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.

Abstract: A power amplifier circuit can be linked to an antenna arrangement of a communication system for transmission of ASK RF data signals. The power amplifier circuit includes an amplifier core with several cascode amplifier cells in parallel. Each cascode amplifier cell is composed of three NMOS transistors in triode mounting between an output terminal connected to the antenna arrangement, and an earth terminal. A first transistor of each cascode amplifier cell is controlled by a carrier frequency signal, whereas a second transistor of each cascode amplifier cell is controlled by a smoothing control loop in order to modulate data to be transmitted on carrier frequency by amplitude shift keying. The smoothing control loop is provided for generating an increasing gate voltage for the second transistors on the basis of an increasing current ramp from a first minimum current value to a second maximum current value during a “0” to “1” data transition.

Abstract: A power amplifier circuit can be linked to an antenna arrangement of a communication system for transmission of ASK RF data signals. The power amplifier circuit includes an amplifier core with several cascode amplifier cells in parallel. Each cascode amplifier cell is composed of three NMOS transistors in triode mounting between an output terminal connected to the antenna arrangement, and an earth terminal. A first transistor of each cascode amplifier cell is controlled by a carrier frequency signal, whereas a second transistor of each cascode amplifier cell is controlled by a smoothing control loop in order to modulate data to be transmitted on carrier frequency by amplitude shift keying. The smoothing control loop is provided for generating an increasing gate voltage for the second transistors on the basis of an increasing current ramp from a first minimum current value to a second maximum current value during a “0” to “1” data transition.