Abstract: A multilayer electronic component including: a body including a dielectric layer and internal electrodes; and external electrodes disposed outside the body and connected to the internal electrodes, wherein 1.5?Hfs/Hfc?5.0 when the internal electrode includes hafnium (Hf), Hfc indicates an average Hf content (at %) in a center of the internal electrode, and Hfs indicates an average Hf content (at %) in the internal electrode, measured from the center of the internal electrode to an interface thereof in contact with the dielectric layer.

Abstract: A fiber to the home (FTTH) system based on a passive optical network (PON) includes an optical line terminal (OLT) block, an optical network terminal (ONT) block, and an optical distribution network (ODN). The ONT block includes a video-optical line terminal (V-OLT) and an OLT to output optical signals of the V-OLT and the OLT by multiplexing the optical signals. The V-OLT receives cable TV (CATV), master antenna (MATV), and satellite broadcasting (SB) optical signals inputted from a broadcasting service network to output received signals as a first optical signal having a predetermined wavelength band. The ONT block includes a video-optical network terminal (V-ONT) and an (ONT) to split multiplexed data communications signals, and CATV broadcasting, MATV broadcasting, and (SB) optical signals. The V-ONT processes the split CATV broadcasting, MATV, and (SB) optical signals to provide subscribers with the split cable CATV, MATV and SB optical signals.

Abstract: A bottom level detection device is disclosed for a burst mode optical receiver. The receiver includes a converter for converting a burst mode signal into a voltage signal and an automatic gain controller for automatically controlling a gain of the converter. The bottom level detection device detects a bottom level of an output signal from the converter and controls the automatic gain controller on the basis of the detected bottom level. The bottom level detection device includes an amplification circuit for receiving the output signal from the converter at its first input terminal and a fed-back output signal from the device at its second input terminal, respectively, and amplifying a difference between the received signals, a detector for detecting a bottom level of an output signal from the amplification circuit, and an output buffer.

Abstract: A burst mode optical receiver is disclosed and includes a converter for converting a burst mode signal into a voltage signal, a bottom level detector for detecting a bottom level of an output signal from the converter, an automatic gain controller for automatically controlling the gain of the converter on the basis of the bottom level detected by the bottom level detector in order to maintain an amplitude of the output signal from the converter and generating a reset signal when the bottom level is lower than a predetermined reference value, and a power level detector for detecting a power level of the output signal from the converter and generating the reset signal and an LOS signal indicative of the presence of no input signal when the detected power level is lower than a predetermined reference value.

Abstract: A burst-mode optical receiver of a differential-output structure is disclosed.

Abstract: In an optical receiver having a pre-amplifier for converting a current signal outputted from an optical detector to a voltage signal, a signal level detecting device is provided to provide an LOS (loss of signal) signal and a reset signal from the output of the pre-amplifier. The signal level detecting device comprising: a capacitor for receiving the output from the pre-amplifier; first and second transistors each consisting of an emitter and a collector connected to the output of the pre-amplifier and a base connected to the collector; a third transistor having a collector connected to the collector of the first transistor and an emitter connected to the collector of the second transistor; and, a common emitter circuit with a pair of resistors connected, respectively, to the emitter and collector of the third transistor and capable of detecting the level of a signal inputted from the collector of the third transistor.

Abstract: A peak detector for detecting a peak value of a burst signal in a burst mode optical receiver is disclosed, which comprises: an amplifying terminal configured to reduce an offset of a peak value in a received burst signal using feedback in the peak detector; a transistor that functions as a diode when a positive signal is received from the amplifying terminal; a peak hold capacitor for charging a peak value when the transistor received the positive signal; a signal amplitude detector to monitor the received burst signal amplitude; and a current source to drive a current responsive to the output signal amplitude detector.

Abstract: A solution for allowing conditional access to IP-based broadcast services in a passive optical network is disclosed. When a subscriber requests broadcast services by selecting a broadcast channel, an IP set-top converts the request into an IGMP join message and forwards the message to an ONU/ONT, a unit on the subscriber's side. The ONU/ONT delivers the message to an OLT interworking with a router while storing mapping information of the port that received the message and a MAC address of the selected channel. Thereafter, the OLT extracts information on MAC address of the IP set-top box and the requested broadcast data. The OLT compares the extracted information to the subscriber's subscription information and determines whether to provide the requested broadcast services. If the broadcast services may be provided, the broadcast data provided from the broadcast server is transmitted to the IP set-top box via ONU/ONT based on the stored mapping information.

Abstract: A bit-rate independent optical receiver and a method thereof. In the bit-rate independent optical receiver, an optoelectric converter converts an input optical signal to an original electrical signal, a bit rate identifying unit forms a resultant signal by performing an exclusive-OR (XOR) logic operation on the original electrical signal received from the optoelectric converter and a second signal corresponding to the original electrical signal delayed by a predetermined quantity of time, and detects a bit rate from the resultant signal, a reference clock generator generates a reference clock signal according to the detected bit rate, and a clock and data recovery circuit recovers a clock signal and data from the input signal according to the reference clock signal.

Abstract: A fiber to the home (FTTH) system based on a passive optical network (PON) includes an optical line terminal (OLT) block, an optical network terminal (ONT) block, and an optical distribution network (ODN). The ONT block includes a video-optical line terminal (V-OLT) and an optical line terminal (OLT) in order to output optical signals of the video-optical line terminal (V-OLT) and the optical line terminal (OLT) by multiplexing the optical signals. The VOLT receives cable TV, master antenna TV, and satellite broadcasting optical signals inputted from a broadcasting service network so as to output received signals as a first optical signal having a predetermined wavelength band. The OLT includes a first downstream data optical transmitter and a first upstream data optical receiver and outputs a data communication signal inputted from a data service network as a second optical signal having different wavelength from the video-optical line terminal.

