Deutsche Forschungsanstalt Fur Luft-Und Raumfahrt E.v.

Oliver Mayer

Volker Tank

Peter Haschberger

Helmut Dietl

Erwin Lindermeir

Rainer Thiessen

A method for measuring and determining a rotation angle of a rotating object in which a clock track corresponding to a desired angular resolution is applied on a magnetic, optical or optomagnetic storage medium. The storage medium is then rotated synchronously with the rotating object, and during the operation a pulse sequence corresponding to the clock track is read from said storage medium. The read pulse sequence is then supplied for further processing to following electronics in which the actual rotation angle is firstly stored in a FIFO memory and secondly directly available for further uses. Furthermore, the invention provides an apparatus for measuring and determining a path difference in Michelson interferometers in which path difference are generated via a rotary movement, for example of a rotating retroreflector. A memory medium is rigidly connected to the rotation shaft of the rotating retroreflector generating a path difference and on said medium a clock track corresponding to the sampling theorem is applied and during the rotation movement is read by a read head fixedly associated with the storage medium. During operation said pulse sequence is read by the read head and supplied to following signal electronics in which from the pulse sequence the desired clock pulse and thus the path information is then obtained.

Method for measuring and determining a rotation angle of a rotating

A method and an apparatus are provided for determining a path difference in a Michelson interferometer which comprises at least one reciprocably moving mirror element and an analog to digital converter, and which is provided for the determination of an electromagnetic spectrum without a laser having to be permanently used for that purpose. On the contrary, magnetic, optical and optomagnetical storage media are arranged parallelly to the travel path of the mirror element of the interferometer. A clock track is written on the storage medium in accordance with the sample theorem. In operation a pulse sequence derived from the clock track is read by a read head mounted on the movable mirror element and the desired clock pulse and thus the path information is derived therefrom.

Method and apparatus for determining a path difference in a Michelson

In a Michelson interferometer for producing optical path differences, from a beam divider, a deflection mirror, an externally silvered corner mirror, a collective lens and a radiation detector an input/output module is formed, from two rotating retroreflectors and two stationary retroreflectors an intermediate module is formed, and from two further rotating retroreflectors and from a bilaterally silvered plane-parallel plate a termination module is formed. The three modules can be combined to an interferometer in such a manner that the plane mirrors of the corner mirror of the input/output module are each arranged opposite a respective input-side half of the two rotating retroreflectors of the intermediate module and between said reflectors which in turn are arranged directly next to and adjacent the two further rotating retroreflectors of the termination module in such a manner that the output-side aperture halves of the two stationary retroreflectors are aligned opposite the input-side aperture halves of the two further rotating retroreflectors of the termination module. In operation the respective adjacent rotating retroreflectors of the modules fixedly connected to each other in exact match rotate in-phase with respect to their rotational angle position and in opposite phase of 180.degree. with respect to the corresponding opposite retroreflectors.

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Neubiberg, Germany

Oliver Mayer