A radiofrequency device includes at least the following elements: an antenna, linked to a first transmission channel or reception channel selection device K.sub.1, followed by a front-end stage whose output is linked to a second transmission channel or reception channel selection device K.sub.2, a group of filters connected between the second selection device K.sub.2 and a third transmission channel or reception channel selection device K.sub.3, the third selection device K.sub.3 is connected to a transceiver, the transceiver comprises a converter part, wherein the group of filters comprises N filters having distinct frequency bands B.sub.N in a given bandwidth B.sub.T, the group of filters is linked to a manager selecting at least one of the filters Fj of the group of filters in order to attenuate a first type of disturbing signals P.sub.1, in the vicinity of the centre frequency of the channel to be received, the transceiver comprises a stage comprising a variable filter, the variable filter is configured in order to eliminate a second type of disturbing signals P.sub.2, the stage is connected between the group of filters and the analog-digital and digital-analog conversion set, the number N of filters of the group of filters is chosen by taking into account the operating frequency band value of the antenna, the value of a selected bandwidth Bc and a coefficient δ taking into account overlap effects.

A radio frequency module includes a first terminal, a second terminal, a third terminal, a first switching circuit, a bandpass filter, a first band elimination filter, and a first wiring conductor. The first switching circuit switches between a connection between a first switch terminal and a second switch terminal and a connection between the first switch terminal and a third switch terminal. The bandpass filter is disposed on a first signal path connecting the first terminal to the first switch terminal, and has a first passband. The first band elimination filter is disposed on a second signal path connecting the second switch terminal to the second terminal, and has a first elimination band included in the first passband. The first wiring conductor forms a third signal path connecting the third switch terminal to the third terminal.

A front-end circuit includes an antenna connection terminal, a selection terminal, and a selection terminal, a switching circuit including a common terminal and selection terminals, a receive filter configured to pass a radio-frequency signal in Band B, a signal path connecting the selection terminal and the selection terminal and including the receive filter, a signal path connecting the selection terminal and the selection terminal and defining and functioning as a bypass path without any filter, and a filter coupled between the antenna connection terminal and the common terminal and configured to pass a first frequency range group including Band B.

A switch module switches among a first state where first and second frequency bands are used in parallel, a second state where only the first frequency band is used, and a third state where none of the first and second frequency bands is used, and includes first, second, and third filters and an antenna switch. In the first state, a common terminal and the first and second filters are connected and the common terminal and the third filter are not connected. In the second state, the common terminal and the first and third filters are connected, and the common terminal and the second filter are not connected.

Embodiments of the present invention provide a communication terminal apparatus and a method. The communication terminal apparatus includes: a switch unit, a radio frequency unit, and a controller. The controller controls the switch unit to perform switching according to a preset ratio of uplink signal time duration resources to downlink signal time duration resources. The embodiments of the present invention can solve a problem of inflexible uplink and downlink time duration resource configuration.

A phase shifter includes a signal input, a signal output, an ESD protection circuit, first and second signal paths between the signal input and the signal output. The ESD protection circuit includes first and second two port devices, each two port device being switchable between a high impedance state and a low impedance state. The first signal path includes the first two port device of the ESD protection circuit and a first delay line configured to provide a first phase shift to a signal transmitted from the signal input to the signal output via the first signal path. The second signal path includes the second two port device of the ESD protection circuit and a second delay line configured to provide a second phase shift, different from the first phase shift, to the signal transmitted from the signal input to the signal output via the second signal path.

An elastic wave device includes an LiNbO.sub.3 substrate, a first elastic wave resonator including a first IDT electrode and a first dielectric film, and a second elastic wave resonator including a second IDT electrode and a second dielectric film. A Rayleigh wave travels along at least one surface of the elastic wave device. A thickness of the first dielectric film differs from a thickness of the second dielectric film. A propagation direction of an elastic wave in the first elastic wave resonator coincides with a propagation direction of an elastic wave in the second elastic wave resonator. Euler angles of the LiNbO.sub.3 substrate fall within a range of (0°±5°, θ, 0°±10°).

A method of operating a radio receiver device comprises receiving a plurality of signals with a plurality of corresponding frequencies; applying respective gains to each of the plurality of signals; and storing the gain applied to each signal and its corresponding frequency. The method comprises subsequently receiving a further signal with a further frequency; and applying a further gain to the further signal. The further gain is determined using at least one of the stored gains according to a difference between the further frequency and at least one of the plurality of corresponding frequencies.

Systems and methods for detecting radio frequency (“RF”) signals and corresponding origination locations are disclosed. An RF sensor device includes a software-defined radio and an antenna pair for receiving RF signals. Furthermore the RF sensor device may include a processing unit for processing/analyzing the RF signals, or the processing unit may be remote. The system calculates a phase difference between an RF signal received at two separate antennas of an antenna pair. The phase difference, the distance between the antennas, and the frequency of the RF signal are used for determining the origination direction of the RF signal. In various embodiments, the origination direction may indicate the location of a UAV controller or base station. The software-defined radio may include more than one antenna pair, connected to multiplexers, for efficiently scanning different frequencies by alternating active antenna pairs. Moreover, the system may execute packet-based processing on the RF signal data.

A high frequency circuit includes a main module and a diversity module. The main module includes a duplexer that transmits and receives a signal of a first communication band of a first communication system. The diversity module includes a duplexer that transmits and receives a signal of a second communication band of a second communication system, a reception filter that uses a reception band of the first communication band of the first communication system as a pass band, a power amplifier, a low noise amplifier, and a switch that exclusively switches between connection between a reception filter and the low noise amplifier and connection between the reception filter and the low noise amplifier. The first communication band and the second communication band have the same frequency band.