Patent application number | Description | Published |
20090085786 | SIGNAL MODULATION METHOD, SIGNAL MODULATION APPARATUS, ELECTRONIC DEVICE, AND COMPUTER PROGRAM PRODUCT - A signal modulation method by an electronic device which includes a minimal reducing unit that minimally reduces an integrated signal returned to an adder from an integrator. | 04-02-2009 |
20090295437 | SIGNAL WAVEFORM GENERATING CIRCUIT AND METHOD - A signal waveform generating circuit includes a first part storing waveform data of a signal to be generated, a second part storing additional data for adjusting the waveform data, and a third part adjusting the waveform data read from the first part by the additional data read from the second part. | 12-03-2009 |
20120128377 | OPTICAL DIGITAL COHERENT RECEIVER - An ALC processing unit to adjust the signal level of outputs from an adaptive equalizer to a target value is provided in a stage later than the adaptive equalizer and earlier than a frequency offset estimation/compensation unit in an optical digital coherent receiver. The ALC processing unit generates a histogram that counts the number of samples for discrete monitored values corresponding to amplitude values of outputs from the adaptive equalizer, and determines a level adjustment coefficient that is to be multiplied by an output from the adaptive equalizer so as to multiply the determined coefficient by the output from the adaptive equalizer so that the monitored value of the peak value of the histogram is the target value. | 05-24-2012 |
20120134684 | Adaptive equalizer, optical receiver, and tap coefficient correcting method - An adaptive equalizer includes a finite impulse response filter with a predetermined number of taps; and a tap coefficient adaptive controller having a register to hold tap coefficients for the filter, a weighted center calculator to calculate a weighted center of the tap coefficients, and a tap coefficient shifter to shift the tap coefficients based on a calculation result of the weighted center. During an initial training period, the tap coefficient shifter shifts the tap coefficients on a symbol data basis such that a difference between the calculated weighted center of the tap coefficients and a tap center defined by the number of taps is minimized. | 05-31-2012 |
20130254728 | COMPUTER PRODUCT, DESIGN SUPPORT METHOD, AND DESIGN SUPPORT APPARATUS - A computer-readable recording medium stores a design support program that causes a computer to execute a process that includes generating based on a control flow graph conversion result for operation description information concerning a circuit-under-design, a first synthesis result according to which a time length of 1 clock cycle of the circuit-under-design is greater than or equal to a clock period in which the circuit-under-design operates; calculating based on the generated first synthesis result, first circuit scale information indicating a circuit scale of the circuit-under-design; acquiring a second synthesis result that is for the circuit-under-design and conforms to a timing constraint that is based on the control flow graph conversion result; calculating second circuit scale information indicating the circuit scale of the circuit-under-design, based on the generated second synthesis result; and outputting the calculated first circuit scale information and the calculated second circuit information. | 09-26-2013 |
20130317802 | METHOD FOR SIMULATING DATA TRANSMISSION AMONG A PLURALITY OF HARDWARE ELEMENTS - An event-driven simulation is performed on an operation of data transmission from a source hardware element to a destination hardware element. Upon receiving a first request for transmitting first data at a first time-point, data stored in a storage area of the destination hardware element is saved as backup data in a memory, and the first data is stored in the storage area. A first time-period for transmitting the first data is measured from the first time-point. When a second request having a higher priority than the first request is received at a second time-point, a portion of the backup data is restored to the storage area so that the storage area stores third data estimated to have been transmitted to the destination hardware element. After a second time-period for the second request is measured, the first data is again stored in the storage area. | 11-28-2013 |
20150098714 | OPTICAL COMMUNICATION RECEIVING DEVICE AND FREQUENCY OFFSET COMPENSATION METHOD - A receiving device that converts, to a digital signal, a signal in which signal light from an optical transmission path and local oscillation light are mixed, so as to perform digital signal processing, the optical communication receiving device comprising: a frequency offset compensation unit configured to calculate a frequency offset of the digital signal and to, based on the frequency offset, compensate for a phase of the digital signal; a carrier phase recovery unit configured to calculate a carrier phase of the digital signal whose phase is compensated for in the frequency offset compensation unit; and a residual frequency offset detection unit configured to calculate an average of differences in the carrier phase, and to output the average as a residual frequency offset, wherein the frequency offset compensation unit is configured to correct the frequency offset using the residual frequency offset output by the residual frequency offset detection unit. | 04-09-2015 |
20150147071 | FREQUENCY OFFSET ESTIMATION CIRCUIT AND FREQUENCY OFFSET ESTIMATION METHOD - A frequency offset estimation circuit estimates a frequency offset that indicates a difference between a carrier frequency of a received optical signal and a frequency of a local oscillation light used to recover a transmission signal from the received optical signal. The frequency offset estimation circuit includes: a phase difference detector configured to detect a phase difference due to the frequency offset between a first symbol and a second symbol that is transmitted after the first symbol by a specified symbol interval based on a phase of the first symbol and a phase of the second symbol; an estimator configured to estimate the frequency offset based on the phase difference detected by the phase difference detector; and a symbol interval controller configured to specify the symbol interval based on the frequency offset estimated by the estimator. | 05-28-2015 |