Fujitsu Corporation

Yukihiro Moriyama

Koji Takata

Masaru Kabashima

Yuji Kaneko

Yoshiya Ohsaki

Yasuyuki Oishi

Takeshi Takano

Kazuhiko Nobunaga

Shigeaki Matsumoto

Haruhiro Noma

Kouzou Tokuyama

Saburo Kamei

The present invention relates to a radio receiver or a diversity receiver where reception waves respectively reaching a plurality N of branches in parallel are cyclically selected at a first frequency equal to a value of the product of a symbol frequency, the plurality N being a total number of branches, and a prescribed number E equal to or greater than &ldquo;2&rdquo;, the instantaneous values of selected reception waves are sequentially sampled at a second frequency equal to or higher than the first frequency, and a resulting sequence of instantaneous values is cyclically split at the first frequency, whereby sequences of instantaneous values individually corresponding to the plurality N of reception waves are output. In a radio transmission system applying the above radio receiver or diversity receiver, reception waves reaching a plurality of branches are received in parallel without largely increasing hardware in scale.

Radio receiver and diversity receiver

Radio equipment for communicating digital data includes a clock modulation part for angular-modulation of a clock signal by a given modulation signal; and a data processing part processing the digital data based on the clock signal angular-modulated in the clock modulation part and producing angular-modulated digital data. In the radio equipment, levels of harmonics generated from the clock signal and the digital data are reducible.

Radio equipment and peripheral apparatus

A digital wireless receiving apparatus performs AGC control. A desired wave level is detected at a modulator, and AGC control is performed for a high frequency portion by detecting a desired wave level at a demodulator. A tap number of a digital filter in the demodulator is controlled or another analog filter of an intermediate frequency detects an input level of an interfering wave or a desired wave, thereby performing AGC control for the high frequency portion and controlling the tap number of the digital filter at the demodulator.

Digital wireless receiving apparatus

A radio communication apparatus includes: a transmission unit for transmitting a radio wave; and a reception unit for receiving a radio wave and demodulating the same, the reception unit including: an analog filter provided in a first stage of the reception unit; a digital filter provided in a second stage of the reception unit so as to compensate a characteristic of the analog filter by having a filter characteristic of the digital filter varied by varying a tap factor; a test signal generation unit for supplying a test signal to the reception unit; an error state detection unit for detecting an error based on a digital demodulated signal derived from the test signal; and a tap factor setting unit for temporarily setting a tap factor of the digital filter that reduces a level of the error. Supplying of the test signal and detecting of the error are repeated until a target tap factor that minimizes the error is determined, whereupon the target tap factor is set in the digital filter.

Digital radio communication apparatus and method of controlling the same

Disclosed is a radio apparatus in which modulating signals (I, Q signals) from an arithmetic/control unit are converted to analog signals, which are then applied to an orthogonal modulator. A modulated wave for transmission, which has been produced by orthogonally modulating a reference carrier wave by the modulating signals, is demodulated by the orthogonal detector. The arithmetic/control unit compares the modulating signals and the demodulated signals and, based upon the comparison, updates distortion compensation coefficients and applies pre-distortion processing to the modulating signal using the distortion compensation coefficients. Leakage carrier produced due to offset of the orthogonal modulator is detected and the arithmetic/control unit adjusts the level of the modulating signals or shifts the phase of the reference carrier wave in such a manner that the leakage carrier (offset) becomes zero.

Radio apparatus

Radio apparatus and offset compensating method

Disclosed is a radio apparatus in which modulating signals (I and Q signals) from an arithmetic/control unit are converted to analog signals, which are then applied to an orthogonal modulator. A modulated wave for transmission, which has been produced by orthogonally modulating a reference carrier wave by the modulating signals, is demodulated by the orthogonal detector. The arithmetic/control unit compares the modulating signals and the demodulated signals and, based upon the comparison, updates distortion compensation coefficients and applies pre-distortion processing to the modulating signal using the distortion compensation coefficients. Leakage of carrier produced due offset of the orthogonal modulator is detected and the arithmetic/control unit adjusts the level of the modulating signals or shifts the phase of the reference carrier wave in such a manner that the leakage of carrier (offset) becomes zero.

Growing community of inventors

Kawasaki, Japan

Yukihiro Moriyama