KR20000021872A - Method for automatically searching channels of reception system in broadcast satellite - Google Patents

Abstract

PURPOSE: A method for automatically searching channels is provided to exactly distinguish available channels, when searching channels in a broadcast satellite system. CONSTITUTION: A method for automatically searching channels of a reception system in a broadcast satellite, comprises the steps of: detecting each channel by raising tuning frequency of the each channel in order, from a broadcast signal of the lowest channel among transmitted channel through a cable, when a key for detecting broadcast signals of predetermined channels is pressed; deciding whether NTSC(National Television System Committee) signals are inputted; storing channels which the NTSC signals are inputted after deciding the channels as available channels; deciding whether a channel which is currently detected is the last channel; and finishing the channel detecting when the channel which is currently detected is the last channel.

Description

Automatic Channel Detection Method for Complex Satellite Broadcasting System

The present invention relates to a composite satellite broadcasting receiving system capable of receiving both a satellite broadcasting channel and a cable broadcasting channel, and more particularly, to a channel automatic searching method of a composite satellite broadcasting receiving system for automatically searching for an effective channel among cable broadcasting channels. .

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 second 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. have. 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.

At this time, the cable broadcast, that is, the search for the NTSC channel is searched according to the determination of the effective channel according to the number of sync signals. When the channel search key is pressed by the user, the user tunes and separates the sync signal from the tuned broadcast signal. To count the number. At this time, if the number of counted synchronization signals is the number according to the effective channel determination, it is determined to be an effective channel and stored as an effective channel for the currently tuned channel. Tuning is performed on the channel, and the determination of whether this is a valid channel is performed continuously until the last channel.

However, as described above, a method of determining an effective channel by counting the number of synchronization signals does not provide accurate timing in counting synchronization signals, or a channel that does not have accurate synchronization separation due to high noise. The accuracy of valid channel determination is reduced because the number of accurate synchronization signals is not counted, and the system load occurs as the synchronization signals are counted.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a channel automatic search method of a composite satellite broadcasting system for more accurate determination of an effective channel during channel search.

In order to achieve the above object, the present invention allocates a channel to a plurality of satellite broadcasts and a plurality of cable broadcasts and transmits them through a cable, and receives a composite satellite broadcast to detect only a broadcast signal of a predetermined channel among the broadcast signals on the cable. A channel automatic search method of a system, comprising: when a key for detecting only a broadcast signal of a predetermined channel is pressed, a tuning frequency of each channel is sequentially sequentially from the broadcast signal of the lowest channel among the broadcast signals of each channel transmitted through the cable; A first step of detecting each channel while going up; Determining whether an NTSC signal is input while detecting the channel; A third step of judging and storing the channel into which the NTSC signal is input as a valid channel as a result of the determination of the second step; Determining whether the channel currently being detected is the last channel; And a fifth step of terminating the channel detection of the first step if the channel currently being detected is the last channel.

1 is a block diagram of a composite satellite broadcast reception system for performing a channel automatic search method of the present invention;

2 is a detailed flowchart illustrating a preferred embodiment of the channel auto-discovery method of the present invention.

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

100: satellite broadcasting receiver 110: QAM modulator

120: trans modulator 130: tuner

140: control unit 150: key input unit

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

180: NTSC signal detection unit 190: switching 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 hybrid satellite broadcast reception system for performing the channel automatic search method of the present invention, the satellite broadcast receiver 100, QAM modulator 110, transmodulator 120, tuner 130, control unit 140, a key input unit 150, a satellite broadcast signal processing unit 160, an NTSC signal processing unit 170, an NTSC signal detection unit 180, and a switching unit 190.

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 a broadcast signal of a corresponding channel 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 broadcast channel search from the user through the key input unit 150, and the control unit 140 transmits the tuning control signal according to the tuner 130. Will output 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 the signal detected by the tuner 120 is, for example, a general cable broadcast signal, the signal is input to the NTSC signal processor 170, and when the detected signal is a satellite broadcast signal, the corresponding signal is a satellite broadcast signal processor ( 160).

At this time, the satellite broadcast signal processor 160 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 ( 190).

