| 摘要 |
PURPOSE:To attain stable attenuation of an audio stereo signal with voice by detecting the presence of voice in a 2-channel signal and using a data near the distribution center of a phase difference data so as to control a delay means. CONSTITUTION:A 1st delay means 3 retards one of 2-channel signals for a prescribed time and a 2nd delay means 4 retards the other variably. The signals are inputted to a voice presence detection means 13 via 1st and 2nd band pass filter means 5, 6. The output of the means 5, 6 is inputted to a phase detection means 12, where a phase deviation is detected. A subtraction means 8 calculates the difference of outputs of the means 3, 4 and sends the result to a mixing means 10. A pitched sound detection means 9 detects a low pitched sound from the output of the means 3, 4 and gives the result to the mixing means 10. The means 10 mixes outputs of the means 8, 9 and outputs to apply phase control without disturbing the relation of phase in the part absent in the voice and with good tracking in the presence of voice thereby attenuating the audio signal stably at all times. |
