JPH0650852B2 - Signal distribution method - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a signal distribution method for distributing and transmitting a signal transmitted by performing WDM on a plurality of FDM video signals, audio signals, data signals, and control signals. Regarding

[Technical background of the invention and its problems]

The CATV system, which was initially considered as a measure against the difficult-to-view area of television in the modern age of the advanced information society, is now capable of transmitting a large amount of information quickly and in good quality in combination with the optical communication technology which has been rapidly developed in recent years. In the CATV system, which has traditionally transmitted only the video and audio of a television, stereo audio, Hi-Fi music, still image information service as necessary, and high quality image transmission in the future and a large computer of the transmitting station. Computer network services and the like that utilize Internet are also considered, and optical communication technology is indispensable for transmitting such various large amounts of information. In this optical CATV system combined with the optical communication technology, it is necessary to design the system by taking advantage of the feature of the optical communication that the transmission band is wide and high speed. Among them, a method of distributing a signal transmitted to a subscriber's house by an optical fiber from a home distributor to a plurality of receivers is being studied.

The conventional optical CATV system has a configuration as shown in FIG. 6, and a signal as shown in FIG. 7 requested by each receiver in the subscriber's premises by the optical fiber (11), that is, a video signal, left The right voice signal and the data signal are subjected to FDM, and these FDM signals corresponding to the number of receivers desired to be simultaneously used in the subscriber's house are WDM-transmitted to the subscriber's house. Also, as shown in FIG. 8, FDM control signals (41) from the receivers such as setting of receiver channels and data signals, and response signals to the transmitting station are transmitted by the FDM as shown in FIG. Performs WDM with light of different wavelengths and transmits it to the transmitting station. The WDM signal transmitted to the subscriber's house is demultiplexed by the optical demultiplexer-multiplexer (13) into wavelengths assigned to each receiver as shown in FIG. 6, and each of them is divided into an optical-electrical converter (14). After being converted into an electric signal by the frequency separator (61) and separated into a video signal left and right audio signal and a data signal, each wire (16) is used from the in-home distributor (60) to each receiver (18). Transmit. The control signal (22) from each receiver (18) is generally slower than the video signal, etc., and is transmitted to the in-home distributor (60) by the respective conductors (16), and the control signal synthesizer ( After FDM as shown in Fig. 8 at 19), it is converted to light by the electrical / optical converter (111), and WDM is performed with the optical signal toward the subscriber's house at the optical demultiplexer-multiplexer (13) to the transmitting station. It is transmitting.

However, this method requires a large number of conductors for connection from the in-home distributor to each receiver, which makes the view very complicated and complicated. There is also a problem with maintenance, and it is possible that reliability may drop. Furthermore, the use of a large number of conductive wires also leaves an economic problem.

[Object of the Invention]

The present invention improves the above-mentioned problems of the conventional signal distribution system and provides a highly practical signal distribution system.

[Outline of Invention]

According to the present invention, a WDM optical signal transmitted to an optical fiber subscriber's house is demultiplexed by an optical demultiplexer / demultiplexer into lights of wavelengths assigned to respective receivers, and the respective optical signals are converted into optical signals.
Video signals, left and right audio signals, and data signals are converted into electric signals while being FDM by an electric converter, and are transmitted to corresponding receivers by a conductor. At that time, control signals from each receiver are directed to each receiver. The video signal, the audio signal, and the data signal are FDM-transmitted to the home distributor through the above-mentioned conductor, the control signal separator separates the control signals, and the control signal combiner FDMs the control signals to each other to generate electricity. The optical signal is converted into an optical signal by an optical converter, and WDM is performed with the optical signal toward the subscriber's house by the optical demultiplexer-multiplexer, or the control signal from each of the receivers is arranged in parallel with each of the conductors. Optical signals transmitted to a home distributor by a conductor, FDMed by the control signal combiner, converted into optical signals by an electric / optical converter, and sent to a subscriber's house by an optical demultiplexer / multiplexer. And WDM By is to obtain each video signal to a plurality of receivers of the customer premises, a voice signal, a signal distribution system for distributing service data signal.

〔The invention's effect〕

According to the present invention, one video signal, one audio signal, and one data signal transmitted to the subscriber's house are sent from the in-home distributor to each receiver.
It becomes possible to transmit by the conductor of the book, and the control signal from each receiver can be used together by transmitting the video signal, the audio signal, and the data signal by FDM, or the control signal from each receiver can be transmitted. If transmission is carried out by another conductor arranged in parallel with each conductor, the connection from the in-home distributor to each receiver will be simple, easy to handle and easy to maintain, and the scenery will be good. Furthermore, reliability is improved and economic efficiency is also increased. In addition, a plurality of frequency separators for separating each FDM signal assigned to each receiver into a video signal, an audio signal, and a data signal are installed in each receiver,
Compared with the conventional method, the home distributor is very compact and its practical advantage is great.

