Patent ID: 9729254
Date: 2017-08-08
CPC Classifications: H03D,H04B

Claim:
1. An apparatus, comprising: a first low pass filter (LPF), including an input configured to receive a real part of a second order intermodulation (IM2) tone, and an output; a second LPF, including an input configured to receive an imaginary part of the IM2 tone, and an output; a first analog-to-digital converter (ADC), including a first input connected to the output of the first LPF, and an output; a second ADC, including a first input connected to the output of the second LPF, and an output; a first discrete Fourier transform (DFT) unit, including an input connected to the output of the first ADC, and an output; a second DFT unit, including an input connected to the output of the second ADC, and an output; an IM2 tone amplitude measurement unit, including a first input connected to the output of the first DFT, a second input connected to the output of the second DFT, and an output; and a calibration logic unit, including an input connected to the output of the IM2 tone amplitude measurement unit, a first output, and a second output, configured to apply at least one plane-fitting method to the output of the IM2 tone measurement unit to determine two sets of valley points of wing-shaped surfaces of a real part of a DFT and an imaginary part of the DFT, respectively, and to simultaneously determine an in-phase mixer (I-mixer) digital-to-analog (DAC) code and a quadrature-phase mixer (Q-mixer) DAC code from an intersection of two lines formed from the two sets of valley points.