| 摘要 |
PURPOSE:To selectively switch a real time display mode, and a real time and maximum value holding display mode if necessary, by providing a means for switching a display mode. CONSTITUTION:Audio signals which is fed from input terminals 1a, 1b are supplied to maximum value holding circuits 30a, 30b and mean level detectors 29a, 29b through plural filters 2a, 2b connected in parallel. Subsequently, outputs of each holding circuit 30a, 30b and detector 29a, 29b are converted to pulse width signals corresponding to its level by comparators 32a, 32b, 31a and 31b, and after that, are supplied to multiplexers 5V, 5H, and are fetched serially at every frequency band. In this state, when a switch S7 is off, an output of the multiplexer 5V is supplied to an image receiving tube through an OR gate 34 and an adding gate 10, and a real time level is displayed. On the other hand, when the switch S7 is turned on, outputs of the multiplexers 5V, 5H are fetched from the OR gate 34, and a real time level and a maximum value level are displayed. |
