Abstract: A radio frequency signal can be received in an intermediate frequency mode suitable for radio wave reception conditions. An oscillator has a variable oscillation frequency. A quadrature demodulator includes a frequency mixer and generates an intermediate frequency signal having an intermediate frequency lower than the frequency of the radio frequency signal. An ADC receives the intermediate frequency signal passed through an analog filter and converts the received intermediate frequency signal to a digital signal. A channel selection signal processing section generates a demodulated signal from the intermediate frequency signal converted to the digital signal. A mode control section switches the operating mode of the quadrature demodulator between a zero intermediate frequency mode and a low intermediate frequency mode in accordance with the radio wave reception conditions.

Abstract: A radio frequency signal can be received in an intermediate frequency mode suitable for radio wave reception conditions. An oscillator has a variable oscillation frequency. A quadrature demodulator includes a frequency mixer and generates an intermediate frequency signal having an intermediate frequency lower than the frequency of the radio frequency signal. An ADC receives the intermediate frequency signal passed through an analog filter and converts the received intermediate frequency signal to a digital signal. A channel selection signal processing section generates a demodulated signal from the intermediate frequency signal converted to the digital signal. A mode control section switches the operating mode of the quadrature demodulator between a zero intermediate frequency mode and a low intermediate frequency mode in accordance with the radio wave reception conditions.

Abstract: A power line carrier transmission apparatus for transmitting a transmission symbol via a power line, the power line carrier transmission apparatus including an interleave unit interleaving the transmission symbol, a modulation unit for modulating the transmission symbol interleaved by the interleave unit, and a transmission unit repeatedly transmitting the transmission symbol modulated by the modulation unit M times (where M is an integer larger than 1), wherein M symbols (where M denotes the number of the symbols), which are generated by repeatedly transmitting the transmission symbol M times by the transmission unit, are transmitted without guard intervals being added therebetween.

Abstract: In the signal processing device, which is capable of performing an FFT and performing a window function process as preprocessing before the FFT and achieves OFDM demodulation, the window function process is skipped to perform an FFT on a received signal if the frequency of narrow-band noise included in the received signal coincides with the subcarrier frequency of OFDM within a predetermined range. If the frequencies do not coincide with each other, the FFT is performed after the window function process is performed on the received signal. The signal processing device includes an NBN detection/determination section, which determines whether narrow-band noise is included in a subcarrier, and a window function determination section, which determines, in accordance with the degree of coincidence between the frequency of narrow-band noise and the frequency of a subcarrier, whether or not to perform the window function process.

Abstract: A semiconductor device contains a narrow band noise detector section to detect narrow band noise in an input signal that is input by way of a power line. The semiconductor device further includes a reference signal generator section to generate a second reference signal whose amplitude value which corresponds to the narrow band noise frequency of a pre-established first reference signal is reduced, and a correlation calculation section to calculate the correlation value between the input signal and the second reference signal utilized in the frame synchronization processing of the input signal.

Abstract: Disclosed is a signal processing device that reduces the influence of an interfering wave to suppress the deterioration of a BER even if narrow-band noise is included in a communication band. In the signal processing device, which is capable of performing an FFT and performing a window function process as preprocessing before the FFT and achieves OFDM demodulation, the window function process is skipped to perform an FFT on a received signal if the frequency of narrow-band noise included in the received signal coincides with the subcarrier frequency of OFDM within a predetermined range. If the frequencies do not coincide with each other, the FFT is performed after the window function process is performed on the received signal.

Abstract: A power line carrier transmission apparatus for transmitting a transmission symbol via a power line, the power line carrier transmission apparatus including an interleave unit interleaving the transmission symbol, a modulation unit for modulating the transmission symbol interleaved by the interleave unit, and a transmission unit repeatedly transmitting the transmission symbol modulated by the modulation unit M times (where M is an integer larger than 1), wherein M symbols (where M denotes the number of the symbols), which are generated by repeatedly transmitting the transmission symbol M times by the transmission unit, are transmitted without guard intervals being added therebetween.

Abstract: Disclosed is a signal processing device that reduces the influence of an interfering wave to suppress the deterioration of a BER even if narrow-band noise is included in a communication band. In the signal processing device, which is capable of performing an FFT and performing a window function process as preprocessing before the FFT and achieves OFDM demodulation, the window function process is skipped to perform an FFT on a received signal if the frequency of narrow-band noise included in the received signal coincides with the subcarrier frequency of OFDM within a predetermined range. If the frequencies do not coincide with each other, the FFT is performed after the window function process is performed on the received signal.

Abstract: A power line carrier transmission apparatus according to an aspect of the present invention is a power line carrier transmission apparatus that transmits a transmission symbol via a transmission path. The transmission apparatus includes a frequency/time interleave unit that interleaves the transmission symbol, an OFDM modulation unit that OFDM-modulates the interleaved transmission symbol, a time-domain repeated transmission unit that repeatedly transmits the transmission symbol, which is modulated by the OFDM modulation unit, M times (M is an integer larger than 1) in a time domain.

Abstract: A receiving device according to the present invention includes: a receiver for receiving an OFDM symbol that is modulated by phase shift keying; an FFT processor for applying an FFT process to the received OFDM symbol to obtain a subcarrier signal; a demapping unit for demapping the subcarrier signal to generate a bit string; a norm calculator for calculating the norm of the subcarrier; a weighting factor generator for generating a weighting factor by taking the statistics of the calculated norm; and a weighting unit for obtaining a soft decision value by weighting the bit string after demapping, based on the particular weighting factor. Thus, the receiving device can obtain a soft decision value to achieve good decoding performance with a small number of known signals and processes.

