Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Akira Kisoda

Sadashi Kageyama

Noritaka Iguchi

Yukihiro Shimasaki

Ryosuke Mori

Koji Setoh

Tomohiro Kimura

Kenichiro Hayashi

Yuji Mido

Daisuke Hayashi

Hiroki Furukawa

Kazunori Sakamoto

Tetsuya Yagi

Yuji Nakai

Hidekuni Yomo

Ippei Kanno

Tomiharu Hosaka

Takehiro Kamada

Nobuyuki Aoki

Masanaru Hasegawa

Yoshitaka Mizoguchi

Hiroyuki Senda

Izumi Usuki

Yuji Midou

Hiroshi Suzuki

Takumi Haneda

A transmission method of a digital broadcast, which is compatible with a DVB-T terrestrial digital broadcast system in Europe, saves a battery in a mobile terminal. Superframes in DVB-T are divided into units each including plural symbols so that an integer number of TS packets can be carried in each slot. At least one slot is used to transmit one service. Energy dispersion, Reed-Solomon coding, byte interleaving, convolutional coding, and time interleaving are applied to each service. When services for mobile terminal reception and services for fixed terminals are transmitted as the provided services, null packets may be transmitted before and after the slot carrying the mobile receiver service so that the fixed reception service and the mobile reception services are not mixed.

OFDM signal transmission method, transmission apparatus, and reception apparatus

Time slice transmission methods transmit data in bursts, thus creating a delay until playback of a service can begin when changing the service and therefore preventing smooth zapping. To solve this problem, a first stream used for burst transmission of packet sets and a second stream for continuously transmitting packets at a speed determined according to the transmission rate required for a particular service are multiplexed and transmitted. The content is reproduced using the continuously transmitted second stream during zapping, and the first stream transmitted in bursts is reproduced after zapping ends.

Method and apparatus for broadcasting to a portable terminal

An OFDM reception device detects a time at which impulse noise occurs in a received OFDM signal, and specifies a start position candidate period that does not have intersymbol interference and is estimated to have a guard interval signal in a symbol. When setting a FFT window of an effective symbol length in a symbol duration of each symbol, if the impulse noise occurrence time is included in the symbol, the OFDM reception device determines a start position of the FFT window within a range of the start position candidate period so as to exclude the impulse noise occurrence time as much as possible.

OFDM reception device

A mobile receiver performs oblique interpolation in such a direction that a symbol number increases by one and a carrier number decreases by three with respect to a position of each Scattered Pilot Signal to interpolate a first signal whose channel characteristics have not been obtained. The mobile receiver then performs, in a frequency axis direction, frequency axis interpolation to interpolate channel characteristics of a second signal whose channel characteristics have not been obtained, using the estimated channel characteristics and the interpolated channel characteristics.

OFDM receiver, integrated circuit and receiving method

For a data group composed of pieces of data each indicating channel characteristics of a scattered pilot signal position whose phase is adjusted by dividing scattered pilot signals included in an OFDM signal by a scattered pilot signal at the time of transmission, a carrier extension circuitinserts data having a same value as a value of data of a lower end into an outside of the lower end of a band, and inserts data having a same value as a value of data of an upper end into an outside of the upper end of the band. On the data group composed of 2pieces of data including the data inserted by the carrier extension circuit, IFFT processing by an IFFT circuit, noise removal processing by a noise removal filter, and FFT processing by a FFT circuitare performed. The data inserted by the carrier extension circuitis removed from the data group outputted from the FFT circuit, and the data group after the data removal is used for interpolation in a symbol direction.

Receiving apparatus, integrated circuit and receiving method

Disclosed is an OFDM signal receiving apparatus for diversity reception, with a plurality of antennas, of an OFDM signal containing Y sub-carriers, where 2&#x3c;Y&#x3c;2and X&#x3e;1. The OFDM signal receiving apparatus includes a plurality of receiving systems, and a diversity processing unit connected to the receiving systems and fed with sequences of data on sub-carriers demodulated by the respective receiving systems. At least one of the receiving systems includes an FFT circuit for Fast Fourier transforming, in parallel, only a sequence of data on 2sub-carriers contained in the OFDM signal received with a corresponding antenna, where X&#x3e;Z. The diversity processing unit performs a diversity process on sequences of data on sub-carriers, out of all the Y sub-carries, redundantly demodulated.

OFDM signal receiving apparatus

A synchronous signal position detection unit detects symbol synchronous signals according to OFDM from the signals received by the respective antennas. A delay measurement unit measures a relative delay between the symbol synchronous signals for each antenna series and makes a notice to a memory unit via a delay amount notification unit. A diversity operation implementation unit temporally aligns the carrier data positions of the OFDM symbols for each antenna series so as to implement a space diversity operation.

Diversity system and diversity method

The present invention provides an error correction circuit for receiving and decoding a trellis-encoded signal of a series of data Z , Z , . . . ,Z which comprises convolutional-encoded bits and unencoded bits, the convolutional-encoded bits being obtained by convolutional-encoding lower t bits X , X , . . . ,X of an input p-bit series of data X , X , . . . , X (where p&gE;2, q&gE;p, and p>t&gE;1), and the unencoded bits being obtained by not convolutional-encoding upper (p-t) bits thereof. The circuit includes: a maximum likelihood decoder for preselecting one of m parallel paths of transition from state x at time k to state y at time k&plus;1.

Error correction circuit and error correction method

In the magnetic recording medium, the spherical particles are added in the surface magnetic layer of the magnetic film having multilayer configuration (structure). And the spherical particles have a diameter in the range of from 0.5 to 1.5 times as large as the thickness of surface magnetic layer, and the amount of the spherical particles is in the range of from 0.1 parts to 1 part per 100 parts by weight of magnetic powder included in the surface magnetic layer. Fine studs are formed on the surface of the surface magnetic layer, and it results in both small surface roughness and low coefficient of friction.

Magnetic recording medium

A coating film of a double-layer structure for a recording medium is formed by providing a non-magnetic buffer layer just beneath a magnetic recording layer composed of magnetic hexagonal platelet ferrite particles, wherein the thickness of the magnetic recording layer is 0.1-0.6 .mu.m and the ratio of thickness of the buffer layer to that of the magnetic recording layer is 1:1 to 4:1. This coating film makes it possible to realize the excellent medium surface characteristics that could not be obtained with the conventional techniques and to obtain a high recording density excelling those of the conventional in-plane longitudinal recording media.

Magnetic recording medium having a magnetic layer containing hexagonal

A magnetic coating composition prepared by a method comprising a wetting step for wetting powder materials including a magnetic powder with a small amount of a solvent in a kneading machine having an agitation means in a closed container, a first kneading step comprising adding an amount of a binder resin and an amount of a solvent to a mixture from the wetting step and mixing and kneading it, a second kneading step comprising continuously adding the solvent till a consumed power of a kneading apparatus reaches maximum, a third kneading step comprising stopping the addition of the solvent at the maximum consumed power and further kneading the mixture, and a dilution step comprising gradually adding the solvent to the mixture while applying shear force, in which composition, the magnetic powder is highly dispersed and which provides a coating type magnetic recording medium having good properties.

Method for producing magnetic coating composition and magnetic recording

By polishing a surface of a magnetic layer of magnetic recording medium in a direction which coincides with a track angle defined during the recording and reproducing thereof, drop out is decreased and electromagnetic characteristics are improved.

Growing community of inventors

Moriguchi, Japan

Akira Kisoda