Example of Invention

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention. If there are n receivers that are desired to be used at the same time in the optical CATV subscriber's house, the video signals, audio signals, and data signals that make up the channels selected by the receivers are, for example, baseband images as shown in FIG. The signal (31) is frequency-modulated and further subjected to four-phase phase shift keying (Q-PSK) for the left audio signal (32), the right audio signal (33) and, if necessary, frequency shift keying (F
The SK) data signal 34 is subjected to FDM, and these n FDM signals are subjected to WDM with light of n different wavelengths and transmitted to the subscriber's home through the optical fiber 11. The signal transmitted to the subscriber's house is a home distributor
The optical demultiplexer-multiplexer (13) demultiplexes the light into n wavelengths assigned to each receiver, and the optical signal of each wavelength is electrically converted by the optical-electrical converter (14). Convert to signal. The respective electric signals are the FDM signals shown in FIG. 2, and the respective electric signals are transmitted to the respective receivers (18) through the conductors (16). As shown in FIG. 3, each control signal from each receiver (18) is further FDMed to the signal of FIG. 2 to be transmitted to the in-home distributor (10) through each conductor (16). Each wire (16) in the home distributor (10)
Each control signal is separated by the control signal separator (15) provided in the above, and each control signal is combined by the control signal combiner (19) to FDM each control signal as shown in FIG. This FDM control signal is converted into an optical signal of the (n + 1) th wavelength by the electric / optical converter (111), and the video signal is converted by the optical demultiplexer-multiplexer (13).
WDM optical signals of n wavelengths, which are WDM signals of voice signals and data signals, are transmitted to the transmitting station. According to this, it is not necessary to provide another line for transmitting the control signal from each receiver to the in-home distributor.

Next, FIG. 5 shows another embodiment of the present invention. In this embodiment, in the embodiment of FIG. 1, the control signal from each receiver (18) is transmitted to the in-home distributor (20) by each conductor (16) arranged in parallel with the conductor (16). The control signal combiner (19) in the in-home distributor is used for combining.

[Brief description of drawings]

FIG. 1 is a conceptual configuration diagram of an embodiment of the present invention, and FIGS.
1 is a diagram for explaining the embodiment shown in FIG. 1, FIG. 5 is a diagram showing another embodiment of the present invention, and FIGS. 6 to 8 are diagrams showing a conventional example. 10 …… In-home distributor, 11 …… Optical fiber, 12 …… WDM signal, 13 …… Optical demultiplexer / multiplexer, 14 …… Optical / electrical converter, 15 ……
Control signal separator, 16 ... Lead wire, 17 ... FDM signal, 18 ...
… Receiver, 19 …… Control signal synthesizer, 111 …… Electric / optical converter.

Claims (4)

[Claims] 1. A video signal, an audio signal, and a data signal, which are frequency-division-multiplexed from a transmitting station based on a control signal transmitted from each of a plurality of receivers, have wavelengths assigned to the respective receivers. In the signal distribution method of distributing and transmitting the wavelength-division-multiplexed first optical signal to each of the receivers via an in-home distributor, each of the receivers that transmits the control signal output from each of the receivers A signal combiner for frequency-division-multiplexing the control signals transmitted by the transmission line; and a second optical signal for the frequency-division-multiplexed control signal. And an electro-optical converter that converts the second optical signal to the transmitting station side, and allocates the first optical signal transmitted from the transmitting station to each of the receivers. Wavelength And an optical demultiplexer-multiplexer for demultiplexing, and each demultiplexed signal is converted into an electrical signal composed of the frequency-division-multiplexed video signal, audio signal, and data signal and transmitted to each receiver. A signal distribution method comprising an opto-electric converter for transmission using a transmission line or another transmission line. 2. The signal distribution system according to claim 1, wherein the frequency division multiplexed video signal is a baseband signal, and the audio signal and the data signal are angle-modulated signals. . 3. The signal distribution system according to claim 2, wherein the angle-modulated voice signal and the data signal are angle-modulated by separate carrier waves. 4. The signal distribution system according to claim 2, wherein the voice signal and the data signal are subjected to pulse code modulation, time division multiplexing, and angle modulation.