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:
Jun. 22, 2004
Filed:
Feb. 10, 2003
Carl W. Moreland, Oak Ridge, NC (US);
Analog Devices, Inc., Norwood, MA (US);
Abstract
Variable-gain amplifiers (VGAs) are provided that realize gain accuracy (e.g., over variations in temperature and fabrication processes) while also providing this accuracy over a wide bandwidth and without the signal-to-noise degradation typically associated with signal attentuating elements. Differential signal and gain amplifiers of these VGAs include current sources which are controlled by a common error signal S . The gain amplifier is supplemented by feedback structure that generates the error signal S and controls the amplifier's transconductance to be the ratio of at least one of currents and resistors. Because such ratios can be well matched (especially in integrated circuit realizations of the variable-gain amplifiers) and because the current source of the signal amplifier is also controlled by the error signal S , this wide-band, low-noise open-loop amplifier's gain is accurately controlled.