Patent application number | Description | Published |
20090159804 | Positron emission tomography scanner and radiation detector - A positron emission tomography (PET) scanner is provided which uses information on the time-of-flight difference (TOF) between annihilation radiations for image reconstruction. The scanner has detection time correction information (memory) corresponding to information on coordinates in a radiation detection element (e.g., scintillator crystal), in the depth and lateral directions, at which an interaction has occurred between an annihilation radiation and the crystal. Reference is made to the detection time correction information, thereby providing information on time-of-flight difference with improved accuracy. As such, an improved signal to noise ratio and spatial resolution are provided for image reconstruction using time-of-flight (TOF) difference. | 06-25-2009 |
20100032574 | RADIATION DETECTING METHOD UTILIZING ENERGY INFORMATION AND POSITIONAL INFORMATION AND EQUIPMENT THEREOF - Upon detection of radiation by using a (three-dimensional) detector capable of distinguishing a detection position in a depth direction and energy, an energy window for distinguishing between a signal and noise is changed depending on the detection position in the depth direction, thus making it possible to obtain scattering components inside the detector. Alternatively, a weight is given to a detection event depending on the detection position in the depth direction and energy information to obtain scattering components inside the detector. Thereby, scattering components inside the detector can be obtained to increase the sensitivity of the detector. In this case, different detecting elements can be used depending on the detection position in the depth direction. | 02-11-2010 |
20100046818 | IMAGE RECONSTRUCTION METHOD FOR TOMOGRAPHY SCANNER, FAILURE DIAGNOSIS METHOD, TOMOGRAPHY SCANNER AND MANAGEMENT PROGRAM FOR SYSTEM MATRIX - In a case where an error is included in measurement data corresponding to one or a plurality of detecting elements in a tomography scanner, a system matrix to be calculated or referenced on image reconstruction calculation is corrected in accordance with the error. Thus, even when an error such as a defect or a fault occurs in a detector, influence of the error is eliminated, thereby reducing an artifact generated in an image. At that time, positional information of the detecting elements including the error and information on the degree of the error are stored in a storage device and referenced inside image reconstruction software, thus making it possible to correct the system matrix in accordance with the error. | 02-25-2010 |
20110001049 | METHOD FOR DETECTING RADIATION, DEVICE THEREOF, AND POSITRON EMISSION TOMOGRAPHY SCANNER - A light receiver for detecting incident time is installed on the side of a radiation source of a scintillator (including a Cherenkov radiation emitter), and information (energy, incident time, an incident position, etc.) on radiation made incident into the scintillator is obtained by the output of the light receiver. It is, thereby, possible to identify an incident position and others of radiation into the scintillator at high accuracy. | 01-06-2011 |
20110101229 | DOI TYPE RADIATION DETECTOR - This aims to provide a DOI type radiation detector in which scintillation crystals arranged two-dimensionally on a light receiving surface to form rectangular section groups in extending directions of the light receiving surface of a light receiving element are stacked up to make a three-dimensional arrangement and responses of the crystals that have detected radiation are made possible to identify at response positions on the light receiving surface, so that a three-dimensional radiation detection position can be obtained. In the DOI type radiation detector, scintillation crystals are right triangle poles extending upwards from the light receiving surface and the response positions on the light receiving surface are characterized. With this structure, DOI identification of a plurality of layers can be carried out by simply performing an Anger calculation of a light receiving element signal. | 05-05-2011 |
20120165651 | DETECTOR ROTATION TYPE RADIATION THERAPY AND IMAGING HYBRID DEVICE - An imaging device, or a PET device, opposed gamma camera type PET device, or open PET device in particular, that is combined with a radiation therapy device, in which detectors are rotated to reduce incidence of nuclear fragments on the detectors. For example, in an opposed gamma camera type PET device, beam irradiation and detector rotation can be synchronized to prevent the detectors from interfering with the treatment beam and reduce the incidence of nuclear fragments on the detectors. This makes it possible to reduce the incidence of nuclear fragments on the detectors without interfering with a treatment beam, thereby enabling measurement of annihilation radiations and three-dimensional imaging of the irradiation field immediately after irradiation or during irradiation. | 06-28-2012 |
