PURPOSE: To analyze and reconstitute source analog signals by detecting the maximum points and minimum points of respective signals and recording a time between the pair of the respective adjacent maximum point and minimum point.

CONSTITUTION: Analog input signals Vin are applied to a low-pass filter 2 and the output of the filter 2 is sent to the input terminals of a positive tracking holding device 4 and a negative tracking holding device 5. The outputs 10 and 11 of the holding device 4 are sent to a positive gradient comparator 6 and the outputs 12 and 13 of the holding device 5 are sent to a negative gradient comparator 7. The holding devices 4 and 5 and the comparators 6 and 7 detect relative maximum and minimum within the signals Vin and a positive gradient timer 8 and a negative gradient timer 9 measure the duration time of both positive and negative gradients of the signals Vin. A microprocessor 35 stores the gradient time of the signals Vin and amplitude data in a RAM 36. Thus, the signals Vin are analyzed and reconstituted.