| 摘要 |
PURPOSE: To reduce the acoustic deterioration of sound quality and to cope with the comparatively high frequency by providing a phase shift means which applies the phase shift processing to the sound signals if the howling is detected by a detection means. CONSTITUTION: The sound signals are supplied to a BPF 3-1 to 3-n which extract only each precribed component of the sound signals. The howling detection members 4-1 to 4-n detect whether the input narrow band signals have the howling. If the howing is detected, a detection signal HD is outputted. Receiving the signal HD, the phase shift members 5-1 to 5-n apply the phase shift processing to the input sound signals by every necessary extent. The one-round transmission function of an audio system is created by the frequency having its gain of 1 or more and its phase characteristic 0 deg.. Thus it is possible to suppress the howling by changing the phase condition of the frequency and also to reduce the deterioration of sound quality since the human acoustic sense is not sensitive to the phase condition. |
