Example access network devices are described. One example access network device includes a signal processing apparatus. The signal processing apparatus includes a first power amplifier, a second power amplifier, a first filter, a second filter, and a combiner. The first filter filters a second signal obtained by the first power amplifier, to obtain a first sub-signal belonging to a first frequency band and a second sub-signal belonging to a second frequency band. The second filter filters a fourth signal obtained by the second power amplifier, to obtain n sub-signals including at least a third sub-signal belonging to a third frequency band. The combiner combines the first sub-signal and i sub-signals in the n sub-signals based on a preset condition, to obtain a first combined signal. The communication module sends the first combined signal by using a first port, and sends the second sub-signal by using a second port.

The present disclosure relates to a circuit including an input terminal configured to receive a first signal at a first frequency; a demodulation chain connected to the input terminal and including a low-noise amplifier having an input coupled to the terminal; a controllable variable impedance connected between a first node and a node configured to receive a reference potential, the first node being connected to the input terminal and/or to the amplifier input; and a current source configured to deliver a current at the first frequency to the first node.

A 5th generation (5G) or pre-5G communication system for supporting a higher data rate than previous 4th generation (4G) communication systems is provided. A switching circuit in a wireless communication system is provided. The switching circuit includes a first coil, a second coil electrically coupled to the first coil, a first switch electrically connected to the second coil, a third coil electrically coupled to the first coil, a second switch electrically connected to the third coil, and a control unit configured to control the opening or closing of the first switch and the second switch. The control unit can be configured to close the first switch and open the second switch to form a first path using the first coil and the second coil, and open the first switch and close the second switch to form a second path using the first coil and the third coil.

The radio frequency front-end systems herein include modules having bandwidth controllable components, such as amplifier and filters. By implementing the modules with bandwidth control, the same module can be used for operation of multiple frequency bands including a first frequency band and a second frequency band. Thus, when implementing features such as carrier aggregation, multiple-input multiple-output (MIMO), and/or sounding resource signaling (SRS) for supporting the multiple frequency bands, the total number of modules used can be reduced and/or additional feature support can be provided compared to an implementation in which each module supports a single frequency band.

Radio frequency front-end systems with filter reuse. In certain embodiments, a front-end system includes a filter, a low noise amplifier (LNA), and a switch interposed between the filter and an input to the LNA. In a first state of the switch, the filter serves to filter a radio frequency signal that is amplified by the LNA. The front-end system further includes a power amplifier that is coupled to the switch. Additionally, in a second state of the switch, the filter serves to filter an amplified radio frequency transmit signal provided by the power amplifier. Accordingly, a filter along a receive path of the front-end system is reused for transmit.

A high-frequency power amplifying module is provided for a communication device that simultaneously uses at least a radio wave in a first band and a radio wave in a second band, and a first high-frequency power amplifier for the first band and a second high-frequency power amplifier for the second band are mounted. The first band and the second band are frequency bands that produce intermodulation distortion of a frequency included in the receive frequency band of the second band, due to a transmit frequency of the first band received by the first high-frequency power amplifier and a transmit frequency of the second band received h the second high-frequency power amplifier. The second high-frequency power amplifier includes a filter that blocks a signal at the transmit frequency of the first band.

Disclosed is a frequency selective limiter with a switched multiplexer filter bank having a plurality of filters coupled between antenna and receiver ports, wherein the switched multiplexer filter bank is configured to enable and disable selected ones of the plurality of filters in response to control signals. First detector circuitry is coupled to the antenna port and configured to detect signal voltage at the antenna port and generate a first detector voltage. Second detector circuitry is coupled to the receiver port and configured to detect signal voltage at the receiver port and generate a second detector voltage, and a digital controller is coupled between the first detector circuitry, the second detector circuitry, and a control interface, wherein the digital controller is configured to limit interfering signals by sending control signals to the switched multiplexer filter bank in response to the first detector voltage and the second detector voltage.

A radio frequency module includes: a module board that includes a first principal surface and a second principal surface on opposite sides of the module board; a first power amplifier disposed on the first principal surface and configured to amplify a transmission signal in a first frequency band; a second power amplifier disposed on the first principal surface and configured to amplify a transmission signal in a second frequency band different from the first frequency band; and a switch disposed on the second principal surface and connected to an output terminal of the first power amplifier and an output terminal of the second power amplifier.

Apparatus and methods for envelope controlled radio frequency (RF) switches are provided. In certain embodiments, a power amplifier provides an RF signal to an antenna by way of an RF switch. Additionally, the envelope signal is used not only to control a power amplifier supply voltage of the power amplifier, but also to control a regulated voltage used to turn on the RF switch. For example, a level shifter can use a regulated voltage from charge pump circuitry to turn on the RF switch, and the envelope signal can be provided to the charge pump circuitry and used to control the voltage level of the regulated voltage over time.

A system and method integrates signal filters in a multiband transceiver. A preferred embodiment comprises an amplifier with a first tunable capacitor coupled to a signal input and a tunable filter. The tunable filter comprises an input stage with a first pair of inductors arranged in a dipole configuration and a second tunable capacitor coupled in parallel to the first pair of inductors and an output stage inductively coupled to the input stage, the output stage includes a second pair of inductors also arranged in a dipole configuration and a third tunable capacitor coupled in parallel to the second pair of inductors. The inductors are realized using bond wire or any other high Q material. The first tunable capacitor, the second tunable capacitor, and the third tunable capacitor can be tuned using a master-slave tuning configuration to adjust the operating frequency of the amplifier and the tunable filter to enable frequency band compatibility with multiple communications protocols.