Abstract: A method and apparatus for continuously measuring and indicating the variations of the intensity of an electric signal, such as a signal to be recorded on a tape recorder, which provides measuring to take place at successive measuring periods in such a manner that a measured result is yielded representing the maximum value of the signal intensity. The signal intensity is measured during consecutive measuring periods and registered. The indicator has the ability to maintain the read-out of a maximum value, read during a measuring period, during a following hold period, whereby the measuring periods provided have a duration being an order of size less than the time of reaction of the human eye. The system stores the maximum intensity values being detected during each of a series of consecutive measuring periods, and provides hold periods having substantially longer durations by being an order of size longer than the time of reaction of the human eye.