KR19990070246A - Broadcast receiver on cable TV subscriber - Google Patents

Abstract

The present invention relates to a cable television capable of receiving satellite broadcasting, and in particular, to provide a broadcast receiving apparatus on the cable television subscriber side that can accommodate the received digital satellite broadcasting signal to the subscriber in a digital form. It is for. A broadcast receiving apparatus on the cable television subscriber side according to the present invention comprises: a tuner unit capable of receiving new media broadcasts transmitted from the cable television provider side; A demodulation section configured to demodulate a broadcast signal modulated by the quadrature amplitude modulation from the tuner section; A demultiplexer for transmitting only video and audio signals of a channel desired by a subscriber among demodulated and outputted broadcast signals; A signal processor for MPEG-decoding and transmitting video and audio signals output from the demultiplexer; A decoding module for converting the intermediate frequency of cable television broadcasting or terrestrial broadcasting from the tuner into a broadcasting scheme set in the television receiver of the subscriber; And a switch for selectively transmitting the video and audio signals output from the decoding module and the video and audio signals output from the signal processor to the television receiver of the subscriber according to the channel information designated by the subscriber. Thus, even in the case of public hearing, the subscriber can receive all channels of satellite broadcasting and can accommodate services such as CA.

Description

Broadcast receiver on cable TV subscriber

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable television capable of receiving satellite broadcasts (hereinafter referred to as CATV), and more particularly, to a broadcast receiving apparatus of a cable television subscriber side implemented to receive digital satellite broadcasts transmitted from a cable television provider. It is about.

Early CATV was implemented to provide only analog CATV broadcasting and off-air broadcasting to subscriber's TV receiver. However, with the advent of digital satellite broadcasting, CATV service providers are equipped with analog / digital satellite broadcasting receivers in addition to existing broadcasting receivers and transmitters to provide new media broadcasting combining CATV / terrestrial / satellite broadcasting through subscriber's cable. It came to offer by TV receiver.

FIG. 1 is a schematic block diagram of a conventional cable television system for providing subscribers with the above-mentioned new media broadcasting. The CATV service office 100 has one analog / one antenna per antenna 101, 102, and 103. Referring to FIG. Digital satellite broadcast receivers (111, 112, 113) are connected to receive a program transmitted through satellite broadcast. At this time, the analog / digital satellite broadcasting receivers 111, 112, and 113 for each channel are fixedly operated to receive only one channel of satellite broadcasting. Each of the analog / digital satellite broadcast receivers 111, 112, and 113 modulates and decodes the received digital satellite broadcast signal to output a baseband video signal and an analog audio signal (A / V) signal. Here, the baseband video signal means a video signal before modulation. The A / V signals output from the analog / digital satellite broadcasting receivers 111, 112, and 113 are transmitted to the RF modulator 120.

When the A / V signal is transmitted from each analog / digital satellite broadcasting receiver (111, 112, 113), the RF modulator 120 performs up-converting to the channel designated by the operator and outputs the existing analog CATV. Broadcast and terrestrial broadcasts are output as they are. The new media broadcast output from the RF modulator 120 is transmitted to the TV receivers 151, 152, and 153 of the subscribers provided in each home through the existing analog cable.

However, the existing CATV is implemented so that the CATV service provider can operate one satellite broadcasting receiver for one channel for each channel. Therefore, channel waste is severe and limited reception is achieved by demodulating and transmitting the received digital satellite broadcasting signal as an analog signal. There is a disadvantage in that it is difficult to accommodate services such as a system (Conditional Access System, hereinafter referred to as CAS). In order to solve this problem, CATV operators are currently developing technologies for transmitting new media broadcasting signals to subscribers utilizing the advantages of digital satellite broadcasting signals received from broadcasting stations.

SUMMARY OF THE INVENTION The present invention has been made in accordance with the above-described trend, and an object thereof is to provide a broadcast receiving apparatus on the cable television subscriber side capable of receiving the new media broadcast as described above transmitted from the cable television provider side.

