TRANSPONDER WITH RECEIVING MEANS HAVING A LOW ELECTRICAL CONSUMPTION IN A LISTENING MODE
First Claim
1. A transponder comprising an antenna and a receiver circuit for receiving Amplitude Modulated RF signals (AM-RF signals), this receiver circuit comprising a wake-up circuit and further at least a demodulator, the receiver circuit being associated to a control mechanism of the transponder activating this receiver circuit at least periodically in a listening mode in which the wake-up circuit analyzes received RF signals and controls the activation of at least the demodulator in function of these received RF signals, wherein this wake-up circuit receives as entry an alternating signal branched from the signal chain through the receiver circuit upstream from said demodulator and having the carrier frequency of the received RF signals, wherein the wake-up circuit comprises a frequency discriminator arranged for detecting if said carrier frequency is within a given frequency range, wherein the wake-up circuit further comprises a field clock generator and a digital modulation or preamble detector downstream from this field clock generator, and wherein the wake-up circuit activates at least the demodulator only when said carrier frequency of a received RF signal detected by the frequency discriminator is within a given frequency range and a modulation or a preamble is detected in this received RF signal by the digital modulation or preamble detector.
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Accused Products
Abstract
The transponder comprises an antenna and a receiver circuit (2) for receiving RF signals, this receiver circuit is implemented with a control mechanism to activate it at least periodically in a listening mode. This receiver circuit is comprises a decoding circuit (4), formed at least by a demodulator (8) and a decoder (10), and a wake-up circuit (14B) to analyze received RF signals in the listening mode and arranged for controlling the activation of the decoding circuit in this listening mode. The wake-up circuit comprises a frequency discriminator (17) and a digital modulation or preamble detector (18) downstream from a field clock generator (28). The wake-up circuit receives as entry an alternating signal branched from the signal chain through the receiver circuit upstream from the demodulator and it activates the decoding circuit only when a modulation or a preamble is detected in a received RF signal by the digital modulation or preamble detector.
45 Citations
24 Claims
- 1. A transponder comprising an antenna and a receiver circuit for receiving Amplitude Modulated RF signals (AM-RF signals), this receiver circuit comprising a wake-up circuit and further at least a demodulator, the receiver circuit being associated to a control mechanism of the transponder activating this receiver circuit at least periodically in a listening mode in which the wake-up circuit analyzes received RF signals and controls the activation of at least the demodulator in function of these received RF signals, wherein this wake-up circuit receives as entry an alternating signal branched from the signal chain through the receiver circuit upstream from said demodulator and having the carrier frequency of the received RF signals, wherein the wake-up circuit comprises a frequency discriminator arranged for detecting if said carrier frequency is within a given frequency range, wherein the wake-up circuit further comprises a field clock generator and a digital modulation or preamble detector downstream from this field clock generator, and wherein the wake-up circuit activates at least the demodulator only when said carrier frequency of a received RF signal detected by the frequency discriminator is within a given frequency range and a modulation or a preamble is detected in this received RF signal by the digital modulation or preamble detector.
Specification