| 摘要 |
PROBLEM TO BE SOLVED: To improving the sharpness of speaking voices, to suppress the increase of background noises and to attain reduction in the generation probability of howling by collecting sounds through plural sound collecting elements, independently controlling the gains of respective transmission voices converted to digital signals by converters and stabilizing the speech state of line. SOLUTION: Analog signals respectively inputted from plural sound collecting elements 12 are converted to digital signals by plural converters 13 and a power operation circuit 14 calculates the average power in movement between respective blocks of digital signals outputted from the converters 13. Then, a voice detection circuit 15 detects the presence/absence of voice with the block move average power as an evaluation signal, a gain multiplication circuit 17 compares the block move average power of voice section detected by the voice detection circuit 15 between the respective sound collecting elements and multiplies the gain adaptive to its power ratio to each converter, and an adder circuit 16 synthesizes the respective digital signal inputs. Thus, the relation of input signal levels is made clear and there is not influence caused by unwanted indirect voices or background noises. |
