| 摘要 |
PURPOSE:To simply vary the direction of the directivity of voice by giving one of outputs of 1st and 2nd microphones to a delay circuit via a changeover switch while being provided with a prescribed distance in the forward/backward direction to the video camera and giving the other output to an input terminal of an arithmetic circuit so as to apply arithmetic operation to both microphone outputs switchingly. CONSTITUTION:Suppose that the 1st and 2nd microphones 5, 6 have the same and prescribed directivity and the identical sensitivity. The microphone 5 is placed before the microphone 6 by a prescribed distance. For example, in a video camera 4, the directivity of the two nondirectional microphones is synthesized to offer a cardioide characteristic (a characteristic expressed in equation of 1+costheta, the value of equation is 2 at theta=0 and 0 at theta=180 deg.). Then the changeover switch 7 is operated to switch the direction of the combined directivity by 180 deg.. Thus, the operator of the video camera 4 can select whether the voice from an object, that is, forward sound is to be recorded or the narration of the operator itself is to be recorded with priority by having only to operate the switch. |
