| 摘要 |
PROBLEM TO BE SOLVED: To prevent oscillation even in the case where characteristics of a speaker are fluctuated or varied, to suppress a distortion by continuously changing a control signal, and to reduce cost.SOLUTION: A driving device 100 includes an amplifier 10, a current detection section 11, and a drive control section 101 formed from a digital circuit. A current flowing to a voice coil of a speaker 1 is detected by the current detection section 11, A/D conversion is performed on a detection signal according to &Dgr;&Sgr; system by an ADC section 12, and down-sampling is performed by a DSF section 13. In an adjustment section 14, gain compensation, phase compensation and compressor processing are performed on a down-sampled signal and an output signal of the adjustment section 14 are added with a signal for which an input signal Vi to the driving device 100 is processed by a characteristic compensation filter 15, by an adder 16. The added signal is over-sampled by an OSF section 17, then D/A converted according to the &Dgr;&Sgr; system by a DAC section 18 and amplified, thereby driving the speaker 1. |
