A system and method include a modulator configured to combine satellite codes with carrier signals on an in-phase channel and a quadrature-phase channel to produce I-channel and Q-channel signal components. The powers of the combined satellite codes are selected according to desired code power fractions. A processor pre-distorts the signal components such that they can be transmitted as a unit-amplitude constant envelope transmission that preserves the desired code power fractions. The pre-distortion may also account for data filtering effects that tend to distort the code power fractions.

A quadrature transmitter includes a first and second matched transmitter path. Each transmitter path receives respective sets of quadrature baseband signals. At least one local oscillator port receives respective sets of quadrature LO signals. Mixer stage(s) respectively multiply the sets of quadrature baseband signals with the respective sets of quadrature LO signals to produce a respective output radio frequency signal. A combiner combines the output RF signals. The first set of quadrature signals is a substantially 45 phase shifted version of the second set of quadrature signals; and the first set of quadrature LO signals is a reverse substantially 45 phase shifted version of the second set of quadrature LO signals. A baseband error correction circuit corrects a phase error between the quadrature baseband signals at baseband and a LO error correction circuit corrects a phase error between the quadrature baseband signals at a LO frequency.

This application relates to the field of communications technologies, and in particular, to a digital predistortion processing method and apparatus. This application provides a digital predistortion processing method and apparatus. Digital predistortion processing of a multichannel power amplifier is supported through deprecoding processing by using one feedback link and one digital predistortion processor. In addition, after being amplified by a power amplifier, a precoded signal is fed back to the feedback link for predistortion parameter calculation, to improve quality of a transmit signal. The digital predistortion processing method and apparatus that are provided in embodiments of this application are intended to improve output linearity and efficiency of a multi-transmit-channel power amplifier while reducing implementation costs and complexity of a transmit device, and further improve overall system performance.

A system for interference mitigation including a transmit coupler that samples the RF transmit signal to create a sampled RF transmit signal; a transmit analog canceller that transforms the RF transmit signal to an RF interference cancellation signal, according to a first configuration state; a first receive coupler that combines the RF interference cancellation signal and the RF receive signal to generate a composite RF receive signal; a sampling analog interference filtering system that, in order to remove interference in the transmit band, filters the sampled RF transmit signal to generate a cleaned transmit signal; a first frequency downconverter that converts the transmit signal to a BB transmit signal; a second frequency downconverter that converts the composite RF receive signal to a composite BB receive signal; and an analog-to-digital converter that converts the transmit signal to a digital transmit signal.

High efficiency amplitude DACs (Digital-to-Analog Converters) and RFDACs (Radio Frequency DACs) employing such amplitude DACs are discussed. One exemplary embodiment is a DAC comprising a plurality of DAC stages, wherein each DAC stage of the plurality of DAC stages is associated with a respective predetermined voltage of a plurality of predetermined voltages, wherein each DAC stage of the plurality of DAC stages can receive a digital signal at the respective predetermined voltage associated with that DAC stage when the respective predetermined voltage of that DAC stage is a selected predetermined voltage, wherein the selected predetermined voltage is based on an amplitude of the digital signal, and wherein each DAC stage of the plurality of DAC stages can generate a respective analog signal associated with that DAC stage based on the digital signal received at that DAC stage when the respective predetermined voltage of that DAC stage is the selected predetermined voltage.

A device for monitoring a health parameter of a person is disclosed. The device includes a semiconductor substrate including at least one transmit component and multiple receive components, at least one transmit antenna configured to transmit millimeter range radio waves over a 3D space below the skin surface of a person, and multiple receive antennas configured to receive radio waves, the received radio waves including a reflected portion of the transmitted radio waves, wherein the semiconductor substrate includes circuits for processing signals received on the multiple receive antennas, wherein the semiconductor substrate includes at least one output configured to output a signal that corresponds to a health parameter of a person in response to received radio waves, and wherein the at least one transmit antenna is collocated with the at least one transmit component and the multiple receive antennas are collocated with respective ones of the multiple receive components.

A wearable device is disclosed. The wearable device includes a housing, an attachment device configured to attach the housing to a person, at least one transmit antenna configured to transmit millimeter range radio waves over a 3D space below the skin surface of the person, multiple receive antennas configured to receive radio waves, the received radio waves including a reflected portion of the transmitted radio waves, and a processor configured to isolate a signal from a particular location in the 3D space in response to receiving the radio waves on the multiple receive antennas and outputting a signal that corresponds to a health parameter of the person in response to the isolated signal.

A wireless communication device for asymmetrical frequency spreading including a processor configured to receive a frequency band message comprising a maximum difference and a minimum difference, wherein the maximum difference is between a maximum frequency of a sub-band and a signal frequency, and wherein the minimum difference is between the minimum frequency of the sub-band and the signal frequency compare the maximum difference and the minimum difference with each other; and generate a frequency shift based on the comparison.

A system for monitoring a health parameter in a person is disclosed. The system includes at least one transmit antenna configured to transmit millimeter range radio waves over a 3D space below the skin surface of a person, multiple receive antennas configured to receive radio waves, the received radio waves including a reflected portion of the transmitted radio waves, and means for isolating a signal from a particular location in the 3D space in response to receiving the radio waves on the multiple receive antennas and outputting a signal that corresponds to a health parameter of the person in response to the isolated signal.

A method for monitoring a blood glucose level in a person involves transmitting millimeter range radio waves over a three-dimensional (3D) space below the skin surface of a person. receiving radio waves on multiple receive antennas, the received radio waves including a reflected portion of the transmitted radio waves, isolating a signal from a particular location in the 3D space in response to receiving the radio waves on the multiple receive antennas, and outputting a signal that corresponds to a blood glucose level in the person in response to the isolated signal.