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:
Apr. 14, 2009
Filed:
May. 27, 2005
Normand Dery, Quebec, CA;
Normand Dery, Quebec, CA;
DEI Headquarters, Inc., Vista, CA (US);
Abstract
An AM/FM modulation scheme is presented for optimizing communications between a remote control device held by a user and a receiving unit installed in a vehicle. Historically, these systems communicated with amplitude modulated signals having good range but poor immunity to ambient random radio frequency noise. Frequency modulated systems provide improved immunity to noise however at the expense of range. The object of this invention is to use two or more modulation modes to combine their advantages. A scheme has been devised whereby circuitry capable of alternately operating in at least two modes is used. The same information is therefore transmitted using two or more modulation techniques in succession. The receiving unit also has circuitry and has listening cycles ensuring eventual synchronization with the transmitting unit. If one mode fails due to distance or ambient noise, the other can then attempt to establish a link.