This paper studies how nonlinear distortion is generated in the combination of an inverter-based low-noise amplifier and a passive mixer. The dominant nonlinearity appears to be the quadratic \(V_{gs}V_{ds}\) mixing term in the passive mixer that first causes low-frequency IM2 and then upconverts it to IM3. Adding a common-mode feedback (CMFB) cancels the IM2 in a pseudo-differential structure, and hence also reduces the IM3 caused by the cascaded second order nonlinearities significantly. The effect of CMFB gain, bandwidth and linearity were analyzed, and it is concluded that from the linearity point of view, the feedback circuit does not have to be very wideband since the dominant distortion products originate from baseband. Finally, the paper takes a look at the spurious tones rising in the mixing, and how to extend the analysis to include the actual frequency translation effect.

本文研究了在基于逆变器的低噪声放大器和无源混频器的组合中如何产生非线性失真。主要的非线性似乎是二次方\(V_{gs}V_{ds}\)无源混频器中的混频项，首先产生低频 IM2，然后将其上变频为 IM3。添加共模反馈 (CMFB) 在伪差分结构中抵消了 IM2，因此也显着降低了由级联二阶非线性引起的 IM3。分析了 CMFB 增益、带宽和线性度的影响，得出的结论是，从线性度的角度来看，反馈电路不必非常宽带，因为主要的失真产物来自基带。最后，本文研究了混音中上升的杂散音，以及如何扩展分析以包括实际的频率转换效果。