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Yukio Nishikawa Phones & Addresses

  • 15311 Francis Oaks Way, Los Gatos, CA 95032
  • 13180 Valewood Rd, Poway, CA 92064 (858) 748-2817
  • 4987 Speak Ln, San Jose, CA 95118
  • 1312 Greenwich Ct, San Jose, CA 95125
  • San Diego, CA
  • Santa Clara, CA
  • Carlsbad, CA
  • Milpitas, CA

Publications

Us Patents

Tuneable I.c. Active Integrator

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US Patent:
4374335, Feb 15, 1983
Filed:
May 19, 1980
Appl. No.:
6/151419
Inventors:
Kiyoshi Fukahori - San Jose CA
Yukio Nishikawa - San Jose CA
Assignee:
Precision Monolithics, Inc. - Santa Clara CA
International Classification:
H03H 1112
H03L 708
US Classification:
307521
Abstract:
An I. C. integrator circuit is provided with an active tuneable element by which a precise integrator time constant can be established, despite variations in the values of individual circuit components. A plurality of integrator circuits are connected in an overall frequency responsive circuit, each integrator circuit having a input transconductance stage, an output integrating stage, and an adjustable intermediate conditioning stage, the latter stage preferably comprising a Gilbert multiplier circuit. The time constant of each integrator circuit is controlled by the conditioning stage, which in turn is under the control of a bias circuit common to all of the integrator circuits. A desired net frequency response characteristic can be achieved by simple adjustments to the common bias circuit, despite normal tolerances and variations among individual integrator circuits. The circuit is completely integrated, is capable of operating at audio as well as at higher frequency ranges, has a greater tuneable range than prior art devices, and is highly linear.

Powerless Starting Circuit

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US Patent:
4340851, Jul 20, 1982
Filed:
Jun 18, 1980
Appl. No.:
6/160674
Inventors:
Yukio Nishikawa - San Jose CA
Assignee:
Precision Monolithics, Inc. - Santa Clara CA
International Classification:
G05F 316
US Classification:
323311
Abstract:
An improved start-up circuit is provided for self-biased circuits of the type connected to a supply voltage and having biasing currents stable at two operating points at which the biasing currents are either zero or nonzero in value when the supply voltage is nonzero and having sufficient regenerative feedback to raise the level of the biasing currents to the nonzero value when an initial current is provided to the circuit. The start-up circuit includes a resistive element which provides a current path from the supply voltage to the self-biased circuit and a transistor element, responsive to the current flow through the path for supplying an initial current to the self-biased circuit, whereupon the regenerative feedback causes the circuit to draw a current related to the biasing current through the current path as the biasing currents reach the nonzero operating point. The current flow through the path causes the transistor element to disconnect the initial current from the self-biased circuit as the nonzero operating point is reached. The start-up circuit draws no power from the voltage supply after the disconnection occurs.

Quasi-Resistive Battery Feed For Telephone Circuits

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US Patent:
4272656, Jun 9, 1981
Filed:
Apr 5, 1979
Appl. No.:
6/027503
Inventors:
Yukio Nishikawa - San Jose CA
Assignee:
Precision Monolithics, Inc. - Santa Clara CA
International Classification:
H04B 158
US Classification:
179170NC
Abstract:
An electronic circuit simulates the direct current characteristics of the hybrid transformer portion of the telephone system call-handling equipment. The circuit is connected across a two-wire telephone subscriber loop and supplies a loop current that is proportional to the difference between a constant current and a reference current. The circuit contains a voltage sensing circuit which senses the voltage across the loop and transfers the sensed voltage across a reference resistor, thereby developing a reference current through the resistor which is proportional to the voltage across the subscriber loop. An integral current generator supplies a constant current to the circuit. An integral current subtractor, connected between the output of the voltage sensing circuit and the current generator subtracts the constant current from the reference current. The resulting current forms the input current to an integral current amplifier. The current amplifier amplifies the current from the current subtractor, thereby producing an amplified current which is proportional to the reciprocal of a constant plus the resistance of the subscriber loop.
Yukio Nishikawa from Los Gatos, CA, age ~80 Get Report