Wide band quadrature signal generation includes a frequency synthesizer generating a LO or 2LO signal, a polyphase filter coupled to receive the LO signal and generate first in-phase and quadrature LO signals, a 2:1 frequency divider coupled to receive the 2LO signal and generate second in-phase and quadrature LO signals, and a LO signal selector for selecting either the first or second in-phase LO signals as an output in-phase LO signal and either the first or second quadrature LO signals as an output quadrature LO signal based on an output frequency. In some embodiments, when the output frequency is above a threshold, the first in-phase and quadrature LO signals are selected as the output in-phase and quadrature LO signals and when the output frequency is at or below the threshold, the second in-phase and quadrature LO signals are selected as the output in-phase and quadrature LO signals.

An apparatus and method for in-phase/quadrature (I/Q) imbalance correction in a transceiver. The apparatus includes an I/Q imbalance correction circuit and a correction coefficient generation circuit. The I/Q imbalance correction circuit is configured to modify I/Q data in a frequency domain using correction coefficients to generate corrected I/Q data. The correction coefficient generation circuit is configured to generate the correction coefficients for the I/Q imbalance correction circuit based on the I/Q data and reference data.

A FMCW radar receiver includes a LO providing a chirped LO signal, an in-phase (I) channel for outputting I-data and a quadrature (Q) channel for outputting Q-data. A dynamic correction parameter generator generates IQ phase correction values (P[n]s) and IQ gain correction values (G[n]s) based on a frequency slope rate of the chirped LO signal for generating during intervals of chirps including a first sequence of P[n]s and G[n]s during a first chirp and a second sequence of P[n]s and G[n]s during a second chirp. An IQ mismatch (IQMM) correction circuit has a first IQMM input coupled to receive the I-data and a second IQMM input receiving the Q-data, and the P[n]s and G[n]s. During the first chirp the IQMM correction circuit provides first Q-data and first I-data and during the second chirp the IQMM correction circuit provides at least second Q-data and second I-data.

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.

A device and method for correcting in-phase and quadrature phase (IQ) baseband components to drive a speaker is provided. The device: controls a local oscillator of an RF downmixing device to a plurality of baseband frequency offsets over a range that includes a given baseband frequency offset; determines, at the plurality of baseband frequency offsets, for a received RF signal, amplitude ratio error and phase error for respective IQ baseband components of the received RF signal; generates, using the amplitude ratio error and the phase error for the respective IQ baseband components, for the given offset, filter coefficients for a given baseband frequency range which compensates for respective amplitude ratio error and respective phase error for the given baseband frequency range; and filters, with the filter coefficients, IQ baseband components of the received RF signal, with the local oscillator operating at the given offset, to generate corrected IQ baseband components.

An I/Q imbalance calibration method includes sequentially inputting a first in-phase and quadrature signals calibration signal to a front-end circuit of the transmitter system to acquire and estimate a first and second calibration signal strengths sequentially, wherein a delta estimation is adopted; calculating an I/Q gain imbalance according to estimated first and second calibration signal strengths; sequentially inputting a second in-phase calibration signal and both of the second in-phase and quadrature calibration signal to the front-end circuit of the transmitter system to acquire and estimate a third and fourth calibration signal strengths sequentially, wherein an I/Q gain imbalance compensation is formed on the first in-phase and quadrature calibration signals to generate the second in-phase and quadrature calibration signals; and calculating an I/Q phase imbalance according to estimated third and fourth calibration signal strengths.

A method for providing IQ mismatch (IQMM) compensation includes: sending a single tone signal at an original frequency; determining a first response of an impaired signal at the original frequency and a second response of the impaired signal at a corresponding image frequency; determining an estimate of a frequency response of the compensation filter at the original frequency based on the first response and the second response; repeating the steps of sending the single tone signal, determining the first response and the second response, and determining the estimate of the frequency response of the compensation filter by sweeping the single tone signal at a plurality of steps to determine a snapshot of the frequency response of the compensation filter; converting the frequency response of the compensation filter to a plurality of time-domain filter taps of the compensation filter by performing a pseudo-inverse of a time-to-frequency conversion matrix; and determining a time delay that provides a minimal LSE for the corresponding time domain taps.

A receiver apparatus models and corrects the frequency-dependent and the frequency-independent mismatches between I and Q paths jointly by polynomial estimations. The receiver apparatus may sample digitized I and Q path signals. The sampled data point may be modeled in equations with real and imaginary components. The sampled discrete time-domain data may be converted to frequency-domain data. Multiple statistics values based on the frequency-domain data may be computed. Coefficients for the polynomial equations may be estimated based on the computed statistic values. The channel mismatches may be estimated from the polynomial equations and used to compensate the mismatch either on the I path or the Q path.

Various embodiments provide for systems and methods for signal conversion of one modulated signal to another modulated signal using demodulation and then re-modulation. According to some embodiments, a signal receiving system may comprise an I/Q demodulator that demodulates a first modulated signal to an in-phase (I) signal and a quadrature (Q) signal, an I/Q signal adjustor that adaptively adjusts the Q signal to increase the signal-to-noise ratio (SNR) of a transitory signal that is based on a second modulated signal, and an I/Q modulator that modulates the I signal and the adjusted Q signal to the second modulated signal. To increase the SNR, the Q signal may be adjusted based on a calculated error determined for the transitory signal during demodulation by a demodulator downstream from the I/Q modulator.

A method of optimizing at least one IQMC parameter value for an IQMC includes: generating a set of tested IQMC candidate parameter values by performing an iterative method including selecting a first IQMC candidate parameter value for the at least one parameter of the IQMC; determining, using the first IQMC candidate parameter value, a performance metric value that comprises at least one of (i) an image rejection ratio (IRR) value, (ii) a signal-to-interference-plus-noise ratio (SINR) value, or (iii) a signal-to-image ratio (SImR) value; and determining a second IQMC candidate parameter value that is an update to the first IQMC candidate parameter value. The method of optimizing at least one IQMC parameter value for an IQMC further includes determining an IQMC candidate parameter value of the set of tested IQMC candidate parameter values that optimizes the performance metric.