Embodiments of resonator circuits and modulating resonators and are described generally herein. One or more acoustic wave resonators may be coupled in series or parallel to generate tunable filters. One or more acoustic wave resonances may be modulated by one or more capacitors or tunable capacitors. One or more acoustic wave modules may also be switchable in a filter. Other embodiments may be described and claimed.

Embodiments of resonator circuits and modulating resonators and are described generally herein. One or more acoustic wave resonators may be coupled in series or parallel to generate tunable filters. One or more acoustic wave resonances may be modulated by one or more capacitors or tunable capacitors. One or more acoustic wave modules may also be switchable in a filter. Other embodiments may be described and claimed.

A first and second input tone are applied to a continuous-time complex filter within an integrated circuit. The magnitude of the output of the filter at the frequency of each of the first and second input tones are measured and compared to determine the value of a filter tuning control signal. A tuning control signal is applied to the filter with the determined value to tune the filter.

Embodiments of resonator circuits and modulating resonators and are described generally herein. One or more acoustic wave resonators may be coupled in series or parallel to generate tunable filters. One or more acoustic wave resonances may be modulated by one or more capacitors or tunable capacitors. One or more acoustic wave modules may also be switchable in a filter. Other embodiments may be described and claimed.

System and methods are provided for calibration of low pass filter mismatch. An example system includes: a tone generator configured to generate a tone signal with a baseband frequency value; one or more low pass filters configured to filter one or more analog signals associated with the tone signal; one or more analog-to-digital converters (ADCs) configured to generate one or more aliases associated with the one or more analog signals; and a calibration processor configured to detect low pass filter mismatch based at least in part on the one or more aliases associated with the tone signal.

RF circuitry, which includes a first passive voltage-gain network and a first MOS-based RF receive amplifier, is disclosed. The first passive voltage-gain network provides a first passive RF receive signal using a first RF receive signal, such that an energy of the first passive RF receive signal is obtained entirely from the first RF receive signal by the first passive voltage-gain network. A voltage of the first passive RF receive signal is greater than a voltage of the first RF receive signal. The first MOS-based RF receive amplifier receives and amplifies the first passive RF receive signal to provide a first amplified RF receive signal.

Embodiments of radio frequency (RF) front-end circuitry are disclosed where the RF front-end circuitry includes a tunable RF filter structure and a calibration circuit. The tunable RF filter structure includes (at least) a pair of weakly coupled resonators and defines a transfer function with a passband. The calibration circuit is configured to shape the passband so that the passband defines a center frequency. Additionally, the calibration circuit is configured to detect a phase difference at the target center frequency between the pair of weakly coupled resonators and adjust the phase difference of the pair of weakly coupled resonators at the target center frequency so as to reduce a frequency displacement between the center frequency of the passband and the target center frequency. In this manner, the calibration circuit calibrates the tunable RF filter structure to correct for errors in the center frequency of the passband due to component manufacturing variations.

RF front-end circuitry, which includes a first RF low noise amplifier (LNA) and a first reconfigurable RF filter, is disclosed. The RF front-end circuitry operates in one of a group of operating modes. The first reconfigurable RF filter, which has a first reconfigurable RF filter path, includes a first receive (RX) shunt switching element coupled between the first reconfigurable RF filter path and ground. The first reconfigurable RF filter path is coupled to an input of the first RF LNA. The group of operating modes includes a first operating mode and a second operating mode. During the first operating mode, the first RX shunt switching element is ON. During the second operating mode, the first RX shunt switching element is OFF and the first RF LNA receives and amplifies a first filtered RF receive signal from the first reconfigurable RF filter to provide a first receive signal.

An acoustic-wave device with active calibration mechanism is provided. The acoustic-wave device with active calibration mechanism includes at least one acoustic-wave duplexer, a voltage-controlled oscillator (VCO), a frequency discriminator and a control circuit. The acoustic-wave duplexer includes a TX filter and an RX filter. The voltage-controlled oscillator includes a calibration resonator and a tunable negative impedance circuit. The TX filter, the RX filter and the calibration resonator are disposed on the same piezoelectric substrate. The frequency discriminator generates a calibration signal according to a frequency deviation of the calibration resonator. The control circuit is connected to the acoustic-wave duplexer and the frequency discriminator. The control circuit adjusts an operating frequency of the TX filter or an operating frequency of the RX filter according to the calibration signal.

Apparatus and methods for control and calibration of tunable filters are provided. In certain embodiments, a tunable filter includes at least one controllable component (for instance, a controllable inductor or a controllable capacitor) having a value that changes or adjusts a center frequency of the tunable filter. For example, the controllable component can correspond to a controllable inductor or a controllable capacitor of an inductor-capacitor (LC) resonator of the tunable filter. The tunable filter further includes a control circuit implemented with an approximation function for estimating a value of the controllable component for achieving a desired center frequency indicated by a frequency control signal.