Abstract: An automatic-gain-control device in an optical receiver is provided and includes a pre-amplifier for converting a current signal outputted from an optical detector to a voltage signal and a bottom level detector for detecting the bottom level from the output of the pre-amplifier, the automatic-gain-control device comprising a bottom signal-level-determining section for analyzing the bottom level from the bottom level detector and outputting a signal denoting the presence of a signal and a reset signal for initialization at intervals between packets; and an automatic-gain-control signal generating section for providing an automatic-gain-control signal by showing the presence of a signal, the automatic-gain-control-signal-generating section including a first transistor which turns on according to a signal from the bottom signal-level-determining section and a second transistor which is connected to a capacitor for charging or discharging a voltage applied by the first transistor, and the drain voltage of which

Abstract: An automatic threshold control device for a burst mode optical receiver is disclosed. The receiver includes a converter that converts a burst mode signal into a voltage signal and an automatic gain controller for automatically controlling a gain of the converter, independently generating a reset signal and applying it to the automatic threshold control device. The automatic threshold control device is adapted to detect a voltage level of an output signal from the converter.

Abstract: A peak detector for detecting a peak value of a burst signal in a burst mode optical receiver is disclosed, which comprises: an amplifying terminal configured to reduce an offset of a peak value in a received burst signal using feedback in the peak detector; a transistor that functions as a diode when a positive signal is received from the amplifying terminal; a peak hold capacitor for charging a peak value when the transistor received the positive signal; a signal amplitude detector to monitor the received burst signal amplitude; and a current source to drive a current responsive to the output signal amplitude detector.

Abstract: An automatic gain control (AGC) apparatus with a short settling time in a burst mode optical receiver is disclosed. The AGC apparatus includes a variable gain amplifier for variably amplifying an input signal according to an AGC adjustment control signal; a clipper coupled to an output terminal of the variable gain amplifier for comparing an output signal of the variable gain amplifier with a preset signal Vcut and for outputting a signal corresponding to the difference between these two signals if the output signal of the variable gain amplifier is higher than or equal to the preset signal Vcut in amplitude; an exponential amplifier for exponentially amplifying an output signal of the clipper; and a peak holder for detecting a peak value from an output signal of the exponential amplifier and for generating the AGC adjustment control signal for controlling a gain of the variable gain amplifier.

Abstract: A bottom level detection device is disclosed for a burst mode optical receiver. The receiver includes a converter for converting a burst mode signal into a voltage signal and an automatic gain controller for automatically controlling a gain of the converter. The bottom level detection device detects a bottom level of an output signal from the converter and controls the automatic gain controller on the basis of the detected bottom level. The bottom level detection device includes an amplification circuit for receiving the output signal from the converter at its first input terminal and a fed-back output signal from the device at its second input terminal, respectively, and amplifying a difference between the received signals, a detector for detecting a bottom level of an output signal from the amplification circuit, and an output buffer.

Abstract: In an optical receiver having a pre-amplifier for converting a current signal outputted from an optical detector to a voltage signal, a signal level detecting device is provided to provide an LOS (loss of signal) signal and a reset signal from the output of the pre-amplifier. The signal level detecting device comprising: a capacitor for receiving the output from the pre-amplifier; first and second transistors each consisting of an emitter and a collector connected to the output of the pre-amplifier and a base connected to the collector; a third transistor having a collector connected to the collector of the first transistor and an emitter connected to the collector of the second transistor; and, a common emitter circuit with a pair of resistors connected, respectively, to the emitter and collector of the third transistor and capable of detecting the level of a signal inputted from the collector of the third transistor.

Abstract: An automatic threshold control device for a burst mode optical receiver is disclosed. The receiver includes a converter that converts a burst mode signal into a voltage signal and an automatic gain controller for automatically controlling a gain of the converter, independently generating a reset signal and applying it to the automatic threshold control device. The automatic threshold control device is adapted to detect a voltage level of an output signal from the converter.

Abstract: An automatic-gain-control device in an optical receiver is provided and includes a pre-amplifier for converting a current signal outputted from an optical detector to a voltage signal and a bottom level detector for detecting the bottom level from the output of the pre-amplifier, the automatic-gain-control device comprising a bottom signal-level-determining section for analyzing the bottom level from the bottom level detector and outputting a signal denoting the presence of a signal and a reset signal for initialization at intervals between packets; and an automatic-gain-control signal generating section for providing an automatic-gain-control signal by showing the presence of a signal, the automatic-gain-control-signal-generating section including a first transistor which turns on according to a signal from the bottom signal-level-determining section and a second transistor which is connected to a capacitor for charging or discharging a voltage applied by the first transistor, and the drain voltage of which

Abstract: A burst mode optical receiver is disclosed and includes a converter for converting a burst mode signal into a voltage signal, a bottom level detector for detecting a bottom level of an output signal from the converter, an automatic gain controller for automatically controlling the gain of the converter on the basis of the bottom level detected by the bottom level detector in order to maintain an amplitude of the output signal from the converter and generating a reset signal when the bottom level is lower than a predetermined reference value, and a power level detector for detecting a power level of the output signal from the converter and generating the reset signal and an LOS signal indicative of the presence of no input signal when the detected power level is lower than a predetermined reference value.

Abstract: A burst-mode optical receiver of a differential-output structure is disclosed.