Electricity: measuring and testing – Impedance – admittance or other quantities representative of... – Lumped type parameters
Patent
1997-07-09
1999-04-20
Ballato, Josie
Electricity: measuring and testing
Impedance, admittance or other quantities representative of...
Lumped type parameters
324720, 324602, 73769, G01B 716
Patent
active
058960333
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method and device for the compensation of electrical disturbances caused by disturbing impedances, preferably capacitances, which method and device are suitable for applications in which high demands are placed upon the suppression of the disturbances, e.g. in a vibrating solid-state gyroscope, and are based upon measurement and compensation of disturbances caused by a superposed measuring signal of known characteristics.
PRIOR ART
It is known that electrical voltages and currents can disturb the environment in an undesirable manner. The undesirable energy leakage can very often be represented with stray impedances. Stray capacitances usually represent the disturbances well.
In a number of applications, it is sufficient to design the electronics and the environment well to minimize the values of the disturbing impedances. Higher suppression can be obtained by using a fixed compensation of the effect of the disturbances. This presupposes that the amplitude, phase and location of the disturbances are known or that their effect at least is measured.
Certain applications place very high demands upon the suppression of disturbances. For these applications, ageing and temperature variations can cause disturbing impedances to vary with time and temperature to an unacceptably high degree. The mutual strength of the signals which leak by way of the disturbing impedances and the components which are used for fixed compensation can also vary to an unacceptably high degree. For these applications, optimally designed geometry, electronics layout and fixed compensation are not sufficient.
In those applications in which it is essential for the effect of disturbing impedances to be minimized, an active compensation of the energy leakage should be used. An optimal suppression of the disturbances pre-supposes that their effect can be measured and compensated for on a continuous or virtually continuous basis. This can be realized, for example, by the electronics or mechanics periodically suppressing the normal signal. During this switching, the effect of the disturbing impedances can be measured. This information can then be used for a virtually continuous compensation.
Certain applications do not allow the strength of the normal signal to be altered periodically. Nor is it always possible to separate the abnormal disturbance signals from the normal signal. In these cases, measurement of the disturbance by means of switching cannot be used. There is therefore a need for an alternative method for the continuous, active compensation of disturbance signals caused by actual or represented stray impedances.
The proposed invention is intended to resolve the abovementioned problems.
ACCOUNT OF THE INVENTION
There is a need to be able to measure and compensate for disturbances caused by disturbance impedances, e.g. stray capacitances, in an active and continuous manner. In certain applications, the disturbance signals cannot easily be separated from normal signals.
Examples of applications in which the solution described below for the suppression of disturbances can advantageously be used can be found, inter alia, in structures produced by micromechanics. A specific example is constituted by vibrating solid-state gyros, e.g. such as described in SE 8900666-2, in which two vibration modes whose amplitude differs by many powers of ten are used. The vibration having the larger amplitude is normally excited by electrostatic or piezoelectric means, at its mechanical resonance frequency, with a signal of the order of magnitude of about one or a few Volts. The amplitude of the lesser vibration provides a measure of the imposed rotation speed. A piezoelectric detection of this amplitude produces a signal in the order of magnitude of pA or nA where quartz is used as the piezoelectric material. The signal levels mean that even very small disturbing impedances produce an undesirably large disturbance signal superposed upon the detected signal. Since the disturbance signal can be expecte
REFERENCES:
patent: 3073973 (1963-01-01), Rodewald
patent: 4288741 (1981-09-01), Dechene
patent: 4346311 (1982-08-01), Aue et al.
patent: 4377842 (1983-03-01), Cambier
patent: 4481464 (1984-11-01), Noguchi
patent: 4947130 (1990-08-01), Kitayoshi
patent: 5251483 (1993-10-01), Soderkvist
patent: 5347870 (1994-09-01), Dosch
Ballato Josie
Colibri Pro Development AB
Solis Jose M.
LandOfFree
Method and device for electronic compensation of electrical dist does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and device for electronic compensation of electrical dist, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and device for electronic compensation of electrical dist will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2250248