Abstract: A method for dynamic testing of digital logic circuits includes the application of cyclically-occurring digital signals to the inputs of a logic circuit and identifying anticipated output values in comparison to the inputs. Blank or dummy cycles are introduced after a predetermined number of test cycles, the blank or dummy cycles having the character that modifications no longer appear at the input signals. The predetermined number of test cycles is greater than or equal to 2.

Abstract: A carrier frequency communication transmission system has a premodulation band above the transmission position of the base primary group of 60-108 kHz and utilizes mechanical filters as channel filters and also a common group filter in order to filter out the primary group band. Bending resonators having longitudinal coupling are utilized as the mechanical filters. The frequency range of the premodulation band at its lower limit is determined by a frequency spacing of at least 4 kHz from the upper band limit of the primary group band and the upper limit of the frequency range is determined in that the interfering natural oscillations, inasmuch as they occur in the lower stop band of the channel filter, lie at least 12 kHz below the lower limit of the primary group band. Highly stabilized piezo ceramics is used as the electromechanical transducer material.

Abstract: Received signal is filtered by a filter tuned to a predetermined harmonic the modulation frequency lying outside of the modulation region of the received signal. Such harmonic results from modulation distortion due to multipath reception. Output of filter is irregularly occurring pulse sequence which is converted to a constant signal which in turn energizes an indicator.