Meanwhile, the NTSC signal processor 170 converts the general cable broadcast signal detected by the tuner 120 into a baseband broadcast signal and provides it to the switching unit 190.

The NTSC signal detector 180 determines whether the NTSC signal is detected from the NTSC signal processor 170, that is, whether a synchronization signal according to the NTSC signal processing is detected, and provides the resultant signal to the controller 140. For example, when the NTSC signal processor 170 detects an NTSC signal, the NTSC signal detector 180 provides a high level logic signal to the controller 140, and when the NTSC signal processor 170 does not detect the NTSC signal. The low level logic signal is provided to the controller 140.

At this time, the controller 140 determines whether to store channel information currently detected according to a logic signal provided from the NTSC signal detector 180. That is, when it is determined that the NTSC signal is detected, the controller 140 determines that the channel being detected is a valid channel, and stores channel information currently detected. If the NTSC signal is not detected, the controller 140 determines that the channel being detected is not a valid channel. Do not store channel information.

The switching unit 190 is controlled by the control unit 140 and selects and provides a general cable broadcast signal from the NTSC signal processor 170 or a satellite broadcast signal from the satellite broadcast signal processor 160 to the TV. Do it.

In addition, the control unit 140 functions to control the overall satellite broadcasting reception system. As can be seen, the control unit 140 controls the tuner 130 to detect a broadcast signal of a predetermined channel, and the satellite broadcast signal processing unit. The operation of the 160 and the NTSC signal processing unit 170 is controlled, and the switching operation of the switching unit 190 is controlled.

FIG. 2 is a detailed flowchart for performing a channel automatic search method of a composite satellite broadcast reception system according to the present invention, which is executed by the composite satellite broadcast reception system shown in FIG. 1. A method of automatically searching for a channel of a composite satellite broadcast reception system according to a preferred embodiment of the present invention will be described with reference to FIG.

First, when the signal for the channel search key is input through the key input unit 150 in the normal viewing mode (S1), the controller 140 outputs a control signal for performing the channel search mode (S2). That is, when a signal for the channel search key is input, the controller 140 provides a control signal to the tuner 130 to tune a channel corresponding to the input channel search key, and the tuner 130 sequentially processes the channels. By varying the tuning frequency, only the corresponding broadcast signal under the control of the controller 140 is detected (S3) and provided to the satellite broadcast signal processor 160 and the NTSC signal processor 170.

At this time, when the detection of the NTSC signal is determined, the control unit 140 is that the broadcast signal detected by the tuner 130 is an NTSC broadcast signal, and thus is processed by the NTSC signal processing unit 170 and through the NTSC signal detection unit 180. If an NTSC signal is detected (S4), it is determined to be a valid channel, and the channel information is stored in a memory (not shown) (S5). If an NTSC signal is not detected, it is not a valid channel. Detect the broadcast channel.

The controller 140 performs the detection process up to the last channel (S6) and stores the channel information when the NTSC signal is detected, but does not store the channel for which the NTSC signal is not detected. When the channel search process is performed to the last channel, the controller 140 completes the channel search (S7) and switches to the normal viewing mode.

As described above, according to the present invention, when the channel is searched, the channel is determined to be an effective channel only for the channel where the NTSC signal is detected and stored, thereby reducing the system load and performing an accurate channel search.

Claims (1)

In the channel automatic search method of a composite satellite broadcast receiving system for allocating a channel to a plurality of satellite broadcasts and a plurality of cable broadcasts and transmitting through a cable, and detects only a broadcast signal of a predetermined channel of each broadcast signal on the cable: When a key for detecting only the broadcast signal of the predetermined channel is pressed, the first channel detects each channel while sequentially increasing the tuning frequency of each channel from the broadcast signal of the lowest channel among the broadcast signals of each channel transmitted through the cable. step; Determining whether an NTSC signal is input while detecting the channel; A third step of judging and storing the channel into which the NTSC signal is input as a valid channel as a result of the determination of the second step; Determining whether the channel currently being detected is the last channel; And a fifth step of terminating the channel detection of the first step if the currently detected channel is the last channel.