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.

Methods, circuits, and apparatus for calibrating an in-phase and quadrature (IQ) imbalance of a communication signal including an in-phase component and a quadrature component in a communication apparatus, the method including determining whether to calibrate the IQ imbalance of the communication signal in the communication apparatus; selecting, in response to a determination to calibrate the IQ imbalance of the communication signal, at least one of an amplitude calibration or a phase calibration; controlling, in accordance with the selected amplitude calibration or phase calibration, at least one of an in-phase delay circuit or a quadrature delay circuit to adjust a pulse of at least one of a first LO signal or a second LO signal to thereby generate at least one pulse-adjusted LO signal; and multiplying the at least one pulse-adjusted LO signal with the communication signal to thereby calibrate the IQ imbalance.

A method for providing IQ mismatch (IQMM) compensation includes: estimating an overall frequency response of a compensation filter by stepping through a frequency range starting at an initial frequency and performing (1) through (3) at each step, a selected frequency at each step being a multiple of a subcarrier frequency of the initial frequency: (1) sending a single tone signal at the selected frequency, (2) determining a first response of a mismatched signal at the selected frequency and a second response of the mismatched signal at an image frequency of the selected frequency, and (3) estimating a frequency response of the compensation filter at the selected frequency based on the first response and the second response; generating time-domain filter taps based on the estimated overall frequency response of the compensation filter; determining a time delay based on the time-domain filter taps; and generating a compensated signal based on the time delay.

An estimation apparatus for IQ imbalance of an optical transmitter, a compensation apparatus for IQ imbalance of an optical transmitter and electronic equipment; wherein, estimation and compensation of IQ imbalance of an optical transmitter are performed by directly using an estimation model based on a transform matrix of received signals and transmitted signals, therefore, a phase offset shift may be estimated accurately, and precision of estimation of drifts of various angles is ensured, furthermore, accurate recovery of the constellation diagram of received signals is achieved.

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.

A transmitter generates programmable upstream and downstream signal pulses for transmission through a fluid whose flow rate is being measured. A receiver receives the upstream and downstream signal pulses and stores digital representations of the pulses. A multiple pass algorithm such as a time domain windowing function and/or an algorithm that equalizes amplitude operates on the stored digital representations prior to demodulation. A quadrature demodulator generates in-phase and quadrature components of the digital representations and an arctangent function using the in-phase and quadrature components determines angles associated with the upstream and downstream signal pulses. The difference between the upstream and downstream angles, from which a difference in time of flight between the upstream and downstream signal pulses can be derived, is used to determine flow rate.

A novel and useful apparatus and method for an image-interferer aware single quadrature RF downconversion (SQRD) low intermediate frequency (LIF) receiver and related power reduction techniques utilized therein. The invention applies zero-margin adaptive transceiver (ZMAT) design principles to considerably reduce the receiver's power consumption in an adaptive fashion in accordance with the instantaneous reception conditions. In a low IF dual-branch (i.e. quadrature) downconversion receiver, the radio monitors the image strength and shuts off the receiver's Q branch (or I branch) when image rejection is not needed (i.e. when the relative image strength is below a threshold), thus significantly reducing power consumption in the RF receiver. A zero IF receiver is switched to a SQRD low IF receiver of lower power consumption when the image interferer strength is low enough to allow for a given required level of performance.

A novel and useful apparatus and method for an image-interferer aware single quadrature RF downconversion (SQRD) low intermediate frequency (LIF) receiver and related power reduction techniques utilized therein. The invention applies zero-margin adaptive transceiver (ZMAT) design principles to considerably reduce the receiver's power consumption in an adaptive fashion in accordance with the instantaneous reception conditions. In a low IF dual-branch (i.e. quadrature) downconversion receiver, the radio monitors the image strength and shuts off the receiver's Q branch (or I branch) when image rejection is not needed (i.e. when the relative image strength is below a threshold), thus significantly reducing power consumption in the RF receiver. A zero IF receiver is switched to a SQRD low IF receiver of lower power consumption when the image interferer strength is low enough to allow for a given required level of performance.

A novel and useful apparatus and method for an image-interferer aware single quadrature RF downconversion (SQRD) low intermediate frequency (LIF) receiver and related power reduction techniques utilized therein. The invention applies zero-margin adaptive transceiver (ZMAT) design principles to considerably reduce the receiver's power consumption in an adaptive fashion in accordance with the instantaneous reception conditions. In a low IF dual-branch (i.e. quadrature) downconversion receiver, the radio monitors the image strength and shuts off the receiver's Q branch (or I branch) when image rejection is not needed (i.e. when the relative image strength is below a threshold), thus significantly reducing power consumption in the RF receiver. A zero IF receiver is switched to a SQRD low IF receiver of lower power consumption when the image interferer strength is low enough to allow for a given required level of performance.

Local oscillator (LO) leakage and Image are common and undesirable effects in typical transmitters. Typically, fairly complex hardware and algorithms are used to calibrate and reduce these impairments. A single transistor that draws essentially no dc current and occupies a very small area detects the LO leakage and Image signals. The single transistor operating as a square-law device is used to mix the signals at the input and output ports of a power amplifier. The mixed signal generated by the single transistor enables the simultaneous calibration of the LO leakage and Image Rejection.