Abstract: A transceiver may include first and second transmit chains that generate first and second radio-frequency signals at first and second frequencies using first and second local oscillator (LO) signals. A transmit chain may include a digital front end, upconversion circuitry, an adder coupled to an input of the upconversion circuitry, and first and second paths coupled between the digital front end and the adder. The first path may generate a first signal at a first sample rate. The second path may generate a second signal at a second sample rate equal to a greatest common divisor of the first and second frequencies and that is out of phase with the first signal. The adder may generate a combined signal based on the first and second signals. The upconversion circuitry may generate a radio-frequency signal based on the combined signal that is free from signal spurs associated with LO crosstalk.

Abstract: Embodiments provide a pre-distortion circuit and apparatus, a method and computer program for pre-distorting, a transmitter, a radio transceiver, a communication device, a mobile transceiver, a base station transceiver and a storage. The pre-distortion circuit (10) is configured for a digital quadrature signal. The pre-distortion circuit (10) comprises a first input (12) for an inphase component of the quadrature signal and a second input (14) for a quadrature component of the quadrature signal. The pre-distortion circuit 10 comprises a signal processing circuit (16) configured to determine whether polarities of the inphase component and quadrature component are equal, and to determine pre-distortion coefficients based on the amplitude of the inphase component, the amplitude of the quadrature component, and based on whether the polarities are equal.

Abstract: Embodiments provide a pre-distortion circuit and apparatus, a method and computer program for pre-distorting, a transmitter, a radio transceiver, a communication device, a mobile transceiver, a base station transceiver and a storage. The pre-distortion circuit (10) is configured for a digital quadrature signal. The pre-distortion circuit (10) comprises a first input (12) for an inphase component of the quadrature signal and a second input (14) for a quadrature component of the quadrature signal. The pre-distortion circuit 10 comprises a signal processing circuit (16) configured to determine whether polarities of the inphase component and quadrature component are equal, and to determine pre-distortion coefficients based on the amplitude of the inphase component, the amplitude of the quadrature component, and based on whether the polarities are equal.

Abstract: A communication system receives an input signal along a signal processing path and generates a converted output signal via a digital-to-analog converter (DAC). The signal processing path branches into two different branches, a magnitude branch and a sign branch for different components of the baseband signal. A local oscillator (LO) provides a carrier signal to the signal processing path at the DAC and further generates an LO leakage signal comprising a signed LO leakage and an unsigned LO leakage during the up-conversion of signals of the sign branch with a carrier. An unsigned LO suppression component is configured to reduce or eliminate the unsigned LO leakage and a signed LO suppression component is configured to reduce or eliminate the signed LO leakage form a baseband signal of the signal processing path.

Abstract: A communication system using an increased sampling rate includes a baseband signal generator and a PLL that generates an LO signal and an inverted LO signal. An interpolator generates an interpolated/delayed data stream from a baseband original data stream, and a cell control circuit generate control signals based on the interpolated data stream and the baseband original data stream. An RFDAC generates an RF output signal from the baseband signal using an increased sampling rate, the LO signal, the inverted LO signal, and the control signals.

Abstract: Techniques are disclosed to provide a data dependent delay for a multi-phase transmitter architectures. These techniques include identifying a current segment occupied by a symbol associated with in-phase (I) and quadrature phase (Q) data within a data constellation based upon the number of phases used. Once the segment is identified, vector components are calculated as a function of the segment used to re-map the symbol within the constellation defined in accordance with the number of phases. The data delay may be performed in the baseband or at the RF rate to time-align local oscillator clocks with the delayed data, which is represented as the calculated vector components, for transmission. Further modifications to the RF-DAC operation to facilitate operation with the multi-phase system are also disclosed.

Abstract: An apparatus for generating a radio frequency signal based on a symbol within a constellation diagram is provided. The constellation diagram is spanned by a first axis representing an in-phase component and an orthogonal second axis representing a quadrature component. The apparatus includes a processing unit configured to select one of a plurality of segments of the constellation diagram containing the symbol. The segment is delimited by two radially extending boundaries, wherein the two radially extending boundaries span an opening angle of the segment that is different from 90°. The processing unit is further configured to calculate a first coordinate of the symbol with respect to a third axis, and a second coordinate of the symbol with respect to a fourth axis. At least one of the third axis and the fourth axis coincides with one of the two radially extending boundaries.

Abstract: An apparatus for generating a radio frequency signal based on a symbol within a constellation diagram is provided. The constellation diagram is spanned by a first axis representing an in-phase component and an orthogonal second axis representing a quadrature component. The apparatus includes a processing unit configured to select one of a plurality of segments of the constellation diagram containing the symbol. The segment is delimited by two radially extending boundaries, wherein the two radially extending boundaries span an opening angle of the segment that is different from 90°. The processing unit is further configured to calculate a first coordinate of the symbol with respect to a third axis, and a second coordinate of the symbol with respect to a fourth axis. At least one of the third axis and the fourth axis coincides with one of the two radially extending boundaries.

Abstract: A communication system receives an input signal along a signal processing path and generates a converted output signal via a digital-to-analog converter (DAC). The signal processing path branches into two different branches, a magnitude branch and a sign branch for different components of the baseband signal. A local oscillator (LO) provides a carrier signal to the signal processing path at the DAC and further generates an LO leakage signal comprising a signed LO leakage and an unsigned LO leakage during the up-conversion of signals of the sign branch with a carrier. An unsigned LO suppression component is configured to reduce or eliminate the unsigned LO leakage and a signed LO suppression component is configured to reduce or eliminate the signed LO leakage form a baseband signal of the signal processing path.

Abstract: An apparatus for generating a transmit signal includes an up-conversion module and a delay module. The up-conversion module up-converts a first component signal of a multi-phase baseband transmit signal using a first oscillator signal and up-converts a delayed second component signal of the multi-phase baseband transmit signal using a second oscillator signal to generate a radio frequency transmit signal. The first oscillator signal and the second oscillator signal comprise an oscillator signal phase offset so that an edge of the second oscillator signal occurs earlier than a corresponding edge of the first oscillator signal. The delay module delays a second component signal of the multi-phase baseband transmit signal relative to the first component signal of the multi-phase baseband transmit signal by a predefined component signal delay to generate the delayed second component signal of the multi-phase baseband transmit signal.

Abstract: An apparatus for generating a transmit signal includes an up-conversion module and a delay module. The up-conversion module up-converts a first component signal of a multi-phase baseband transmit signal using a first oscillator signal and up-converts a delayed second component signal of the multi-phase baseband transmit signal using a second oscillator signal to generate a radio frequency transmit signal. The first oscillator signal and the second oscillator signal comprise an oscillator signal phase offset so that an edge of the second oscillator signal occurs earlier than a corresponding edge of the first oscillator signal. The delay module delays a second component signal of the multi-phase baseband transmit signal relative to the first component signal of the multi-phase baseband transmit signal by a predefined component signal delay to generate the delayed second component signal of the multi-phase baseband transmit signal.