20130009064 | COINCIDENCE DETERMINATION METHOD AND APPARATUS OF PET DEVICE - In a coincidence determination processing of a PET device for regarding and counting a pair of annihilation radiations detected within a predetermined time as occurring from the same nuclide, a priority of a line of response to acquire is set and a true coincidence is extracted from multiple coincidences by using information on a detection time difference if a plurality of coincidences are detected with the predetermined time. Consequently, a true coincidence is extracted from multiple coincidences which have heretofore been discarded. This improves detection sensitivity at high radioactive concentration and contributes to an improved dynamic range. | 01-10-2013 |
20130020489 | COINCIDENCE DETERMINATION METHOD AND APPARATUS FOR PET DEVICE - For coincidence determination, a PET device that regards and counts a pair of annihilation radiations detected within a predetermined time as occurring from the same nuclide changes a coincidence time width according to a maximum detection time difference. This prevents the inclusion of extra noise data for improved image quality. | 01-24-2013 |
20130037722 | METHOD AND SYSTEM FOR IMAGING USING NUCLEAR MEDICINE IMAGING APPARATUS, NUCLEAR MEDICINE IMAGING SYSTEM, AND RADIATION THERAPY CONTROL SYSTEM - In imaging on the basis of list mode data of a list of radioactive count data detected by a nuclear medicine imaging apparatus for measuring radiation in a pulse mode, the processing from the measurement to imaging of radiation is accelerated substantially to the real time level by selecting the number of count data to be used for online imaging computations on the basis of the counting rate of radiation. | 02-14-2013 |
20140061483 | COINCIDENCE DETERMINATION METHOD AND APPARATUS OF PET DEVICE - In a coincidence determination of a PET device, the PET device uses a scintillator of radioactive isotope containing background noise due to intrinsic radioactivity as a radiation detector. The PET device counts a pair of annihilation radiations that is assumed to occur from a same nuclide. The annihilation radiations are detected within a predetermined coincidence time window by a plurality of radiation detectors. The method includes determining a coincidence with a wide energy window that allows detecting the background noise due to intrinsic radioactivity as multiple coincidences; removing the multiple coincidences; and using an energy window narrower than the wide energy window to limit a coincidence event to a coincidence event in a photopeak from a positron nuclide only. | 03-06-2014 |
Patent application number | Description | Published |
20090008798 | SEMICONDUCTOR DEVICE SUITABLE FOR A STACKED STRUCTURE - A semiconductor device is provided that forms a three-dimensional semiconductor device having semiconductor devices stacked on one another. In this semiconductor device, a hole is formed in a silicon semiconductor substrate that has an integrated circuit unit and an electrode pad formed on a principal surface on the outer side. The hole is formed by etching, with the electrode pad serving as an etching stopper layer. An embedded electrode is formed in the hole. This embedded electrode serves to electrically lead the electrode pad to the principal surface on the bottom side of the silicon semiconductor substrate. | 01-08-2009 |
20110092065 | SEMICONDUCTOR DEVICE SUITABLE FOR A STACKED STRUCTURE - A semiconductor device is provided that forms a three-dimensional semiconductor device having semiconductor devices stacked on one another. In this semiconductor device, a hole is formed in a silicon semiconductor substrate that has an integrated circuit unit and an electrode pad formed on a principal surface on the outer side. The hole is formed by etching, with the electrode pad serving as an etching stopper layer. An embedded electrode is formed in the hole. This embedded electrode serves to electrically lead the electrode pad to the principal surface on the bottom side of the silicon semiconductor substrate. | 04-21-2011 |
20130088908 | SEMICONDUCTOR DEVICE - Memory cells adjacent to each other in a second direction are formed in a first p-type well region, a first n-type well region, and a second p-type well region arranged in a first direction. Each memory cell includes a first transfer transistor and a first driver transistor formed in the first p-type well region, a second transfer transistor and a second driver transistor formed in the second p-type well region, and first and second load transistors formed in the first n-type well region. In an SRAM, gate electrodes of the first and second transfer transistors of the memory cells adjacent to each other in the second direction are electrically connected to first and second word lines, respectively. The first and second word lines are electrically connected to the first and second p-type well regions, respectively. | 04-11-2013 |
