A finite impulse response (FIR) filter including an input of the FIR filter that receives an RF input signal, a clock input configured to receive a clock signal, an output of the FIR filter that provides a filtered output signal, a plurality of signal paths including a plurality of sample-and-hold circuits and a plurality of multipliers arranged in parallel, each signal path including a respective sample-and-hold circuit and a respective multiplier being configured to receive the RF input signal and the clock signal to provide a modulated output signal, an adder configured to receive n modulated output signals from the plurality of signal paths and combine the n modulated output signals to produce the filtered output signal, and a controller.

A finite impulse response (FIR) filter including an input of the FIR filter that receives an RF input signal, a clock input configured to receive a clock signal, an output of the FIR filter that provides a filtered output signal, a plurality of signal paths including a plurality of sample-and-hold circuits and a plurality of multipliers arranged in parallel, each signal path including a respective sample-and-hold circuit and a respective multiplier being configured to receive the RF input signal and the clock signal to provide a modulated output signal, an adder configured to receive n modulated output signals from the plurality of signal paths and combine the n modulated output signals to produce the filtered output signal, and a controller.

A FIR filter (15), comprising an input terminal for receiving an input signal, a first filtering circuit comprising: a first transconductance device (30a) configured to generate a first current signal (i1) proportional to the input signal; a first analog switch (41a) commuted in n by a first digital gate signal (ϕ1) and configured to block the current signal when the first digital gate signal has a first value and to transmit the current signal to a first integrating capacitor (45a) when the first digital gate signal has a second value; characterized in that the first digital gate signal (ϕ1) comprises a periodic series of pulses, wherein the pulses have widths proportional to the filter coefficients.

A variable bandwidth filter is described herein, wherein a bandwidth of a passband of the variable bandwidth filter is dynamically tunable. The variable bandwidth tuner is implemented on a CMOS chip, and acts to filter analog signals. The variable bandwidth filter comprises a plurality of finite impulse response (FIR) filters, wherein each FIR filter comprises a plurality of tunable transconductors. The tunable transconductors are tunable in their gain.

Described herein is a power-efficient Gm-C filter, wherein the Gm-C filter includes several operational transconductance amplifiers (OTAs). In an example, at least two of the OTAs share a common bias current. Further, output of one of the OTAs is used to bias another one of the OTAs. Also described herein is a power-efficient clock generator circuit that is configured to output non-overlapping clock signals. The clock generator circuit includes a ring oscillator circuit, which includes several inverter stages. The clock generator circuit is well-suited for controlling operation of switches.

A method and an apparatus for tuning an FIR filter in an in-band full duplex transceiver. The method for tuning an FIR filter may include: setting attenuation of the FIR filter to be a first value and then estimating input information of the FIR filter; estimating a delta response using the estimated input information of the FIR filter; and updating the attenuation of the FIR filter to a second value using the estimated delta response.

An equalizer circuit includes an phase-to-phase connectors including an phase-to-phase capacitor and four phase-to-phase switches, four output buffers, and control signal generation circuitry. One terminal of each phase-to-phase switches is connected to one of four connection paths on which four conversion signals being different in phase by 90 are input. The other one terminal of each phase-to-phase switches is connected to the phase-to-phase capacitor. Each output buffer is connected to one of the four connection paths and outputs an output signal. The control signal generation circuitry outputs control signals to control turning-on/off of the respective four phase-to-phase switches. A closing of the first, second, third, and fourth phase-to-phase switches are started from any one of phase-to-phase switches in one of a first ascending circulation and a first descending circulation based on the 4-phase control signals.

A tunable analog noise-cancelling transversal reconfigurable filter for filtering an RF signal. The filter includes a noise-cancelling balun responsive to the RF signal and providing gain and noise suppression, and a time delay network responsive to the signal from the balun. The time delay network includes a single continuous three-dimensional air coaxial line where a separate tap is provided between sections of the line. The filter also includes a multiplication and summing network having a plurality of multiplication stages, where each stage is fed by a voltage signal from at least one of the taps, and each stage includes a multiplication amplifier that amplifies the voltage signal. A tuning element provides a multiplication coefficient to the amplified signal. Each amplified signal in each stage is added on an output line, where the multiplication and summing network operates under Millman's Theorem.

A FIR filter (15), comprising an input terminal for receiving an input signal, a first filtering circuit comprising: a first transconductance device (30a) configured to generate a first current signal (i1) proportional to the input signal; a first analog switch (41a) commuted in n by a first digital gate signal (1) and configured to block the current signal when the first digital gate signal has a first value and to transmit the current signal to a first integrating capacitor (45a) when the first digital gate signal has a second value; characterized in that the first digital gate signal (1) comprises a periodic series of pulses, wherein the pulses have widths proportional to the filter coefficients.

An equalizer circuit includes an phase-to-phase connectors including an phase-to-phase capacitor and four phase-to-phase switches, four output buffers, and control signal generation circuitry. One terminal of each phase-to-phase switches is connected to one of four connection paths on which four conversion signals being different in phase by 90 are input. The other one terminal of each phase-to-phase switches is connected to the phase-to-phase capacitor. Each output buffer is connected to one of the four connection paths and outputs an output signal. The control signal generation circuitry outputs control signals to control turning-on/off of the respective four phase-to-phase switches. A closing of the first, second, third, and fourth phase-to-phase switches are started from any one of phase-to-phase switches in one of a first ascending circulation and a first descending circulation based on the 4-phase control signals.