Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Yuichiro Murata

Masaru Okada

Junichi Abe

Naoki Nakagawa

Yasushi Takeuchi

Takao Tsurimoto

Nobuyuki Zumoto

Youichi Hisamori

Hirofumi Ouchi

Hiroshi Miwa

Hiroshi Isoya

Yuji Ohmura

Yoshinobu Hirokado

Shinichiro Eguchi

A surge absorbing circuit capable of absorbing surge stably without affecting a signal on a signal line even in the case of a high frequency signal, and an electronic device using the surge absorbing circuit. The surge absorbing circuit includes at least one surge suppression circuit, the at least one surge suppression circuit including, with respect to the same signal line at least: a power supply; a diode connected between the signal line and the power supply; and a power supply line for connecting the diode and the power supply to each other. In each of the at least one surge suppression circuit, a direction of the diode and a voltage of the power supply with respect to the signal line are determined so that the diode is reversely biased.

Surge absorbing circuit and electric device using the same

In power line communications using carrier waves of high frequencies in the MHz range such as 2 to 30 MHz, when a coaxial cable for performing transmission of signals and a power line are signal-coupled using a capacitive signal coupling unit, even if an impedance matching circuit is installed in the capacitive signal coupling unit, we have found that leakage current of levels that cannot be neglected from leakage noise considerations flows through the outer sheath of the coaxial cable that transmits the signals, and, accordingly, leaking electromagnetic waves induced by the leakage current flowing through the coaxial cable due to impedance mismatch between the power line and the capacitive signal coupling unit are reduced by an impedance member showing high impedances at high frequencies in the MHz range.

Power line communication system and capacitive signal coupling unit

To provide a structure capable of securing satisfactory induction coupling efficiency and high reliability in manufacturing an induction coupling apparatus used in power line carrier communication, the induction coupling apparatus having a magnetic core formed from a first core element part and a second core element part so that a gap would be formed between the core element parts, includes: a core parallel moving mechanism for carrying out relative and parallel movement of the first core element part and the second core element part in a direction that the length of the gap varies; and a predetermined gap length regulating member for limiting parallel movement in a direction that the first core element part and the second core element part approach each other to regulate the gap length to the predetermined gap length in the case that the core parallel moving mechanism is used for the parallel movement.

Induction coupling apparatus

On the surface of a back board outermost-layer signal lines have different lengths. A difference in lengths of connector lines connected to the outermost-layer signal lines makes the total signal line lengths substantially equal. A digital signal generated in the circuit of a daughter board reaches a through hole through an internal-layer signal line traced within the internal layer of the daughter board, and is further transmitted to an internal-layer signal line of the back board through the a connector line, the an outermost-layer signal line, and a through hole. The digital signal is further transmitted to another internal-layer signal line via another through hole, another connector line, and another through hole.

Printed circuit board

A multi-pin connector for connecting a signal line on a backboard side and a signal line on a daughter board side has open pins where the signal lines are not connected. In order to prevent transmission loss on the signal lines caused by these open pins, terminating resistances are connected to both ends of the open pins, and ends of the terminating resistances opposite to the open pins are connected to ground or to a power supply.

Printed-circuit board for high-speed communication

In an electrical connector, a female terminal is inserted into a corresponding through-hole of a printed board, copper plating is divided into two copper plating parts having knife edge-like end portions, and land portion is also divided into two land parts having knife edge-like end portions. As a result, the copper plating parts are connected to two copper pattern parts through the separate land parts, respectively. The separate parts thus obtained form a signal portion and a ground portion, respectively. That is, the first copper plating part, the first land part, and the first copper pattern part constitute a signal portion, and the second copper plating part, the second land part, and the second copper pattern part constitute a ground portion.

Multi-connector for use in high-speed communication apparatus and method for mounting the same multi-connector into printed board

In relation to the magnetic head using a polycrystalline Mn-Zn ferrite as a core material, a magnetic head manufacturing method is provided for preventing the generation of the post-recording noise which is a pulse noise generated immediately after the completion of a current flow through the recording and reproducing coil. A fused core block is manufactured using Mn-Zn ferrite having a mean crystal grain size of equal to or less than 30 .mu.m as the core material of at least the recording and reproducing head and glass fusion using one type of glass, and the fused core block is annealed at a temperature equal to or higher than the strain point of the glass.

Method for manufacturing a magnetic head

A composite magnetic head having a head chip including an erasing core, a recording/reproducing core and a center core disposed between the erasing core and the recording/reproducing core. The erasing core is joined to the center core via a first nonmagnetic material which forms an erasing gap, and the recording/reproducing core is joined to the center core via a second nonmagnetic material which forms a recording/reproducing gap. The composite magnetic head has an erasing coil, a recording/reproducing coil, a first back bar for magnetically coupling the erasing core with the center core, and a second back bar for magnetically coupling the recording/reproducing core with the center core. The composite magnetic head satisfies both of following conditional expressions:

Composite magnetic head having minimal crosstalk, maximal head output

A multiple head arrangement for recording and reproducing magnetic information on a magnetic recording medium. The head structure includes an I core body and two core half bodies. A first glass member is interposed between the I core body and the first core half body at a position laterally adjacent a first read/write gap and a second glass member is interposed between the I core body and the second core half body at a position laterally adjacent a second read/write gap. A non-magnetic thin film insulation layer is interposed between the first and second core half bodies and substantially perpendicularly with respect to the read/write gaps.

Growing community of inventors

Tokyo, Japan

Yuichiro Murata