| 摘要 |
<p>PURPOSE:To accomplish a D/A conversion easily without using an A-D converter, by converting a digital signal in n-bit into an analog signal easily through the use of a transformer only. CONSTITUTION:A transformer 12 is provided, and primary coils 13a-13d corresponding to the bit number (n) of a PCM signal are wound and a secondary coil 14 is connected to a voice coil 1 of a spealer main body 10. In this case, the PCM signal is applied to each primary coil from output terminals 9a-9d, so that currents proportional to the weight 2<0>, 2<1>, 2<2> and 2<3> of each bit are supplied or the winding ratio of windings 9a-9d is selected to a value inversely proportional to the said bit weight when the same current is supplied. To the bits of 2<0>, 2<1>, 2<2>, 2<3>, the winding ratio is selected as 2<3>, 2<2>, 2<1> and 2<0>.</p> |
