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:
Oct. 02, 1984
Filed:
Dec. 21, 1982
Percy P Batlivala, Arlington Heights, IL (US);
Richard S Kommrusch, Schaumburg, IL (US);
Ronald H Chapman, Wheaton, IL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
An apparatus for minimizing the spillover signal from the transmitter to the receiver in a same frequency repeater includes a mechanism for generating a receiver first injection signal carrying the modulation component of the transmitter signal, and a first mixer for mixing the received signals and the first injection signal to produce a first IF signal having one unmodulated IF component signal and another modulated IF component signal. A correlation and cancellation circuit is utilized to cancel the unmodulated IF component signal. A mechanism is provided for generating a second injection signal which carries the modulation component of the transmitter signal. A second mixer mixes the first IF signal and the second injection signal to produce a second IF signal such that the modulation component of the spillover signal is substantially cancelled. Time synchronization mechanisms are preferably provided to adjust the phase of the modulation component of the transmitted signal as carried by the first and second injection signals such that it arrives at the first and second mixers in phase synchronization with the modulation component of the spillover signal. This invention also contemplates a method for canceling the modulation component of the spillover signal.