| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce a quantization error when an analog signal showing the result of a measurement is converted to a digital signal. <P>SOLUTION: A controller 18 transmits an instruction to start the measurement to a pulse wave measuring instrument 2. A control circuit 21 controls a driving circuit 22 in response to the instruction. The driving circuit 22 applies voltage to a light-emitting element 23 under the control of the control circuit 21 and the light-emitting element 23 emits light when the voltage is applied. Light radiated from the light-emitting element 23 is reflected on a target 3 of the measurement and received by a light-receiving element 24. The light-receiving element 24 outputs an analog signal corresponding to the quantity of the received light to an amplification circuit 25. The analog signal amplified by the amplification circuit 25 is converted to an analog signal temporally differentiated through a differentiation circuit 26 and outputted to the analyzer 1. The A/D conversion circuit 111 of the analyzer 1 converts the analog signal outputted by the differentiation circuit 26 to a digital signal. An integration section 112 temporally integrates the value shown by the digital signal. <P>COPYRIGHT: (C)2012,JPO&INPIT |
