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:
Jul. 12, 2011
Filed:
Jul. 06, 2005
Adam S. Leitch, Brighton, GB;
Adam S. Leitch, Brighton, GB;
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
A time-of-flight ranging system, such as a keyless access Control system, comprises a first part and a second part, e.g., a portable device such as a key fob. Both parts have a transceiver for effecting communication with each other. At least the first part includes a device, e.g., a processor, for determining the distance between the two parts based on time-off-light. To save power, when the two parts are a relatively great distance apart, a time-of-flight measuring device computes the time based on a relatively coarse algorithm, and when the parts are relatively close, the computation is carried-out using a more precise algorithm. The clock frequency may be reduced when the two parts are a relatively great distance apart, and increased when they are closer. Further the transmitter power may be reduced when the two parts are relatively close together and increased when they are a relatively great distance apart.