In order to achieve the above object, the broadcast receiving apparatus on the cable television subscriber side according to the present invention is a new media mixed with digital satellite broadcasting, analog cable television broadcasting and terrestrial broadcasting digitalized from the operator side of the cable television capable of receiving satellite broadcasting signals. A cable television configured to transmit a broadcast to a subscriber's television receiver, comprising: a tuner unit for tuning a broadcast of a channel desired by the subscriber when new media broadcasting is applied; A demodulation unit for demodulating the quadrature amplitude modulated signal while outputting a signal for automatically adjusting the gain of the tuner unit when the quadrature amplitude modulated signal is output from the tuner unit; A demultiplexer for selecting and transmitting only video and audio signals of a channel designated by a subscriber among signals output from the demodulator; A signal processor for MPEG decoding the video and audio signals output from the demultiplexer, converting the video and audio signals into video and audio signals suitable for the broadcasting method set in the television receiver of the subscriber and outputting the video and audio signals; A decoding module for outputting a signal for automatically adjusting the gain of the tuner section when the intermediate frequency of the cable television or the terrestrial wave is output from the tuner section, converting the video and audio signals suitable for the broadcasting scheme set in the television receiver of the subscriber and outputting the signal; An automatic gain control switch for selectively transmitting the automatic gain control signal output from the demodulator and the decoding module to the tuner unit; And an audio and video switch for selectively outputting the video and audio signals output from the signal processor and the video and audio signals output from the decoding module to the television receiver of the subscriber.

1 is a functional block diagram of a cable TV capable of receiving conventional satellite broadcasting,

2 is a functional block diagram of a cable TV with a broadcast receiving apparatus according to the present invention;

3 is a detailed block diagram of the set-top box shown in FIG.

Explanation of symbols for main parts of the drawings

200: Cable TV operator side (SO) 201: Signal conversion and generator

210: cable TV subscriber side (HOME) 211, 212: broadcasting receiver

213 and 214: TV receiver 301: Tuner part

302: decoding module 303: AGC switch

304: QAM demodulator 305, 307, 309: Memory

306: demultiplexer 308: MPEG decoder

310: video decoder

311: Audio digital / analog converter 312: A / V switch

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a functional block diagram of a CATV having a broadcast receiving apparatus at the subscriber side of the CATV according to the present invention, which can transmit satellite broadcasts received through an antenna using a quadrature amplitude modulation scheme. CATV operator side (SO) 200 having a signal conversion and generator 201 that modulates a digital signal having a frequency band and generates a new media broadcast mixed with a modulated satellite broadcast signal and an existing analog CATV and terrestrial broadcast. And, broadcast receiving apparatuses for receiving new media broadcasts transmitted from the CATV operator side 200 through the cable with the existing TV receivers 213 and 214 and transmitting them to the corresponding TV receivers 213 and 214 ( CATV subscriber side (HOME) 210 consisting of 211, 212.

FIG. 3 is a detailed block diagram of the broadcast receiving apparatuses 211 and 212 according to the present invention shown in FIG. 2 and includes a tuner unit 301, a decoding module 302, an AGC switch 303, and a QAM demodulator 304. ), Memories 305, 307, 309, demultiplexer 306, MPEG decoder 308, video decoder 310, audio digital analog converter (hereinafter referred to as DAC) 311, and A / V switch 312.

The operation of the broadcast receiving apparatus configured as described above is as follows.

First of all, new media broadcasting transmitted from CATV service provider is a combination of satellite broadcasting with QAM-modulated digital data format and CATV broadcasting and terrestrial broadcasting with same analog data format (satellite broadcasting / CATV / OFF-Air). it means. When such new media broadcasting is applied through a cable, the broadcast receiving apparatuses 211 and 212 transmit to the tuner unit 301.

The tuner 301 is configured to receive not only an analog broadcast signal but also a digital broadcast signal, and outputs a signal tuned to a broadcast that a subscriber wants to receive by a tuning control signal provided by a controller (not shown). At this time, in the case where the broadcast that the subscriber intends to receive is satellite broadcasting, the tuner unit 301 outputs a QAM signal having a 6 MHz frequency band, and outputs an intermediate frequency (IF) in the case of CATV or terrestrial broadcasting.

When the QAM signal is output from the tuner unit 301, the output QAM signal is transmitted to the QAM demodulator 304. The QAM demodulator 304 demodulates the applied QAM signal and restores it to a signal having a frequency band before QAM (24 MHz) and outputs it. In this restoration process, the QAM demodulator 304 outputs a DC level signal for automatic gain control (hereinafter abbreviated AGC) for the tuner unit 301. The output signal is transmitted to the AGC switch 303.

The AGC switch 303 selectively transmits DC levels output from the QAM demodulator 340 and the decoding module 302 to be described later to automatically control the gain of the tuner 301 to the tuner 301. Play a role. In order to perform such a role, the AGC switch 303 is controlled by a controller not shown. The controller (not shown) outputs a signal for controlling the AGC switch 303 to transmit the DC level output from the QAM demodulator 304 to the tuner unit 301 when the channel selected by the subscriber is a satellite broadcasting channel. In the case of a terrestrial broadcast channel, the AGC switch 303 outputs a signal for controlling to select the DC level output from the decoding module 302 to be described later and transmit it to the tuner unit 301.

