KR0168933B1 - Optic spliter of a low price video network - Google Patents

Abstract

The present invention is multiplexed to 155.520Mb / s after digital switching in a video network, and the multiplexed data is transmitted through an optical transmission to broadcast TV programs, video-on-demand video services, and telephone network services by using an extra telephone line in a telephone box near the subscriber. It is an object of the present invention to provide an optical terminator in a low-cost video network that can be provided. To achieve the above object, an optical signal including multiplexed communication and video and clock signals from an image distribution center 3 of a network is provided. An optical transmitter 41 for converting the digital signal into a digital signal, and converting the multiplexed communication signal from the subscriber side into an optical signal and outputting the optical signal to an image distribution center 3 of the network; and the optical transmitter 41 Demultiplexes and outputs digital signals from subscribers, and multiplexes and frames communication data from subscribers And modulating the signals from the channel multiplexing (MUX) and demultiplexing (DMX) device 46 and the channel multiplexing and demultiplexing device 46, which are configured and provided to the optical transmission device 41, to the subscriber side. And a plurality of high frequency modulation / demodulation devices 44 which transmit and demodulate analog signals from the subscriber side into digital signals and provide them to the channel multiplexing and demultiplexing device 46.

Description

Fiber Terminators for Low Cost Video Networks

1 is an overall configuration diagram of a low cost video network to which the present invention is applied.

2 is a schematic diagram of a low-cost video network that handles telephone and narrowband general information services.

3 is a system structure diagram of a low-cost video network that processes broadcast TV program services.

4 is a schematic diagram of a low-cost video network that handles on-demand video program services.

5 is a configuration diagram of a channel MUX and a channel DMX type custom semiconductor according to the present invention.

6 is a detailed configuration diagram of an optical terminator according to the present invention.

* Explanation of symbols for main parts of the drawings

41: 155M optical transmission device 44: High frequency modulation / demodulation device

45: Channel Multiplexing (MUX) / Channel Demultiplexing (DMX) Device

46: power inverter

The present invention relates to an optical terminal of a subscriber access network applied to a low-cost video network system capable of providing on-demand video programs and broadcast-type TV programs required by viewing menus displayed on a TV receiver in a subscriber premises.

The function of the optical terminator in the conventional analog coaxial CATV system simply converts the analog optical signal into an analog signal and transmits it through a coaxial cable. Could not provide other digital services due to the limited speed. After the subscriber access network is transmitted by optical cable to the optical terminator, the technology of using the telephone line in the premises has not been developed yet.

Thus, the present invention is multiplexed to 155.520 Mb / s after digital switching in a video network, and the multiplexed data is broadcast-type TV program, video-on-demand video service and telephone network by using an extra telephone line in a telephone box near the subscriber via optical transmission. Its purpose is to provide optical terminators in low-cost video networks that can provide services.

In order to achieve the above object, the present invention converts and outputs an optical signal including multiplexed communication and video and clock signals from an image distribution center of a network to an electrical digital signal, and outputs the multiplexed communication signal from the subscriber side. An optical transmission device that converts a signal to an image distribution center of the network and demultiplexes and outputs a digital signal from the optical transmission device, and multiplexes and frames the communication data from subscribers to the optical transmission device. A channel multiplexing (MUX) and demultiplexing (DMX) device and a signal from the channel multiplexing and demultiplexing device are modulated into an analog signal and transmitted to a subscriber, and the analog signal from the subscriber is demodulated into a digital signal. Multiple high frequency modulation / demodulation fields provided by channel multiplexing and demultiplexing devices And a.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

1 is an overall configuration diagram of a low cost video network to which the present invention is applied.

As shown in the drawing, a low-cost video network to which the present invention is applied is connected to a telephone network 1 and a head-end device 2 to receive telephone service, narrowband comprehensive information service, and TV broadcast service information, and distribute the information to a desired subscriber. And a video distribution center 3 having a plurality of video programs embedded therein and provided according to a subscriber's request signal, and an optical terminator connected to the video distribution center through an optical cable to perform an interface with the subscriber side. 4) and connected to the optical terminator 4 through a telephone line to supply the corresponding service information to the ISDN terminal, the telephone and the TV receiver in the subscriber's home, and transmit the service request signal of the subscriber side to the optical terminator 4 side. A subscriber premises 5 was provided.

