Optimized Design of Pulsed Waveform Oscillators and Frequency Dividers

Abstract

A technique is presented for the optimized design of oscillators and frequency dividers based on nonlinear transmission lines (NLTLs). The oscillator design relies on a closed-loop configuration containing a high-efficiency amplifier, with the loop output matched to a short NLTL. Attention is paid to the oscillator phase noise. A simple and general-application method is presented for an accurate calculation of the phase sensitivity functions with respect to specific noise sources. The predictions obtained when considering stationary and cyclo-stationary noise-source models are compared. The influence of crucial design parameters on the oscillator efficiency, pulse amplitude, and duty cycle is analyzed, as well as their impact on the phase-noise behavior. An efficient simulation technique enables the evaluation of the injection-locking capabilities during this global optimization of the oscillator in the free-running regime. The phase-noise spectrum in injection-locked conditions is analyzed in detail, considering the influence of flicker noise. A frequency division by 2 is observed in the amplifier stage loaded by the NLTL. The origin of this division is investigated, as well as the influence of the number of cells on the pulsed waveform and the division bandwidth. The techniques have been successfully applied to the design of a pulsed oscillator at 900 MHz.

Rotary Traveling-Wave Oscillator With Differential Nonlinear Transmission Lines

“…, as shown in [42][43]. In the numerical calculation of (8), a small corner frequency, in the order of 1 Hz, is introduced to avoid singularity in the integral [44].…”

Analysis of Two Coupled NLTL-Based Oscillators

“…In this case, we have chosen a Class-E oscillator topology, since the NLTL must be driven with sufficiently high amplitude to ensure the nonlinear operation of the diodes. The oscillator is composed by an amplifier with low output impedance [15] and a parallel feedback network to sustain the self-oscillation [ Fig. 4(a)].…”

“…When doing so, the exponentials of the phase variables are approached as (13) It is also taken into account that the complex-frequency increment gives rise to a time-derivative operator [29]- [32], so the perturbed system can be written (14) where superindexes and indicate real and imaginary parts and the following functions have been defined and . By grouping terms, one obtains the following LTI system, in matrix form: (15) where the matrixes and are given by (16) Note that the phase derivatives must be particularized to each steady-state solution, given by , . This provides (17) The stability is determined by the eigenvalues of the matrix [M] in (15).…”

“…The soliton is a solitary wave that maintains its shape while travelling through the NLTL at a constant speed [9]. Some previous works [1], [12]- [16] have demonstrated the possibility to obtain an autonomous soliton generator by suitably loading an active element with an NLTL (reflection configuration) [14], [15] or by using the NLTL as the feedback block of an amplifier [1], [16]. This provides a periodic pulsed waveform, with no need of an input periodic signal.…”

Design of injection‐locked oscillator circuits using an HBT X‐parameters™‐based model

“…This methodology is fully measurement-based, accurate and simple, in comparison to other previously proposed synchronised oscillator design procedures [6][7][8][9][10][11][12] being more thorough in terms of their theoretical background. Nevertheless, the new proposed methodology quickly provides a possible design solution, saving design simulation time.…”