| 摘要 |
PURPOSE:To expand a dynamic range, and to obtain an excellent logarithmic characteristic with a few differences by providing plural logarithmic both wave rectifiers inputting the voltages of the input terminal at a first stage and an output terminal at each stage of a differential amplifier and outputting a current having a logarithmic both wave rectifying characteristic to this voltage respectively, and an adder adding the output current of these plural logarithmic both wave rectifiers and outputting a signal corresponding to this added current. CONSTITUTION:Plural logarithmic both wave rectifiers 21-2(m+1) are provided to the output terminals at each stage, input the volgates of the input terminal at the first stage and the output terminals at each stage of these differential amplifiers 11-1m, and output a current IRSJ (J=1-m+1) having the logarithmic both wave rectifying characteristic to this voltage respectively. An adder 3 adds the output current IRSJ of the plural logarithmic both wave rectifiers 21-2(m+1), and outputs a signal (V0) corresponding to this added current. And, the adding means of each logarithmic both wave rectifier 2J(J=1-(m+1) forms first and second current mirror circuits of each squared both wave rectifier by a pair of first and second current mirror circuits 40A and 40B common to these squared both wave rectifiers. |
