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:
Dec. 07, 1982
Filed:
Feb. 25, 1981
Yukinobu Ishigaki, Yokohama, JP;
Yutaka Haramoto, Yokohama, JP;
Victor Company of Japan, Limited, Yokohama, JP;
Abstract
A noise reduction system having a compressor and an expander. The compressor comprises series connected high and low frequency band filters of the variable frequency type, the cut-off frequencies of which are respectively controlled in response to high and low frequency components of the output of the series connected filters so that they are shifted in opposite directions to each other independently as a function of the amplitude of the respective frequency components, whereby the amplitude range of the respective frequency band is emphasized to a constant value while the frequency range of the emphasized band is varied in response to the amplitude of the respective component. The expander comprises series connected high and low frequency band filters of the variable frequency type of which the cut-off frequencies are respectively controlled in response to high and low frequency components of the input to the expander so that they are shifted in opposite directions to each other in a manner similar to that of the compressor. Each of the filters of the expander has a complementary frequency response characteristic to that of the corresponding filter of the compressor to de-emphasize the emphasized frequency components to restore the normal amplitude and frequency ranges of the original signal.