| 摘要 |
PURPOSE:To keep the input/output characteristic linear by giving a specific signal larger than the lower limit of a linear region to an offset analog input of one converter, giving the sum of the offset signal and the analog input signal to the other converter and using a difference of outputs of both the converters as an analog output signal. CONSTITUTION:An external analog signal input Ain and an analog signal input Yin constant and larger than an analog signal input Bin at the lower limit of a nonlinear region are fed to an input of a summing amplifier 1 as an offset voltage signal, where the signals are added. An output of the summing amplifier 1 converted into a value within a range of the signals Yin-Zin is led to the analog signal input of a multiplication type digital-analog converter 2a having an input/output characteristic. Further, the external digital input Din is led to the digital input of the multiplication type digital-analog converter 2a. The multiplication type digital-analog converter 2a outputs a corresponding analog signal output and is acted at the linear portion of the input/output characteristic curve in this case. On the other hand, the external digital input Din is led to the analog signal input terminal of another multiplication type digital-analog converter 2b.
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