Abstract: A single side band modulation device includes a first Mach Zehnder interferometer and a second Mach Zehnder interferometer. The first Mach Zehnder interferometer includes at least two output arms, and the second Mach Zehnder interferometer includes at least two output arms. Terminals of the output arms are connected with one another.

Abstract: A method for checking for elevated activity of mixed-function oxidases using a single insect, includes homogenizing a single insect in an acid pH buffer, preferably by grinding it in a small tube, such as an Eppendorf tube, with a pestle, adding a buffered tetramethylbenzidine solution as substrate, adding hydrogen peroxide as oxidant, and checking the blue coloration, the intensity of which indicates the degree of elevated mixed function oxidase activity. The invention also provides a test kit for use in the method which comprises separate containers of: I. an acid pH buffer, preferably an acid buffer about pH5 II. tetramethylbenzidine III. a solvent for tetramethylbenzidine, preferably methanol, and IV. hydrogen peroxide.

Abstract: A duobinary optical transmission apparatus is provided to generate duobinary optical signals, without using an electric low-pass-filter (LPF), by restricting a bandwidth of a Mach-Zehnder-interferometer-type optical intensity modulator (MZ MOD). Alternatively, a LPF having a single pole with a single capacitor is implemented instead of an expensive LPF, thereby providing a simple transmitter with a lower production cost in comparison with a transmitter using a conventional electric LPF.

Abstract: Disclosed is a duobinary optical transmitter, which includes a laser source for outputting light with a predetermined wavelength; a Mach-Zehnder interferometer-type optical intensity modulator for modulating the intensity of the light according to a three-level data signal inputted through a modulation terminal; a low-pass filter for converting an inputted two-level binary data signal into a three-level data signal through an interference among codes; and, a modulator driver/amplifier for amplifying the three-level data signal and then outputting it to the modulation terminal, wherein the overall bandwidth of the low-pass filter, the modulator driver/amplifier, and the optical intensity modulator corresponds to approximately ¼ of the clock frequency of the two-level binary data signal.

Abstract: Disclosed is a duobinary optical transmission apparatus. The duobinary optical transmission apparatusenhances nonlinear and dispersion characteristics for an intermediate-long distance transmission at a high-speed transfer rate without the use an electric LPF. The duobinary optical transmission apparatus includes a light source for generating a carrier wave, a duobinary optical signal generator for receiving a Non Return to Zero (NRZ) signal and generating a modulated optical signal generated by modulating the carrier wave according to the NRZ signal, and a Return to Zero (RZ) signal generator for converting the NRZ signal into a RZ (Return to Zero) signal. Therefore, optical intensity and a phase are modulated using only a single interferometer-type optical modulator.

Abstract: A precoder for an optical duo-binary transmission apparatus disposing the precoder before a time division multiplexer includes a judgment unit for judging whether an odd number or even number of ‘1’s exist in data input signals of N channels inputted at an nth time of channel input. Further included in the precoder is a toggle unit for toggling an output signal of the judgment unit when the judgment is odd, and for determining an output value for one of the channels. The precoder also has an output unit for determining output values of other channels according to a respective data input signal and a predetermined channel from among the N channels.

Abstract: A wireless remote access base station for converting a downstream optical signal to a downstream radio frequency (RF) signal, transmitting the converted downstream RF signal wirelessly, converting a received upstream RF signal to an upstream optical signal, and transmitting the upstream optical signal is provided. The remote base station includes: an electro-absorption modulator (EAM) for converting a downstream optical signal to a downstream RF signal and an upstream RF signal to an upstream optical signal; an antenna for transmitting the downstream RF signal wirelessly and outputting the upstream RF signal received wirelessly to the EAM; and an amplifier, which is located between the EAM and the antenna, amplifies the downstream RF signal and outputs the amplified downstream RF signal to the antenna.

Abstract: A radio over fiber (ROF) link apparatus capable of a stable TDD wireless service for a time division duplexing (TDD) baseband signal includes a central access platform (CAP) for receiving various kinds of data including the TDD baseband signal from upper layers, multiplexing the data, electro-optically converting the multiplexed data, and transmitting the converted data as downstream data through an optical fiber, and opto-electrically converting upstream data received through the optical fiber, demultiplexing the converted upstream data, and transmitting the demultiplexed upstream data to the respective upper layers, and a remote access unit (RAU) for receiving the downstream data through the optical fiber, opto-electrically converting the received downstream data to the multiplexed data, demultiplexing the multiplexed data, performing a wireless access process of the demultiplexed data, and transmitting the wireless access processed data to a wireless local area network (WLAN) service terminal through an an

Abstract: Disclosed is an ROF link apparatus for selecting an IF band in order to process various service signals through an MMF, which including transmitters for receiving the service signals, performing IF modulation for the service signals, and transferring the modulated IF signals, a first controller for scanning frequency characteristics of the MMF, searching for flat frequency bands, and transferring information regarding the flat frequency band, thereby controlling IF modulation to be performed, a link unit for combining the IF signals with output signals of the first controller, converting the combined signals into optical signals, transmitting the optical signals, converting the optical signals into electrical signals, and splitting the electrical signals, a second controller for receiving the output signals of the first controller, detecting information regarding the flat frequency band, and transferring the information to receivers, thereby controlling modulation to be performed, and the receivers for receiv

Abstract: A single side band modulation device includes a first Mach Zehnder interferometer and a second Mach Zehnder interferometer. The first Mach Zehnder interferometer includes at least two output arms, and the second Mach Zehnder interferometer includes at least two output arms. Terminals of the output arms are connected with one another.