20130210207 | FABRICATION METHOD OF SEMICONDUCTOR DEVICE AND FABRICATION METHOD OF DYNAMIC THRESHOLD TRANSISTOR - A method includes: etching a silicon substrate except for a silicon substrate portion on which a channel region is to be formed to form first and second trenches respectively at a first side and a second side of the silicon substrate portion; filling the first and second trenches by epitaxially growing a semiconductor layer having etching selectivity against silicon and further a silicon layer; removing the semiconductor layer selectivity by a selective etching process to form voids underneath the silicon layer respectively at the first side and the second side of the substrate portion; burying the voids at least partially with a buried insulation film; forming a gate insulation film and a gate electrode on the silicon substrate portion; and forming a source region in the silicon layer at the first side of the silicon substrate portion and a drain region at the second side of the silicon substrate portion. | 08-15-2013 |
20140193960 | FABRICATION METHOD OF SEMICONDUCTOR DEVICE AND FABRICATION METHOD OF DYNAMIC THRESHOLD TRANSISTOR - A method includes: etching a silicon substrate except for a silicon substrate portion on which a channel region is to be formed to form first and second trenches respectively at a first side and a second side of the silicon substrate portion; filling the first and second trenches by epitaxially growing a semiconductor layer having etching selectivity against silicon and further a silicon layer; removing the semiconductor layer selectivity by a selective etching process to form voids underneath the silicon layer respectively at the first side and the second side of the substrate portion; burying the voids at least partially with a buried insulation film; forming a gate insulation film and a gate electrode on the silicon substrate portion; and forming a source region in the silicon layer at the first side of the silicon substrate portion and a drain region at the second side of the silicon substrate portion. | 07-10-2014 |
Patent application number | Description | Published |
20120032272 | SEMICONDUCTOR DEVICE, SEMICONDUCTOR INTEGRATED CIRCUIT, SRAM, AND METHOD FOR PRODUCING Dt-MOS TRANSISTOR - A semiconductor device includes a silicon substrate; an element isolation region; an element region including a first well; a contact region; a gate electrode extending from the element region to a sub-region of the element isolation region between the element region and the contact region; a source diffusion region; a drain diffusion region; a first insulating region contacting a lower end of the source diffusion region; a second insulating region contacting a lower end of the drain diffusion region; and a via plug configured to electrically connect the gate electrode with the contact region. The first well is disposed below the gate electrode and is electrically connected with the contact region via the silicon substrate under the sub-region. The lower end of the element isolation region except the sub-region is located lower than the lower end of the first well. | 02-09-2012 |
20120119267 | SEMICONDUCTOR DEVICE PRODUCTION METHOD AND SEMICONDUCTOR DEVICE - A semiconductor device production method includes: forming a semiconductor region including a first region, a second region connecting with the first region and having a width smaller than that of the first region, and a third region connecting with the second region and having a width smaller than that of the second region; forming a gate electrode including a first part crossing the third region and a second part extending from the first part across the first region; forming a side wall insulation film on the gate electrode to cover part of the second region while exposing the remaining part of the second region; implanting a second conductivity type impurity into the first region and the remaining part of the second region; performing heat treatment; removing part of the side wall insulation film, and forming a silicide layer on the first region and the remaining part of the second region. | 05-17-2012 |
20120193717 | SEMICONDUCTOR DEVICE AND METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE - A semiconductor device includes a first device isolation insulating film formed in a semiconductor substrate, a first well having a first conductivity type, defined by the first device isolation insulating film, and shallower than the first device isolation insulating film, a second device isolation insulating film formed in the first well, shallower than the first well, and defining a first part of the first well and a second part of the first well, a gate insulating film formed above the first part, a gate electrode formed above the gate insulating film, and an interconnection electrically connected to the second part of the first well and the gate electrode, wherein an electric resistance of the first well in a first region below the second device isolation insulating film is lower than an electric resistance of the first well in a second region other than the first region on the same depth level. | 08-02-2012 |
