A demodulator circuit receives an envelope signal for comparison against a switched reference signal that is generated as a function of the envelope signal and as a function of an output signal of the demodulator circuit. The switched reference signal is filtered by an RC filter prior to comparison. The output signal is dependent on a difference between the filtered switched reference signal and the envelope signal.

A demodulator circuit receives an envelope signal for comparison against a switched reference signal that is generated as a function of the envelope signal and as a function of an output signal of the demodulator circuit. The switched reference signal is filtered by an RC filter prior to comparison. The output signal is dependent on a difference between the filtered switched reference signal and the envelope signal.

A method for producing an output bit stream for a first signal of a first carrier frequency by a security module involves the security module receiving an input signal comprising the first signal and a second signal of a second carrier frequency. A mixed signal is formed which has the first signal at the first carrier frequency, the second signal at the second carrier frequency, and a mixed product at an intermediate frequency. The mixed product is demodulated by a second nonlinear component to output a second baseband signal for generating a second bit stream relating to the first signal in the mixed product. The output logic produces the output bit stream for the first signal, and selects either the first bit stream or the second bit stream as the output bit stream for the first signal.

A method for producing an output bit stream for a first signal of a first carrier frequency by a security module involves the security module receiving an input signal comprising the first signal and a second signal of a second carrier frequency. A mixed signal is formed which has the first signal at the first carrier frequency, the second signal at the second carrier frequency, and a mixed product at an intermediate frequency. The mixed product is demodulated by a second nonlinear component to output a second baseband signal for generating a second bit stream relating to the first signal in the mixed product. The output logic produces the output bit stream for the first signal, and selects either the first bit stream or the second bit stream as the output bit stream for the first signal.

A resonant power feeding system that can provide high power transmission efficiency between a power feeding device and a power reception device without dynamically controlling the oscillation frequency in accordance with the distance between the power feeding device and the power reception device. High power transmission efficiency between the power feeding device and the power reception device is obtained by addition of a structure for adjusting the matching condition to both the power reception device and the power feeding device. Specifically, a transmission-reception circuit and a matching circuit are provided in both the power reception device and the power feeding device, and wireless signals for adjusting the matching circuit are transmitted and received through a resonant coil. Thus, the power feeding device can efficiently supply power to the power reception device without adjusting the oscillation frequency.

A resonant power feeding system that can provide high power transmission efficiency between a power feeding device and a power reception device without dynamically controlling the oscillation frequency in accordance with the distance between the power feeding device and the power reception device. High power transmission efficiency between the power feeding device and the power reception device is obtained by addition of a structure for adjusting the matching condition to both the power reception device and the power feeding device. Specifically, a transmission-reception circuit and a matching circuit are provided in both the power reception device and the power feeding device, and wireless signals for adjusting the matching circuit are transmitted and received through a resonant coil. Thus, the power feeding device can efficiently supply power to the power reception device without adjusting the oscillation frequency.

An apparatus with a first branch and a second branch that is configured to receive a first signal and a second signal from a same device, where the second signal indicates the apparatus to enter a connected state. The first branch includes a first frequency-amplitude converter configured to obtain first amplitude information of a third signal which is obtained by performing frequency mixing on the first signal and a first local oscillator signal. The second branch is configured to demodulate a fourth signal which is obtained by performing frequency mixing on the second signal and a second local oscillator signal which is obtained by performing frequency offset correction on the first local oscillator signal based on the first amplitude information, the second branch includes a second frequency-amplitude converter, and a linear working interval of the second frequency-amplitude converter is smaller than that of the first frequency-amplitude converter.

An apparatus with a first branch and a second branch that is configured to receive a first signal and a second signal from a same device, where the second signal indicates the apparatus to enter a connected state. The first branch includes a first frequency-amplitude converter configured to obtain first amplitude information of a third signal which is obtained by performing frequency mixing on the first signal and a first local oscillator signal. The second branch is configured to demodulate a fourth signal which is obtained by performing frequency mixing on the second signal and a second local oscillator signal which is obtained by performing frequency offset correction on the first local oscillator signal based on the first amplitude information, the second branch includes a second frequency-amplitude converter, and a linear working interval of the second frequency-amplitude converter is smaller than that of the first frequency-amplitude converter.