The memory 305 stores condition information necessary for demodulation in the QAM demodulator 304 and provides the information according to the request of the QAM demodulator 304.

The demodulated broadcast signal output from the QAM demodulator 304 is transmitted to the demultiplexer 306. The demultiplexer 306 selects and outputs a video and audio signal of a corresponding channel among the digital satellite broadcast signals transmitted from the QAM demodulation unit 304 according to channel information output from a controller (not shown) according to a channel designation of a corresponding subscriber. The memory 307 is used for storing the broadcast signal transmitted from the QAM demodulator 304 in the operation of the demultiplexer 306.

The satellite broadcast output from the demultiplexer 306 is transmitted to the MPEG decoder 308 to output MPEG decoded video and audio signals, respectively. The output video signal is transmitted from the video signal processor 310 to be converted into a broadcasting method used in the corresponding TV receiver and output. The audio DAC 311 converts an audio signal output from the MPEG decoder 308 into an analog signal and outputs the analog signal.

The video and audio signals respectively output from the video signal processor 310 and the audio DAC 311 are transmitted to the A / V switch 312.

The A / V switch 312 is switched by a control signal applied from a control unit (not shown) and is transmitted from a video and audio signal transmitted from the video decoder 310 and the audio DAC 311 or the decoding module 302 to be described later. Output video and audio signals selectively. The output video and audio signals are transmitted to the corresponding TV receivers 213 or 214, respectively.

On the other hand, when the intermediate frequency of the CATV or terrestrial broadcast is output from the tuner 301 by the tuning control signal applied from the control unit (not shown), it is transmitted to the decoding module 302. When the intermediate frequency of the broadcast received from the tuner unit 301 is applied, the decoding module 302 outputs a video and audio signal converted into a broadcast signal suitable for the broadcast method set in the TV receiver 213 or 214. . The output video and audio signals are output to the A / V switch 312. At this time, the A / V switch 312 is operated to select and transmit the video and audio signals transmitted from the decoding module 302 by the control signal applied from the controller (not shown).

In addition, the decoding module 302 transmits the DC level signal output through the AGC circuit (not shown) provided in the self-controlling unit to the AGC switch 303 to automatically control the gain of the tuner unit 301. At this time, the AGC switch 303 is controlled by a controller (not shown) to operate the DC level applied from the decoding module 302 to the tuner unit 301.

As described above, the present invention provides a cable TV subscriber side with a broadcast receiver capable of receiving new media broadcasting (digitalized satellite broadcasting + CATV broadcasting + terrestrial broadcasting) transmitted to the cable TV provider side, thereby providing all the satellite broadcasting. By making the channel available to subscribers, channel waste can be prevented, and digital broadcasting can be received on the subscriber side as it is, so it is easy to introduce services such as a CA.

Claims (1)

A cable television configured to transmit, to a subscriber's television receiver, a new media broadcast, which is a combination of digitalized satellite broadcasting, analog cable television broadcasting, and terrestrial broadcasting, from a provider of a cable television capable of receiving satellite broadcasting signals. A tuner unit configured to tune a broadcast of a channel desired by the subscriber when the new media broadcast is applied; A demodulator for demodulating the quadrature amplitude modulated signal when the quadrature amplitude modulated signal is output from the tuner unit, while outputting a signal for automatically adjusting the gain of the tuner unit; A demultiplexer which selects and transmits only a video and audio signal of a channel designated by the child care unit from the signal output from the demodulator; A signal processor which MPEG-decodes the video and audio signals output from the demultiplexer, converts the video and audio signals into video and audio signals suitable for the broadcasting system set in the television receiver of the subscriber and outputs the converted video and audio signals; When the intermediate frequency of the cable television or terrestrial wave is output from the tuner unit, the decoding module outputs a signal for automatically adjusting the gain of the tuner unit and converts it into a video and audio signal suitable for the broadcasting method set in the television receiver of the subscriber. ; An automatic gain control switch for selectively transmitting the automatic gain control signal output from the demodulator and the decoding module to the tuner unit; And And an audio and video switch for selectively outputting the video and audio signals output from the signal processor and the video and audio signals output from the decoding module to the television receiver of the subscriber. Receiver.