| 摘要 |
PURPOSE:To allow the use of an inexpensive A/D converter of a low resolving power (>=10 bits) by biasing an analog input signal with a D/A converter in such a manner that the A/D conversion of the previous time is the center of the reference voltage in the A/D converter. CONSTITUTION:The electrocardiogram signal detected from an electrode mounted to a person to be detected is amplified by a differential main amplifier section 1. The electrocardiogram signal outputted therefrom is subjected to A/D conversion by the A/D conversion section 3. The difference between the conversion data obtd. therefrom and the center of the reference voltage 8 in the A/D converter 3 is calculated in a computing section 4. The output of a differential amplifier 2 is biased by the D/A converter 6 to the center of the reference voltage 8 according to the digital data obtd. therefrom. On the other hand, the output of the computer 4 is delivered as the result of the analysis and is stored into a memory section 5. Only the difference from the data of the previous time is inputted to the A/ D converter 3 and the reference voltage 8 thereof is dropped. |