20130075743 | SEMICONDUCTOR DEVICE AND METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE - A semiconductor device includes a first device isolation insulating film defining a first region, a first conductive layer of a first conductivity type formed in the first region, a semiconductor layer formed above the semiconductor substrate and including a second conductive layer of the first conductivity type connected to the first conductive layer and a third conductive layer of the first conductivity type connected to the first conductive layer, a second device isolation insulating film formed in the semiconductor layer and isolating the second conductive layer and the third conductive layer from each other, a gate insulating film formed above the second conductive layer, and a gate electrode formed above the gate insulating film and electrically connected to the first conductive layer via the third conductive layer. | 03-28-2013 |
20130154023 | SEMICONDUCTOR DEVICE, SEMICONDUCTOR INTEGRATED CIRCUIT, SRAM, AND METHOD FOR PRODUCING Dt-MOS TRANSISTOR - A semiconductor device includes a silicon substrate; an element isolation region; an element region including a first well; a contact region; a gate electrode extending from the element region to a sub-region of the element isolation region between the element region and the contact region; a source diffusion region; a drain diffusion region; a first insulating region contacting a lower end of the source diffusion region; a second insulating region contacting a lower end of the drain diffusion region; and a via plug configured to electrically connect the gate electrode with the contact region. The first well is disposed below the gate electrode and is electrically connected with the contact region via the silicon substrate under the sub-region. The lower end of the element isolation region except the sub-region is located lower than the lower end of the first well. | 06-20-2013 |
20140051222 | METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE - A method of manufacturing a semiconductor device includes forming a first insulating film above a semiconductor substrate, patterning the first insulating film to form a first and a second opening, forming a first sidewall film on side walls of the first and the second openings, etching the semiconductor substrate with the first insulating film and the first sidewall film as a mask to dig down the first opening and the second opening, removing the first sidewall film to form a first offset portion in the first opening and a second offset portion in the second opening, the first and the second offset portion including a part of a surface of the semiconductor substrate, and etching a bottom of the first opening with the first insulating film as a mask. | 02-20-2014 |
20140285164 | POWER SUPPLY DEVICE AND SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE - A power supply device includes a linear regulator including an output stage amplifier, a current sensing circuit, and a switching regulator. The current sensing circuit detects an output current of the linear regulator, and is disposed in parallel with the output stage amplifier, in a configuration corresponding to the output stage amplifier. The switching regulator operates in accordance with an output signal of the current sensing circuit. The linear regulator and the switching regulator operate in collaboration with each other to generate an output voltage at an output node. | 09-25-2014 |
20140315504 | POWER SUPPLY CIRCUIT, POWER SUPPLY SYSTEM, AND RADIO COMMUNICATION APPARATUS - A power supply circuit includes: a direct current to direct current converter; a linear amplifier; and a first capacitance, one terminal of the first capacitance being coupled an output of the linear amplifier, another terminal of the first capacitance being coupled to an output terminal, wherein the linear amplifier configured to operate in a variable voltage mode and the linear amplifier configured to stop operating and couples an output of the linear amplifier to a ground in a fixed voltage mode. | 10-23-2014 |
20150147041 | OPTICAL FIBER AND OPTICAL FIBER MANUFACTURING METHOD - An optical fiber includes a core, a cladding, and a thermally conductive member. The cladding is formed in a surrounding of the core. The thermally conductive member is formed in a surrounding of the cladding and includes a thermal conductivity higher than thermal conductivities of the core and the cladding. | 05-28-2015 |
Patent application number | Description | Published |
