Patent application number | Description | Published |
20080215656 | FAST FOURIER TRANSFORM CIRCUIT AND FAST FOURIER TRANSFORM METHOD - A fast Fourier transform circuit includes a computation component, an extraction component and a setting component. The extraction component, at each step of the computation, extracts, from computation result data points calculated by the computation component, data in a pre-specified range with a number of bits the same as a predetermined number of bits, which is an effective range for a butterfly computations. The setting component sets the data points of the predetermined number of bits which have been extracted by the extraction component to serve as input data when butterfly computations of a next step are to be performed by the computation component. | 09-04-2008 |
20090004987 | RADIO FREQUENCY RECEIVING APPARATUS, RADIO FREQUENCY RECEIVING METHOD, LSI FOR RADIO FREQUENCY SIGNAL AND LSI FOR BASE BAND SIGNAL - A receiving apparatus may achieve optimal RF and IF gain control while suppressing saturated amplification due to interference. The receiving apparatus includes an RF variable gain Amp that amplifies a received RF signal, a mixer that converts an output signal of the RF variable gain Amp into an IF signal, an IF variable gain Amp that amplifies the IF signal, a demodulator that demodulates an output signal of the IF variable gain Amp, and an AGC circuit. The AGC circuit sets a period of gain control for the RF variable gain Amp to be shorter than a period of gain control for the IF variable gain Amp when gains of the RF variable gain Amp and the IF variable gain Amp are controlled based on the output signal of the IF variable gain Amp. | 01-01-2009 |
20090052562 | CORRELATION CALCULATION UNIT AND CORRELATION CALCULATION APPARATUS - A correlation calculation unit includes: four arithmetic units each including a first differential arithmetic section calculating a difference between an OFDM (orthogonal frequency division multiplexing) signal and a first delay signal, a second differential arithmetic section calculating a difference between a second delay signal and a third delay signal, and a multiplication section multiplying arithmetic results of the first and second differential arithmetic sections; four polarity conversion units converting arithmetic results of the multiplication sections of the corresponding arithmetic units into polarity signals indicating polarities of the arithmetic results, respectively; four integrating units integrating the polarity signals obtained by the corresponding polarity conversion units, respectively; and an addition unit adding up integrating results of the four integrating units, and outputting an addition result as a correlation signal indicating a correlation between the OFDM signal and the second delay signal. | 02-26-2009 |
20090092200 | DELAY PROFILE GENERATOR - A delay profile generator that includes a delay profile generating component, a delay profile extracting component, an integrating component, a comparing component and a correcting component, is provided. The integrating component, in the delay profile extracted by the delay profile extracting component, integrates a signal component of a delay profile of a first time period, and integrates a signal component of a delay profile of a second time period that does not overlap the first time period. The comparing component compares integration values of the two time periods obtained by the integrating component. The correcting component corrects a time position of the delay profile window on the basis of results of comparison of the comparing component. | 04-09-2009 |
20090129457 | EQUALIZER CIRCUIT - In an equalizer circuit of one aspect, a first Fourier transform circuit Fourier-transforms an input signal and outputs a corresponding first Fourier-transformed signal, and a first extracting circuit extracts a plurality of pilot symbols from the first Fourier-transformed signal. An inverse Fourier transform circuit calculates a complex gain of each path of the input signal by inverse-transforming the plurality of pilot symbols extracted by the first extracting circuit. A detecting circuit detects at least one of a power value and a mean amplitude of the input signal, and a coefficient determining circuit determines a coefficient corresponding to the at least one of the power value and the mean amplitude detected by the detecting circuit. A second extracting circuit extracts complex gains having a power larger than a threshold obtained by multiplying the coefficient determined by the coefficient determining circuit by a value obtained by integrating the power for a period of time, wherein the power is obtained from the complex gains of each path of the input signal calculated by the inverse Fourier transform circuit. A second Fourier transform circuit Fourier-transforms the extracted complex gains from the second extracting circuit to obtain a corresponding second Fourier-transformed signal, and an equalizing calculation circuit equalizes the input signal using the second Fourier-transformed signal. | 05-21-2009 |
20090209219 | RF RECEIVER DEVICE - A radio-frequency receiver includes an RF amplification circuit which amplifies a received RF signal and generates an amplified RF signal, a mixing circuit which converts the amplified RF signal into an intermediate-frequency signal, an IF amplification circuit which generates an amplified IF signal, a first level detection circuit which detects a level of the amplified RF signal, a second level detection circuit which detects a level of the IF signal, a third level detection circuit which detects a level of the amplified IF signal, a RF reference level generation circuit which generates an RF reference level based on one of respective detection signal levels of the first and second level detection circuits, and an RF gain control circuits which controls an amplification gain of the RF amplification circuit so that a detection signal level of the third level detection circuit becomes equal to the RF reference level. | 08-20-2009 |
