Abstract-We introduce a single-loop PLL that operates in a narrower-bandwidth, integer-mode during phase lock and in a wider-bandwidth, fractionalmode during transient. This hybrid PLL, as a generalization of the conventional variable-bandwidth PLL that shifts only its bandwidth, simultaneously achieves the fast-locking advantage of the fractional-PLL and design simplicity of the integer-PLL, and as such, brings benefits in certain important PLL applications. In addition, the frequency division mode switching, unique in the hybrid PLL, enables a new, more digital protocol to execute bandwidth switching. A CMOS IC prototype attests to the validity of the proposed approach.Index Terms-Charge-pump phase-locked loops, fractionalfrequency synthesizers, integer-frequency synthesizers, phaselocked loops.
The nonlinear transmission line is a structure where short-duration pulses called electrical solitons can be created and propagated. By combining, in a closed-loop topology, the nonlinear line and a special amplifier that provides not only gain but also mechanisms to tame inherently unruly soliton dynamics, we recently constructed the first electrical soliton oscillator that self-generates a stable, periodic train of electrical soliton pulses (Ricketts et al., IEEE Trans. MTT, 2006). This paper starts with a review of this recently introduced circuit concept, and then reports on new contributions, i.e., further experimental studies of the dynamics of the stable soliton oscillator and a CMOS prototype demonstrating the chip-scale operation of the stable soliton oscillator. Finally, we go to the opposite end of the spectrum and present a numerical study showing the possibilities that deliberate promotions of the unruly soliton dynamics in the closed-loop topology can produce chaotic signals.
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