20120070159 | SIGNAL GENERATING CIRCUIT, OPTICAL SIGNAL TRANSMITTING APPARATUS, SIGNAL RECEIVING CIRCUIT, METHOD FOR ESTABLISHING OPTICAL SIGNAL SYNCHRONIZATION, AND OPTICAL SIGNAL SYNCHRONIZATION SYSTEM - To enable signal position detection, frequency offset compensation, clock offset compensation, and chromatic dispersion amount estimation in a communication system based on coherent detection using an optical signal, even on a signal having a great offset in an arrival time depending on a frequency due to chromatic dispersion. An optical signal transmitting apparatus generates specific frequency band signals having power concentrated on two or more specific frequencies and transmits a signal including the specific frequency band signals. An optical signal receiving apparatus converts a received signal into a digital signal, detects positions of the specific frequency band signals from the converted digital signal, estimates frequency positions of the detected specific frequency band signals, and detects a frequency offset between an optical signal receiving apparatus and an optical signal transmitting apparatus. Moreover, the optical signal receiving apparatus detects a clock offset between the optical signal receiving apparatus and the optical signal transmitting apparatus from an interval between the estimated frequency positions of the specific frequency band signals. Furthermore, the optical signal receiving apparatus estimates temporal positions of the detected specific frequency band signals and detects a chromatic dispersion amount from a difference between the temporal positions of the specific frequency band signals corresponding to different frequencies. | 03-22-2012 |
20120099864 | CHROMATIC DISPERSION VALUE CALCULATING APPARATUS, OPTICAL SIGNAL RECEIVING APPARATUS, OPTICAL SIGNAL TRANSMITTING APPARATUS, AND CHROMATIC DISPERSION VALUE CALCULATION METHOD - In order to compensate for chromatic dispersion caused by optical fiber transmission in a communication system with coherent detection using optical signals, specific frequency band signals are used to enable estimation of a chromatic dispersion value. The chromatic dispersion value calculating apparatus is provided with: a signal distributing circuit which distributes, into a plurality of signal sequences, an electrical digital signal converted from received optical signals of an optical signal transmitted by an optical signal transmitting apparatus, in which a known signal with concentrated frequency components of a plurality of specific frequencies is appended to a signal generated from a transmission data sequence; a plurality of frequency band pass filter circuits, each of which separating only each of a plurality of specific frequency components in which the known signal is included from each of the signal sequences distributed by the signal distributing circuit, and passing each of the specific frequency components therethrough; a plurality of power calculating circuits which are provided so as to correspond respectively to the plurality of frequency band pass filter circuits and which calculate power values of signals output from the corresponding frequency band pass filter circuits; a delay time calculating circuit which detects times at which power has the maximum value or times at which the power exceeds a predetermined threshold value, respectively from signal sequences of the power values output from the plurality of power calculating circuits, and which compares the detected times; and a chromatic dispersion value calculating circuit which calculates a chromatic dispersion value based on a comparison result of the times by the delay time calculating circuit. | 04-26-2012 |
20120106618 | METHOD FOR RECEIVING FREQUENCY DOMAIN MULTIPLEXED SIGNAL AND DEVICE FOR RECEIVING FREQUENCY DOMAIN MULTIPLEXED SIGNAL - A frequency domain multiplexed signal receiving method which decodes received signals that are multiplexed in a frequency domain, includes: a digital signal acquisition step of acquiring digital signals from the received signals that are multiplexed in the frequency domain; an offset discrete Fourier transform step of applying an offset discrete Fourier transform to odd discrete point numbers based on the acquired digital signals; and a decode step of decoding frequency domain digital signals in the frequency domain obtained by the offset discrete Fourier transform, and that are the frequency domain digital signals of one or more frequency channels. | 05-03-2012 |
20120155865 | OPTICAL SIGNAL TRANSMITTER, AND BIAS VOLTAGE CONTROL METHOD - An optical signal transmitter of the present invention includes: two phase modulating portions; a phase shifter which displaces carrier phases of two output lights from the phase modulating portions by π/2; a multiplexing portion which multiplexes two signal lights, carrier phases of the two signal lights being made orthogonal to each other by the phase shifter; a drive signal electrode portion which supplies a differential data signal to each of four paths of interference optical waveguides, each of the two phase modulating portions having the interference optical waveguides, the differential data signal having an amplitude which is equal to a half-wave voltage Vπ of the two phase modulating portions; a drive amplifier which amplifies the differential data signal to be supplied to each of the four paths of the interference optical waveguides; a data bias electrode portion which supplies a total of four data bias voltages to two arms, each of the two phase modulating portions having the two arms; an orthogonal bias electrode portion which supplies an orthogonal bias