Abstract: A signal-generating circuit includes a voltage-controlled oscillator that generates an oscillated signal; a first frequency divider that generates a first divided signal by dividing the oscillated signal; a second frequency divider that generates a second divided signal by dividing the divided signal; a phase comparator that receives as input the second divided signal and a reference signal and outputs two signals corresponding to a phase difference therebetween; a loop filter that extracts a low frequency signal between the two signals to be output to the voltage-controlled oscillator; a third frequency divider that generates a third divided signal by dividing the first divided signal; a first frequency converter that generates a first frequency converted signal by multiplying the oscillated signal by the third divided signal; and a first multiplier that generates a multiplied signal by multiplying the first frequency converted signal by a first multiplication number.

Abstract: A wireless communication device of the present disclosure has: a transmitter having a plurality of transmission circuit branches; a receiver having a plurality of reception circuit branches; a transmission phase switch; a reception phase switch; and a phase/transmission-reception controller, and has a beam-forming function. When phase switching is performed during a plurality of training packets for setting directivity, the phase/transmission-reception controller controls the transmission phase switch and the reception phase switch by setting a same phase for each of m (m being an integer of 2 or more) number of continuous training packets. In addition, the phase/transmission-reception controller performs control such that the transmission of the transmitter and the reception of the receiver are set to an OFF state in at least one or more training packets from the beginning of the m number of continuous training packets.

Abstract: A nonlinear distortion detection device that includes a test signal generator that generates a test signal and outputs the test signal to have the power amplifier amplify the test signal, a Fourier transformer that converts an output signal of the power amplifier to a signal in a frequency domain, and a distortion factor calculator that calculates a distortion factor of the power amplifier based on amplitude information and phase information of the signal in the frequency domain.

Abstract: A wireless communication device includes a BBIC for performing baseband signal processing, an RFIC for performing radio-frequency signal processing, and a quartz resonator. The RFIC has a storage unit which stores an adjustment value for adjustment of a clock frequency that is based on an oscillation frequency of the quartz resonator, and outputs the adjustment value when its resetting active state is canceled; a frequency adjusting unit for adjusting the clock frequency according to the adjustment value; and an RF signal processing unit which operates based on the clock signal and performs the radio-frequency signal processing.

Abstract: A signal-generating circuit includes a voltage-controlled oscillator that generates an oscillated signal; a first frequency divider that generates a first divided signal by dividing the oscillated signal; a second frequency divider that generates a second divided signal by dividing the divided signal; a phase comparator that receives as input the second divided signal and a reference signal and outputs two signals corresponding to a phase difference therebetween; a loop filter that extracts a low frequency signal between the two signals to be output to the voltage-controlled oscillator; a third frequency divider that generates a third divided signal by dividing the first divided signal; a first frequency converter that generates a first frequency converted signal by multiplying the oscillated signal by the third divided signal; and a first multiplier that generates a multiplied signal by multiplying the first frequency converted signal by a first multiplication number.

Abstract: A wireless communication device includes a digital modulation signal generator that generates digital modulation signals, a DAC that converts digital output of the digital modulation signal generator into analog signals, a modulator that generates amplified quadrature modulation signals by exerting quadrature modulation and amplification on the analog signals, an antenna that radiates the amplified quadrature modulation signals, a power detector that outputs power detected signals obtained from power detection of the amplified quadrature modulation signals, a controller that adjusts gain of the modulator by using the power detected signals and a desired power value, a thermometer that measures ambient temperatures at a plurality of burst transmission periods, and a high-power prevention circuit that readjusts the gain of the modulator for a present burst transmission period.

Abstract: A variable gain amplifier amplifies a baseband signal. A quadrature modulator quadrature-modulates the amplified baseband signal to generate a high-frequency signal. A power amplifier amplifies the generated high-frequency signal. An antenna transmits the amplified high-frequency signal. A detector detects the amplified high-frequency signal. A first nonvolatile memory stores the desired transmission power of the high-frequency signal to be transmitted from the antenna. A controller adjusts the gain of the variable gain amplifier depending on the output of the detector and the transmission power stored in the first nonvolatile memory.

