A system with an acoustic filter array for analog processing of radio signals above 8 GHz includes a receiver and a downconverter to down-convert an incoming signal into an intermediate frequency range (IF). Downconverter includes suppression of local oscillator image. An active manifold splits the IF signal into separate parallel feeds into individual acoustic filter elements in an acoustic filter array. Acoustic filter array provides individually channelized IF outputs. Each IF manifold feed and corresponding acoustic filter output channel is associated with an analog-to-digital converter or system switch.

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.

Disclosed is a cable module comprising a cable and a notch filter including a metal foil and a plurality of capacitors, wherein the metal foil is wrapped around the cable, wherein the metal foil includes a first through section and a second through section respectively arranged on opposite sides of the cable. For an antenna to be placed in the through sections to capture frequency signals of the core wire by connecting to the detection device, and then the frequency signals can be collected and transmitted to the detection device for comparison and analysis, allowing for the detection of defective product. Thus, the said design eliminates the need for cumbersome disassembly of the notch filter product before detection thereof, thereby streamlining the detection process and making cable testing more efficient and precise.

Radio frequency (RF) acoustic wave resonator (AWR) filter circuits and methods. Embodiments essentially de-couple the stopband or notch characteristics of an RF filter from the passband characteristics. Accordingly, the de-coupled parameters can be individually designed to meet the specifications of a particular application. Partially-hybridized or fully-hybridized series-arm and parallel-arm AWR filter building blocks enable “de-coupled” RF filters having (1) wideband and low insertion loss passbands and (2) wideband deep notches (stopbands) with a specifically placed notch center frequency, without compromising the passband characteristics. The AWR filter building blocks include an inductance L that matches (resonates with) the electrostatic capacitance CO of the corresponding AWR within a desired passband. The resonance and anti-resonance frequencies of the building block AWRs are selected to be spaced apart from the specified passband in order to provide independent stopband or notch characteristics without substantially affecting the passband characteristics.

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.

Aspects of this disclosure relate to a radio frequency system with tunable notch filtering. The radio frequency system includes a first tunable filter and a second tunable filter. The first tunable filter is coupled between an output of a power amplifier and a radio frequency switch. The second tunable filter includes mutually coupled inductors and a tunable impedance circuit electrically connected to at least one of the mutually coupled inductors. The second tunable filter is coupled between an antenna switch and an antenna node. Related methods and wireless communication devices are also disclosed.

Systems, methods, and computer program product embodiments are disclosed for removing any fixed frequency interfering signal from an input signal without introducing artifacts that are not part of the original signal of interest. An embodiment operates by using a virtual buffer with a length that matches a length of one cycle of an interfering signal. The embodiment extracts the interfering signal into the virtual buffer. For a sample in the next cycle of the interfering signal that corresponds to a virtual memory location for the virtual buffer, the embodiment can update one or more physical memory locations of the virtual buffer that are in the vicinity of the virtual memory location. This use of virtual buffer can remove any interfering signal without creating the artifacts associated with conventional notch filters.

A receiver circuit includes an ADC, a processing channel, and an interference detection path. The processing channel is configured to process data samples provided by the ADC, and includes a notch filter. The interference detection path is configured to detect interference in the data samples, and includes a slicer, a slicer error circuit, and an interference detection circuit. The slicer is configured to slice input of the notch filter. The slicer error circuit is configured to compute an error of the slicer. The interference detection circuit configured to detect an interference signal in the error of the slicer, and set the notch filter to attenuate the interference signal.

Systems, methods, and computer program product embodiments are disclosed for removing any fixed frequency interfering signal from an input signal without introducing artifacts that are not part of the original signal of interest. An embodiment operates by using a virtual buffer with a length that matches a length of one cycle of an interfering signal. The embodiment extracts the interfering signal into the virtual buffer. For a sample in the next cycle of the interfering signal that corresponds to a virtual memory location for the virtual buffer, the embodiment can update one or more physical memory locations of the virtual buffer that are in the vicinity of the virtual memory location. This use of virtual buffer can remove any interfering signal without creating the artifacts associated with conventional notch filters.

Disclosed is a radio frequency (RF) amplifier having channel selectivity. The RF amplifier includes a main path including an amplifier, and a feedforward path including a gain/phase compensator, a high-pass filter, and a mixer.