| 摘要 |
An apparatus and method for tracking a DC offset in a mixer circuit used in wireless communication systems and for providing local oscillator DC bias level-shifting to reduce even order distortion resulting from the DC offset is described. The apparatus has an input coupled to a mixer circuit output for receiving a DC voltage present on the mixer circuit output. The DC voltage includes an offset component. A level shifting circuit is coupled to the input for level shifting the received DC voltage a predetermined amount. An output of the level shifting circuit is coupled to a local oscillator input for outputting the level shifted DC voltage to the local oscillator input. The shift in the DC bias level at the local oscillator input of the mixer circuit provided by the apparatus and method reduces even order distortion in the mixer circuit, including second order intermodulation (IM2) distortion.
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