An apparatus and method are provided for setting a local oscillator duty ratio based on an image distortion level. A first signal is transmitted utilizing a first X-phase path of a transmitter. Further, an image distortion level is measured in connection with the first signal. Based on the measurement, a duty ratio of a local oscillator is set, for reducing a distortion in connection with a transmission of a second signal utilizing a second Y-phase path of the transmitter.

Techniques are disclosed implementing a radio partitioning architecture using multiple data streams over a single coaxial cable that does not require external RF filtering. This provides a flexible frequency scheme (e.g., using IF frequency adjustment) that enables the avoidance of Wi-Fi and LTE harmonics. The techniques include leveraging baseband filtering, which may be integrated with the radio head in a common radio frequency intergraded circuit (RFIC).

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.

A carrier leakage correction method for a quadrature modulator according to an embodiment includes inputting a test signal with a frequency f.sub.BB to a transmitter and up-converting the test signal with a frequency f.sub.L0 and down-converting with the frequency f.sub.L0. A frequency 2f.sub.BB component is detected in the down-converted test signal. One or a plurality of parameters of the transmitter is/are adjusted so as to reduce a magnitude of the detected frequency 2f.sub.BB component in the test signal.

The present disclosure discloses a local oscillator feedthrough signal correction apparatus, including a microprocessor control unit, a first digital-to-analog converter, a second digital-to-analog converter, a mixer, a local oscillator, a signal output line, a signal splitter, and a detector tube. The signal splitter is disposed in the signal output line, and the first digital-to-analog converter and the second digital-to-analog converter are configured to provide the mixer with quadrature direct current components VI and VQ used for local oscillator feedthrough signal correction. The mixer outputs a local oscillator feedthrough signal to the signal output line. The signal splitter obtains the local oscillator feedthrough signal by means of splitting, and the detector tube detects the local oscillator feedthrough signal. When a detection value of the local oscillator feedthrough signal exceeds a preset target value, the microprocessor control unit adjusts output values of the VI and the VQ to reduce local oscillator feedthrough.

According to one aspect of the present disclosure, there is provided a device that includes: a first quadrature modulator configured to receive an in-phase portion of a baseband signal and a quadrature portion of the baseband signal, and to produce a first portion of an output signal according to the in-phase and quadrature portions of the baseband signal; a second quadrature modulator configured to receive a first modified signal and a second modified signal, and to produce a second portion of the output signal according to the first and second modified signals; an output circuit configured to sum the first and second portions of the output signal, and to transmit the output signal to an antenna; and a mode selection circuit configured to turn on the first quadrature modulator, to receive a control signal, and to determine whether to turn on the second quadrature modulator according to the control signal.

A spatial position-dependent I/Q domain modulation method, dual domain modulation method and multiple access communication method are provided. The methods eliminate the dependence of physical layer secure communication on channel state information, and realize the function that a receiver at an expected position can communicate normally, while an eavesdropper at other positions cannot receive a signal or can only receive a wrong signal. The security capability of a wireless communication system is improved from the spatial dimension. The multiple access communication method can realize the distinguishing of multiple users according to precise spatial position points. Even if a plurality of users are located in the same sector in an angular domain, as long as the spatial positions of these users are different, the method can be used to perform multiple access communication, thereby further improving the spatial multiplexing rate of the system and increasing the system capacity.

The information processing method includes: receiving transmission mode-related configuration information; determining whether a transmission scheme of a first signal is a first transmission scheme according to the transmission mode-related configuration information; wherein, the transmission mode-related configuration information includes at least one of: transmission mode configuration information, DMRS port indication information of the first signal, TDRA indication information about the first signal, or scenario indication information about whether a terminal is in a high-speed train scenario and/or a frequency pre-compensation scenario; in the first transmission scheme, one layer of the first signal and at least two reference signals have a QCL relationship with respect to at least one large-scale parameter of channel; and/or, one DMRS port of the first signal and at least two reference signals have the QCL relationship with respect to at least one large-scale parameter of channel.

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 enhanced quadrature receive serial interface circuit and methods are provided for calibrating the quadrature receive serial interface circuit. A quadrature receive serial interface circuit comprises a first phase rotator and a second phase rotator generating quadrature clocks of identical frequency. Calibration of the quadrature receive serial interface circuit uses a pseudo random bit sequence (PRBS) received by the quadrature receive serial interface circuit. For calibration, one-half of the received PRBS bits are sampled and the phase rotator generating in-phase 0? and 180? clock signals is adjusted to center the data eye for the sampled half of the PRBS bits. Then all data bits (even and odd data bits) of the received PRBS bits are sampled and the phase rotator generating quadrature phase 90? and 270? clock signals is adjusted to center the data eye of all data bits of the PRBS bits to complete calibration.