Nec Corporation

Mitsubishi Heavy Industries Limited

Leland Stanford Junior University

Shinichi Hori

Masaaki Tanio

Tomoyuki Yamase

Kazumi Shiikuma

Kazuaki Kunihiro

Kouji Esaki

Boris Murmann

Keiichi Motoi

Yuma Kase

Eiichi Sato

Noriaki Matsuno

Takeshi Yano

Kentaro Shindo

Takao Kuroiwa

Masaki Kitsunezuka

Naoki Oshima

Nozomu Kawasetsu

Izumu Fukui

Osamu Inui

Toshio Hayashi

Daisuke Nagai

A transmitting apparatus according to the present disclosure includes: a digital baseband unit configured to separate a baseband signal into an in-phase component and a quadrature component, and output the in-phase and quadrature components; an outphasing signal generation unit configured to generate first and second outphasing signals based on the in-phase and quadrature components; and a time-division combining unit configured to generate a time-division combined signal by combining the first and second outphasing signals in a time-division manner.

Transmitting apparatus, receiving apparatus, communication system, and communication method

A digital modulator according to the present disclosure includes a polar converter that generates a phase signal and an amplitude signal from a baseband signal, an RF phase signal generator that generates an RF phase signal on the basis of the phase signal, a rectangulating unit that generates a rectangular RF phase signal by converting the RF phase signal into a rectangular shape, a time interleaver that time interleaves the amplitude signal and outputs first and second time interleaved signals, a &#x394;&#x3a3; modulator that &#x394;&#x3a3; modulates the first and second time interleaved signals on the basis of the rectangular RF phase signal and outputs first and second &#x394;&#x3a3; modulated signals, and a selector that selects and outputs one of the first and second &#x394;&#x3a3; modulated signals on the basis of the rectangular RF phase signal.

Digital modulator, communication device, and digital modulator control method

An optical wireless transmission systemincludes a transmission device including at least one memory storing instructions, and at least one processor configured to execute the instructions to; generate a plurality of digital outphasing signals; orthogonally modulate the digital outphasing signals at an intermediate frequency; and set an intermediate frequency for satisfying a specified signal-to-distortion power ratio based on a sampling frequency, wherein the digital outphasing signals are orthogonally modulated at the intermediate frequency; a hardware optical fiber module configured to convert orthogonally modulated digital electrical signals into optical signals, transmit the optical signals through an optical fiber, and convert the optical signals into digital electrical signals; and a remote unit configured to combine the digital electrical signals transmitted by the hardware optical fiber module, and transmit a combined signal as a radio signal.

Optical wireless transmission system

This transmitter is provided with: a digital delay circuit which delays a 1-bit digital RF signal on the basis of another 1-bit digital RF signal; an amplifier which amplifies a signal output by the digital delay circuit; and a band-pass filter which allows signals in a prescribed frequency band, from among signals output by the amplifier, to pass. A signal output by the band-pass filter is input into a corresponding one antenna element from among a plurality of antenna elements, and controls the directionality of a beam formed by the plurality of antenna elements.

Transmitter and method of controlling transmitter

An interference signal generation device includes a first converter configured to perform conversion on a frequency of an input signal based on a center frequency of a frequency band to be interfered, and a second converter configured to further perform conversion on a frequency of an output signal of the first converter based on the center frequency.

Interference signal generation device, interference signal generation system, and interference signal generation method

The purpose of the present invention is to provide an amplifier having high signal-to-noise ratio of a transmitted signal and high electrical efficiency. Another purpose is to suppress complexity of amplifier's wiring connecting a signal generator that generates a binary digital signal and an amplification unit that amplifies the same. This amplifier generates a binary digital signal. The amplifier further generates a K-value digital signal (K is an integer greater than or equal to 3) from the binary digital signal and generating a plurality of binary digital signals from the K-value digital signal. The amplifier amplifies each of the plurality of binary digital signals, and combines the plurality of amplified binary digital signals and generating a combined signal having a substantially proportional relationship with the K-value digital signal.

Amplifier and transmitter, and transmission method

This &#x394;&#x3a3; modulator is a &#x394;&#x3a3; modulator using multiple integrators. The integrator: includes a plurality of stages of adder sequences, each of the adder sequences including a plurality of adders connected in series; performs feedback of a result of a second adder sequence as an input to a first adder sequence, the first adder sequence being a first stage of the plurality of stages, and the second adder sequence being a last stage of the plurality of stages; and processes inputs supplied to the plurality of adders of the first adder sequence and supplies it to the second adder sequence.

Delta-sigma modulator, transmitter, and integrator

In a digital transmitter, a digital RF signal generation unit executes digital modulation on I and Q signals to convert the I and Q signal into first and second digital RF signals, respectively, with a bit rate which is twice a carrier frequency. A retiming unit delays the first digital RF signal according to a clock signal with a frequency which is 4n times (n is an integer) the carrier frequency to output the delayed first digital RF signal and delays the phase of the second digital RF signal by 90 degrees with respect to an output of the first digital RF signal to output the delayed second digital RF signal. First and second amplifiers amplify the first and second digital RF signals output by the retiming unit, respectively. A combiner combines the amplified first and second digital RF signals to generate one signal sequence.

