Viscosity measurement method with integral signal processing
Maciej Kozarski, Edward Krauze · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1999
The new method of measurement signal processing applied in the oscillometric viscometer is presented. The method consists in analog integration of a current in the electromagnetic speaker-like actuator. Integration in displacement domain is replaced by the integration in time domain during the period of oscillations. This method of signal processing has advantages as compared to simple amplitude measurement methods i.e. first of all, better resistance to disturbing mechanical vibrations close to the working frequency of oscillations. The measuring circuit is practically insensitive to thermal drifts of electrical zeros and gains and thermal fluctuations of mechanical parameters as well. Also nonlinearities of static characteristics (e.g. of bellows) have a negligible contribution as far as a result of measurements is concerned. Some design aspects and results of examinations concerning a clinical model of the viscometer are presented. The described method of signal processing may be applied in different types of viscometers.