Abstract: In a system for measuring torque, torsional vibrations and power, emitters and sensors are arranged on at least one rotating shaft. From one of the frequencies (f.sub.1 or f.sub.2) of the signals (S.sub.1 or S.sub.2) of the sensors, a new signal (S.sub.3) is generated whose frequency (f.sub.3) corresponds to the sum or difference frequency of the frequencies (f.sub.1, f.sub.2), and which is phase-locked to the signal (S.sub.1 or S.sub.2) from which it is generated. The relation of the initial phase of the new signal (S.sub.3) with the frequency-generating signal (S.sub.1 or S.sub.2) is determined also by the other signal (S.sub.2 or S.sub.1). The signals (S.sub.1, S.sub.2) and the new signal (S.sub.3) are fed to a multiplier. The measure of the torsion-dependent twist of the emitters with respect to each other, from which the torsional vibration signal can be derived, is determined by integration of the signal (S.sub.1.S.sub.2.S.sub.

Abstract: An arrangement for the production of straight-line symmetrical signals from at least two signal generators, which have a periodic structure and which are movable relative to one another, by means of sensors that generate signals corresponding to the position of the signal generators, wherein at least two sensors are provided for at least one of the two signal generators with the output signals of the two sensors being combined in a subtraction or addition stage. The two sensors are positioned to be offset with respect to each other by one half period of the structure of signal generator or by an integer multiple of such period.

Abstract: The circuit arrangement has a key for the serial feeding in of the code signals and is equipped with electronic arrangements for the storage of the code and for the processing of the signals. In the beginning or at the end of each sampling, a signal is produced and the temporal intervals between these signals are identified as "long", "medium" or "short." The sequence of these signal intervals, that is, the signal pauses, is compared with the stored code.Such a code may be remembered with particular ease as the rhythm of a song or as a melody and is accordingly very personal code. The feeding-in of the code and especially the decoding is acomplished "blindly", that is without return communication.In order to carry out the individual functions, separate construction stages or a microcomputer can be used.