| 摘要 |
PURPOSE:To enable to perform an easy visual observation of a waveform and bar graph, by a method wherein the change in the level of an input audio signal is converted into the change in a waveform and the change in the bar graph to simultaneously display them in a picture tube. CONSTITUTION:Audio signals reaching input terminals 1L and 1R are outputted to comparators 5L and 5R via buffer amplifiers 2L and 2R, full-wave rectifiers 3L and 3R and bias setters 4L and 4R, and are compared with a triangular wave signal (b) synchronized with a horizontal synchronizing signal. The comparison output is supplied to a picture tube 11 via a computer 8 and a composite circuit 9 to display a waveform. Meanwhile, the audio signal is supplied also to a spectrum indicating signal forming circuit 10, and a signal, divided into their respective distinct frequency bands, is converted into a pulse width signal corresponding to the level in synchronism with a vertical synchronizing signal. The pulse signal, time-divided in turn and fetched serially for the duration of a horizontal scanning period, is supplied to the composite circuit 9, and a spectrum signal is displayed as a bar graph. |
