An apparatus and a method. The apparatus includes a first low pass filter (LPF), a second LPF, a first analog-to-digital converter (ADC), a second ADC, a first discrete Fourier transform (DFT) unit, a second DFT unit, a second order intermodulation (IM2) tone amplitude measurement unit, and a calibration logic unit configured to simultaneously determine an in-phase mixer (I-mixer) digital-to-analog (DAC) code and a quadrature-phase mixer (Q-mixer) DAC code.

A transmitter that reduces 3.sup.rd order harmonic (HD3) and inter modulation distortion (IMD3) for a gm stage of a mixer while reducing flicker noise is disclosed. The transmitter may include a balanced mixer, a transconductance stage connected to the mixer, and a bias circuit. The bias circuit may include a programmable current source configured to provide a reference current. Further, the bias circuit may include a replica circuit configured to replicate a DC signal of the transconductance stage. The bias circuit may also include a bias transistor configured to level shift a bias signal obtained from a signal source based on the reference current and the DC signal of the transconductance stage as determined from the replica circuit.

A transmitter that reduces 3.sup.rd order harmonic (HD3) and inter modulation distortion (IMD3) for a gm stage of a mixer while reducing flicker noise is disclosed. The transmitter may include a balanced mixer, a transconductance stage connected to the mixer, and a bias circuit. The bias circuit may include a programmable current source configured to provide a reference current. Further, the bias circuit may include a replica circuit configured to replicate a DC signal of the transconductance stage. The bias circuit may also include a bias transistor configured to level shift a bias signal obtained from a signal source based on the reference current and the DC signal of the transconductance stage as determined from the replica circuit.

An acquisition stage receives a digital input signal and generates therefrom a first digital signal and a second digital signal complementary thereto. First and second processing stages receive the first and second digital signals and generate therefrom first and second analog signals in time with first and second complementary clock signals. An output stage generates an internal clock signal equivalent to one of: the first clock signal phase shifted by a duration of a transient occurring during a period of the first clock signal, or the second clock signal phase shifted by a duration of a transient occurring during a period of the second clock signal. The output stage produces an analog output signal equal to the first analog signal when the internal clock signal is at a first logic level, and equal to the second analog signal when the internal clock signal is at a second logic level.

An acquisition stage receives a digital input signal and generates therefrom a first digital signal and a second digital signal complementary thereto. First and second processing stages receive the first and second digital signals and generate therefrom first and second analog signals in time with first and second complementary clock signals. An output stage generates an internal clock signal equivalent to one of: the first clock signal phase shifted by a duration of a transient occurring during a period of the first clock signal, or the second clock signal phase shifted by a duration of a transient occurring during a period of the second clock signal. The output stage produces an analog output signal equal to the first analog signal when the internal clock signal is at a first logic level, and equal to the second analog signal when the internal clock signal is at a second logic level.

Multiplexing circuitry and method for driving multiplexing circuits are provided. A circuit includes a multiplexer circuit having symmetrical data input paths driven by a half-rate clock signal and a first stage multiplexing circuit configured to provide input signals to the multiplexer circuit. The first stage multiplexing circuit is driven by quadrature clocks to generate time-shifted data.

Mixer circuitry can include a first pair of transistors coupled to a first tail node and configured to receive a local oscillator signal, a second pair of transistors coupled to a second tail node and configured to receive the local oscillator signal, a first digital-to-analog converter, a second DAC coupled between the first DAC and of the first pair of transistors, and a third DAC coupled between the first DAC and the second pair of transistors. During a first phase, control circuitry can sweep the first DAC to trim a first and/or other odd order local oscillator feedthrough. During a second phase, the control circuitry can sweep the second DAC to trim a second and/or other even order local oscillator feedthrough. During a third phase, the control circuitry can sweep the second and third DACs to reject signals associated with a second harmonic conversion gain of the mixer circuitry.

An apparatus and method. The method includes filtering an output of an in-phase (I-mixer); filtering an output of a quadrature-mixer (Q-mixer); converting an output of a first low pass filter (LPF); converting an output of a second LPF; buffering an output of a first analog-to-digital converter (ADC); buffering an output of a second ADC; buffering a transmitter signal; generating a reference signal from an output of a transmitter (TX) data capture buffer; removing DC from the reference signal; and adaptively tuning an I-mixer digital-to-analog (DAC) code and a Q-mixer DAC code from an output of a first receiver (RX) data capture buffer, an output of a second RX data capture buffer, an output of a DC removal unit, and a predetermined step size for each of the I-mixer DAC code and the Q-mixer DAC code.

An apparatus is disclosed for oscillator feedthrough calibration, such as a component arrangement that can be calibrated to account for signal leakage from an oscillator coupled to a mixer circuit. In example aspects, the apparatus includes a mixer circuit having a first stage, a second stage, and tuning circuitry. The first stage includes at least one transistor coupled between a mixer input and a mixer output. The second stage includes one or more transistors coupled between the at least one transistor of the first stage and the mixer output. The one or more transistors are also coupled between a local oscillator signal input and the mixer output. The tuning circuitry includes at least one current source coupled to the at least one transistor of the first stage.

Mixer circuitry can include a first pair of transistors coupled to a first tail node and configured to receive a local oscillator signal, a second pair of transistors coupled to a second tail node and configured to receive the local oscillator signal, a first digital-to-analog converter, a second DAC coupled between the first DAC and of the first pair of transistors, and a third DAC coupled between the first DAC and the second pair of transistors. During a first phase, control circuitry can sweep the first DAC to trim a first and/or other odd order local oscillator feedthrough. During a second phase, the control circuitry can sweep the second DAC to trim a second and/or other even order local oscillator feedthrough. During a third phase, the control circuitry can sweep the second and third DACs to reject signals associated with a second harmonic conversion gain of the mixer circuitry.