Landis & Gyr Betriebs Ag

Lgz Landis Gyr Zug Ag

Beat Halg

Radivoje Popovic

Thomas Seitz

Jacob De Vries

Walter Trachslin

Beat Furrer

A calibration process utilizes two nearly identical sensors. The characteristic output curve of the first sensor is obtained using the measuring outputs of the second sensor. In particular, the first sensor has a characteristic output curve f[x] where x is a physical variable to be measured. The second sensor has an output curve y[x].apprxeq.f[x+a]. Starting from an initially known portion of the curve f[x], outputs of the second sensor are utilized to extend the known portion of the characteristic output curve f[x] of the first sensor into ranges of the variable x where this function is not yet known.

Process for automatic calibration or re-calibration of measurements of a

A device for optically measuring a pressure difference in a medium by means of a Fabry-Perot interferometer, comprises a transparent plate and a diaphragm block connected to the transparent plate, the diaphragm block comprising a substrate, a measuring diaphragm formed along the inner surface of the substrate, and a spacer separating the inner surface of the transparent plate and the inner surface of the substrate. A first planar mirror is disposed on the inner surface of the plate and a second planar mirror is disposed on the inner surface of the measuring diaphragm so that they constitute the Fabry-Perot interferometer. The measuring diaphragm is shiftable by a distance (H) in response to a pressure difference (.delta.p) exerted on inner and outer surfaces of the measuring diaphragm whereby the optical length (L) of the Fabry-Perot interferometer changes as a function of the pressure difference (.delta.p). The substrate includes a depression on one side only so that the material remaining under the depression is of a predetermined thickness and comprises the measuring diaphragm. Since the measuring diaphragm constitutes a portion of the substrate and is a continuation of the crystalline structure of the substrate, there are no mechanical stresses at the joining points of the substrate and the measuring diaphragm. Preferably, the measuring diaphragm constitutes a doped layer of the substrate and serves as an etching barrier for the substrate.

Device for optically measuring a pressure differential

A device for measuring a magnetic induction comprises an evaluation device including a source for emitting light and a receiver for receiving light. A resonator is located in the light path between the source and the receiver and comprises first and second parallel mirrors and a gaseous medium occupying the space between the two mirrors. A converter is coupled to one of the mirrors for shifting one of said mirrors along an optical axis of the resonator so that the optical length of the resonator varies in response to the induction to be measured.

Optical device for sensing magnetic inductions

An arrangement which eliminates or reduces the negative influence of small variations in the charge-carrier concentration of a semiconductor material upon the longterm stability of a magnetic field sensor such as a Hall element is disclosed. In an illustrative embodiment, the arrangement comprises a magnetic field sensor, a voltage/current converter which provides a supply current to the magnetic field sensor, an amplifier connected sequentially downstream of the voltage/frequency converter, and an analog/digital or voltage/frequency converter connected sequentially downstream of the amplifier. The amplifier provides a transmission ratio which is proportional to (1+.delta.n/n) or (1-.delta.n/n) where n is the carge-carrier concentration of the semiconductor material in which the magnetic field sensor is formed and .delta.n is a variation in time of the charge-carrier concentration n. The amplifier comprises an inverting amplifier which is formed using an operational amplifier, a feedback resistor and an input resistor. The amplification factor of the amplifier is proportional to the ratio of the resistance values of the two resistors which are incorporated by diffusion in a semiconductor body near the magnetic field sensor. The charge-carrier concentration in one of the two resistors is preferably identical to the charge-carrier concentration (n) in the magnetic field sensor and the charge-carrier concentration in the other resistor is equal to a multiple of the charge-carrier concentration (n). The factor (1+.delta.n/n) or 1-.delta.n/n) compensates for changes in the output voltage of the magnetic field sensor resulting from the variations in the charge-carrier concentration in the magnetic field sensor.

Arrangement for improving the longterm stability of a Hall element

An arrangement for reducing piezo-electric effects in piezo-electric effect sensitive electrical components formed in a semiconductor body is disclosed. The piezo-electric effect sensitive component or components are located in a particular zone of the semiconductor body. The semiconductor body is in general mounted on a support. However, the zone of the semiconductor body containing the piezo-electric sensitive component or components is not attached to the support but instead is separated from the support by a space. The presence of the space results in a certain degree of mechanical isolation of the part of the semiconductor body which contains the piezo-electric effect sensitive components, whereby the negative influence of the piezo-electric effect on the long term stability of an instrument utilizing the semiconductor body is reduced.

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Cham, Switzerland

Beat Halg