Gebr. Hofmann Kg

Friedrich Wenz

A method and apparatus for testing the uniformity of a rotary body whereby an electrical analysis signal is produced by travel measuring or force measuring transducers having an amplitude which varies as a function of the non-uniformities, multiplied by a direct current signal which varies as a function of the speed of rotation of the body to produce a further signal which is then integrated to provide the Fourier coefficients of the Fourier development series of the analysis signal.

Method and apparatus for testing the uniformity of a rotary body

An electrical circuit for digitally displaying an input electrical signal to minimize fluctuations in the output and maximize the speed of response to changes in the input signal whereby the input signal is applied to a first low pass filter and a second low pass filter having both a lower threshold frequency and a slower response time to changes in the input signal than the first filter. The outputs of the two filters are applied to a differential amplifier to produce a differential signal which is applied via a pair of serially and oppositely connected Zener diodes to the output of the second filter, which is also connected to the digital display, to cause rapid response to signal changes. The frequency of a unijunction oscillator is also controlled by the differential signal to increase the measuring rate of the digital display whenever the input signal charges by more than a predetermined value.

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Seeheim, Germany

Friedrich Wenz