Hitachi, Ltd.

Akio Ikeya

Kazunori Nakajima

Kenji Kashiwagi

Naohiro Sezaki

Takashi Aoyagi

Nobuhiko Wakayama

Masanao Yoneya

The present invention aims to improve the signal transmission characteristics by shortening the length of the detour path of the return current. The present invention comprises a return current transmission path relative to a signal transmission path for transmitting signals. The signal transmission path includes a signal pad formed on a circuit board surface layer, and signal through-holes formed on the circuit board surface layer and a circuit board inner layer and connected to the signal pad. The return current transmission path includes a ground pad formed on the circuit board surface layer, and a plurality of ground through-holes formed on the circuit board surface layer and the circuit board inner layer and connected to the ground pad and a ground layer of the circuit board inner layer. Each of the ground through-holes is arranged by being separated on either side of the ground pad.

Signal transmission circuit and printed circuit board

There is provided a printed circuit board having a differential signal transmission line composed of non-skew-adjusting portions and skew-adjusting portions. The non-skew-adjusting portion consists of parallel conductive traces spaced apart by a spacing. The skew-adjusting portion consists of a pair of meander traces for the skew adjustment. The skew-adjusting portion include convex transmission line segments and concave transmission line segments. The convex transmission line segment has parallel traces having a differential trace pair spacing greater than the differential trace pair spacing in the non-skew-adjusting portion. The concave transmission line segment has parallel traces having a differential trace pair spacing smaller than the differential trace pair spacing in the non-skew-adjusting portion.

Different signal transmission line for printed circuit board

A blade server apparatus including a plurality of server modules, a backplane for mounting the plurality of server modules thereon, and an SMP coupling device having wiring lines to SMP couple the plurality of server modules. Each of the server modules has one or more processors controlled by firmware and a module manager for managing its own server module, the module manager has an ID determiner for informing each processor of a processor ID, each processor has a processing unit and an SMP virtual connecting unit for instructing ones of wiring lines of the SMP coupling device through which a packet received from the processing unit is to be transmitted, and an ID converter for converting the processor ID and informing it to the SMP virtual connecting unit is provided within the firmware.

Growing community of inventors

Hiratsuka, Japan

Akio Ikeya