Yamaha Corporation

Takashi Ubayama

Morito Morishima

Takashi Norimatsu

Eiichi Suzuki

Akiho Tamura

Koichi Kaneko

A server/client system provides packet communications between a server and a client by way of a network such as the Internet. The server inputs data such as MIDI data in a sporadic manner while storing timing data representing their input timings. Then, the server performs packetizing of the sporadically input data, which accompany the timing data and are subjected to transmission to the client. The client receives the packetized input data and then outputs them at timings based on the timing data. Thus, it is possible to completely secure the same time relationship of data during transmission and reception of the sporadically input data even though the client differs from the server on a time-axis basis.

Communication method and system for transmission and reception of packets collecting sporadically input data

An EFM-signal comparator which superposes a direct voltage on an input EFM signal, and produces a square wave of a predetermined duty cycle (50% typically) by comparing the superposed signal of the direct voltage and the input EFM signal with a predetermined threshold voltage. The signal comparator having a primary direct-voltage-output circuit which produces a direct voltage corresponding to the '1' level duration of the square wave, a secondary direct-voltage-output circuit which produces a direct voltage corresponding to the '0' level duration of the square wave, a switching circuit which outputs either the direct voltage from the primary direct-voltage-output circuit or the direct voltage from the secondary direct-voltage-output circuit, a voltage-output circuit which outputs a voltage corresponding to the direct voltage outputted from the switching circuit, and a smoothing circuit which smoothes and superposes the voltage outputted from the voltage-output circuit on the input EFM signal. The EFM-signal comparator can be integrated into an LSI except for large-scale wave-smoothing capacitors, because all of the other components are small enough to be manufactured by CMOS, while the large-scale wave-smoothing capacitors are too large to be produced by CMOS.

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Hamakita, Japan

Takashi Ubayama