A method includes receiving a radio frequency (RF) input signal using at least one non-reciprocal circulator. The method also includes generating an RF output signal using at least one of multiple reflective filter elements. Each reflective filter element is configured to receive an RF signal from the at least one non-reciprocal circulator and to provide a filtered RF signal to the at least one non-reciprocal circulator. The reflective filter elements include amplitude change reflectors configured to modify amplitudes of the RF signal at different frequencies. The RF output signal represents the RF input signal as modified by the at least one of the reflective filter elements.

Adaptive RF filters based on modulated resonators are provided. The filter architecture is based on time-interleaved commutation of passive RF resonators. The architecture can behave as a two-port filter network, with a fully tunable instantaneous filter bandwidth. The filters are applicable as miniaturized, environment-aware RF signal processing components and can be used in mobile communications.

A method and device for extracting information from acoustic signals receives acoustic signals by a microphone, processes them in an analog front-end circuit, converts the processed signals from the analog front-end circuit to digital signals by sampling at a rate of less than 1 kHz or more preferably less than 500 kHz; and processes the digital signals by a digital back-end classifier circuit. The analog front-end processing decomposes the received signals into frequency components using a bank of analog N-path bandpass filters having different subband center frequencies.

A receiver comprising a signal phase shifting block generating concurrent phase shifted copies of an input signal, and an impedance translation function block configured to receive the phase shifted copies of the input signal and generate a down converted signal wherein the impedance translation function block is driven by a single clock signal of frequency determined by a desired carrier frequency. The receiver including an energy harvesting block coupled to the phase shifting block to receive one or more in-band or out-of-band interferers in the input signal and reflected signals from the impedance translation function block due to nonlinearities.

A system for wireless communication may include a passive gain front end circuit coupled to an N-path filter. In a transmit mode, signals may be provided to an antenna through the passive gain circuit. In the transmit mode, the N-path filter may provide isolation at the antenna. In a receive mode, the passive gain front end may provide gain to the received signal. In the receive mode, the N-path filter may be used to downconvert the received signal.

A receiver comprising a signal phase shifting block generating concurrent phase shifted copies of an input signal, and an impedance translation function block configured to receive the phase shifted copies of the input signal and generate a down converted signal wherein the impedance translation function block is driven by a single clock signal of frequency determined by a desired carrier frequency. The receiver including an energy harvesting block coupled to the phase shifting block to receive one or more in-band or out-of-band interferers in the input signal and reflected signals from the impedance translation function block due to nonlinearities.

An adaptive capacitive filter circuit includes: a first terminal adapted to be coupled to a rectifier bridge output; a second terminal adapted to be coupled to a ground terminal; a first capacitor having a first electrode and a second electrode, the first electrode of the first capacitor coupled to the first terminal; a second capacitor having a first electrode and a second electrode, the second electrode of the second capacitor coupled to the second terminal; a first switch coupled between the second electrode of the first capacitor and the second terminal; a second switch coupled between the first terminal and the first electrode of the second capacitor; and a third switch coupled between the second electrode of the first capacitor and the first electrode of the second capacitor.

Ultra-Wideband (UWB) technology exploits modulated coded impulses over a wide frequency spectrum with very low power over a short distance for digital data transmission. Such UWB systems through their receivers may operate in the presence of interfering signals and should provide for robust communications. Accordingly, an accurate and sharp filter that operates at low power is required and beneficially one that does not require a highly accurate power heavy clock. Further, many UWB applications require location and/or range finding of other elements and it would therefore be beneficial to provide a UWB based range finding and/or location capability removing the requirement to add additional device complexity and, typically significant, power consumption.

In one aspect, a time division interleaving band-pass filter can be used in voice activity detection, which operates at different central frequencies in respective intervals of a predetermined period of time. The band-pass filter circuitry includes multiple band-pass filtering channels sharing a common transistor circuit, bias circuit and current mirror circuit. The multiple band-pass filtering channels operate in a time division interleaving manner, which enables the sharing of the common set of band-pass filter circuitry components. Thus, the present invention allows a reduced chip area as the area does not increase proportionally with the number of filtering channels. The invention also mitigates the influence of transistor fabrication variations on the filter's central frequencies. Moreover, pulse durations t.sub.i are additionally introduced to the determination of the central frequencies, dispensing with the need for matching of current mirror circuits and transistors and resulting in higher accuracy of the band-pass filter's central frequencies.

A system and method for providing asymmetrical filtering to improve performance in the presence of wideband interference is herein disclosed. According to one embodiment, a method for a global navigation satellite system (GNSS) receiver includes detecting wideband interference in a received target GNSS signal, and applying an asymmetric filter to the received target GNSS signal to mitigate the detected wideband interference.