| 摘要 |
<p>PURPOSE:To generate acoustic pressure with fidelity and high accuracy in response to a digital signal, by providing a driving force generating part in accordance with each bit of a parallel digital signal input, and also making magnitude of each driving force correspond to weight of each bit. CONSTITUTION:To a bobbin 1 connected to a diaphragm 2, coils L0-L3 corresponding to each bit of a digital signal are wound round, and the number of winding of these coils corresponds to weight of each bit, for instance, is 1, 2, 4 and 8. Each one end of the coils L0-L3 is connected to each other and also is connected to the + side of a DC power source E through a variable resistance VR, and the other end is connected to the - side of the power source E through analog switches S0-S3, respectively, which are turned on and off depending on a state of a corresponding bit of the digital signal. The bobbin 1 to which these coils L0-L3 have been wound round are placed in the magnetic air-gap of a magnetic circuit for generating a magnetic field in the direction falling at right angles with the coils.</p> |
