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Recent developments in CMOS passive mixers have demonstrated a number of new and useful capabilities, including dynamic RF port impedance control and filter up-conversion, while also allowing low noise figure and high out-of-band linearity, all of which track wide-ranging LO frequencies and tunable baseband bandwidth. However, these circuits also bring a unique set of challenges and requirements. Here we extend a previously derived LTI model for such mixers to the general N-phase case, and discuss basic limits in performance specifications including impedance matching, noise figure and linearity. We then extend this analysis to include high-frequency effects, especially as they relate to transistor properties. We show that essentially all of the key specification of such mixers can be described in terms of an impedance ratio, a characteristic cut-off frequency, the number of phases of the mixer and some process-related parameters. Finally, we discuss how these properties relate to power consumption of LO circuitry. [ABSTRACT FROM PUBLISHER]

In this article, a decentralized adaptive finite-time tracking control scheme is proposed for a class of nonstrict feedback large-scale nonlinear interconnected systems with disturbances. First, a practical almost fast finite-time stability framework is established for a general nonlinear system, which is then applied to the design of the large-scale system under consideration. By fusing command filter technique and adaptive neural control and introducing two smooth functions, the “singular” and “explosion of complex” problems in the backstepping procedure are circumvented, while the obstacles caused by unknown interconnections are overcome. Moreover, according to the framework of practical almost fast finite-time stability, it is shown that all the closed-loop signals of the large-scale system are almost fast finite-time bounded, and the tracking errors can converge to arbitrarily small residual sets predefined in an almost fast finite time. Finally, a simulation example is presented to demonstrate the effectiveness of the proposed finite-time decentralized control scheme. [ABSTRACT FROM AUTHOR]