digitalized detection circuit as an envelope detector of an analog input signal is disclosed this circuit includes an analog to digital converter converting the analog input signal into first digital data storing means for storing second digital data to be outputted and a comparator comparing the first and second digital data when the first digital data is equal to or larger than the second data the first digital data is supplied to the storing means and when the former is smaller than the latter the storing means receives cyclically third data that is the second data minus a predetermined value a digitalized peak or bottom envelope detector is thereby obtained application_number US 93790086 A description fig1 shows an envelope detector according to an embodiment of the present invention an analog input signal a in is supplied via an input terminal 1 to an analog to digital converter called hereinafter an 34 a d converter 34 2 the a d converter 2 converts the analog signal a in into digital data of four bits construction in synchronism with a first clock pulse train u03c6 1 supplied to a clock terminal u03c6 thereof the converted digital data is supplied to a register 3 and a comparator 4 the register 3 introduces the supplied digital data in.