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:
Apr. 14, 2009
Filed:
Sep. 09, 2005
Robert Matthews, San Diego, CA (US);
Robert Matthews, San Diego, CA (US);
Quantum Applied Science & Research, Inc., San Diego, CA (US);
Abstract
An amplifier circuit with current noise reduction employs first and second variable impedance devices between a signal source and an amplifier. A modulation frequency generator establishes a modulation frequency fto alter the first and second impedance values out of phase from one another at the modulation frequency so that the sum of the first and second impedance values at the input of the amplifier is relatively constant. The modulation at frequency fshifts the signal to side bands about the modulation frequency. The output from the amplifier is passed to a bandpass filter centered on the modulation frequency in order to remove all frequencies outside the bandwidth of interest. The signal itself is recovered by demodulating the output of the bandpass filter using a synchronization signal that is derived from the modulation signal.