Abstract: An optical communication system for transmitting telephone voice data to a subscriber terminal using an optical line is disclosed. The system includes an OLT (Optical Line Terminal) multiplexing the telephone voice data together with the broadcasting data and communication data, converting the optical signals transferred upward into electric signals, demultiplexing and converting the uplink telephone voice data into analog telephone voice signals to transfer the converted analog telephone voice signals to a PSTN; a plurality of ONTs (Optical Network Terminals) for converting the optical signals transferred from the OLT into electric signals, demultiplexing and converting the demultiplexed downlink telephone voice data into analog signals to transfer the converted analog signals to subscribers' telephones; and an optical branching filter for branching the signals from the OLT to the plurality of ONTs, combining, and transferring the signals from the plurality of ONTs to the OLT.

Abstract: Disclosed is a transport stream transmission apparatus, for example an MPEG Motion Picture Experts Group)—transport stream transmission apparatus.

Abstract: A fiber to the home FTTH network for convergence of broadcasting and communication is disclosed. The network includes: an OLT for receiving and converting a first predetermined number of broadcast signals and an Ethernet signal into a plurality of converted optical signals, combining the converted optical signals into converged optical signals for subsequent transmission by an optical wavelength division multiplexing method; and an optical network unit (ONU) for classifying the optical signal transmitted from the OLT into the first predetermined number of broadcast signals and the Ethernet signal, switching a second predetermined number of broadcasting signals of the first predetermined number of broadcasting signals according to each SIU by channel selection information contained in upstream Ethernet information, and switching the Ethernet signal to be transmitted to the SIU according to each SIU so as to transmit the switched signal.

Abstract: Disclosed is a device for filtering out a null packet in a data stream for example an MPEG-2 TS (Transport Stream) to avoid bandwidth waste when it is transmitted to a backbone network. The device includes a plurality of receiving interfaces, a filter unit, and a controller. The receiving interfaces receive parallel data, such as DVB-ASI (Digital Video Broadcasting-Asynchronous Serial Interface) inputs as channel-by-channel MPEG-2 data. The filter unit counts the respective numbers of data packets and non-data packets of the data input from the receiving interfaces and filters a null packet in the data. A network transmission unit transmits the filtered data to a backbone network. The controller calculates a bit rate based on both of the count numbers received from the filter unit.

Abstract: An optical subscriber network system is disclosed, which comprises: a server bi-directional optical transmitter including a multiplexer to multiplexes communication data and broadcast data, a server laser diode to converts the multiplexed data into an optical signal, and a server photo diode receive communication data from a subscriber, wherein the server bi-directional optical transmitter transmits the upstream communication data; and a subscriber bi-directional optical receiver including a subscriber laser diode to transmit upstream communication data, a subscriber photo diode to receive the optical signal transmitted from the server bi-directional optical transmitter, and a demultiplexer to demultiplex and divide the multiplexed signal into communication data and broadcast data. In the optical subscriber network system, the optical transmitter and the optical receiver can transceive image signals and Ethernet communication signals in a two-way direction by means of a single laser diode and photo diode.

Abstract: An image data transmission apparatus in an optical subscriber network is disclosed, which comprises: one optical line termination for receiving MPTS data from an outside, packetizing the received MPTS data into HDLC packets, and transmitting the HDLC packets as optical signals; and a plurality of ONUs connected to the OLT, the ONU receiving the optical signal transmitted from the OLT, converting the optical signal into an electrical signal, extracting MPTS data from the converted HDLC packet, and switching the MPTS data to each subscriber. The image data transmission apparatus processes HDLC-based MPTS data, increases degree of integration of data, and therefore enables the optical subscriber network to include more channels.

Abstract: A clock and data recovery (CDR) device is disclosed that is capable of recovering a clock signal from a data signal that has a variable data rate. The CDR device includes a reference clock generating section for dividing a basic clock by a first predetermined value P, synchronizing the clock and multiplying the clock by a second predetermined value Q to generate a reference clock corresponding to the variable data rate; a clock and data recovery section for receiving the transmitted data, recovering a clock and data from the received data and outputting the recovered clock and data; and a control section for generating a control signal according to the variable data rate and sending the signal to the reference clock generating section and the clock and data recovery section.

Abstract: A subscriber optical distributor and method for a broadcasting-telecommunications convergence service over an FTTH (Fiber To The Home) optical transmission network. An optical transceiver receives a TDM broadcasting-telecommunications optical signal, converts the optical signal to an electrical signal, and converts an uplink electrical signal received from a subscriber to an optical signal. A broadcasting/telecommunications signal distributor receives the electrical broadcasting-telecommunications signal and separates the received electrical signal into a broadcasting signal and a telecommunications signal. A broadcasting interface interfaces the broadcasting signal received from the broadcasting/telecommunications signal distributor. A telecommunications interface transmits the telecommunications signal received from the broadcasting/telecommunications signal distributor, and provides the uplink signal to the optical transceiver.

Abstract: A clock recovery method for a TDM digital video signal and a transmitting/receiving apparatus for the clock recovery method are disclosed. A transmitter inserts a user clock code containing a predetermined number of points into the digital video signal during TDM processing and transmits the digital video signal. A receiver receives the TDM digital video signal and detects the user clock code from the TDM digital video signal. It counts a reference clock signal and recovers a transmission clock signal in an LMS algorithm using the user clock code and the count value.

Abstract: A system for integrating broadcast and communication technologies is provided. The integration system performs a connection between an optical-network unit (ONU) and a user as well as a connection between an optical-line terminal (OLT) and the ONU using an optical line, and processes a broadcast signal on the basis of time division multiplexing (TDM) such that the quality of a broadcast service can be ensured. The OLT receives at least one digital-broadcast signal through an external broadcast network and at least one external data-communication signal, then electro-optically converts the received signals, combines the electro-optically converted signals to form an optical signal, and transmits the optical signal on the basis of optical wavelength-division multiplexing (WDM).

Abstract: An optical transmission system for optimizing the bias of a laser diode during an SCM analog optical transmission includes an optical transmitter for converting a baseband electric signal into an optical signal using a laser diode according to the set bias and outputting the optical signal through an optical line, an optical receiver for converting the optical signal transmitted from the optical transmitter into the baseband electric signal, a recovery unit for detecting an error generated according to the bias of the laser diode on the basis of the electric signal converted by the optical receiver, and a bias adjuster for optimally adjusting the bias of the laser diode on the basis of a value of the error detected by the reproducer.

Abstract: Disclosed is an optical subscriber network system for performing bidirectional transmission/reception of digital broadcast signals and Internet signals. The optical subscriber network system of the invention includes a server-end bidirectional optical transmitter and a subscriber-end bidirectional optical receiver. The server-end bidirectional optical transmitter includes: a first semiconductor laser for transmitting digital broadcast signals; a second semiconductor laser for transmitting downstream Internet data; a server-end photodiode for receiving upstream Internet data; a BPF (Band Pass Filter) mounted in front of the service-end photodiode, for selecting the upstream Internet data only; and, a multi-branch optical waveguide element for selecting I/O (Input/Output) data.