Abstract: An input signal to a filter device is allowed to be written into one of a plurality of sequentially connected cells if the input signal is not the zero-valued sample. Each cell receives the input signal and multiplies the input signal by one of a plurality of weight coefficients. The input signal is stopped to be written into any of the cells if the input signal is the zero-valued sample. A result of a filtering operation is output from the last cell.

Abstract: A distortion in an amplified signal obtained by amplifying a first input signal, is compensated for by applying a correction factor to the first input signal. The correction factor is updated based on the first input signal and the amplified signal. Updating the correction factor is prohibited when a value of the first input signal is same as a value of a second input signal among a plurality of input signals input previous to the first input signal.

Abstract: A transmitter includes: a limiter performing clipping in which an amplitude part at a level higher than an amplitude level based on a predetermined clipping level is clipped from an input signal, separating the input signal into an input signal after the clipping, which contains a predetermined out-of-band component, and a clip signal clipped from the input signal through the clipping, and outputting the input signal after the clipping and the clip signal; a high-pass filter subjecting the clip signal inputted from the limiter to high-pass filtering for blocking an in-band component contained in the clip signal while passing an out-of-band component contained in the clip signal, which is opposite in phase to the out-of-band component contained in the input signal after the clipping; an adder performing an addition process on the out-of-band component received from the high-pass filter and the input signal after the clipping received from the limiter; and an amplifier performing power amplification on a signal

Abstract: An apparatus for updating a coefficient for distortion compensation includes a compensation coefficient storing unit configured to store a plurality of distortion compensation coefficients used for a pre-distortion-compensation processing; a correction value generator configured to generate one or more correction values for one or more distortion compensation coefficients, based on a correction value which is calculated using a transmission signal before distortion compensation processing and an amplified signal after the distortion compensation processing to which a distortion compensation coefficient is applied, other than the applied distortion compensation coefficient; and an adder configured to add the correction value to the applied distortion compensation coefficient and add the one or more correction values to the one or more distortion compensation coefficients to update the plurality of distortion compensation coefficients.

Abstract: A transmitter includes a first limiter for performing a first clipping in which an amplitude part at a level higher than an amplitude level based on a first clipping level is cut out from an input signal to be subjected to power amplification, a second limiter for performing a second clipping in which an amplitude part at a level lower than the amplitude level based on a second clipping level is cut out from a first signal that has undergone the first clipping, a separation section for separating a second signal that has undergone the second clipping into an amplitude modulated part and a constant amplitude part, a first amplifier for amplifying the amplitude modulated part, a second amplifier for amplifying the constant amplitude part, and a combiner for outputting a third signal obtained by combining the amplitude part amplified by the first amplifier and the constant amplitude part amplified by the second amplifier.

Abstract: A transmitter includes: a limiter performing clipping in which an amplitude part at a level higher than an amplitude level based on a predetermined clipping level is clipped from an input signal, separating the input signal into an input signal after the clipping, which contains a predetermined out-of-band component, and a clip signal clipped from the input signal through the clipping, and outputting the input signal after the clipping and the clip signal; a high-pass filter subjecting the clip signal inputted from the limiter to high-pass filtering for blocking an in-band component contained in the clip signal while passing an out-of-band component contained in the clip signal, which is opposite in phase to the out-of-band component contained in the input signal after the clipping; an adder performing an addition process on the out-of-band component received from the high-pass filter and the input signal after the clipping received from the limiter; and an amplifier performing power amplification on a signal

Abstract: In a receiving apparatus in a multicarrier communication system for transmitting data independently via a plurality of subchannels, (1) a soft-decision target value lnD0 is calculated, this being the difference between the probability that data received from a subchannel of interest is one of two values and the probability that the data is the other of the two values; (2) a non-linear operation is performed using degrees of coupling ?1, ?2 with other subchannels and soft-decision target values lnD1, lnD2 that have entered from receivers on the other channels, and the soft-decision target value lnD0 on the subchannel of interest is adjusted subchannel by subchannel based upon results of the non-linear operation; and (3) a decision is rendered on receive data based upon the soft-decision target value that has been adjusted.

Abstract: The present invention is a multi-carrier communication system for transmitting/receiving signals via at least four sub-channels, comprising: a transmitter for transmitting data independently via the four sub-channels; a receiver comprising a receive unit disposed for each sub-channel for receiving data from a corresponding sub-channel and performing soft decision of the receive data; and means for inputting soft decision target values in receive units corresponding to three sub-channels other than a target sub-channel to a receive unit of the target sub-channel, wherein the receive unit of the target sub-channel adjusts its own soft decision target value using the soft decision target values that are input from the receive units of the other sub-channels, and decides the receive data based on this adjusted soft decision target value.

Abstract: Two correlation signals which are obtained by computing correlations between two reference signals and a reception signal are inputted to a level-0 cell, the reference signals being generated on the basis of combinations of crosstalk coefficients. A level-1 soft judgment target signal is produced by using soft judgment target signals that are outputted by two sets of level-0 cells respectively and, similarly, a level (N+1) cell is formed by using two sets of level-N cells, whereby a soft judgment target signal creation portion with a hierarchical structure is constituted. A judgment unit outputs a soft judgment value of the target subchannel on the basis of the soft judgment target signal that is outputted by the level (N+1) cell, and judges a reception signal.

Abstract: A reception device receives and demodulates, for each subchannel, data transmitted independently via three subchannels, which are a subchannel of interest and the two upper and lower adjacent subchannels which interfere with the subchannel of interest. A reception portion provided for each subchannel computes, as a soft decision value, the probability that data received from the subchannel of interest is “0” and the probability that the data is “1”, taking into account the degree of coupling between channels, and moreover uses the soft decision values input from the two upper and lower adjacent reception devices to adjust and output the soft decision value for the subchannel of interest, and based on the adjusted soft decision value, decides whether the received data is “0” or “1”.