Corrections are provided for mismatches between an in-phase (I) signal and a quadrature-phase (Q) signal, the I and Q signals having a first frequency band. A frequency filter circuit filters the I and Q signals to produce a filtered I and Q output with a second frequency band that is a subset of the first frequency band. Digital circuitry includes a multiple-tap correction filter having a plurality of taps and configured to generate I and Q output signals by filtering the I and Q signals according to respective sets of coefficients for the plurality of taps. A coefficient estimator generates the sets of coefficients relative to different frequency bands.

The disclosure relates to a module for a radio receiver. The module comprises an input terminal; an output terminal; a main signal path for communicating in-phase and quadrature signals between the input terminal and the output terminal; and a second signal path. The second signal path is connected in parallel with the main signal path and is configured to: extract in-phase and quadrature signals from the main signal path; filter the extracted in-phase and quadrature signals; detect an error in the filtered, extracted in-phase and quadrature signals; and apply a correction to in-phase and quadrature signals on the main signal path based on the error.

Faults in a periodically oscillating MEMS mass are detected by processing a position signal, having an amplitude and oscillation frequency, generated as a function of mass position. First and second reference signals formed by samples of quadrature sinusoids at the oscillation frequency are generated. First and second multipliers generate a first product signal and a second product signal, respectively, via multiplication of the position signal by the first and second reference signals. The first and second product signals are low pass filtered to generate first and second filtered signals, respectively. An estimator circuit determines estimates of the amplitude as a function of the first and second filtered signals. A decision circuit detects the presence of faults on the basis of a comparison of the estimates with a range of values.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a network entity may transmit a signal generated using a mixer, wherein the signal is subject to local oscillator (LO) leakage in connection with the generation using the mixer. The network entity may transmit an LO leakage estimate indicator based at least in part on the LO leakage of the signal in connection with the generation using the mixer. Numerous other aspects are described.

An apparatus for reducing an amplitude imbalance and a phase imbalance between an in-phase signal and a quadrature signal is provided. The in-phase signal and the quadrature signal are based on a radio frequency receive signal. The apparatus includes an imbalance estimation module configured to generate a first correction signal related to a first phase shift, and to generate a second correction signal related to a second phase shift. Further, the apparatus includes a first digital-to-time converter configured to receive the first correction signal and a local oscillator signal. The first digital-to-time converter is further configured to supply a first replica of the local oscillator signal for a first mixer generating the in-phase signal, wherein the first replica of the local oscillator signal has the first phase shift with respect to the local oscillator signal. The apparatus further includes a second digital-to-time converter configured to receive the second correction signal and the local oscillator signal. The second digital-to-time converter is further configured to supply a second replica of the local oscillator signal for a second mixer generating the quadrature signal, wherein the second replica of the local oscillator signal has the second phase shift with respect to the local oscillator signal.

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may transmit a capability message indicating a capability of the UE to estimate a frequency domain imbalance between an in-phase portion of a transmission chain of a network entity and a quadrature-phase portion of the transmission chain of the network entity. The UE may receive, based on the capability message, an indication of a coherence bandwidth associated with the frequency domain imbalance. The coherence bandwidth may indicate a quantity of subcarriers (SCs) over which a characteristic of the frequency domain imbalance (e.g., a change in amplitude of the frequency domain imbalance) satisfies a threshold. The UE may perform an estimation of the frequency domain imbalance based on the coherence bandwidth. In some examples, the UE may receive downlink signals from a network entity and may perform a correction of the downlink signals based on the estimation.

A method and system of compensating for distortion in a baseband in-phase (I) and a corresponding baseband quadrature (Q) signal. The circuit includes an in-phase I attenuator configured to attenuate the baseband in-phase I signal and an in-phase Q attenuator configured to attenuate the baseband Q signal. There are one or more circuits that are configured to receive the attenuated in-phase I signal and the attenuated baseband Q signal. Each circuit performs a different calculation based on predetermined equations configured to determine the IM2, HD2@0, HD2@90, IM3@0, IM3@90, HD3@0, and HD3@90. The distortion compensation circuit is configured to use the result of at least one of the calculation circuits to generate I and Q distortion compensation signals.

A method for in-phase-quadrature (I-Q) imbalance calibration is described. A signal is transmitted by a first transmitter in a first system. The signal includes a constant value. The signal is received at a second receiver in a second system. An I-Q imbalance is estimated for the second receiver based on the received signal.

In some examples, a method and apparatus for wireless communication are disclosed. A wireless user equipment (UE) may receive an over-the-air tone pilot and apply the received pilot to a mixer. The mixer may mix the pilot with a local tone to generate a baseband signal. Here, the UE may determine an estimate of one or more parameters corresponding to a residual side band (RSB) in the baseband signal resulting from the mixer, and may accordingly apply the estimated one or more parameters to compensate for the RSB. The estimated RSB parameters may be refreshed online, by taking samples of the over-the-air tone pilot at a suitable refresh rate.

Method embodiments are provided herein for dynamically calibrating and adjusting a direct conversion receiver system. One embodiment includes applying one or more gain control signals to one or more gain elements of a receiver system, where the applying one or more gain control signals results in a gain change to the receiver system; in response to the gain change, determining whether the receiver system exhibits a DC (direct conversion) offset; and in response to a determination that the receiver system exhibits the DC offset, applying one or more DC offset correction control signals to one or more gain elements of the receiver system, where the one or more DC offset correction signals are configured to correct the DC offset.