In addition, the video distribution center 3 uses a PSTN / ISDN matching unit 31 for interfacing the telephone and narrowband comprehensive information service with the telephone network 1, and a network synchronizer clock through the PSTN / ISDN matching unit 31. A network synchronizer 32 for receiving and generating a system clock, a communication channel mapper / demapper 33 for mapping / demapping a signal exchanged with the PSTN / ISDN matching unit 31, and the communication channel A communication multiplexer (MUX) 310 for multiplexing and outputting information through the mapper / demapper 33 and the communication channel information from the subscriber side are demultiplexed and provided to the communication channel mapper / demapper 33. 2.5 Gbps class that receives and outputs a communication channel demultiplexer (DMX) 39 and TV signals and video program signals from the head end 2 and transmits new program registration signals on the subscriber side to the head end 2. The optical transmission device 34 and the new program registration request signal from the subscriber A network management and maintenance device 36 for receiving and transmitting the 2.5 Gbps optical transmission device 34, and a transmission DMX 35 for demultiplexing and outputting the output from the 2.5 Gbps optical transmission device 34; And a video server 39 that receives and stores video program information during output of the transmission DMX 35, and provides a TV signal and a video signal of the video server 39 during output of the transmission DMX 35. A plurality of channel MUXs 311 for multiplexing and outputting the space division switch 314 for switching and transmitting the communication information from the communication MUX 310 and the image information from the space division switch 314, and the subscriber side. Demultiplexing the communication information of the multiple channel DMX (312) for transmitting to the communication DMX (39), and the output of the channel MUX (311) is converted into an optical signal to the subscriber side through the optical cable, from the subscriber side It converts optical communication information into an electric signal and uses channel DMX ( A plurality of 155 Mbps optical transmitters 313, the communication channel mapper / demapper 33, the video server 37, and the spatial partition switch 314, which are transmitted to the subscriber station, are controlled. The control unit 38 provides a communication operation signal to the communication MUX 310 and receives a new program request signal from the subscriber through the communication DMX 39 and provides the communication management signal to the network management and maintenance device 36. .

Further, each optical terminator 4 is a 155 Mbps optical transmitter in optical terminator 1 (4) which communicates one-to-one with the 155M optical transmitter 313 in the image distribution center 3 via an optical cable ( 41) and the channel DMX 42 for demultiplexing and outputting the signal output from the 155M optical transmission device 41, and outputting the signal of the channel DMX 42 to the subscriber's telephone line by performing high frequency modulation. A plurality of high frequency demodulation / demodulation devices 44 for demodulating and outputting signals from the plurality of signals, and a channel MUX for multiplexing subscriber-side signals through the high frequency modulation / demodulation device 44 and outputting them to the 155M optical transmission device 41. 43 is provided.

In addition, each subscriber premises 5 is connected one-to-one with the high frequency modulation / demodulation device 51 in the optical terminator 4 through a telephone line to demodulate and provide a signal from the optical terminator 4 side. And a high frequency modulation / demodulation device 51 for modulating and transmitting a signal at the subscriber side to the optical terminator 4, and a channel matching device for interfacing signals between the high frequency modulation / demodulation device 51 and the subscriber telephone and the ISDN terminal. And a set top 35 which modulates the digital program data demodulated by the high frequency modulation / demodulation device 51 into an analog signal of an NTSC signal and provides it to a subscriber's TV receiver.

Meanwhile, in the network according to the present invention, up to M 155 Mbps optical transmission devices 313 in the image distribution center 3 are connected to 155 Mbps optical transmission devices 41 in the optical terminator 4 by one-to-one optical cable. In the optical terminal 4, up to N subscriber premises devices are connected by one-to-one telephone line. Accordingly, the video distribution center 3 may expand the subscriber premises 5 to MN (MxN).

Here, the video distribution center 3 is located in the telephone company, and remotely installs up to M optical terminators 4 remotely with optical cables, and the power required by the optical terminators 4 is a power supply device of the video distribution center. At 315 is supplied to the power conversion device 45 of the optical terminator 4 directly with the optical cable. The optical terminal 4 is located near the subscriber's single or multi-unit residential area, and is directly connected to the subscriber's home device 5 located at a short distance by a telephone line from the high frequency modulator / demodulator 44 within the optical terminal 4. It is possible to simultaneously receive narrowband comprehensive information service (ISDN), and through the TV receiver, it is possible to receive a reception service by selecting one program among K broadcast TV programs or on-demand video provided by the video server 37. One program can be selected from among L programs to receive a reception service.

