US 2009/0154595 A1 · I-Q MISMATCH CALIBRATION AND METHOD

Abstract

Techniques are provided for reducing mismatch between the in-phase (I) and quadrature (Q) channels of a communications transmitter or receiver. In an exemplary embodiment, separate voltages are applied to bias the gates or bulks of the transistors in a mixer of the I channel versus a mixer of the Q channel. In another exemplary embodiment, separate voltages are applied to bias the common-mode reference voltage of a transimpedance amplifier associated with each channel. Techniques are further provided for deriving bias voltages to minimize a measured residual sideband in a received or transmitted signal, or to optimize other parameters of the received or transmitted signal. Techniques for generating separate bias voltages using a bidirectional and unidirectional current digital-to-analog converter (DAC) are also disclosed.

Claims57

Dependent claims

An apparatus comprising:

an in-phase (I) signal path and a quadrature (Q) signal path, the I signal path having at least one I bias voltage or I bias current, and the Q signal path having at least one corresponding Q bias voltage or Q bias current;
and
an offset calibration control for controlling at least one of the I bias voltage, I bias current, Q bias voltage, or Q bias current, such that at least one of the I bias voltage or I bias current has a different value from a corresponding one of the Q bias voltage or Q bias current.

Dependencies are inferred from the claim text.

I-q mismatch calibration and method

Life of this patent

I-q mismatch calibration and method

Life of this patent

Abstract

Claims57