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:
Sep. 02, 1986
Filed:
Jul. 31, 1985
Robert L Rodgers, Dallas, TX (US);
Circuit Research Labs, Inc., Tempe, AZ (US);
Abstract
A noise reduction system including a signal path (34) between an input terminal (12) and an output terminal (36), a voltage control amplifier (38) and a control path (40) between the input terminal and the voltage control amplifier is disclosed. A nonlinear element such as a voltage squarer (32) is in the controlled path. In one arrangement, the control path also includes a signal level detector (22), a one-pole high pass filter (16) and a direct current level shifter (26). A precision diode (30) is interposed in the control path between the direct current level shifter and the signal squarer. One form of the noise reduction system includes a voltage-controlled low pass filter (20) interposed in the signal path between the input terminal and the voltage-controlled amplifier. A weighing control path (46) provides the control signal for the voltage-controlled low pass filter. A two-pole high pass filter (18) followed by a level sensor (48) is interposed in the weighting control path.