Hitachi, Ltd.

Hitachi Automotive Engineering Co., Ltd.

Hitachi Video Engineering, Incorporated

Hitachi Ltd., Hitachi Video Engineering, Inc.

Tsutomu Noda

Keiro Shinkawa

Takao Arai

Masaharu Kobayashi

Shigeki Inoue

Yoshimi Iso

Toshiyuki Sakamoto

Nobutaka Hotta

Hiroyuki Kimura

Hiroo Okamoto

Nobutaka Amada

Kenji Katsumata

Toshiaki Arai

Hiromichi Tanaka

Tetsuya Mochida

Tomoki Sekiguchi

Toshinori Murata

Isao Nakagawa

Tsuyoshi Watanabe

Takanori Eda

Toshio Nagashima

Tetsuo Sato

Takatoshi Shirosugi

Satoshi Iimuro

Yutaka Enko

Akihide Okuda

Isao Akitake

Reki Yamamoto

Kazuhiro Ooyagi

Naofumi Shouji

Kazuhiko Yamazaki

Shinichi Ohashi

The parallelism of execution of processes in a memory shared multi-processor is enhanced. Each of a plurality of processors is provided with a run queue for holding executable processes, and a watch process for each processor to watch the execution status of its own to notify the rebuilding of the run queue to other processor and a rebuild step for rebuilding the run queue in response to the notice are stored in a shared memory as a program.

Process management method and system

A digital signal transmission system including a transmitter and a receiver and capable of transmitting highly efficiently compressed/coded digital video signals and receiving the video signals so that the text of emergency information or the like can be displayed together with video images without once expanding/decoding the digital video signals on the transmitter side. In this system, the multiplexer of the transmitter multiplexes digital video signals and digital audio signals with a digital information signal of text which is produced and has N-level priority information added by the information stream generator, and transmits the multiplex signal to the receiver. The receiver determines whether the text of the digital information signal is to be displayed on the basis of the priority information added to the digital information signal, and when it is determined that the text are to be displayed, the receiver can display the text of the digital information signal together with the image of the digital video signal.

Digital signal transmission system with priority information forcing

A transmission distortion elimination device for eliminating from a transmitted TV signal, for example, signal distortion such as ghost under fuzzy inferenced control based on an iterative correction method with the capabilities of fast control settling, and a flexible and stable distortion removal operation. The device comprises a filter section for suppressing such transmission distortion as ghost, a controller for controlling the tap coefficients of the filter section, and a fuzzy inference section for receiving distortion information obtained by the controller. The fuzzy inference section iteratively infers and evaluates a correction value of tap coefficients of the filter section. The tap coefficient correction value is determined through fuzzy inference, and the control method for counteracting disturbance coefficients to the control system is described in rules of IF-THEN form based on fuzzy levels, which facilitates the organization of the control algorithm. By the capability of deriving from these rules the correction value which is made continuously variable, the fast control settling, and the stable and flexible transmission distortion elimination operation can be accomplished.

Ghost canceller using fuzzy control

A ghost elimination device equipped in a television receiver extracts a reference signal from the television signal, the reference signal being inserted in the television signal in a certain sequence or at random with the intention of ghost elimination, implements the sequence decoding process and noise elimination process for the reference signal, and controls the characteristics of the ghost eliminating transversal filter which suppresses the transmission distortion. The device includes a sequence decoding circuit for decoding the transmission sequence of the reference signal, a transversal filter for suppressing the distortion of transmission path disposed in a rear stage of sequence decoding circuit, and a controller which introduces the reference signal provided by the filter to control the characteristics of the filter or apply the output of the sequence decoding circuit to the transversal filter through a noise elimination filter. The transversal filter has a tapped delay line formed of registers with an initialization terminal and an input terminal for controlling the initialization terminal.

Ghost reduction device for removing ghost components of a television

A sync generator which generates a reference horizontal synchronizing signal, a time difference detector which detects the time difference between the reference horizontal synchronizing signal and a horizontal synchronizing signal within a received television signal, and a variable delay circuit which responds to an output signal of the time difference detector to control the delay time and delay the received television signal are installed in a television receiver. When a plurality of horizontal synchronizing signals exist in one horizontal scanning period of the received television signal, the time difference between the horizontal synchronizing signal with the maximum amplitude and the reference horizontal synchronizing signal is detected, and the delay time of the received television signal is controlled in the variable delay circuit according to this time difference. As a result, the phase of the horizontal synchronizing signal with the maximum amplitude matches the phase of the reference horizontal synchronizing signal. Therefore, when changes in the receiving environment cause the signal strength of ghosts to become greater than that of an original signal and it becomes desirable to receive the ghost as a main signal in place of the original signal, it is possible to switch from reception of the original signal to reception of the ghost signal without resulting in distortion of synchronization.

