A calibration system comprises an actuator circuit comprising a first delay circuit that receives a plurality of data pulses and a second delay circuit that receives the pulses, wherein one of the first and second delay circuits delays the data pulses independently of the other of the first and second delay circuits; a data switch that receives an output of the actuator circuit including delay data signals of the data pulses from the first and second delay circuits and switches and outputs a plurality of local oscillator (LO) signals for output as a controlled LO signal according to control signals of the delay data signals and applied to the data switch. At least one calibration switch receives the output of the actuator circuit and the plurality of LO+ and LO− signals, and outputs a second controlled LO signal output to a sense circuit.

Aspects of the disclosure relate to devices, wireless communication apparatuses, methods, and circuitry implementing a low noise amplifier (LNA) with phase-shifting circuitry to achieve a continuous phase at the output of the LNA. One aspect is an amplifier including a high gain active path comprising active circuitry, and a low gain path comprising passive circuitry and phase-shifting circuitry. In one or more aspects, the phase-shifting circuitry is configured to shift a phase of an input signal within the low gain path such that the phase of an output signal outputted from the low gain path approximately matches a phase of an output signal outputted from the high gain active path. In at least one aspect, a gain of the high gain active path is higher than a gain of the low gain passive path.

A filter circuit comprises in a signal line a band filter (BF) allowing to let pass a useful frequency band and a notch filter (NF) circuited in series to the band filter for filtering out a stop band frequency. The notch filter comprises a series circuit of a number of parallel shunt elements (SE1 . . . SE6) wherein each shunt element is shifted infrequency against the other shunt elements that the frequencies thereof are distributed (f1 . . . F6) over a notch band. All shunt elements may be realized as a SAW one-port resonator (TR.sub.NF) including regions with different pitches.

A system may include a first IQ modulator configured to: based on an I and a Q, produce a zero to ninety degree variable phase shifted output signal that changes relative to an input envelope of an RF drive waveform of the RF drive. The system may include a first amplifier path configured to: output a first phase modulated signal. The system may include a second IQ modulator configured to: based on the I and the −Q, produce a zero to negative ninety degree variable phase shifted output signal that changes relative to the input envelope. The system may include a second amplifier path configured to: output a second phase modulated signal, wherein the second phase modulated signal is complementary to the first phase modulated signal. The system may include a vector generator configured to: generate the Q and the −Q for the first and second IQ modulators, respectively.

Technology is disclosed that systematically improves the noise figure (NF) on the receive path of front end architectures. The disclosed technologies tune the elements of the receive path in concert with one another to achieve superior or optimal NF performance. This may occur even where the NF performance of individual components is sub-optimal because it is the combination of the components that is tailored to provide superior or optimal NF performance. The disclosed technologies account for trade-offs in performance that arise when tuning individual components on the receive path, taking a holistic approach to the design of the receive path rather than focusing on optimizing individual elements or selected combinations of elements on the receive path.

An acoustic structure is provided. The acoustic structure includes an acoustic resonator structure configured to resonate in a series resonance frequency (e.g., passband frequency) to pass a signal, or cause a series capacitance to block the signal in a parallel resonance frequency (e.g., stopband frequency). The parallel resonance frequency may become higher than the series resonance frequency when the tunable capacitance is lesser than or equal to two times of the series capacitance (C.sub.Tune≤2C.sub.0), or lower than the series resonance frequency when the tunable capacitance is greater than two times of the series capacitance (C.sub.Tune>2C.sub.0). In this regard, the acoustic structure can be configured to include a tunable reactive circuit to generate the tunable capacitance (C.sub.Tune) to adjust the parallel resonance frequency. As such, it may be possible to flexibly configure the acoustic resonator structure to block the signal in desired stopband frequencies.

A transmitter for a communication system comprises a digital pre-distortion (DPD) circuit and adaptation circuitry. The DPD circuit is configured to generate a digital intermediate signal by compensating an input signal for distortions resulting from an amplifier. The amplifier is configured to output an output signal based on the digital intermediate signal. The DPD circuit includes one or more an infinite impulse response (IIR) filters configured to implement a first transfer function based on a first parameter, and a second transfer function based on the first parameter and a time constant. The DPD circuit is configured to generate an adjustment signal based on the first transfer function and the second transfer function. The adaptation circuitry is configured to update the first parameter based on the adjustment signal, the input signal, and the output signal.

One example includes a device that is comprised of a pre-power amplifier, a power amplifier, a signal path, and a dynamic bias circuit. The pre-power amplifier amplifies an input signal and outputs a first amplified signal. The power amplifier receives the first amplified signal and amplifies the first amplified signal based on a dynamic bias signal to produce a second amplified signal at an output thereof. The signal path is coupled between an output of the pre-power amplifier and an input of the power amplifier. The dynamic bias circuit monitors the first amplified signal, generates the dynamic bias signal, and outputs the dynamic bias into the signal path.

Systems and methods for a tunable impedance are provided. A tunable impedance includes a transistor assembly having two terminals and a control input. The transistor assembly includes one or more transistors electrically connected between the two terminals to provide a first impedance between the two terminals, based upon a control signal. One or more replica transistors react to the control signal in a similar fashion as the transistor assembly, to provide a replica impedance based upon the control signal. A control circuit is configured to generate the control signal based upon a voltage across the replica transistor(s) and/or a current through the replica transistor(s).

Provided is a generator including a power amplifier, at least one sampler, an RF output, a signal generator, a controller including a digital control portion and an analogue control portion, an analogue feedback path between the at least one sampler and the controller enabling an analogue signal representation of a signal to be provided to the controller, and a digital feedback path between the at least one sampler and the controller enabling a digital signal representation of the signal to be provided to the controller. The controller is configured to adjust the RF signal at the RF output from a first state into a second state based on the analogue signal representation and/or the digital signal representation.