Abstract: A wireless communication device includes a BBIC for performing baseband signal processing, an RFIC for performing radio-frequency signal processing, and a quartz resonator. The RFIC has a storage unit which stores an adjustment value for adjustment of a clock frequency that is based on an oscillation frequency of the quartz resonator, and outputs the adjustment value when its resetting active state is canceled; a frequency adjusting unit for adjusting the clock frequency according to the adjustment value; and an RF signal processing unit which operates based on the clock signal and performs the radio-frequency signal processing.

Abstract: When communicating with a second wireless station, a first wireless station judges, based on link-related information received from the second wireless station and link-related information extracted from a signal transmitted by a fourth wireless station, whether a transmission link from the third wireless station to the fourth wireless station and a transmission link from the first wireless station to the second wireless station can be concurrently established without interference with each other. If judging affirmatively, the first wireless station transmits a signal to the second wireless station in synchronization with a signal transmitted by the third wireless station to the fourth wireless station.

Abstract: A modulation section including a feedback circuit configured to conduct feedback control of an output signal from a voltage controlled oscillator based on an inputted modulation signal, and a feed-forward circuit configured to calibrate the modulation signal and outputting the calibrated modulation signal to the voltage controlled oscillator; a signal output section configured to output, to the modulation section, a predetermined reference signal instead of the modulation signal when a calibration is conducted; and a gain correction section configured to, in a state where the feedback circuit is forming an open loop, calculate a frequency transition amount of the reference signal outputted by the voltage controlled oscillator, and correct a gain used for calibrating the modulation signal at the feed-forward circuit based on the calculated frequency transition amount.

Abstract: An AGC unit starts a gain control of the variable gain amplifying unit when a bit saturation occurs in the digital baseband signal output from the A/D converting unit, and starts a gain control of the variable gain amplifying unit when a detection of STS from the digital baseband signal output from the A/D converting unit is started. The AGC unit performs the gain control of the variable gain amplifying unit once when the detection of STS is started, and performs the gain control of the variable gain amplifying unit twice when the bit saturation occurs, namely a larger number of times than when the detection of STS is started.

Abstract: A wireless transmission system performs multi-station simultaneous transmission of data. The wireless transmission system includes wireless stations for transmitting and receiving data. Transmitter-side wireless stations, a multipath channel, and receiver-side wireless stations constitute a system for path diversity. At least one wireless station among the wireless stations determines, depending on a response packet with respective to a multi-station simultaneous transmission request packet transmitted by itself or other stations, delay amounts from a reference timing during multi-station simultaneous transmission in the wireless transmission system, and symbol waveforms that are a basis for a modulated waveform. A difference between each delay amount is set to be larger than or equal to a predetermined delay resolution for each symbol waveform, and a difference between maximum and minimum values of the delay amounts is set to be smaller than or equal to a predetermined maximum delay.

Abstract: Disclosed are an angle modulator, a transmission apparatus, and a radio communication apparatus that can compensate phase discontinuity when an operational mode of a voltage controlled oscillator is switched. Angle modulator (100) includes phase difference detection section (150) that detects a difference of phases between an input signal of subtractor (141) and an angle modulated signal, using the result of subtraction by subtractor (141) of frequency locked loop circuit (140); correction control section (160) that generates a control signal for compensating that difference of phases based on that difference of phases; correction section (120) that corrects the phase of the angle modulated signal by adding the control signal to an input signal of angle modulator (100), an input signal of loop filter (142), or an input signal of VCO (143) during a predetermined period after VCO (143) switches the operational mode (from time t3 to time t4).

Abstract: A reception station 1b compares its BSSID with BSSID included in a signal that has arrived thereat. As BSSIDs included in signals transmitted by interfering stations 1c and 1d both match BSSID of the reception station 1b, the reception station 1b identifies each of the interfering stations 1c and 1d as a non-suppression target transmission source. As neither of BSSIDs included in signals transmitted by interfering stations 2a and 2b matches BSSID of the reception station 1b, the reception station 1b identifies each of the interfering stations 2a and 2b as a suppression target transmission source. The reception station 1b uses characteristic amounts of signals that are associated with the interfering stations (i.e., suppression target transmission sources) 2a and 2b and that have been measured in the past as characteristic amounts of interfering signals that are used to suppress the interfering signals from a received signal.

