CASCADE A/D CONVERTER

PROBLEM TO BE SOLVED: To perform linearity adjustment at high speed in simple circuit configuration by finding an adjustment quantity through a detecting means by determining a circuit to be adjusted on the basis of the output of an analog multiplexer circuit, and adjusting a subtracter or D/A converter on the basis of the output of the detecting means. SOLUTION: Outputs from the analog multiplexer are converted by an A/D converter 21, selected by a multiplexer circuit 22 on the basis of the timing of a control signal 103 and successively stored in storage circuits 23a-23c. The multiplexer circuit 22 is controlled so as to fetch the output of the analog multiplexer circuit at the time of a value at the prescribed position of an analog input signal as the control signal 103. An arithmetic circuit 24 successively reads values stored in the storage circuits 23a-23c, determines the circuit to be adjusted and finds the quantity of that adjustment. Plural D/A converters 25a-25f for supplying an adjust signal to the circuit to be adjusted are controlled and the found adjustment quantity is impressed to this circuit.