| 摘要 |
PURPOSE:To change the directivity continuously from a sharp directivity to a wide stereophonic state by adaptive signal processing. CONSTITUTION:A sum signal SM of stereo signals SL, SR from a couple of unidirectional microphones 11L, 11R having a major sensitivity to the left and right respectively is fed to a subtractor circuit 18 as a major signal. A signal from a unidirectinal microphone 21 having a major sensitivity in the rear direction is fed to an adaptive filter 24 as a reference signal. The output of the adaptive filter 24 is subtracted from the sum signal Sm at the subtractor circuit 18 and an output of the subtractor circuit 18 is fed back to the adaptive filter to apply adaptive signal processing. The obtained adaptive processing signal SA and the stereo signals SL, SR are fed to a mixing circuit 14 comprising a couple of potentiometers 14L, 14R, to mix the signals at a variable ratio in response to the position of a slider operated by the user. |