A low-cost video network to which the present invention for processing such services is applied will be described in detail with reference to FIGS. 2 to 4 for each system structure for processing the service.

2 is a structural diagram of a low-cost video network for simultaneously processing a telephone and narrowband comprehensive information service.

The service channels (hereinafter referred to as communication channels) received from the telephone network 1 located in the same telephone company to the Public Services Telecommunication Network (PSTN) / Integrated Services Data Network (ISDN) matching unit 31 are referred to as communication channel mappers and demappers. 33 is delivered to the device. The communication channels are semi-permanently exchanged and connected to the subscriber indoor device 5 of the corresponding subscriber upon receiving the command of the control device 38, and through the output of the communication channel mapper / demapper 33, the communication multiplexing (MUX) device 310 Is entered. The communication MUX device 310 serves to multiplex a communication channel together with a request signal for selecting a broadcast TV or an on-demand video program. The channel MUX device 311 is a device that multiplexes the video data of the switched program and the signal output from the communication MUX device 310.

The communication DMX (demultiplexing) device 39 has a demultiplexing function to perform the reverse function of the communication MUX device 310, and the channel DMX 312 has a demultiplexing function to perform the opposite function of the channel MUX 311. Have When the communication channel for the telephone and narrowband comprehensive information service output from the communication MUX 310 is input to the channel MUX 311, and the output of the channel MUX 311 is transmitted to the 155M optical transmission device 311, an electrical signal is transmitted to the optical signal. Is converted to. The communication channel converted to the optical signal is transmitted to the 155M optical transmission device 41 in the optical terminal 4 via the optical cable.

The communication channel shown at the output end of the 155M optical transmission of the optical terminator 4 is demultiplexed in the channel DMX 42, and the demultiplexed communication channel is modulated with an analog signal by the digital data in the high frequency modulation / demodulation device 44, thereby making a general telephone line. It is delivered to the subscriber premises (5) through.

The high frequency modulation / demodulation device 51 of the subscriber indoor device 5 demodulates the analog signal via the telephone line into digital data and outputs it to the channel matching device 52. Here, the communication channel input to the channel matching device 52 is divided into a telephone channel and a narrowband synthesis information channel, and the separated channels are respectively input to the telephone and the ISDN terminal.

The channels output from the telephone and the ISDN terminal are input to the channel matching device 52 again, and the digital data combined into the communication channel is modulated into an analog signal by the high frequency modulator / demodulator 51. The communication channel modulated with the analog signal is transmitted to the high frequency modulator / demodulator 44 of the optical terminator 4 via a telephone line. Here again, the communication channel of the analog signal is converted into digital data, input to the channel MUX device 43, and multiplexed. In the multiplexed communication channel, electrical digital data is transmitted from the 155M optical transmission device 41 to the image distribution center 3 through the optical cable as a digital optical signal.

The communication channel converted by the 155M optical transmitter 313 of the image distribution center 3 into an electrical signal is input to the communication channel mapper / demapper 33 via the channel DMX 312 and the communication DMX 39. In this case, in order to confirm that the corresponding subscriber is transmitted as an HDB3 signal through the PSTN / ISDN matching unit 31 according to a confirmation command of the control unit 38, it is inputted to an electronic switchboard (not shown) of the telephone network 1. .

FIG. 3 is a schematic diagram of a low-cost video network that processes a TV program when a subscriber home device views a menu of a TV receiver and selects a channel to watch from among K broadcast TV programs.

When the subscriber applies for a channel of a broadcast type TV program to be watched, the set top 53 transmits a program selection signal (hereinafter referred to as a request signal) to the high frequency modulation / demodulation device 51, and the high frequency modulation / demodulation device ( In 51), digital data is modulated into an analog signal and then transmitted to the optical terminator 4 via a telephone line. The analog request signal received by the optical terminator 4 is demodulated back to digital data by the high frequency modulation / demodulation device 44, multiplexed together with the communication channel described above by the channel MUX device 43, and sent to the 155M optical transmission device 41. Is entered. The electrical request signal is then converted into an optical signal and input to the 155M optical transmission device 313 of the image distribution center 3 via the optical cable.

