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 novel and useful discrete time IIR bandpass filter is disclosed that takes advantage of clock phase reuse thereby leading to significant improvements in filtering, especially stop band rejection in comparison to prior art filters. The bandpass filter of the present invention achieves improved filtering performance without adding any additional clock phases to the circuit. In particular, reuse of the already existing clock phases increases the order and performance of the filter. The invention exploits reuse of the clock phases to provide higher order filtering along with a discrete time IIR filter design which is capable of operating at high frequency. Consequently, much better filtering is achieved and the quality factor of the filter is improved leading to sharper transition bands especially for close-in band blockers in modern 4G/5G receivers.

A novel and useful discrete time IIR bandpass filter is disclosed that takes advantage of clock phase reuse thereby leading to significant improvements in filtering, especially stop band rejection in comparison to prior art filters. The bandpass filter of the present invention achieves improved filtering performance without adding any additional clock phases to the circuit. In particular, reuse of the already existing clock phases increases the order and performance of the filter. The invention exploits reuse of the clock phases to provide higher order filtering along with a discrete time IIR filter design which is capable of operating at high frequency. Consequently, much better filtering is achieved and the quality factor of the filter is improved leading to sharper transition bands especially for close-in band blockers in modern 4G/5G receivers.

A radio frequency (RF) unit and a method for RF isolation. The RF unit includes first and second RF couplers, an RF filter, and an RF canceler connected in parallel with the RF filter. The first RF coupler is configured to receive an input signal. The RF filter is configured to receive a first portion of the input signal from the first RF coupler and attenuate frequencies outside of a passband of the RF filter from the first portion of the input signal. The RF canceler is configured to receive a second portion of the input signal from the first RF coupler and generate a cancellation signal from the second portion of the input signal based on a target frequency band of the RF canceler. The second RF coupler is configured to combine the cancellation signal with an output of the RF filter to generate an output signal.

An adaptive analog parallel combiner circuit for receiver data recovery from a communication signal is provided. The circuit includes a summer that sums outputs of a plurality of filter taps in parallel, including zeroth and first through Nth filter taps, each filter tap having as input the communication signal or a version thereof, wherein N is a finite integer greater than or equal to two. The zeroth filter tap has an amplifier with gain controlled by a zeroth adaptive gain control coefficient, and each of the first through Nth filter taps having an all pass filter and gain controlled amplification, with gain controlled by a corresponding one of a first through Nth adaptive gain control coefficients and the all pass filter implementing a transfer function having a zero and a pole equaling each other and at a base frequency divided by a corresponding integer from one through N.

An adaptive analog parallel combiner circuit for receiver data recovery from a communication signal is provided. The circuit includes a summer that sums outputs of a plurality of filter taps in parallel, including zeroth and first through Nth filter taps, each filter tap having as input the communication signal or a version thereof, wherein N is a finite integer greater than or equal to two. The zeroth filter tap has an amplifier with gain controlled by a zeroth adaptive gain control coefficient, and each of the first through Nth filter taps having an all pass filter and gain controlled amplification, with gain controlled by a corresponding one of a first through Nth adaptive gain control coefficients and the all pass filter implementing a transfer function having a zero and a pole equaling each other and at a base frequency divided by a corresponding integer from one through N.

Systems and methods for analog finite impulse response (FIR) filters are provided. In certain embodiments, a receiver includes a cascade of a mixer, an analog FIR filter, and an analog-to-digital converter (ADC). By including the analog FIR filter along the signal path between the mixer and the ADC, design constraints of the ADC are relaxed. For example, the ADC can operate with relaxed specifications with respect to resolution and/or dynamic range when the analog FIR filter is included. The analog FIR filter can include a controllable transconductance circuit that delivers an integration current to a capacitor over an integration period, with the analog FIR filter's coefficients used to change the transconductance setting of the controllable transconductance circuit to different values over the integration period.

Systems and methods for analog finite impulse response (FIR) filters are provided. In certain embodiments, a receiver includes a cascade of a mixer, an analog FIR filter, and an analog-to-digital converter (ADC). By including the analog FIR filter along the signal path between the mixer and the ADC, design constraints of the ADC are relaxed. For example, the ADC can operate with relaxed specifications with respect to resolution and/or dynamic range when the analog FIR filter is included. The analog FIR filter can include a controllable transconductance circuit that delivers an integration current to a capacitor over an integration period, with the analog FIR filter's coefficients used to change the transconductance setting of the controllable transconductance circuit to different values over the integration period.

Systems and methods for analog finite impulse response (FIR) filters are provided. In certain embodiments, a receiver includes a cascade of a mixer, an analog FIR filter, and an analog-to-digital converter (ADC). By including the analog FIR filter along the signal path between the mixer and the ADC, design constraints of the ADC are relaxed. For example, the ADC can operate with relaxed specifications with respect to resolution and/or dynamic range when the analog FIR filter is included. The analog FIR filter can include a controllable transconductance circuit that delivers an integration current to a capacitor over an integration period, with the analog FIR filter's coefficients used to change the transconductance setting of the controllable transconductance circuit to different values over the integration period.

Systems and methods for analog finite impulse response (FIR) filters are provided. In certain embodiments, a receiver includes a cascade of a mixer, an analog FIR filter, and an analog-to-digital converter (ADC). By including the analog FIR filter along the signal path between the mixer and the ADC, design constraints of the ADC are relaxed. For example, the ADC can operate with relaxed specifications with respect to resolution and/or dynamic range when the analog FIR filter is included. The analog FIR filter can include a controllable transconductance circuit that delivers an integration current to a capacitor over an integration period, with the analog FIR filter's coefficients used to change the transconductance setting of the controllable transconductance circuit to different values over the integration period.