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. 03, 1987
Filed:
Feb. 06, 1985
Ralph Deutsch, Sherman Oaks, CA (US);
Kawai Musical Instrument Mfg. Co., Ltd., Hamamatsu, JP;
Abstract
In a musical instrument in which a plurality of data words corresponding to the amplitudes of a corresponding number of evenly spaced points defining a cycle of an audible musical waveform are transformed at an average rate corresponding to the fundamental frequency of the tone being generated, a frequency generator is provided using a single clock source for selectively producing the entire frequency range of selected musical notes. A non-integer frequency generator is implemented which periodically adds a frequency number, corresponding to an actuated keyswitch, to itself in an accumulator. The integer portion of the accumulator content is used to address out waveshape values stored in a memory. The decimal portion of the accumulator content is used to select the time at which either the current read out waveshape data value or a previously read out waveshape data value is converted into an analog signal by means of a digital-to-analog converter. The time selection reduces the undesirable spectral noise components produced by the unequally spaced advance of the waveshape addresses associated with the integer portion of the accumulated content.