The request signal input to the 155M optical transmission device 313 of the image distribution center 3 as an optical signal is converted into an electrical signal and transmitted to the channel DMX 312. In the channel DMX device 312, the communication channel and the request signal are demultiplexed and input to the communication DMX 39. The input communication channel and the request signal are separated from each other while being demultiplexed in the communication DMX device 39. The separated request signal is transmitted to the control device 39, and the control device 38 transmits a command to the space division switch device 314 to switch the broadcast type TV program requested by the subscriber. At this time, K broadcast programs are multiplexed and received from the headend device 2 through the 2.5G optical transmission device 34, and the program K demultiplexed from the transmission DMX device 35 and input to the space division switch 314. The program according to the request command requested by the subscriber is switched to the corresponding output terminal of the space division switch 314. Therefore, the switched TV program is multiplexed together with the communication channel in the channel MUX 311 device, and the multiplexed TV program is converted into an optical signal by the 155M optical transmission device 313 to the optical terminator 4 through the optical cable. Is sent.

The program input to the 155M optical transmission device 41 of the optical terminator 4 is converted into an electrical signal, the converted subscriber request TV program is demultiplexed in the channel DMX 42 device, and the demultiplexed program is a high frequency modulation / demodulation. The device 44 is modulated from the digital data into an analog signal. The modulated TV program is delivered to the subscriber premises 5 via the telephone line, and the selected TV program is demodulated back to digital data in the high frequency modulation / demodulation device 51 of the subscriber premises. The digital data of the demodulated program is transmitted to the TV receiver after being modulated from the digital data into an analog signal of the NTSC signal in the set-top device 53. Eventually, the subscriber can watch the broadcast-type TV program.

FIG. 4 is a schematic structural diagram of a low-cost video network in which a video program is serviced when a subscriber home apparatus 5 views a menu of a TV receiver and selects a channel to be watched from among L on-demand video programs stored in the video server 37. .

When a subscriber applies for a channel of an on-demand video program to be watched, a program selection signal (hereinafter referred to as a request signal) is set on the set top 53 and then modulated from digital data to an analog signal by the high frequency modulation / demodulation device 51. It is transmitted to the optical terminal 4 through the telephone line. The analog request signal received by the optical terminator 4 is demodulated back into digital data by the high frequency modulation / demodulation device 44, multiplexed together with the aforementioned communication channel by the channel MUX device 43, and the 155M optical transmission device 41. Is entered. The electrical request signal is converted into an optical signal and input to the 155M optical transmission device 313 of the image distribution center 3 through the optical cable.

The request signal inputted to the 155M optical transmission device 313 of the image splitter 3 as an optical signal is converted into an electrical signal and transmitted to the channel DMX 312. In the channel DMX device 312, the communication channel and the request signal are demultiplexed and input to the communication DMX 39. The input communication channel and the request signal are separated from each other while being demultiplexed in the communication DMX device 39. The separated request signal is transmitted to the control device 38, and the control device 38 transmits a command to the space division switch device 314 to switch the on-demand video program requested by the subscriber, and simultaneously to the video server 37. Pass the command.

At this time, L video programs stored in the video server 37 are input to the space dividing switch 314. Among the video programs, the video program is switched to the corresponding output terminal of the space division switch 314 according to a request command requested by the subscriber.

The switched on-demand video program is multiplexed together with the communication channel in the channel MUX device 311, and the multiplexed on-demand video program is converted from the electrical signal to the optical signal in the 155M optical transmission device 313 and is connected to the optical terminal 4 through the optical cable. Is sent to.

The on-demand video program input to the 155M optical transmission device 41 of the optical terminator 4 is converted into an electrical signal, and the video program converted into digital data requested by the subscriber is demultiplexed in the channel DMX device 42 and demultiplexed. The programmed program is modulated from digital data into an analog signal through a high frequency modulator / demodulator 44. The modulated TV program is delivered to subscriber premises 5 via a telephone line, and the selected on-demand video program is demodulated back to digital data in high frequency modulator / demodulator 51 of subscriber premises 5.

