A radio-frequency module includes a mounting board having first and second major surfaces opposite to each other and a duplexer including a transmit filter coupled to a node and a receive filter coupled to the node. The transmit filter is mounted on the first major surface, and the receive filter is mounted on the second major surface. When the mounting board is viewed in a plan view, a footprint of the transmit filter at least partially overlaps a footprint of the receive filter.

A network communication device includes an input port configured to receive a downstream signal from a network, a first output port in communication with the input port and configured to receive a first reduced-power version of the signal received at the input port, one or more second output ports, and a converting circuit configured to receive a second reduced-power version of the signal received at the input port, down-convert a high-frequency portion thereof, and produce a down-converted signal. The one or more second output ports receive at least a portion of the down-converted signal.

A radio-frequency module includes a module substrate. The module substrate includes a first principal surface; a second principal surface on a side of the module substrate that is opposite to the first principal surface; a third principal surface that is recessed toward the first principal surface from the second principal surface in a plan view of the second principal surface; a recessed region in which the third principal surface is a bottom surface; and a protruding region located on an outer periphery of the recessed region, in a plan view of the second principal surface, wherein the protruding region has a via conductor disposed therein, the via conductor extending in a direction perpendicular to the second principal surface and having an end exposed on the second principal surface.

A network communication device includes an input port configured to receive a downstream signal from a network, a first output port in communication with the input port and configured to receive a first reduced-power version of the signal received at the input port, one or more second output ports, and a converting circuit configured to receive a second reduced-power version of the signal received at the input port, down-convert a high-frequency portion thereof, and produce a down-converted signal. The one or more second output ports receive at least a portion of the down-converted signal.

In some implementations, an electronics system includes a voltage regulator circuit of a PDN configured to generate a power signal, a printed circuit board (PCB) comprising a power rail to deliver the power signal to a digital circuit generating an interfering signal. The PDN radiating the interfering signal or its harmonics impacting the functionality of destination antenna and circuits (such as Wi-Fi, Bluetooth, cellular, etc.). The system includes a filtering element configured to filter an interfering signal generated by the digital circuit. The filtering element includes a first set of low impedance (low-Z) segments and a second set of high impedance (high-Z) segments. The low-Z and high-Z segments are formed using a copper trace of the power rail and are serially connected to each other. The filtering element forms a low pass filter and filters out high frequency interfering signal going to the destination antenna and circuits by radiated means.

In a radio frequency module, the first inductor is disposed on the first principal surface of the mounting board and located on the first reception path through which a first reception signal of a first frequency passes, on an input side of the first low noise amplifier. The second inductor is disposed on the first principal surface of the mounting board and located on the second reception path through which a second reception signal of a second frequency lower than the first frequency passes, on an input side of the second low noise amplifier. The radio frequency component is disposed between the first inductor and the second inductor. A distance between the first inductor and the shielding layer is greater than a distance between the second inductor and the shielding layer. The first inductor overlaps the first low noise amplifier in a thickness direction of the mounting board.

Provided in the present application are a band14 signal suppression circuit and a smart terminal device being equipped with a duplexer, an active low-pass filter, and a resonant filter in a band14 transmission path, implementing filtering and suppression on the second harmonic in the band14 signal, and eliminating the interference of band14 signals on assisted global positioning system signals.

A transmission/reception device is configured to convert an optical signal based on a plurality of first optical signals having frequency bands different from each other into an electric signal and output the electric signal as a plurality of first electric signals; receive the plurality of first electric signals, change frequency bands of some or all of a plurality of second electric signals to narrow an interval between frequency bands of two second electric signals having frequency bands adjacent to each other, and output, as third electric signals, electric signals; to receive a plurality of the third electric signals, combine and output the plurality of third electric signals as a fourth electric signal; and receive the fourth electric signal, convert the fourth electric signal into an optical signal, and output the optical signal as a second optical signal.

A radio frequency module includes: a switch that includes: a common terminal connected to a first common transmission path; a first selection terminal connected to a first transmission path; and a second selection terminal connected to a second transmission path, and switches between connecting the common terminal to the first selection terminal and to the second selection terminal; a transmission power amplifier disposed on the module board and on first common transmission path; and first circuit components disposed on a reception path. The first transmission path is a path through which a transmission signal of a first communication band is transferred, the second transmission path is a path through which a transmission signal of a second communication band is transferred, the switch is disposed on a first principal surface, and at least one of the first circuit components is disposed on a second principal surface.

A receiving device is provided. The receiving device includes an antenna device, a filter circuit, a transceiver, an adjustable attenuator, a circulator, and a processor. The antenna device receives a received signal. The filter circuit separates an in-band signal and an out-band signal from the received signal. The adjustable attenuator adjusts the attenuation value corresponding to the in-band signal and transmits the adjusted in-band signal to the transceiver. The circulator receives the received signal from the antenna device and transmits the received signal to the filter circuit, and the circulator receives a reflected signal from the filter circuit. The processor determines how to adjust the attenuation value corresponding to the in-band signal according to information related to the out-band signal and information related to the in-band signal that has been processed by the adjustable attenuator and the transceiver.