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:
Aug. 28, 1990
Filed:
Jan. 09, 1989
James R Ashley, Tampa, FL (US);
Hercules Defense Electronics Systems, Inc., Clearwater, FL (US);
Abstract
An active voltage divider circuit is applied to the loop filter of a phase-lock loop, thereby providing a variable gain factor, wherein the gain with large phase error is substantially greater than the gain with small phase error. This results in improved acquisition time for large frequency offsets, while providing in the phase-lock state the same performance as a conventional loop having the same natural loop frequency and damping factor. By sampling the applied radio frequency signal with an amplitude detector and applying the sampled output and the output of a phase sensitive detector to an analog divider, amplitude variations of the input signal are cancelled, thereby making the loop filter essentially independent of the amplitude of the input signal. In a further embodiment the input signal is coupled to a quadrature detector wherefrom I and Q output signals are coupled to a divider which provides error signals to the loop filter that are independent of the input signal amplitude.