Abstract: An eddy current sensor (1) has at least one measuring coil (2) that can be supplied with an alternating current, and an evaluation circuit (3). The eddy current sensor allows the temperature influences on the impedance of the measuring coil to be reliably compensated with a simple design and an evaluation circuit. For this purpose, the eddy current sensor has a compensating coil (4) which can also be supplied with an alternating current and which is arranged closely to the measuring coil, i.e. in thermal contact therewith, in such a way that the electric fields of compensating coil (4) and measuring coil (2) are orthogonal to each other. More particularly, the measuring coil (2) is in an annular form and the compensating coil (4) is wound around the measuring coil in the form of a torus.
Type:
Grant
Filed:
February 2, 1999
Date of Patent:
September 11, 2001
Assignee:
Microepsilon Messtechnik GmbH & Co. KG
Inventors:
Roland Mandl, Felix Mednikov, Mark Netschaewsky, Karl Wisspeintner
Abstract: There is provided a speed and position signal generator which operates irrespective of mechanical error, and also operates without any delay of signal transmission. The speed and position signal generator generates A, B phase pulse signals corresponding to a frequency set value and direction setting, and outputs these two phase pulse signals and a Z phase pulse signal corresponding to a teeth number set value, and includes a reference clock generator as a reference, a frequency arithmetic operation circuit, a frequency division circuit for frequency dividing an output phase train from the frequency arithmetic operation circuit, an A, B phase generation circuit for generating A, B phase pulse signals using the frequency division signal, and a Z phase generator circuit for generating a Z phase pulse signal.
Abstract: A method of analyzing defects in a magnetic thin film is provided. A magnetic field is applied to the magnetic thin film. The magnetization of the magnetic thin film is measured over a range of different field strengths. A value representative of a magnetic hardness coefficient is calculated for the magnetic thin film from the magnetizations measured. The calculated value is compared with a reference value. Defect information is determined in dependence upon the comparison made.
Type:
Grant
Filed:
August 20, 1999
Date of Patent:
March 13, 2001
Assignee:
Data Storage Institute
Inventors:
Jian-Ping Wang, Lea Peng Tan, Thomas Yun Fook Liew
Abstract: A method and device for calculating vehicle wheel speed which counts either one of the rise or the fall of each one of the pulse signals of the wheel sensor when the wheel speed is higher than a certain amount and counts both the rise and the fall of the pulse signals when the wheel speed is lower than the certain amount. This invention reduces the calculation time for the vehicle wheel speed.