Television receiver

A multiplex transmission method using especially a vestigial-sideband amplitude-modulated carrier modulated by a video signal. The method includes modulating a carrier having a quadrature phase with respect to an amplitude-modulated carrier by a multiplex-transmitted signal such as a digital-coded signal with a lower level as compared with the amplitude-modulated carrier, suppressing signal components of a signal obtained by modulating the carrier by a multiplex-transmitted signal, which is located near the carrier frequency, combining the result with the amplitude-modulated carrier, and thereafter transmitting the combined signal.

Multiplex transmission method and apparatus

A phase locked loop circuit for use in a heterodyne receiver for stably demodulating a carrier-suppressed double-sideband signal such as a 2-phase or 4-phase PSK signal. The phase locked loop circuit comprises a reference oscillator oscillating at a frequency corresponding to an intermediate frequency, and the frequency difference between the reference frequency and the input frequency is detected by a Costas loop, a signal indicative of the frequency difference being fed back to a local oscillator through a loop filter thereby stabilizing the intermediate frequency.

Phase locked loop circuit for demodulating suppressed carrier signals

A PCM signal processor which converts an analog signal into a digital signal to transmit or record the digital signal. When the PCM signal processor receives a PCM signal whose data has been compressed in such a manner that one or more lower bits are cut off from a plurality of bits for forming the PCM signal and indicating the signal level of the analog signal, in accordance with the signal level of the analog signal, one or more bits corresponding to the number of bits having been cut off are added in the processor to the compressed PCM signal at the position following the least significant bit of the compressed PCM signal. Correction data indicating about one half the largest one of numerical values that can be expressed by the added bit or bits, is given to the added bit or bits.

Expansion circuit for digital signals

A digital-to-analogue converter for use in a digitally-recorded-signal reproducing apparatus comprises a first constant current source, a switch for allowing the constant current of the first constant current source to flow therethrough for a period corresponding to the digital data, a second constant current source generating a current flowing in the direction opposite to that of the current generated by the first constant current source, a switch for allowing the current of the second constant current source to flow therethrough for a predetermined constant period, and an integrator, wherein the sum of the first and second constant currents is integrated by the integrator. The analogue signal outputted by the integrator has a center level in the vicinity of the ground potential level.

Digital/analogue converter

A signal conversion apparatus for use in a PCM signal processing system in which a series of multi-bit digital signals is produced through sampling and quantization of a multi-channel analog signal. The series of multi-bit digital signals includes groups of multi-bit digital signals being representative of respective analog signal portions constituting the multi-channel analog signal. The apparatus comprises a translating section for producing substitutional multi-bit digital signals from at least one of the groups of digital signals corresponding to at least one analog signal portion, which substitutional digital signals represent amplitudes of the one analog signal portion at sampling points different from those at which the one analog signal was sampled to provide the one group of digital signals. The substitutional digital signals are substituted, in the translating section, for the one group of the digital signals to produce a corresponding group of sampling point-shifted multi-bit digital signals. The resulting PCM multi-bit digital signals are acceptable by digital-to-analog conversion processor requiring PCM digital signals generated through sampling at shifted or different sampling points as compared with the above-mentioned series of digital signals.

Signal conversion apparatus for use in PCM signal processing system

In a pulse width detector circuit, a high-level pulse width and a low-level pulse width of a digital signal derived by slicing an analog signal reproduced from a disc at a predetermined level are independently measured and maximum or minimum values thereof in a predetermined time interval are stored, and an average value, sum or difference of the maximum or minimum high-level pulse width and the maximum or minimum low-level pulse width is calculated to detect a correct pulse width of original data recorded on the disc.

Digital player using a pulse width detector

An information reproducing apparatus having a tracking servo control loop for causing an information reading unit including device for detecting a tracking error signal for tracking an information bearing track on a disc, to track the information bearing track in accordance with the tracking error signal so as to reproduce information in accordance with an information signal read by the information reading unit. A circuit for extracting a discrimination signal for discriminating a negative feedback region of the tracking error signal is provided so that a tracking servo control loop is closed in the negative feedback region.

Tracking servo control unit for an information reproducing apparatus

An AM stereophonic demodulator circuit for an amplitude/angle modulation system, comprising an AM detector circuit for producing a stereophonic sum signal (L+R), an FM or PM detector circuit for producing a stereophonic difference signal (L-R), and control means for extracting a DC voltage proportional to an antenna input level from the AM detector circuit so as to use the DC voltage to control the gain and amplitude of an FM or PM detector stage including the FM or PM detector circuit.

Growing community of inventors

Yokohama, Japan

Tsutomu Noda