The demodulated program is modulated from digital data into an analog signal of NTSC signal by the set top device 53 and then transferred to the TV receiver, so that the subscriber can watch the video program on demand.

Now, the optical terminator 4 of the present invention applied to the low-cost video network as described above will be described in detail.

5 is an internal configuration diagram of the channel MUX 43 and the channel DMX 42 among the components constituting the present invention. In the embodiment of the present invention, these two functional units are configured as one application-specific semiconductor.

In the drawing, Si is an input terminal through which digital data is input at a speed of 155.520 Mb / s from a 155M optical transmission device 41, and So is an output terminal through which digital data is output to a 155M optical transmission device 41 at a speed of 155.520 Mb / s. Indicates. The digital data of Si is demultiplexed into three DS3 forms in the 155M DMX 421 and demultiplexed into four low-speed data in the DS3 DMX 412. Data corresponding to a quarter speed of the DS3 rate is then input from the DS3 / 4 reframe unit (RFM) 423 to the demultiplexer (DMX) 424 via a reverse process of the frame. At this time, the output of one end of the DMX 424 is output to the output terminal Vo as digital data for video. On the other hand, the remaining output of the DMX is input to the E1 leaframer (RFM) 425 and output to the output terminal To through the reverse process of the European (E1; asynchronous digital transmission hierarchy with 2.048 Mb / s data rate) frame.

As described above, the downlink signal is the video output Vo and the communication output To, and the upstream signal is input to the video input Vi, the communication input Ti, and the custom semiconductor. Here, Vi is directly input to the multiplexing device (MUX) 434, Ti is input to the E1 frame device (FRM) 435, output in E1 framing, and input to the MUX 434 to be multiplexed with Vi. The multiplexed digital data is data corresponding to one-quarter speed of the DS3 rate, and is input to the DS3 MUX 432 through a frame process in four DS3 / 4 FRMs 433 and multiplexed. Three data multiplexed by the DS3 MUX 432 are input to the 155M MUX 431 and input to the 155M MUX 431 to be multiplexed. The multiplexed digital data appears at the output stage So at 155.520 Mb / s.

The CLKi terminal provides an input clock to the clock generator 410 as a clock input terminal for receiving a clock reproduced from the 155M optical transmission device 41. The clock generator 410 divides and provides the clocks needed in the on-demand semiconductor at the input clock 155.520 Mb / s. The CLKo terminal is an output terminal for outputting a required clock from the high frequency modulation / demodulation device 44 to the clock output terminal.

FIG. 6 shows the construction of an optical terminator according to the present invention using the custom semiconductor for channel MUX and channel DMX of FIG.

The optical terminator 4 includes a 155M optical transmission device 41, one on-demand semiconductor 46 for channel MUX and channel DMX, N high frequency modulation / demodulation device 44, and a power conversion device 45, The inter-operation of is as follows.

The downlink signal (signal to the subscriber side) received from the video distribution center 3 is converted into an optical digital signal of 155.520 Mb / s by the 155M optical transmitter 41, and this data is converted into an on-demand for channel MUX and channel DMX. It is input to the Si stage of the semiconductor 46, and a clock of 155.520 Mb / s is reproduced and input to the CLKi stage.

The data is demultiplexed, the demultiplexed video data Vo # 1 and the communication data To # 1 are input to the high frequency modulation / demodulation device # 1 44, and the Vo # 12 and To # 12 are high frequency modulation / demodulation devices. Entered # 12 respectively. These data are respectively modulated from the digital data into analog signals and transmitted to the subscriber premises 5 via telephone lines.

The analog signal input from the subscriber premises device 5 to the optical terminator 4 is an uplink signal and demodulated as digital data in the high frequency modulation / demodulation device 44 so that communication data is input from Ti # 1 to Ti # 12, respectively. In video data Vi # 1, Vi # 12 is not used. These communication data are output to So of the on-demand semiconductor 46 for channel MUX and channel DMX through multiplexing and frame processes, and are input to the 155M optical transmission device 41. The input digital data is converted into an optical signal and transmitted upward to the image distribution center 3. Here, the power is directly supplied with power from the video distribution center 3 to supply power for each device via the power conversion device 45.

