Abstract: A voltage controlling transformer circuit comprises a setting unit to the input terminals of which an alternating input voltage is applied and the output terminals of which provide an alternating output voltage the amplitude of which can selectively be changed. For this purpose the setting unit comprises a transformer having a first winding connecting one of the input terminals with one of the output terminals while the other input terminal and the other output terminal are directly connected by a conductor. The transformer also comprises at least one further winding the number of turns of which is greater than the number of turns of the first winding, and to which different control voltages can be applied by means of switches in order to induce in the first winding a voltage the amplitude of which is, in dependence on the winding sense of the further winding, either additionally or subtractively imposed on the amplitude of the input voltage.

Abstract: The distance of a target object is determined from the time of travel of a measuring light pulse which is emitted by a transmitter toward the target object, reflected thereby and received by a receiver. In timed relation with the instant of generation of the measuring light pulse, a start signal for beginning a measuring signal transit time measurement is generated, and, on receipt of the reflected measuring light pulse, a stop signal is generated for terminating this time measurement. A completely independent reference light pulse is generated and forwarded along a reference light path establishing a predetermined time of travel from the transmitter to the receiver, and the respective reference signal transit time is measured which contains the same undesirable additional time spans contained in the measured transit time of the measuring signal.

Abstract: The invention provides a method and an apparatus for determining the difference between the transit times of measuring pulse signals from a transmitter to a receiver along a measuring signal path establishing an unknown time of travel which is representative for a physical quantity of interest, and the transit times of reference pulse signals generated by the same transmitter and forwarded to the same receiver along a reference signal path establishing a known, constant time of travel, whereby for the measurement of each of said transit times the time distance between a trigger signal triggering the generation of the respective measuring pulse or reference pulse signal and a time-significant signal is measured which is generated in a defined time relation to the instant at which the respective pulse signal is received by said receiver.

Abstract: The invention provides a distance measuring apparatus for determining the distance of a target object as a function of the transit time of a measurement light pulse which is emitted by a transmitter in the transmission portion of the apparatus towards the target object, reflected thereby and received by the receiving portion of the measuring apparatus and for attainment of superior measurement accuracy the intensity of the measurement light pulse is correlated to the distance and reflectivity of the target object as well as to the "transparency" of the transmission medium between the measuring apparatus and the target object, such correlation being effected by optical damping of either the transmitted light pulses and/or the reference light pulse and/or the light pulses reflected by the target.