The described technology is generally directed towards a sensor signal multiplexer and digitizer with analog notch filter and optimized sample frequency, and corresponding methods of use and manufacture. In some examples, the disclosed technologies can be used to reduce vibration sensitivity of an inertial measurement unit (IMU). The disclosed sensor signal multiplexer can sample sensor inputs on multiple input channels at a first, higher frequency, and integrate samples for each channel in order to generate lower frequency sensor outputs. The lower frequency sensor outputs can be converted to digital form.

This application provides a narrowband interference isolation method and a communication apparatus. An example method includes: determining a parameter of a narrowband interference signal; determining a coefficient of a first filter based on the parameter of the narrowband interference signal, wherein the first filter is located at a receive end of a master communication device, and the coefficient of the first filter is for filtering out the narrowband interference signal; and sending the parameter of the narrowband interference signal or the coefficient of the first filter to M slave communication devices using an Ethernet operation, administration, and maintenance (OAM) frame, wherein the master communication device is connected to the M slave communication devices, M≥1, and M is an integer.

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.

This frequency tripler system uses a cascade of integrated transistor circuit differential limiting amplifiers and tunable notch filters that can directly serve one or more outputs, such as a direct clock or local oscillator drive. With this topology, filtering is distributed between two or more stages of differential limiting amplifiers and tunable notch filters. This enables suppression of smaller fundamental tone by the differential limiting amplifiers along with the tunable notch filters and yields a strong third harmonic signal to directly drive high performance mixers and digital-to-analog converters.

One example includes a receiver system. The receiver system includes an analog-to-digital converter (ADC) configured to convert an analog input signal into a digital output signal at a sampling frequency. The receiver system also includes a spur correction system configured to receive the digital output signal and to estimate spurs associated with the digital output signal and to selectively correct a subset of the spurs associated with a set of frequencies that are based on the sampling frequency.

A noise reduction system for a digital receiver reduces noise in signals received at the digital receiver. The digital receiver includes an input for receiving an analogue signal, analogue signal processing circuitry for processing an analogue signal, and an output for providing the processed signal to a digital signal processor. The noise reduction system is located between the input and the digital receiver input, and includes a first component that outputs results of a noise signal identification and a second component that applies one or more counter-measure to the received analogue signal to produce a modified analogue signal. The modified analogue signal has a reduced level of noise compared to the received analogue signal, wherein the noise reduction system is arranged to assess the effectiveness of the one or more counter-measures applied by the second component to determine whether any further counter-measures are required.

An electronic device may include wireless circuitry with one or more antennas that transmit radio-frequency signals and that receive corresponding reflected signals. The wireless circuitry may detect a range to an external object based on the transmitted and received signals. The wireless circuitry may include a receive path having a mixer, an analog-to-digital converter (ADC), and a filter between the mixer and the ADC. The receive path may include a bypass path with a switch coupled around the filter. The wireless circuitry may detect the range to the external object within an ultra-short range (USR) domain when the switch is closed, thereby bypassing the filter in the receive path. The wireless circuitry may detect the range to the external object within a far-field domain when the switch is open. The filter may filter the reflected signals to remove undesired leakage and maximize dynamic range.

A noise reduction system for a digital receiver reduces noise in signals received at the digital receiver. The digital receiver includes an input for receiving an analogue signal, analogue signal processing circuitry for processing an analogue signal, and an output for providing the processed signal to a digital signal processor. The noise reduction system is located between the input and the digital receiver input, and includes a first component that outputs results of a noise signal identification and a second component that applies one or more counter-measure to the received analogue signal to produce a modified analogue signal. The modified analogue signal has a reduced level of noise compared to the received analogue signal, wherein the noise reduction system is arranged to assess the effectiveness of the one or more counter-measures applied by the second component to determine whether any further counter-measures are required.

Architectures and techniques relate to selectively implementing certain components to suppress emissions. For example, an emissions-suppression circuit can include a notch filter associated with a first frequency range, a switch assembly coupled to the notch filter, and a duplexer coupled to the switch assembly. The switch assembly can be configured to, in a filter state, couple the notch filter to a transmit path and configured to, in a bypass state, decouple the notch filter from the transmit path. The transmit path can be associated with two or more switch connections in the notch-filter state and associated with one switch connection in the bypass state. The duplexer can include a transmit filter that is associated with a second frequency range.

A communication gateway for connecting an LPWAN network to a network for access to a cellular or RAN network, the LPWAN network and the RAN network using radio links. Such a gateway typically allows connected objects and servers on the Internet to communicate according to the Internet of Things (IoT) architecture. However, the proximity of the frequency bands used for the two radio links may lead to mutual interference between them, the transmitter of one interfering with the receiver of the other, especially when the gateway is miniature, of the order of magnitude of the connected objects (approximately 10 cm). The disclosed gateway electromagnetically isolates the two RF channels by means of double filtering: by a bandpass filter on the LPWAN RF channel combined with a rejection filter on the cellular RF channel.