Digital transmitter

Provided are a wireless access system provided with a remote unit capable of handling a high-frequency region without being made complicated, and a control method for the same. A wireless access system according to the present invention is provided with: a center unit (); and a remote unit () that converts a baseband signal generated by the center unit () into a high-frequency signal and emits the high-frequency signal from an antenna (). The center unit () includes a 1-bit modulator () that converts the baseband signal into a 1-bit signal on the basis of a generated clock signal and outputs the 1-bit signal. The remote unit () includes: a local generation unit () that extracts the clock signal from the 1-bit signal output from the center unit (), and generates a local signal using the extracted clock signal as a reference signal; a filter () that extracts a desired band component from the 1-bit signal; and an up-converter () that converts, using the local signal, an output signal of the filter into a high-frequency signal.

Wireless access system and control method for same

A digital modulation device is provided. The digital modulation device includes an input unit; N delta-sigma modulation units; and an output unit. N is an integer greater than or equal to 2, the input unit is configured to: input initial values which differ from each other to the N delta-sigma modulation units; and then, input a same first signal into the N delta-sigma modulation units, each of the N delta-sigma modulation units is configured to: output a second signal by performing delta-sigma modulation processing on the first signal for each first clock cycle, and the output unit is configured to: sequentially output each second signal for each one Nth of the first clock cycle.

Digital modulation device, and digital modulation method

A switching amplifier provided, at a minimum, with: a first input transistor into which one of two input signals that operate in a complementary manner is input; a first cascode transistor cascade-connected between the first input transistor and a power supply; a second input transistor into which the other of the two input signals is input; and a second cascode transistor cascade-connected between the second input transistor and the first input transistor; the switching amplifier extracting an output signal, a connection point between the first input transistor and the second cascode transistor being used as an output terminal; wherein a first potential limiting circuit and a second potential limiting circuit for limiting the potential fluctuation range are respectively connected to the input terminal of the first cascode transistor and the input terminal of the second cascode transistor.

Switching amplifier and radio transmitter

The purpose of the present invention is to provide a high-power-efficiency and low-design-cost transmission device by implementing, with a constant clock, delta-sigma modulation maintaining a zero current switching property in an amplifier. This delta-sigma modulator comprises: a pulse phase signal generation unit for generating a pulse phase signal from a phase signal; a delta-sigma modulation unit for generating a pulse amplitude signal obtained by delta-sigma modulating an amplitude signal with a constant clock; a phase sorting unit for outputting a control signal on the basis of the phase signal; a delay switching unit for delaying the pulse amplitude signal on the basis of the control signal; and a mixing unit for outputting a pulse string obtained by multiplying together the delayed pulse amplitude signal and the pulse phase signal.

Delta-sigma modulator and modulation method, transmission device, and transmission method

A transmitter/receiver apparatus including: a transmitter/receiver terminal; a switching amplifier that includes a low-side switching element connected between a ground terminal and a pulse output terminal and a high-side switching element connected between the pulse output terminal and a power supply terminal and that outputs a pulse signal from the pulse output terminal; a filter that passes therethrough and outputs as a transmitted signal a predetermined frequency component of the pulse signal from a transmitter terminal; and a transmit/receive switch unit that switches the connection status between the transmitter/receiver terminal and the transmitter terminal and also switches the connection status between the transmitter/receiver terminal and a receiver terminal. During receiving, on the basis of the connection status between the transmitter/receiver terminal and the transmitter terminal, the low-side and high-side switching elements are fixed to conductive and non-conductive states, respectively, to non-conductive and conductive states, respectively, or both to non-conductive states.

Transmitter/receiver apparatus, transmitter apparatus and transmitting/receiving method

A transmitter according to an exemplary aspect of the present invention includes: a modulation circuit configured to modulate a baseband signal into a multi-bit digital signal including a component in a radio-frequency band; a plurality of switch-mode power amplifiers corresponding to each bit of the multi-bit digital signal output from the modulation circuit; and a signal synthesis circuit including a band limiting unit configured to perform a band limitation on output signals from the plurality of switch-mode power amplifiers, and a plurality of voltage-to-current converting units configured to perform a voltage-to-current conversion on respective output signals from the plurality of switch-mode power amplifiers, the signal synthesis circuit configured to makes a synthesized signal connecting the band limiting unit and the plurality of voltage-to-current converting units, wherein, depending on an output power at a synthesis point where the synthesized signal is made, a switch-mode power amplifier is selected which is configured to receive input of a pulse, and a pulse number of pulses to be inputted into the selected switch-mode power amplifier is controlled.

Transmitter and transmission method

According to an embodiment, a digital transmitter () includes an amplitude modulation amplitude signal generation unit () that generates a function f(A(t)) of an amplitude signal A(t) as an amplitude modulation amplitude signal A'(t), an amplitude modulation phase signal generation unit () that calculates 'cos{A(t)/f(A(t))}' as a phase &#x3b8;() and generates amplitude modulation phase signals P() and P(), an individual digital transmission unit () that generates an amplified RF-pulse signal based on the signals A&#x2032;(t) and P(), an individual digital transmission unit () that generates an amplified RF-pulse signal based on the signals A&#x2032;(t) and P(), and an RF-synthesizer () that combines outputs of the individual digital transmission units () with each other.

Growing community of inventors

Tokyo, Japan

Shinichi Hori