Circuits and methods that provide fine-resolution measurements of RF signal power within a communication system band, thereby more accurately measuring RF interference or the potential of RF interference. One aspect of embodiments of the present invention is a narrow-band tunable filter that includes two elements coupled in series, a periodic passband filter and a tunable filter. The purpose of the periodic passband filter is to generate multiple periodic passbands for an applied RF signal. The purpose of the tunable filter is to generate a single passband, generally with a tunable center frequency. By serially coupling the two filter types in either order, the single passband of the tunable filter is superimposed over one of the periodic passbands of the periodic passband filter, synergistically resulting in an extremely narrow passband.

A diplexer includes a first filter circuit, and a second filter circuit. The first filter circuit is coupled to a first port for providing a first signal path for a first radio frequency (RF) signal. The second filter circuit is coupled to the first port for providing a second signal path for a second RF signal. The first filter circuit includes a first tunable resonant circuit for tuning a first transmission zero corresponding to a first frequency multiplication of the first RF signal. The second filter circuit includes a second tunable resonant circuit for tuning a first transmission zero corresponding to a first frequency multiplication of the second RF signal. The first frequency multiplication of the first RF signal corresponding to the first filter circuit is a fourth harmonic of the first RF signal.

A correction method (500) for a super-regenerative receiver (100) being configured to resonate at at least one oscillator resonant frequency reference value (111) and comprising at least one control stage (130), at least one varactor (140), at least one reference system (150) and, at least one oscillator (110). The method includes at least one setup (510) of at least one reference signal value (158) by the at least one reference system (150), at least one comparison (560) of at least one oscillator frequency actual value (112) of the at least one oscillator (110) with the at least one reference signal value (158) by the at least one reference system (150) and at least one adjustment (570) of at least one gain of the at least one control stage (130).

An antenna switch circuit and an antenna circuit switching method. The circuit includes an antenna port, a termination port (e.g., for disposal of power reflected back from an antenna and received through the antenna port in a transmit mode), and a receive port (e.g., for receiving a signal from the antenna port via the antenna switch circuit in a receive mode). The circuit also includes a first switch coupled between the antenna port and the termination port. The circuit further includes a resonant inductance coupled between the receive port and the node located between the antenna port and the first switch. The circuit also includes a second switch coupled between a reference potential and a node located between the resonant inductance and the receive port.

Aspects and embodiments provide a transceiver comprising: a transmit signal path; a receive signal path; bidirectional amplification circuitry reconfigurable for use in both the transmit signal path or receive signal path. The amplification circuitry includes at least one resonant tunnelling diode; and the control circuitry is configured to selectively couple the amplification circuitry into the transmit or receive path of the transceiver in dependence upon whether the transceiver is to operate to transmit or receive a signal. The compact and energy efficient transceiver system in accordance with aspects and embodiments recognises that the physical properties of resonant tunnelling diodes provide a mechanism for simplification of transceiver circuitry and may enable transceiver arrangements which can operate in the high mm-wave and terahertz frequency ranges.

The present application relates to a wave limiting circuit, and a pre-calibration method, a dynamic correction method and apparatuses therefor. The circuit comprises: an LC series resonance circuit, a controller and a matching element, wherein a first end of the matching element is connected to a radio frequency circuit; a second end thereof is connected to an antenna, and a third end thereof is connected to one end of the LC series resonance circuit; and the other end of the LC series resonance circuit is connected to the controller so as to adjust parameters of the LC series resonance circuit by means of the controller.

A front-end module (FEM) is disclosed that includes an integrous signal combiner. The integrous signal combiner can process received signals and use a set of resonant circuits to filter signal noise prior to recombination of a plurality of signal bands that form an aggregate carrier signal. These resonant circuits may be placed after a set of low noise amplifiers and can be used to more efficiently reduce noise and parasitic loading within each of a set of signal paths. Each resonant circuit may be configured to filter noise relating to a bandwidth for a signal that is to be combined with the signal of the signal path that includes the resonant circuit. In some implementations, the integrous signal combiner can be a tunable integrous signal combiner with resonant circuits that may be reconfigurable or dynamically configurable.

A diplexer includes a first filter circuit, and a second filter circuit. The first filter circuit is coupled to a first port for providing a first signal path for a first radio frequency (RF) signal. The second filter circuit is coupled to the first port for providing a second signal path for a second RF signal. The first filter circuit includes a first tunable resonant circuit for tuning a first transmission zero corresponding to a first frequency multiplication of the first RF signal. The second filter circuit includes a second tunable resonant circuit for tuning a first transmission zero corresponding to a first frequency multiplication of the second RF signal. The first frequency multiplication of the first RF signal corresponding to the first filter circuit is a fourth harmonic of the first RF signal.

A circuit arrangement for compensating for an attenuation occurring in an antenna signal link between a mobile radio terminal and an antenna has at least one antenna signal amplifier in the antenna signal link and a control unit for adjusting a gain factor. The antenna signal conducted through an associated antenna signal amplifier is amplified or attenuated. The circuit arrangement has a detection unit for detecting an antenna signal power (P.sub.M, P.sub.A) of the antenna signal in the signal path of the antenna signal link. The control unit is configured for changing the gain factor, detecting a change, changing the transmit power (P.sub.M) of the mobile radio terminal, and adapting the gain factor to the coupling attenuation of the antenna signal link in dependence on a detected response of the mobile radio terminal.

A technology is described for direction finding. An example of the technology can include executing stages of an N stage search for a direction finding estimate of a plane wave X. The stages of the N stage search include searching a search space in a calibration set having a plurality of points in space and calculating a direction finding estimate, wherein a first search space is a coarse set of points in space and subsequent search spaces selected for subsequent stages of the N stage search are increasingly finer sets of points in the space, and a solution for the direction finding estimate output by a stage of the N stage search is used to select a next search space for a next stage of the N stage search. A direction finding estimate output by a final stage of the N stage search is the final direction finding estimate.