HOWLING SUPPRESSING DEVICE

摘要

PURPOSE:To attain the proper howling suppression with no excess nor deficiency of the suppression amount by attenuating in steps the signal of the band where the howling is generated. CONSTITUTION:A control circuit 21 compares the level a signal of each band with the level of the signals of the bands adjacent to said band. When the difference between levels of both signals exceeds a certain level of threshold value, the generation of howling is decided. Then either one of attenuators 22-24 corresponding to the band where the howling is generated is controlled to give a certain degree of attenuation. In case the howling is generated again at the same band, the howling is detected in the same way. Then a certain degree of attenuation is given to the attenuator corresponding to the relevant band. Thus the signals passing through said band are attenuated. The suppression of howling is continued until the total amount of attenuation reaches a certain level. Then the suppression of howling is finished when the number of bands where the degree of attenuation reaches a fixed value.