| 摘要 |
<p>PURPOSE:To detect abnormality of source voltage reliably by digitally converting plural system vehicle source voltages inputted to an audio machinery and judging the input power source based on a logical sum output. CONSTITUTION:An on-board radio comprises a receiving antenna 1, a radio receiving section 2, an audio power amplifier section 3 and a speaker 4. Source inputs A, B are fed respectively through voltage regulating circuits 5, 7 to respective sections. Outputs from the voltage regulating circuits 5, 7 are connected through shaping circuits 6, 10 to an OR gate 11, and inputted to a control section 9. Upon droppage of power from any one power source, an output is produced from the OR gate 11 and the control section 9 detects abnormality.</p> |
