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:
Mar. 28, 2017
Filed:
Jun. 24, 2013
Yamaha Corporation, Hamamatsu-shi, JP;
Jun Ishii, Hamamatsu, JP;
YAMAHA CORPORATION, Hamamatsu-shi, JP;
Abstract
An audio signal output from a tone generator is fed into a coil provided in a transducer for vibrating a sound board, so that a sound signal is generated by the vibration of the sound board. A predetermined DC voltage supplied by a constant voltage source circuit is superimposed on the audio signal by an adding circuit, so that the superimposed signal is fed into the coil. A current passing through the coil is sensed by a current sensing resistor, so that only a DC voltage component of a voltage signal on the both ends of the resistor is extracted by a low-pass filter circuit to be supplied to a microcomputer via an A/D converting circuit. The microcomputer figures out a resistance value and a temperature of the coil by use of the DC voltage component and the certain DC voltage value.