The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 30, 1990
Filed:
Feb. 21, 1989
Youichi Masuda, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kanagawa, JP;
Abstract
In an oscillator of this invention, a differential amplifier circuit is constituted by connecting the collectors of first and second transistors to one terminal of a DC power source respectively through first and second resistors, the emitters of the first and second transistors to the other terminal of the DC power source through a common current-source, and the bases of the first and second transistors to a bias circuit for applying a bias voltage, at least one port of a piezo-electric device having at least two ports on a single substrate is connected between the collectors of the first and second transistors, and the remaining port is connected between the bases of the first and second transistors. The transistors can be field effect transistors, and the common current-source can be a resistor. In this oscillator, since no DC voltage is applied across transducers of each port, degradation of a piezo-electric device can be prevented. The circuit has a complete symmetrical arrangement, and only a DC current flows in from the power source. For this reason, the circuit does not serve as a noise source for another circuit connected to the power source, and is not easily influenced by noise from the other circuit. Since no large-capacitance capacitor is required, the oscillator is suitable for an integrated circuit.