Abstract: A semiconductor device contains a narrow band noise detector section to detect narrow band noise in an input signal that is input by way of a power line. The semiconductor device further includes a reference signal generator section to generate a second reference signal whose amplitude value which corresponds to the narrow band noise frequency of a pre-established first reference signal is reduced, and a correlation calculation section to calculate the correlation value between the input signal and the second reference signal utilized in the frame synchronization processing of the input signal.

Abstract: A semiconductor device contains a narrow band noise detector section to detect narrow band noise in an input signal that is input by way of a power line. The semiconductor device further includes a reference signal generator section to generate a second reference signal whose amplitude value which corresponds to the narrow band noise frequency of a pre-established first reference signal is reduced, and a correlation calculation section to calculate the correlation value between the input signal and the second reference signal utilized in the frame synchronization processing of the input signal.

Abstract: A receiving device according to the present invention includes: a receiver for receiving an OFDM symbol that is modulated by phase shift keying; an FFT processor for applying an FFT process to the received OFDM symbol to obtain a subcarrier signal; a demapping unit for demapping the subcarrier signal to generate a bit string; a norm calculator for calculating the norm of the subcarrier; a weighting factor generator for generating a weighting factor by taking the statistics of the calculated norm; and a weighting unit for obtaining a soft decision value by weighting the bit string after demapping, based on the particular weighting factor. Thus, the receiving device can obtain a soft decision value to achieve good decoding performance with a small number of known signals and processes.

Abstract: A communication device includes: an amplifier (62) arranged to amplify a reception signal received from one of the plurality of terminals; a first demodulation unit (26) arranged to demodulate a first frame transmitted using a first communication method operable to communicate when CNR is smaller than 0 dB; a second demodulation unit (27) arranged to demodulate, in parallel with the first demodulation unit demodulating the first frame, a second frame transmitted using a second communication method having a rate higher than a rate of the first communication method at a frequency band same as a frequency band used for the first communication method; and a gain controller (64) arranged to adjust a gain of the amplifier in accordance with a detection outcome of a preamble included in the first frame and the second frame.

Abstract: A receiving device according to the present invention includes: a receiver for receiving an OFDM symbol that is modulated by phase shift keying; an FFT processor for applying an FFT process to the received OFDM symbol to obtain a subcarrier signal; a demapping unit for demapping the subcarrier signal to generate a bit string; a norm calculator for calculating the norm of the subcarrier; a weighting factor generator for generating a weighting factor by taking the statistics of the calculated norm; and a weighting unit for obtaining a soft decision value by weighting the bit string after demapping, based on the particular weighting factor. Thus, the receiving device can obtain a soft decision value to achieve good decoding performance with a small number of known signals and processes.

Abstract: A semiconductor device contains a narrow band noise detector section to detect narrow band noise in an input signal that is input by way of a power line. The semiconductor device further includes a reference signal generator section to generate a second reference signal whose amplitude value which corresponds to the narrow band noise frequency of a pre-established first reference signal is reduced, and a correlation calculation section to calculate the correlation value between the input signal and the second reference signal utilized in the frame synchronization processing of the input signal.

Abstract: A power line carrier transmission apparatus according to an aspect of the present invention is a power line carrier transmission apparatus that transmits a transmission symbol via a transmission path. The transmission apparatus includes a frequency/time interleave unit that interleaves the transmission symbol, an OFDM modulation unit that OFDM-modulates the interleaved transmission symbol, a time-domain repeated transmission unit that repeatedly transmits the transmission symbol, which is modulated by the OFDM modulation unit, M times (M is an integer larger than 1) in a time domain.

Abstract: There is already disclosed a technique for an MB-OFDM communication system whereby an orthogonal demodulation section removes a DC offset generated in a received signal in a region where the received signal is an analog signal, but the removal of the DC offset in the analog region cannot prevent the DC offset from remaining, and therefore the DC offset needs to be effectively removed in a digital region. An offset canceling section 26 calculates an average value of amplitude of a signal which should have an average of amplitude within a predetermined time range of 0, subtracts the average value from the signal and thereby removes an offset included in the signal.

Abstract: A synchronization timing detecting apparatus includes a correlation calculator configured to generate a first correlation value by calculating a cross-correlation between an input signal being sampled and a reference signal or an auto-correlation of the sampled input signal, an interpolation processor configured to generate a second correlation value interpolating a plurality of the first correlation values having a different combination of sampling points of the input signal, and a detector to detect a synchronization timing based on the first and the second correlation values.

Abstract: A symbol timing detection method, executed in a processor, is provided where, upon detecting a symbol timing from a received signal composed of a packet having a preamble with periodically allocated symbols placed at a head of data, correlation results indicating a correlation between the received signal and a fixed pattern of the preamble are obtained, a maximum value in the correlation results are updated and held, and a timing of the maximum value is determined as a symbol timing on a condition that a maximum value currently held by the correlation peak detection unit is not updated in a symbol timing determination period having a predetermined length from the timing and that a number of occurrences of a correlation result exceeding an error detection determination threshold is smaller than a predetermined number in an error detection determination period defined within the symbol timing determination period.