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. 06, 1983
Filed:
Mar. 11, 1981
Daniel B Talbot, Hudson, MA (US);
Other;
Abstract
An improved substantially 'zero distortion' four quadrant modulator of the type including a pair of differential elements respectively coupled to the Y input port terminals of the modulator and exhibiting nonlinear amplitude transfer functions, includes the means for substantially linearizing the nonlinear transfer function. The means includes a pair of operational amplifiers, each having an input coupled to a respective terminal of the Y input port and an output coupled to the corresponding differential element so that the differential element is disposed in the feedback path of the operational amplifier. An improved demodulator is provided by detecting the amplitude modulated signal with a first detector and applying the detected signal to one input of a signal comparator. A feedback loop couples the output of the signal comparator to its other input. In particular the output is coupled to the Y input port of a substantially zero distortion modulator, which has the X input adapted to receive a continuous wave signal. The output of the modulator is detected by a second detector which in turn is coupled to the other input of the signal comparator. The first and second detectors are matched for their nonlinear amplitude transfer functions so that the output of the signal comparator is a substantially zero distorted representation of the envelope component of the amplitude modulated signal.