OUTPUT DATA CALIBRATING CIRCUIT

摘要

PURPOSE:To calibrate a level and an amplitude of an output signal to a reference value by adding an input signal and a calbrating signal and inputting the result to an input signal terminal of a comparison amplifer circuit. CONSTITUTION:A reference level Va is connected to one input (g) of two inputs (f), (g) of a comparison amplifier Q via a resistor Ra. An input signal S is given to the input terminal (f) via a variable resistor Rs. A feedback resistor Rf connects an output O and the input terminal (f) to which an input signal S and a a calibratig signal C are connected. A signal whose DC component is zero is used as the calibrating signal C. The average value <S> of the calibrating signal C and the input signal is divided by resistors Rs, Rc and inputted to the input terminal (f). A maximum value Cmax and a minimum value Cmin of the calibrating signal C are specified in advance and the variable resistors Rs, Rc, the offset of the amplifier circuit Q or the amplification factor is adjusted while observing an output waveform so that the relation of <S>=(Smax+Smin)/2 is obtained at the output O.