| 摘要 |
PURPOSE:To obtain a sound signal whose cross modulation distortion is reduced by converting a PCM audio signal into a PWM signal and giving the converted signal directly to each voice coil of the speaker and to facilitate the assembly by relaxing the accuracy of number of turns of each voice coil. CONSTITUTION:A PCM voice signal is given to a noise shaping code converter 11, in which the signal is converted into a PWM signal. The PWM audio signal is given to delay devices 12a, 12b,...12m connected in cascade. When a PWm pulse current flows from a connecting point of each delay device to voice coils 15a, 15b,...15n formed to a moving body 14, an audio signal from which a high frequency noise component at the outside of the voice band is eliminated is sounded from a speaker main body 13. |
