EP 0469769 A2 19920205 - Magnetically-coupled, two-resonant-circuit, frequency-division tag.
Title (en)
Magnetically-coupled, two-resonant-circuit, frequency-division tag.
Title (de)
Magnetischgekoppelte, Zweiresonanz-Schaltung, Frequenz-Teilungsetikett.
Title (fr)
Etiquette à division de fréquence ayant un circuit birésonnant accouplé magnétiquement.
Publication
Application
Priority
- US 56247190 A 19900803
- US 56247590 A 19900803
Abstract (en)
A batteryless, portable, frequency divider includes a first resonant LC circuit (70) that is resonant at a first frequency for receiving electromagnetic radiation at the first frequency; and a second resonant LC circuit (74) that is resonant at a second frequency that is one-half the first frequency for transmitting electromagnetic radiation at the second frequency. The first circuit is coupled only magnetically to the second circuit to transfer energy to the second circuit in response to receipt by the first circuit of electromagnetic radiation at the first frequency. At least one of the resonant circuits includes a variable reactance element, such as a variable capacitance diode (D1<.>, D1<..>) or a varactor. In a variable reactance element (D1<.>) of the first circuit (70), the reactance varies with variations in energy received by the first circuit for causing the second circuit to vary in reactance due to mutual reactive coupling to cause the second circuit to transmit electromagnetic radiation at the second frequency in response to the energy transferred from the first circuit at the first frequency. In a variable reactance element (D2<.>) of the second circuit (74), the reactance varies with variations in energy transferred from the first circuit for causing the second circuit to transmit electromagnetic radiation at the second frequency in response to the energy transferred from the first circuit at the first frequency. Both resonant circuits include inductance coils (L1<.>, L2<.>) that are disposed on a ferrite rod (72), for enhancing the magnetic coupling. The frequency divider is included in a tag utilized in a presence detection system. <IMAGE>
IPC 1-7
IPC 8 full level
G01V 3/12 (2006.01); G01V 3/00 (2006.01); G01V 15/00 (2006.01); G08B 13/24 (2006.01)
CPC (source: EP)
G08B 13/242 (2013.01); G08B 13/2422 (2013.01); G08B 13/2425 (2013.01); G08B 13/2431 (2013.01); G08B 13/2437 (2013.01); G08B 13/2442 (2013.01)
Designated contracting state (EPC)
AT BE CH DE DK ES FR GB GR IT LI LU NL SE
DOCDB simple family (publication)
EP 0469769 A2 19920205; EP 0469769 A3 19921230; EP 0469769 B1 19970507; AT E152848 T1 19970515; AU 635654 B2 19930325; AU 8132591 A 19920206; CA 2047559 A1 19920204; CA 2047559 C 19990706; DE 69125985 D1 19970612; DE 69125985 T2 19971211; ES 2100934 T3 19970701; JP 3224564 B2 20011029; JP H04233696 A 19920821; NO 912997 D0 19910801; NO 912997 L 19920204
DOCDB simple family (application)
EP 91306658 A 19910722; AT 91306658 T 19910722; AU 8132591 A 19910725; CA 2047559 A 19910722; DE 69125985 T 19910722; ES 91306658 T 19910722; JP 19434291 A 19910802; NO 912997 A 19910801