Abstract: The noise amount information storage unit 161 stores noise amount information which indicates relationships between gain value of the variable gain amplification units 121 and 125 and the amount of noise included in BB signals output from the down converters 131 and 135. The AGC unit 140 controls the gain value of the variable gain amplification units 121 and 125 so that the power of BB signals output from the down converters 131 and 135 becomes constant. The noise amount estimation unit 162 estimates noise amount of noise corresponding to the controlled gain value of the variable gain amplification units 121 and 125 by referring to the noise amount information stored in the noise amount information storage unit 161. The weight generation unit 170 generates weight matrix based on results of estimations performed by the channel characteristic estimation unit 150 and the noise estimation unit 162.

Abstract: A wireless transmission system capable of exerting a maximum path diversity effect by using combinations formed by symbol waveforms. A transmission timing controlling section (23) determines a transmission start timing. A modulating section (21) modulates a signal by using one of a plurality of symbol waveform candidates and by utilizing a modulation scheme in which a phase transition of a symbol waveform represents a waveform being changed, and then transmits the modulated signal at a transmission start timing. A predetermined delay amount is set such that (i) the number of reception timings, each indicating a timing at which a receiving station (12) receives a signal, is a plural number and is less than or equal to a maximum number of effective branches for each symbol waveform, and (ii) each time difference between the reception timings is greater than or equal to a delay resolution and less than or equal to a maximum delay.

Abstract: Included are: a modulation section including a feedback circuit configured to conduct feedback control of an output signal from a voltage controlled oscillator based on an inputted modulation signal, and a feed-forward circuit configured to calibrate the modulation signal and outputting the calibrated modulation signal to the voltage controlled oscillator; a signal output section configured to output, to the modulation section, a predetermined reference signal instead of the modulation signal when a calibration is conducted; and a gain correction section configured to, in a state where the feedback circuit is forming an open loop, calculate a frequency transition amount of the reference signal outputted by the voltage controlled oscillator, and correct a gain used for calibrating the modulation signal at the feed-forward circuit based on the calculated frequency transition amount.

Abstract: An FFT unit (170) separates a received symbol by Fourier conversion into a plurality of subcarriers, and a phase difference detection unit (193) detects a phase difference between 4 pilot carriers and data carriers adjacent to the pilot carriers (adjacent carriers) The decision unit (194) decides whether the phase differences between the pilot carriers and the adjacent carriers detected by the phase difference detection unit (193) fulfill a phase difference condition. Then, the decision unit (194) decides that the received symbol is an HTSIG if the number of phase differences that fulfill the phase difference condition is greater than or equal to a predetermined number, and decides that the received symbol is either a SIG or a DATA if the number of phase differences that fulfill the phase difference condition is less than the predetermined number.

Abstract: Disclosed are an angle modulator, a transmission apparatus, and a radio communication apparatus that can compensate phase discontinuity when an operational mode of a voltage controlled oscillator is switched. Angle modulator (100) includes phase difference detection section (150) that detects a difference of phases between an input signal of subtractor (141) and an angle modulated signal, using the result of subtraction by subtractor (141) of frequency locked loop circuit (140); correction control section (160) that generates a control signal for compensating that difference of phases based on that difference of phases; correction section (120) that corrects the phase of the angle modulated signal by adding the control signal to an input signal of angle modulator (100), an input signal of loop filter (142), or an input signal of VCO (143) during a predetermined period after VCO (143) switches the operational mode (from time t3 to time t4).

Abstract: When communicating with a second wireless station, a first wireless station judges, based on link-related information received from the second wireless station and link-related information extracted from a signal transmitted by a fourth wireless station, whether a transmission link from the third wireless station to the fourth wireless station and a transmission link from the first wireless station to the second wireless station can be concurrently established without interference with each other. If judging affirmatively, the first wireless station transmits a signal to the second wireless station in synchronization with a signal transmitted by the third wireless station to the fourth wireless station.