voltage to the phase shifter; a data bias power supply portion that adjusts delay times in the two phase modulating portions by applying the data bias voltages to the data bias electrode portion; an orthogonal bias power supply portion that adjusts a delay amount relative to a light output from at least one of the two phase modulating portions by applying the orthogonal bias voltage to the orthogonal bias electrode portion; a dither signal adding portion that adds a dither signal to at most three of the four data bias voltages; a dither detecting portion which detects a wave that is n-times a dither component from an output of the multiplexing portion (where n is an integer equal to or greater than one); and an orthogonal bias control portion which feeds back a detection result of the dither detecting portion to the orthogonal bias power supply portion. The orthogonal bias power supply portion adjusts the delay amount relative to the light output from at least one of the two phase modulating portions by controlling the orthogonal bias voltage to be applied to the orthogonal bias electrode portion based on feedback from the orthogonal bias control portion. | 06-21-2012 |
20120315043 | TRANSMISSION METHOD, RECEPTION METHOD, TRANSMITTER APPARATUS, AND RECEIVER DEVICE - A polarization state of a transmission signal can be changed at a high speed based on a symbol-rate By switching a first switch, a second switch, and a third switch with time, one of an X-polarized wave_I-signal as a Y-polarized wave_I-signal, a signal caused by performing logical inversion for an X-polarized wave_I-signal, an X-polarized wave_Q-signal and a signal caused by logical inversion for an X-polarized wave_Q-signal is input to a second modulator. Further, by switching the first switch, the second switch and the third switch with time, the second modulator is input one of the X-polarized wave_I-signal as the Y-polarized wave_Q-signal, the X-polarized wave_I-signal, the signal caused by performing logical inversion for the X-polarized wave_I-signal, the X-polarized wave_Q-signal and the signal caused by performing logical inversion for the X-polarized wave_Q-signal. Thereby, a polarization state of a transmission signal can be changed at high speed based on a symbol-rate speed. | 12-13-2012 |
20130028595 | FREQUENCY OFFSET ESTIMATING METHOD AND FREQUENCY OFFSET ESTIMATING APPARATUS - When a circuit that calculates a frequency offset using a shape of a frequency spectrum is implemented by hardware, the circuit size can be reduced. A frequency offset estimating method for estimating the difference between a carrier frequency of a reception signal and the frequency of an output signal of a local oscillator includes performing a discrete Fourier transform on a reception signal previously sampled at a predetermined sampling frequency and outputting a frequency spectrum with a plurality of frequency components, calculating an average power of the frequency spectrum, calculating a threshold by adding a predetermined value to the average power or power obtained by multiplying the average power by a constant, performing 1-bit quantization on powers of the frequency components of the frequency spectrum based on the threshold, and calculating a centroid frequency by multiplying frequencies of the frequency components by powers of 1-bit quantized frequency components, calculating the sum of multiplied products, and dividing the sum of the products by the sum of the powers of the 1-bit quantized frequency components of the frequency spectrum. | 01-31-2013 |
20130070874 | FREQUENCY OFFSET ESTIMATION APPARATUS, FREQUENCY OFFSET ESTIMATION METHOD, AND RECEPTION METHOD - Provided is a frequency offset estimation apparatus that appropriately estimates and compensates for a frequency offset of a received signal when estimating the frequency offset which is the difference between a carrier frequency of the received signal and the frequency of an output signal of a local oscillator. The frequency offset estimation apparatus converts the received signal sampled in advance with a predetermined sampling frequency into a frequency spectrum having N frequency components, limits a frequency band of negative frequency components from 1 to N/2 of the frequency spectrum and a frequency band of positive frequency components from N/2+1 to N of the frequency spectrum, calculates the sum of the squares of the positive frequency components of the frequency spectrum that have been subjected to frequency band limitation and the sum of the squares of the negative frequency components of the frequency spectrum that have been subjected to frequency band limitation to calculate power of the positive frequency components and power of the negative frequency components, and cyclically shifts all frequency components of the frequency spectrum in a frequency domain until the absolute value of a power difference between the power of the positive frequency components and the power of the negative frequency components is less than or equal to a predetermined threshold value, and estimates the frequency offset based on a shift amount until the absolute value is less than or equal to the threshold value. | 03-21-2013 |
