Wandel & Goltermann Management Holding Gmbh

Wandel & Goltermann Elektronische Messtechnik Gmbh

Helmut Keller

A warning and measuring device for personal protection with a rod-shaped casing shape. The shape of the casing allows the device to be suitable 1. for measuring if held in the hand or mounted on a tripod, 2. for warning when carried on the body and 3. for leak detection in hollow conductors. This is made possible through a compact construction and a movable absorber which in an absorber package within a cap can be fitted to the casing while the cap is detachable and can be used as handle on the other end. The device can be economically manufactured and with regard to quality can be considered a high-quality measuring instrument.

Warning and measuring device for personal protection in electromagnetic

A method of null balancing a hand field-strength meter is described in which the effect of the measurement probe on the balancing is suppressed by short-circuiting the measurement probe by two MOS-FETs connected in series across the probe outputs so that the null balancing can be performed when the field-strength meter is located in the vicinity of a high strength field. In a preferred embodiment of the null balancing circuit for the meter another circuit branch consisting of two other complimentary MOS-FETs connected in series with each other is connected in parallel across the first two MOS-FETs via two resistors R1,R2.

Battery-operated hand field-strength meter and method of null balancing

In a method of improving a distortion ratio of an analog-to-digital converter, an analog signal to be digitized is additively superposed with a band-limited noise signal. The thusly produced sum signal is supplied to the analog-to-digital converter for sampling and quantization.

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Pfullingen, Germany

Helmut Keller