Transponder system
First Claim
1. A transponder system including an interrogator station which is provided with a transmitter and a receiver, said transmitter being arranged for wireless transmission of an interrogation signal in the form of a pulse train having a given carrier frequency, and a responder station comprising a common transmitting and receiving antenna connected to two terminals, a first resonator connected between said terminals and tuned to the incoming carrier frequency, a second resonator connected between said terminals and tuned to a harmonic of the incoming frequency, a rectifier element with a non-linear characteristic coupled between the first and second resonators to produce d.c. trigger pulses from the incoming signal and to excite said second resonator for retransmitting a reply signal at the harmonic frequency, a modulator triggered by said d.c. pulses from the rectifier element an including control means for eliminating and restoring the resonant condition in said second resonantor in response to a binary information signal which is fed into the modulator.
0 Assignments
0 Petitions
Accused Products
Abstract
A responder system in which incoming frequency f0 is converted to a harmonic frequency, e.g. 2f0, by means of a non-linear element, for example a diode, which is connected between capacitance and inductance in two parallel-connected series resonant circuits, one of which is closely tuned to the incoming frequency f0 while the other is closely tuned to the selected harmonic frequency. Incoming frequency f0 is fed to the interconnected ends of the two resonant circuits, whereby both resonant circuits are excited at their respective resonance frequencies, and the harmonic frequency 2f0 is radiated back via a common antenna connected to the interconnected ends of the two series resonant circuits. When transmitting binary information by means of pulses at the harmonic frequency 2f0 the retransmitted pulses can be marked in certain pulse intervals by eliminating the resonance condition in the second resonant circuit (2f0) during a part of the interval, so that a dip will be produced in the retransmitted pulse, while in other intervals the pulse is retransmitted continuously.
-
Citations
7 Claims
- 1. A transponder system including an interrogator station which is provided with a transmitter and a receiver, said transmitter being arranged for wireless transmission of an interrogation signal in the form of a pulse train having a given carrier frequency, and a responder station comprising a common transmitting and receiving antenna connected to two terminals, a first resonator connected between said terminals and tuned to the incoming carrier frequency, a second resonator connected between said terminals and tuned to a harmonic of the incoming frequency, a rectifier element with a non-linear characteristic coupled between the first and second resonators to produce d.c. trigger pulses from the incoming signal and to excite said second resonator for retransmitting a reply signal at the harmonic frequency, a modulator triggered by said d.c. pulses from the rectifier element an including control means for eliminating and restoring the resonant condition in said second resonantor in response to a binary information signal which is fed into the modulator.
Specification