 140, and the tuner 130 is the gain of the tuning frequency varied according to the switching result of the automatic gain adjustment switch 190. The adjusted channel is detected, and the broadcast signal of the detected channel is output to the broadcast signal processor.

Here, the determination of the broadcast signal type for the channel to be switched, that is, the previous channel, is performed by the controller 140. The controller 140 stores the previous channel information and the channel information according to the type of the broadcast signal. The broadcast signal type of the channel is determined.

In addition, when the tuner 130 detects a broadcast signal of a detected channel, for example, a general cable broadcast signal, the corresponding signal is input to the NTSC signal processor 160, and when the detected signal is a satellite broadcast signal, the corresponding signal is satellite broadcast. It is input to the signal processor 170.

At this time, the satellite broadcast signal processing unit 170 QAM demodulates the satellite broadcast signal detected by the tuner 130 to detect the multiplexed packet stream, and a predetermined error correction algorithm, for example, a RS (Reed-Solomon) decoder After correcting the error of the packet stream based on the deinterleaving technique, the control unit 140 detects only the satellite broadcast signal of a predetermined channel from the packet stream, decodes it by MPEG decoding, converts it into an NTSC signal, and then switches the switching unit ( 180).

Meanwhile, the NTSC signal processor 160 converts the general cable broadcast signal detected by the tuner 130 into a baseband broadcast signal and provides it to the switching unit 180. In addition, the switching unit 180 is controlled by the control unit 140, and selects a general cable broadcasting signal from the NTSC signal processing unit 160 or a satellite broadcasting signal from the satellite broadcasting signal processing unit 170 and provides it to the TV. It works.

The control unit 140 controls the overall satellite broadcasting reception system. As described above, the control unit 140 controls the tuner 130 to automatically gain a plurality of channels so that a broadcast signal of a channel desired by the user can be detected. The switching operation of the adjustment switch 190 is controlled, the operations of the satellite broadcasting signal processing unit 170 and the NTSC signal processing unit 160 are controlled, and the switching operation of the switching unit 180 is controlled.

2 is a flowchart illustrating a tuning method of a composite satellite broadcast reception system according to the present invention. The operation of the flowchart shown in FIG. 2 is performed by the hybrid satellite broadcast reception system shown in FIG. 1, and a tuning method of the hybrid satellite broadcast reception system according to the present invention will be described with reference to FIGS. 1 and 2. .

The controller 140 determines whether a signal for the previous channel switching key is input from the key input unit 150 in the normal viewing mode (S1). As a result of the determination, when a signal for a previous channel switching key is input, a mode for searching for a broadcast type of a channel to be switched is performed (S3), and the control unit 140 broadcasts the broadcast type of the channel currently being viewed and the broadcast of the previous channel. Determine whether the types are the same.

That is, the controller 140 determines the broadcast type of the previous channel according to the previous channel switching key in step S2 from the channel information according to the broadcast type stored in the internal memory (not shown) (S4). As a result of the determination, if the broadcast type of the channel currently being watched is not the same as the broadcast type of the previous channel, for example, if the broadcast of the channel currently being viewed is a general cable broadcast and the broadcast of the previous channel is a satellite broadcast, the channel determined in step S3. Provide a switching control signal for switching the automatic gain adjustment switch 190 to correspond to the broadcast type of the broadcast broadcast, i.e., the above-mentioned broadcast signal (S5), and provide a tuning control signal for detecting a previous channel. It is provided to the tuner 130.

At this time, the automatic gain adjustment switch 190 is switched to a switching terminal according to a switching control signal provided from the controller 140, that is, a satellite broadcast signal terminal, and the tuner 130 is switched to the automatic gain adjustment switch 190. The previous channel is detected by adjusting a variable value of the tuning frequency according to the automatic gain adjustment according to the switching terminal, that is, the phase broadcast signal detection (S6). The broadcast signal of the detected channel is provided to the satellite broadcast signal processor 170.

Accordingly, the satellite broadcast signal processor 170 QAM demodulates the satellite broadcast signal detected by the tuner 130 to detect the multiplexed packet stream, and uses a predetermined error correction algorithm, for example, a Reed-Solomon (RS) decoder, After correcting the error of the packet stream based on the deinterleaving technique, the control unit 140 detects only a satellite broadcast signal of a predetermined channel from the packet stream, decodes the signal by MPEG decoding, converts it into an NTSC signal, and then switches the unit 180. ) And the switching unit 190 selects a corresponding broadcast signal under the control of the control unit 140 and provides it to the TV.

As described above, in the method of the present invention, when switching from a channel currently being viewed to a previous channel, the channel is detected by adjusting a tuning frequency that is varied and transmitted by automatic gain adjustment corresponding to the type of broadcast signal of the previous channel. If you switch to a channel with a different broadcast type, you can watch the screen with clear image quality.

Claims (1)

In the tuning method of the composite satellite broadcast reception system to switch from the current channel to the previous channel, Determining a broadcasting type of the previous channel when a key signal for switching to the previous channel is applied; A second step of determining whether the broadcast determined in the first step is identical to the broadcast of the channel currently being viewed; A third step of performing automatic gain adjustment corresponding to the broadcast type of the previous channel if the broadcast determined in the first step and the broadcast of the currently viewed channel are not the same as a result of the determination of the second step; And a fourth step of switching to the previous channel by adjusting a tuning frequency according to the automatic gain adjustment of the third step.