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:
Jan. 08, 1991
Filed:
Dec. 26, 1989
Daniel P Brown, Elmhurst, IL (US);
Larry C Puhl, Sleepy Hollow, IL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A method and apparatus for decoding of frequency inversion based scramblers is disclosed. A quadrature amplitude modulation detector determines the frequency of the tone used for inverting the scrambled signal by determining which of a plurality of quadrature detector pairs, each using a different conversion frequency, has the greatest magnitude difference between the quadraturely related signals. The frequency of the quadrature pair with the greatest difference is the frequency of the inverting tone during the inverting period of time. This frequency information is used to generate a reinversion tone to unscramble the scrambled signal.