摘要 |
<p>A speech amplifier circuit increases the maximum perceived loudness at the speaker (412) and reduces distortion at high volume levels without increasing the power consumed by the speech power amplifier (410). When a low volume is selected by the volume control (414), the microcomputer (418) sets the step attenuator (406) at a correspondingly high attenuation level and the high-pass filter (408) is bypassed. As the volume control (414) is advanced and the speech power amplifier (410) is 12dB into clipping, the microcomputer (418) activates the high-pass filter (408) and simultaneously steps the gain of the step attenuator (406) by 6dB.</p> |