Especially in the automotive domain wheel speed sensors face increasing quality and reliability requirements due to novel vehicle concepts as well as new legal regulations. From this follows, that next generation sensors have to possess a higher robustness against harsh environmental conditions. A large operating temperature range as well as a high stray field immunity are key-requirements. In this paper a novel magnetoresistive wheel speed sensor is presented, whereby its transfer function is linearized in the frequency domain. From this follows directly an improvement of the sensor reliability, since temperature and lifetime drift are significantly reduced. Moreover, the concept enables measurement of disturbing fields perpendicular to sensing direction, which cannot be detected by existing speed sensors. Furthermore, promising measurement results validate the feasibility and performance of the presented sensory system.

A novel magnetoresistive wheel speed sensor with low temperature drift and high stray field immunity

The difficulties to analyse the state space of a special class of nonlinear electronic circuits are illustrated and a new method to treat these problems is presented. Theoretical aspects of circuit equations from a differential geometric point of view are considered and methods for solving circuit equations by means of algorithms from computational differential geometry are presented. In this paper differential geometric methods were applied to a relaxation oscillator and numerical results were achieved. We describe the behaviour of an emitter-coupled multivibrator with differential algebraic equations and compute its state space numerically.

/pdf/numerical-analysis-of-relaxation-oscillators-based-on-a-36x2khzk06.pdf

Numerical analysis of relaxation oscillators based on a differential geometric approach

We present a nonlinear analysis of a new inductively tuned astable multivibrator obtained by connecting a timing inductor across a composite nonlinear resistor with a characteristic of N-type, which is made up of the parallel connection of two complementary pairs of cross-coupled MOS devices Some possible practical applications of the circuit are also envisaged Closed-form expressions for the amplitude and the period of the periodic oscillation are derived in both cases when the circuit exhibits a relaxation oscillation and in the more difficult case when, due to the effect of parasitic capacitances of the devices, the circuit has an almost-discontinuous relaxation oscillation with a nonzero switching time The accuracy of the presented formulas, which are useful for both the analysis and design, is validated through circuit simulations and experimental results Copyright © 2009 John Wiley & Sons, Ltd

A new CMOS astable multivibrator and its nonlinear analysis

Emitter-coupled multivibrators play a decisive role in electrical engineering, especially for phase locked loops which are key-building blocks of analogue RF front-ends. Since multivibrators correspond to relaxation oscillators, in the following the modelling and analysis by the theory of singularly perturbed systems is presented. Models for fast and slow phenomena are derived, and the fast transients of emitter-coupled multivibrators are analysed for the first time. The results of our analysis lead to significant advantages for the design of electrical multivibrators.

https://www.tandfonline.com/doi/pdf/10.1080/13873950701379888

F. A. Probst

Papers

Analysis of emitter-coupled multivibrators by singularly perturbed systems