Therefore, the present invention, which is configured and operated as described above, can provide subscribers with broadcast TV programs and video-on-demand programs, in contrast to the method of serving only broadcast-type TV programs in comprehensive cable broadcasting, and also integrates telephone and narrowband synthesis. As a video network capable of simultaneously providing information services, it is easy to design an out side plant network and provide an optical terminator among video networks that can establish a subscriber access network at low cost. In the current integrated cable system, the use of a tree and branch coaxial cable makes it difficult to wire the premises line due to the problem of upstream convergence noise. However, the present invention has an effect of using an existing telephone line as it is. There is no need to pay for the premises.

Claims (12)

In an optical terminator applied to a low-cost video network, multiplexed communications from the video distribution center 3 of the network, optical signals including video and clock signals are converted into electrical digital signals and output, and multiplexed from the subscriber side. An optical transmission device 41 which converts a communication signal into an optical signal and outputs it to an image distribution center 3 of the network, and demultiplexes and outputs a digital signal from the optical transmission device 41, A channel multiplexing (MUX) and demultiplexing (DMX) device 46 for multiplexing and framing communication data and providing the same to the optical transmission device 41 and the signal from the channel multiplexing and demultiplexing device 46 are analogized. Modulates the signal to the subscriber side and demodulates the analog signal from the subscriber side into a digital signal to the channel multiplexing and demultiplexing apparatus. And a plurality of high frequency modulation / demodulation devices (44) to provide. The optical terminator of a low-cost video network according to claim 1, further comprising a power converter (45) which receives power directly from the video distribution center (3) and supplies power for each device. The optical terminator of claim 1 or 2, wherein the optical transmission device is 155 Mp / s. 4. The optical terminator of claim 3, wherein said channel multiplexing (MUX) and demultiplexing (DMX) device is comprised of an on-demand semiconductor. The apparatus of claim 3, wherein the demultiplexer in the channel multiplexing (MUX) and demultiplexing (DMX) device 46 receives the digital data output from the optical transmission device 41 and demultiplexes the data into three low-speed data. A first demultiplexer 421, three second demultiplexers 422 for demultiplexing three outputs of the demultiplexer 421 into four low-speed data, and four of the second demultiplexer 422. A third demultiplexer for demultiplexing the outputs of the four first reframers (RFMs) 423 for re-outputting the outputs and for dividing the outputs of the four leaf reamers 423 into video data and communication data for video; (424) and a second framer (425) for receiving the communication data among the outputs of the third demultiplexer (E1) and re-raising and outputting the received data. 6. The optical terminator of claim 5, wherein the first demultiplexer (421) is configured to demultiplex and output data with DS3 speed. 7. The optical terminator of claim 6, wherein the second demultiplexer (422) is configured to demultiplex and output data corresponding to a quarter speed of DS3 speed. 6. The apparatus of claim 5, wherein the multiplexer in the channel multiplexing (MUX) and demultiplexing (DMX) device 46 comprises: a first framer 436 which receives communication data from the subscriber side and framing and outputs E1; A first multiplexer 434 for multiplexing the output signal of the first framer 436 and a video signal from the subscriber side, and four second framers for framing and outputting the output signal of the first multiplexer 434. 433, a second multiplexer 432 that receives and outputs the outputs of the four second framers 433, and multiplexes the outputs of the second multiplexer 432 to the optical transmission device ( 41. An optical terminator of a low cost video network, comprising: a third multiplexer (432) for output to 41). 10. The apparatus of claim 8, wherein the clock required for the channel multiplexing (MUX) and demultiplexing (DMX) device 46 is received by receiving a regenerated clock of 155 Mp / s from the optical transmission device 41, and the high frequency modulation / demodulation is performed. An optical terminator of a low cost video network, characterized in that it further comprises a clock (CLOCK) generator (410) for providing the clock required by the device (44). 9. The optical terminator of claim 8, wherein the second framer (433) is configured to frame and output data as data corresponding to a quarter speed of DS3 speed. 11. The optical terminator of claim 10, wherein the second multiplexer (432) is configured to multiplex and output data with DS3 speed. 12. The optical terminator of claim 11, wherein the first multiplexer (431) is configured to multiplex and output at a rate of 155M.