Victor Company of Japan, Limited

Katsumi Takaoka

Keiichi Kaneko

Kazunari Matsui

Takaaki Saiki

Kenji Sugiyama

An orthogonal frequency division multiplexed signal transmitting apparatus executes a time-division multiplexing process that inserts a reference signal at a predetermined interval based on reference signal position information into an information signal to be transmitted. The transmitting apparatus generates an orthogonal frequency division multiplexed signal by digital-modulating the time-division multiplexed signal to radiate into a spatial transmission line. An orthogonal frequency division multiplexed signal receiving apparatus receives the signal from the transmitting apparatus to get the reference signal by demodulating the signal.

Orthogonal frequency division multiplexed signal transmitting apparatus, orthogonal frequency division multiplexed signal receiving apparatus, and orthogonal frequency division multiplexed signal transmitting/receiving system

Data pieces representative of in-phase components and quadrature components of a digital-modulation-resultant signal are assigned to frequencies for inverse fast Fourier transform. The inverse fast Fourier transform is executed at a predetermined sampling frequency Fs to convert the data pieces into a real-part signal and an imaginary-part signal. Phases of the real-part signal and the imaginary-part signal are shifted. Each of the phase-shifted real-part signal and the phase-shifted imaginary-part signal is divided into a sequence of even-numbered samples and a sequence of odd-numbered samples. A digital quadrature-modulation-resultant signal is generated from further manipulation of the even-numbered and odd-numbered samples.

Method and apparatus for modulation and demodulation related to orthogonal frequency division multiplexing

An apparatus for transmitting an orthogonal-multi-carrier signal includes a first device for subjecting an information signal to first inverse discrete Fourier transform to convert the information signal into an orthogonal-multi-carrier signal. The ortogonal-multi-carrier signal generated by the first device is outputted to a transmission line. The orthogonal-multi-carrier signal is received from the transmission line. The received orthogonal-multi-carrier signal is subjected to discrete Fourier transform to recover the information signal from the received orthogonal-multi-carrier signal. A second device contained in the first device operates for subjecting the information signal to M-point inverse discrete Fourier transform and thereby implementing a first stage of the first inverse discrete Fourier transform, and for generating a transform result signal representative of results of the M-point inverse discrete Fourier transform, where M denotes a predetermined natural number greater than 2. A third device contained in the first device operates for subjecting the transform result signal generated by the second device to N-point inverse discrete Fourier transform and thereby implementing a second stage of the first inverse discrete Fourier transform to generate the orthogonal-multi-carrier signal, wherein N denotes a predetermined natural number greater than twice M. The second stage follows the first stage.

Method and apparatus for transmitting orthogonal-multi-carrier signal

A first orthogonal-multi-carrier signal is generated through N-point inverse discrete Fourier transform. The first orthogonal-multi-carrier signal has &ldquo;N&rdquo; or less orthogonal multiple carriers, where &ldquo;N&rdquo; denotes a predetermined natural number equal to or greater than 2. Every 1-unit time segment of the first orthogonal-multi-carrier signal is repeated &ldquo;M&rdquo; times to generate every 1-symbol time segment of a second orthogonal-multi-carrier signal. The second orthogonal-multi-carrier signal has a thinned set of &ldquo;N&rdquo; or less orthogonal multiple carriers spaced at M-carrier intervals, where &ldquo;M&rdquo; denotes a predetermined natural number equal to or greater than 2.

Generation and decoding of multi-carrier signal

An image encoding apparatus for application to images expressed as respective frames of a digital video signal, whereby an image is converted into an array of blocks with specific blocks predetermined as being independent internally encoded blocks and the remainder as predictively encoded blocks, with predicted pixel signal values for a predictively encoded block being derived by interpolation from pixel signal values of at least one pair of blocks which have been already encoded and enclose that predictively encoded block along the row or column directions or both the row and column directions. Encoding efficiency is enhanced by applying Discrete Sine Transform processing along the interpolation direction, when encoding an array of prediction error signal values derived for a block, and by executing adaptive prediction by determining an optimum interpolation direction, when there are two possible directions for deriving predicted pixel signal values for a block.

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Yokosuka, Japan

Katsumi Takaoka