20100027720 | CHANNEL ESTIMATING METHOD AND CHANNEL ESTIMATOR - There is provided a channel estimating method of performing frequency conversion by a first fast Fourier transformation on a reception signal and extracting a desired signal after demodulating the reception signal, and deriving electrical energy against time delay of a channel by inverse fast Fourier transformation of the extracted result, wherein: values of a low pass filter, having an output from oversampling the input to the first fast Fourier transformation, are thinned by a plurality of thinning circuits with the same synchronization and different discrete times, and based on the outputs of the plurality of thinning circuits, the electrical energy against time delay related to the reception signal arrival time position is derived by respectively performing the first fast Fourier transformation and the inverse fast Fourier transformation. | 02-04-2010 |
20100124267 | APPARATUS AND METHOD FOR DETECTING INTERFERENCE WAVE - An interference wave detecting apparatus includes a first Fourier transformer for frequency-converting a received signal using Fourier transform; an extractor for extracting a known information signal from the frequency-converted received signal; an interpolator for performing interpolation to the known information signal in frequency domain, thereby generating a first transmission path estimation signal as a frequency-domain information signal; an inverse Fourier transformer for inverse-Fourier-transforming the known information signal, thereby generating a time-domain information signal; a waveform shaping section for shaping a waveform of the time-domain information signal; a second Fourier transformer for Fourier-transforming the shaped time-domain information signal, thereby generating a second transmission path estimation signal as a frequency-domain information signal; and a comparing-computing section for comparing the first and second transmission path estimation signals, thereby generating an interference wave detection result which indicates a ratio of an interference wave of the received signal. | 05-20-2010 |
20110069771 | OFDM RECEIVER AND DOPPLER FREQUENCY ESTIMATING CIRCUIT - A radiofrequency signal is converted to an intermediate frequency signal by a tuner, which is amplified by a variable gain amplifier. The so-amplified signal is converted into a digital signal by an ADC, which is supplied to an FFT, where it is separated into signals set every carrier, followed by being supplied to equalizers different in characteristic. The digital signal outputted from the ADC is further supplied to a level converting circuit from which a control signal is generated. The control signal is supplied to a DAC and a Doppler frequency detector. The DAC generates a gain control signal and supplies the same to the variable gain amplifier. The Doppler frequency detector outputs a frequency component of the control signal as a Doppler detection signal. The Doppler detection signal is compared with a threshold value by a comparator. A selector selects one of signals outputted from the equalizers, in accordance with a select signal indicative of the result of comparison. | 03-24-2011 |
20110129034 | FSK SIGNAL MODULATOR FOR PRODUCING A BINARY FSK SIGNAL - An FSK signal modulator is provided in a transmitter which receives desired information to be transmitted on its input and which modulates the information to be transmitted to transmit a binary FSK signal. A counter counts a value of addition with the value of addition modified in accordance with a predetermined rule, depending on the value specified by the information to be transmitted, and for holding the counted value . The count value is determined by a threshold value decision circuit with respect to a threshold value. The result from the decision is output in the form of binary FSK signal. An FSK signal modulator will be provided which is simplified in circuit constitution. | 06-02-2011 |
20110255642 | RECEIVING APPARATUS, AND COMPUTER READABLE MEMORY MEDIUM THAT STORES A PROGRAM - Suitable gain control is achieved at low cost. | 10-20-2011 |
20120045004 | CORRELATOR AND DEMODULATION DEVICE INCLUDING THE CORRELATOR - The Present invention provides a correlator including, a read-out processing circuit that reads out an OFDM signal in RAM as 2n−1 number of delay OFDM signals that are increased and delayed sequentially with their adjusted read-out timings. Complex conjugate circuits that outputs complex conjugates of the inputted n | 02-23-2012 |
20120045025 | DIVERSITY RECEPTION DEVICE AND DIVERSITY RECEPTION METHOD - A diversity reception device includes branches, a controller and a combining section. Each branch includes a correlation section that generates a correlation signal that represents a correlation between a received signal and a delayed signal or between the received signal and a reference signal, where the correlation signal level disregarding the received signal level, a time position detector that detects time positions at which the level of the correlation signal is at a peak, a demodulation section that demodulates the received signal, and a multiplication section that multiplies the demodulated signal with a weighting factor. The controller controls the weighting factor on the basis of the respective levels of the correlation signals at the detected time positions. The combining section combines, by adding, the respective demodulated signals of the branches subsequent to the demodulated signal of each branch being multiplied with the weighting factor. | 02-23-2012 |