20130308960 | DIGITAL SIGNAL PROCESSING APPARATUS - A parameter of an adaptive filter is optimized so that inter-symbol interference having an amount corresponding to an inserted fixed filter remains. A digital signal processing apparatus which is included in an optical signal receiver and processes a digital signal converted from an optical signal is provided with: a linear adaptive filter which applies a dynamically controllable linear transfer function to the digital signal; a maximum likelihood sequence decoder which applies a transfer function of a transmission-path model to a plurality of signal sequence candidates to generate a plurality of reference signals, and decodes a reception signal using maximum likelihood sequence estimation which evaluates the differences between an output signal of the linear adaptive filter and the reference signals to estimate the most likely transmission time sequence; a signal regenerator which generates a signal corresponding to decoded data from the maximum likelihood sequence decoder; a feedback distortion adding filter which adds distortion that is equivalent to the transmission-path model used in the maximum likelihood sequence decoder to an output signal of the signal regenerator; and an adaptive equalization filter control block which updates a tap coefficient of the linear adaptive filter in accordance with an LMS algorithm using the difference between a target signal that is an output signal of the feedback distortion adding filter and the digital signal as an error signal. | 11-21-2013 |
20150078762 | SIGNAL GENERATING CIRCUIT, OPTICAL SIGNAL TRANSMITTING APPARATUS, SIGNAL RECEIVING CIRCUIT, METHOD FOR ESTABLISHING OPTICAL SIGNAL SYNCHRONIZATION, AND OPTICAL SIGNAL SYNCHRONIZATION SYSTEM - To enable signal position detection, frequency offset compensation, clock offset compensation, and chromatic dispersion amount estimation in a communication system based on coherent detection using an optical signal, even on a signal having a great offset in an arrival time depending on a frequency due to chromatic dispersion. An optical signal transmitting apparatus generates specific frequency band signals having power concentrated on two or more specific frequencies and transmits a signal including the specific frequency band signals. An optical signal receiving apparatus converts a received signal into a digital signal, detects positions of the specific frequency band signals from the converted digital signal, estimates frequency positions of the detected specific frequency band signals, and detects a frequency offset between an optical signal receiving apparatus and an optical signal transmitting apparatus. Moreover, the optical signal receiving apparatus detects a clock offset between the optical signal receiving apparatus and the optical signal transmitting apparatus from an interval between the estimated frequency positions of the specific frequency band signals. Furthermore, the optical signal receiving apparatus estimates temporal positions of the detected specific frequency band signals and detects a chromatic dispersion amount from a difference between the temporal positions of the specific frequency band signals corresponding to different frequencies. | 03-19-2015 |
20150078765 | SIGNAL GENERATING CIRCUIT, OPTICAL SIGNAL TRANSMITTING APPARATUS, SIGNAL RECEIVING CIRCUIT, METHOD FOR ESTABLISHING OPTICAL SIGNAL SYNCHRONIZATION, AND OPTICAL SIGNAL SYNCHRONIZATION SYSTEM - To enable signal position detection, frequency offset compensation, clock offset compensation, and chromatic dispersion amount estimation in a communication system based on coherent detection using an optical signal, even on a signal having a great offset in an arrival time depending on a frequency due to chromatic dispersion. An optical signal transmitting apparatus generates specific frequency band signals having power concentrated on two or more specific frequencies and transmits a signal including the specific frequency band signals. An optical signal receiving apparatus converts a received signal into a digital signal, detects positions of the specific frequency band signals from the converted digital signal, estimates frequency positions of the detected specific frequency band signals, and detects a frequency offset between an optical signal receiving apparatus and an optical signal transmitting apparatus. Moreover, the optical signal receiving apparatus detects a clock offset between the optical signal receiving apparatus and the optical signal transmitting apparatus from an interval between the estimated frequency positions of the specific frequency band signals. Furthermore, the optical signal receiving apparatus estimates temporal positions of the detected specific frequency band signals and detects a chromatic dispersion amount from a difference between the temporal positions of the specific frequency band signals corresponding to different frequencies. | 03-19-2015 |