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. 11, 1994
Filed:
Dec. 28, 1990
David J Clarke, Bramford, GB;
Edward A Martin, Sunnyvale, CA (US);
Schlumberger Industries Limited, Farnborough, GB;
Abstract
A transponder includes a receiver for receiving a radio interrogation signal. The transponder also includes a phase locked loop decoder for deriving a reference signal from the received interrogation signal, and a radio transmitter for transmitting a transponder reply signal. The phase locked loop has an output which feeds the AC reference signal to the transmitter. The transmitter includes a frequency doubler which generates a transmitter radio frequency at double the frequency of the reference signal. The transmitter radio frequency is therefore controlled by the radio frequency of the interrogation signal. The phase locked loop includes a divide-by-N counter, where N is a predetermined integer parameter. The parameter N determines the derivation of the reference signal frequency from the interrogation signal frequency.