An electrical resonance network comprising a first capacitor and a first inductor whose resonance frequency can be tuned by means of a second capacitor and/or a second inductor. The resulting effective capacitor- or inductor value of a network period is controlled by a variable coupling respectively decoupling interval by means of at least one coupling switch. The coupling respectively decoupling interval is synchronized by a sign change of a current and/or voltage in the network.

Signal generation devices including an auto-tuning electronic circuit module for generating tuned output signals are disclosed. The auto-tuning electronic circuit module may include a tunable resonant electronic circuit element for providing a tuned output signal, including a voltage divider element and a tuning array element and control element.

An RFID reader, tuning method and computer readable medium. A carrier signal is transmitted. A plurality of feedback signals produced in the RFID reader are measured when transmitting the carrier signal with a variable matching network set at a plurality of impedance values that are different from one another. It is determined which impedance value of the plurality of impedance values produced a feedback signal having a highest level of the plurality of feedback signals. The variable matching network is set to the determined impedance value.

An RFID reader, tuning method and computer readable medium. A carrier signal is transmitted. A plurality of feedback signals produced in the RFID reader are measured when transmitting the carrier signal with a variable matching network set at a plurality of impedance values that are different from one another. It is determined which impedance value of the plurality of impedance values produced a feedback signal having a highest level of the plurality of feedback signals. The variable matching network is set to the determined impedance value.

A method and apparatus for adapting an electronic device to receive digital television broadcast signals is disclosed. The device comprises a switch commandable to interpose one or more matching networks as in the RF signal path according to a channel command to match an integrated headset antenna to the tuner receiving the RF signals.

Techniques are disclosed implementing a tunable transformer with additional taps in at least one of the three coils. The tunable transformer enables the resonant frequency within RF transceiver matching networks to be adjusted without substantially impacting the output power at resonance. The tunability of the transformer is partially driven by the insertion of additional coils within the transformer, which are selectively switched and may be further coupled with a tunable capacitance. The tunability of the transformer is further driven via the use of at least one multi-tap transformer coil, which allows electronic components to be coupled to different coil taps to thereby facilitate an adjustable DC inductance. Doing so counteracts changes in mutual inductance between the non-switched coils, and facilitates the stabilization of output power with shifts in resonant frequency.

In one embodiment, a tuning network includes: a controllable capacitance; a first switch coupled between the controllable capacitance and a reference voltage node; a second switch coupled between the controllable capacitance and a third switch; the third switch coupled between the second switch and a second voltage node; a fourth switch coupled between the second voltage node and a first inductor; the first inductor having a first terminal coupled to the fourth switch and a second terminal coupled to at least the second switch; and a second inductor having a first terminal coupled to the second terminal of the first inductor and a second terminal coupled to the controllable capacitance.

Circuits, devices and methods related to impedance tuners. In some embodiments, a capless impedance tuner can include first node and second nodes, a first series path, a second series path, and an inductance path, each between the first node and the second node and including a switch to allow the path to couple or uncouple the first and second nodes. Each series path can be configured to allow a substantially continuous flow of a direct current between the first node and the second node when coupled. The tuner can further include a shunt path with a switch to allow coupling or uncoupling of the second node and ground. The tuner can further include a switchable grounding path implemented along the inductance path and configured to allow the inductance path to function as a series inductance path between the first and second nodes, or as a shunt inductance path between the ground and a node along the inductance path.

Circuits, devices and methods related to impedance tuners. In some embodiments, a capless impedance tuner can include first node and second nodes, a first series path, a second series path, and an inductance path, each between the first node and the second node and including a switch to allow the path to couple or uncouple the first and second nodes. Each series path can be configured to allow a substantially continuous flow of a direct current between the first node and the second node when coupled. The tuner can further include a shunt path with a switch to allow coupling or uncoupling of the second node and ground. The tuner can further include a switchable grounding path implemented along the inductance path and configured to allow the inductance path to function as a series inductance path between the first and second nodes, or as a shunt inductance path between the ground and a node along the inductance path.

Disclosed is an authentication reader intended to be installed on a motor vehicle opening element, the reader including a microcontroller, at least one transmitter, at least one matching circuit and a single antenna, called “primary” antenna, characterized by a working frequency. The matching circuit includes switching element able to switch the matching circuit between a first mode, in which the matching circuit makes it possible to match the primary antenna to a secondary antenna of an authentication device whose resonant frequency is lower than the working frequency, and a second mode, in which the matching circuit makes it possible to match the primary antenna to a secondary antenna of an authentication device whose resonant frequency is higher than the working frequency.