A digital amplifier, a reference voltage generator for reducing a DC component of an amplified pulse width modulated signal of a digital amplifier, and a method of reducing a DC component of an amplified pulse width modulated signal applied to an input node of a load are described in this disclosure. The user memory verifies validity by simple memory readingwriting functions, thus increasing processing speed. Consequently, when acceleration is applied, torsional vibrations act on the spring material. The wire is connected, through a gap formed by the first cut-and-raised portion between the motor cover and the base member and through the second cut-and-raised portion, to the substrate portion. The magnetic layer is typically used in conjunction with an inner shield armor layer to absorb the diffused jet after passing through the magnetic layer.