Fast State-Space Harmonic-Distortion Estimation in Weakly Nonlinear <formula formulatype="inline"><tex>$G_m{-}C$</tex></formula> Filters

Effects of imbalance input on linearity of pseudodifferential ladder Gm‐C filters

“…(19) † Also referring to the current source kG md v od v oc and using the trigonometric function identity cos θ cos 2θ = (cos θ + cos(3θ))/2, we found that according to (6) and (12), the DM-CM cross product the current source kG md v od v oc will produce the 3rd-harmonic current…”

“…14) † Likewise, according to (6) and 8, the current source hG md v oc v od will produce the 2nd-harmonic current…”

“…Fully-differential (FD) structure is widely used in analogue integrated circuits because it provides superior performance to single-ended structure in terms of linearity and immunity to interference including power supply and substrate noise. In the distortion analysis of the FD Gm-C filters in [3][4][5][6][7], it is assumed that the differential-mode (DM) and common-mode (CM) signals in the filter are not interdependent. Nevertheless such an assumption is valid only in the case where the FD transconductors with very high CM rejection (CMR) are employed in the filter.…”

Nonlinear distortion analysis via perturbation method

“…Nonlinear effects play a crucial role in several analog circuits, such as transconductance-C filters, switched-current filters, low-voltage-integrated circuits and analog radio-frequency front-ends of integrated transceivers [1][2][3][4][5][6][7]. Moreover, distortion induced by nonlinearities in electronic amplifiers is crucial for some communication schemes, as in energy division multiple access systems, where it is important to guarantee differences in the energy levels that provide separability among the users.…”

“…(A+DC)x+f(x)+Dp(x) = u (2) with D being a diagonal matrix where each entry is the time derivative of first order. Equation (2) can be easily put in operator form…”