A quadrature modulator and the transmission unit output a modulated wave obtained by performing quadrature modulation on a carrier wave using a first I signal and a first Q signal and wirelessly transmit the modulated wave. A reception unit and the quadrature detector detect a received signal corresponding to a wireless signal transmitted from the wireless tag using the carrier wave and to output a second I signal and a second Q signal. A filter and the amplification unit amplify a frequency component higher than a cutoff frequency in the second I signal and the second Q signal. A detector and the decoding unit decode data based on a detection signal obtained by detecting the amplified second I signal and the amplified second Q signal. A generation unit generates the first I signal and the first Q signal such that the modulated wave is a signal obtained by shifting a frequency of the carrier wave by a frequency shift amount more than the cutoff frequency and to input the first I signal and the first Q signal to the quadrature modulator.

An electronic device and a method performed by an electronic device are provided. A number of frequency bands of a plurality of carriers to be used in a plurality of communication circuits for communication is determined. The plurality of communication circuits process carrier signals in different frequency bands. A switching operation, performed by at least one switch, is controlled based on the number of frequency bands and a specified condition that is based on frequency bands able to be processed by an LNA included in each of the plurality of communication circuits. The carrier signals of the plurality of carriers is processed using at least one communication circuit. The at least one switch is alternately connected to two communication circuits and is configured to provide a reception carrier signal from at least one antenna to one of the two communication circuits based on a switching operation.

A method for communicating between a first radio frequency communications device including a first local oscillator and a second radio frequency communications device including a second local oscillator includes receiving a packet using a receiver of the first radio frequency communications device. The method includes detecting an average frequency offset based on sequential samples of the packet. The method includes applying a first adjustment to the first local oscillator to reduce a frequency offset between the first local oscillator and the second local oscillator. The first adjustment is based on the average frequency offset. The method includes, after adjusting the first local oscillator, transmitting a second packet to the second radio frequency communications device by the first radio frequency communications device using the first adjustment and the first local oscillator.

A channel response generating module and method for generating a channel response based on a ratio of a channel response corresponding to an image signal frequency bin in relation to a channel response corresponding to a traffic signal frequency bin, or a channel response corresponding to a first frequency bin in relation to a channel response corresponding to a second frequency bin, and a zero-IF signal transmitter employing the channel response generating module and method to efficiently suppress image signals or compensate traffic signals during transmission of IQ RF signals.

Some aspects of the present disclosure relate to detection of a Phase Hit and, upon detecting the Phase Hit, determining the magnitude and location of the Phase Hit. Detecting the Phase Hit may involve comparing a phase offset difference for successive pilot symbol to a detection threshold. Determination of the detection threshold may involve a Neyman-Pearson binary hypothesis testing (NP-BHT) approach. Once the magnitude and location of the Phase Hit are known, data symbols received after the location may be processed to remove the magnitude of the Phase Hit.

An in-phase and quadrature mismatch compensator for a quadrature transmitter includes a delay element, a complex-valued filter and an adder. The delay element receives an input transmit signal and outputs a delayed transmit signal. The complex-valued filter receives the input transmit signal and outputs a selected part of a filtered output transmit signal. The adder adds the delayed transmit signal and the selected part of the filtered output transmit signal and outputs a pre-compensated transmit signal. In one embodiment, the selected part of the filtered output transmit signal includes the real part of the complex-valued output transmit signal. In another embodiment, the selected part of the filtered output transmit signal includes the imaginary part of the complex-valued output transmit signal. Two transmit real-valued compensators are also disclosed that combine the in-phase and quadrature signals before being filtered.

A Radio Frequency Impairments (RFI) compensator and a process to remove RFI is disclosed. The RFI compensator including: a conjugator to conjugate a signal {tilde over (x)}[n] to provide a signal {tilde over (x)}*[n]; and a filter to apply coefficients that equalize a linear distortion of the signal {tilde over (x)}[n] and reject an interfering image of the signal {tilde over (x)}*[n]. The signal {tilde over (x)}[n] maybe a single wideband carrier or may include multiple carriers at different carrier frequencies.

Quadrature error correction (QEC) for radio transceivers are provided herein. In certain embodiments, a transceiver includes an in-phase (I) signal path including a first controllable amplifier coupled to a first data converter, and a quadrature-phase (Q) signal path including a second controllable amplifier coupled to a second data converter. The transceiver further includes a QEC circuit operable to correct for a quadrature error between the I signal path and the Q signal path by adjusting a gain of the first controllable amplifier and/or a gain of the second controllable amplifier.

A single channel receiver includes an input terminal that receives an analog input signal, a mixer that down-mixes the analog input signal by use of a phase- and/or frequency-corrected oscillator frequency signal and shifts complex-valued information contained in the analog input signal to the real part (or alternatively to the imaginary part) to obtain an intermediate real-valued analog signal, an analog-to-digital-converter that converts the intermediate analog signal into an intermediate digital signal, a demodulator that demodulates the intermediate digital signal into a digital output signal, a phase tracking loop that detects zero-crossings in the intermediate digital signal to obtain phase error information representing a phase error in the intermediate digital signal, and an oscillator that generates the phase- and/or frequency-corrected oscillator frequency signal by compensating the phase and/or frequency error in the intermediate digital signal by correcting the phase of the oscillator frequency signal with the phase error information.

An in-phase and quadrature mismatch compensator for a quadrature transmitter includes a delay element, a complex-valued filter and an adder. The delay element receives an input transmit signal and outputs a delayed transmit signal. The complex-valued filter receives the input transmit signal and outputs a selected part of a filtered output transmit signal. The adder adds the delayed transmit signal and the selected part of the filtered output transmit signal and outputs a pre-compensated transmit signal. In one embodiment, the selected part of the filtered output transmit signal includes the real part of the complex-valued output transmit signal. In another embodiment, the selected part of the filtered output transmit signal includes the imaginary part of the complex-valued output transmit signal. Two transmit real-valued compensators are also disclosed that combine the in-phase and quadrature signals before being filtered.