| 摘要 |
PURPOSE:To achieve a fast measurement and fast data output with a simple construction as well as without lowering the sensitivity, by performing an arithmetic processing of the output of a detector once converted into digital from analog after a log conversion thereof. CONSTITUTION:A reference cell is set on a cell section 2 and switches S1-S3 are turned to the R position. A reference intensity signal R obtained with a preamplifier 5 and a sample holding circuit 6 is converted 8 into a digital signal after converted into a Log R with a log amplifier 7 to be memorized into a memory 9. Then, a sample cell is set on the section 2 and the switches S1-S3 are turned to the S position and a sample light intensity signal S obtained with the amplifier 5 and the circuit 6 is converted into a Log S with the amplifier 7 to be introduced to one input terminal of a subtraction circuit 11. On the other hand, synchronizing the wavelength of the sample measurement, the signal of the memory 9 is returned to the original Log R with a D/A converter 10 to be introduced to the other input terminal of the circuit 11. Thus, information on the absorbance as difference between the log value and the Log S is obtained and is fed to a computer after converted 8 into a digital signal via a sensitivity switch 12 to obtain a desired absorbance data. |
