| 摘要 |
PURPOSE:To obtain an automatic sound volume control method with low burden on control processing and capable of performing processing completely in real time. CONSTITUTION:A music signal outputted from an audio source 11 is outputted from a speaker 14 in an automobile compartment 15 via an electronic volume 12 and an amplifier 13. Sound in the automobile compartment 15 is detected by a microphone 16. A sound volume control part 20 performs the calculation of the following equation beta+mu{dX(t)/dt-betads(t)/dt}.dS(t)/dt by using an estimated magnification beta previously obtained while assuming a microphone detection signal as X(t), the music signal outputted from the audio source as S(t), the estimated magnification of the music signal in a microphone detection signal X(t) for S(t) as beta, and a prescribed constant as (mu), and obtains a new estimated magnification. The electronic volume 12 can be controlled based on difference between the estimated magnification beta obtained previously and the estimated magnification beta obtained newly at this time. |
