| 摘要 |
#CMT# #/CMT# The converter has a buffer (OP1) and an amplifier (OP2) that are integrated between a charging/discharging capacitor (C1) and a comparator (OP3), where the buffer separates the amplifier from the charging/discharging capacitor. An amplification of the buffer and the amplifier is switched with an analog switch (S5). Analog switches (S1-S3) are provided for switching of different input voltages. A microcomputer (MC1) is provided for implementing addition, subtraction, multiplication and division process to measure the voltages. #CMT#USE : #/CMT# Logarithmic analog-digital converter for use in a photometry. #CMT#ADVANTAGE : #/CMT# The buffer and the amplifier are integrated between the charging/discharging capacitor and the comparator, such that large measuring range of the analog-digital converter is achieved. The amplification of the buffer and the amplifier is switched with the analog switch, such that the measuring range can be adapted to the different input voltages, thus reducing measurement period of the voltage. The converter is designed in such a manner that offset error of the comparator does not influence on the measurement. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a schematic circuit diagram of a logarithmic analog-digital converter. C1 : Charging/discharging capacitor MC1 : Microcomputer OP1 : Buffer OP2 : Amplifier OP3 : Comparator S1-S5 : Analog switches. |
