| 摘要 |
<p>PURPOSE:To convert a PCM signal directly into acoustic energy and to obtain high performance and simplicity of the acoustic device, by switching an electronic switch with a control pulse corresponding to the PCM signal and driving a plurality of voice coils. CONSTITUTION:A 4a-i is a voice coil with the same number of windings, a 4b-i is a control switch for a voice coil current, and a 4c-i is a power supply and they are constituted with a weight corresponding to each pulse of a PCM signal. When each pulse is (0), all the switches are at off-state. When all pulses are at (1), each switch is at on-state and a current flows to all voice coils and a driving force is maximum. When only a coil 4a-1 is at on-state and others are at off-state, a current of 2<0>.E only flows to the voice coils, which shows a minimum driving force. The driving force corresponds to the PCM signal by controlling the switches to the PCM signals. As the switches, electronic switches such as transistors can be used as shown in figure.</p> |