Abstract: Disclosed is a remote access unit for transmitting and receiving upstream and downstream data in which channels having different transmission scheme are multiplexed, and an optical network for bi-directional wireless communication using same. The remote access unit includes an antenna for receiving the downstream data and wirelessly transmitting same and for receiving the upstream data and providing same to the remote access unit, a switch for outputting downstream time division channels of the downstream data to the antenna and for receiving upstream time division channels of the upstream data from the antenna, and a controller for controlling the switch in order to prevent the upstream and downstream time division channels from overlapping.

Abstract: The provided forward error correction (FEC) apparatus for a transmission system includes a low pass filter (LPF) passing only a low frequency component of an input signal having a predetermined transmission rate; an AC power meter converting an energy value of an signal output from the LPF into a DC voltage value; a logarithm amplifier converting the exponentially varying DC voltage value from the AC power meter into a linear logarithmically varying DC voltage value; a digital signal processor (DSP) determining the transmission rate of the input signal according to a magnitude of the linear DC voltage value and outputting a control signal according to the transmission rate; a clock generator receiving the control signal and generating a clock signal according to the control signal; and a FEC module receiving the clock signal and performing FEC operation on the received signal. A method for FEC is also provided.

Abstract: Disclosed is a temperature-compensating device for an APD optical-receiver system using an APD (Avalanche Photo Diode). The device includes a temperature-compensating circuit which employs a digital potentiometer capable of linear compensation through data look-up in compensating the decrease in gain caused by the temperature change of the APD.

Abstract: A chirped RZ-AMI optical transmitter includes a first logic gate for receiving a first signal obtained by pre-coding binary data and a second signal having a waveform obtained by inverting and delaying the first signal, and outputting a third signal obtained by logically operating on the first and second signals. A second logic gate receives a fourth signal having a waveform obtained by inverting the first signal, and a fifth signal having a waveform obtained by delaying the first signal. The second logic gate outputs a sixth signal obtained by logically operating on the fourth and fifth signals. A Mach-Zehnder Modulator (MZM) modulates an input light according to the third and sixth signals and outputs an RZ-AMI optical signal.

Abstract: An optical transmission apparatus using duobinary modulation adapted to an optical communication system using dense wavelength division multiplexing (DWDM) is disclosed. The duo-binary optical transmission apparatus includes an electro-absorption modulated laser (EML) for performing a light intensity modulation operation based on an electrical data signal and producing a modulated optical signal, the EML having a light source for outputting carriers and a modulator for performing the light intensity modulation operation, a precoder for inputting an inverted signal of the electrical data signal and encoding it to an encoded signal, and a modulator for performing a phase modulation of the optical signal modulated by the EML and outputting a duo-binary optical signal, according to the encoded signal.

Abstract: An optical duo-binary transmission apparatus using a duo-binary modulation method is disclosed. The optical duo-binary transmission apparatus using a polarization modulator includes a precoder for coding an inputted binary data signal; a low-pass filter for converting the coded binary data signal into a three-level signal by restricting a bandwidth of the coded binary data signal; a light source for generating light; a polarization modulator for modulating a polarization of the light outputted from the light source according to the three-level signal; and a polarizer for transmitting only an optical signal having a predetermined directionality from among polarization-modulated optical signals.

Abstract: This invention provides an optical transmission with a demultiplexer for demultiplexing an input optical signal into optical signals of different channels and a multiplexer for multiplexing the optical signals outputted from the demultiplexer.

Abstract: An optical duo-binary transmission apparatus using an optical duo-binary transmission method is disclosed. The apparatus includes a duo-binary encoder that performs parallel processing. The duo-binary encoder includes a level change detection unit for detecting that levels of data input signals of N channels input at an nth input of channels change from 0 to 1, or from 1 to 0; a judgment unit for judging whether a number of level changes detected by the level change detection unit is odd or even; and a toggle unit for toggling an output signal of the judgment unit when the number of level change is odd.

Abstract: An optical duo-binary transmission apparatus using an optical duo-binary transmission method is disclosed. The apparatus includes a duo-binary encoder that performs parallel processing. The duo-binary encoder includes a level change detection unit for detecting that levels of data input signals of N channels input at an nth input of channels change from 0 to 1, or from 1 to 0; a judgment unit for judging whether a number of level changes detected by the level change detection unit is odd or even; and a toggle unit for toggling an output signal of the judgment unit when the number of level change is odd.

Abstract: A paint composition containing an insecticide and piperonyl butoxide as a synergist.