Method for digital peak value measurement for ultrasonic test pulses

A method for measuring digital peak values of ultrasonic test pulses which comprises:

• operating within a high dynamic range with a predetermined pulse repetition frequency;
• applying, after linear amplification, a received signal to a measuring circuit having a window comparator circuit with two comparators;
• supplying a reference voltage stepwise by means of a D/A-converter to the window comparator circuit;
• forming a window with the two comparators, the window having a window width within a range of 105 to 110% of one voltage step of the stepwise reference voltage;
• periodically generating for an expected signal range a predetermined time slot;
• connecting the output of the window comparator to a memory means during the predetermined time slot, the memory means having bistable memory units for connecting each output of the two comparators;
• resetting the memory means at the beginning of the predetermined time slot;
• driving the D/A-converter with a digital counter which is clocked with a clock signal having the same frequency as the predetermined time slot, wherein the clock signal being derived from the predetermined time slot;
• controlling the direction of counting of the digital counter with the actual status of the bistable memory units connected to each of the comparators by setting the respective bistable memory unit if the comparators are triggered, and stopping the digital counter if the voltage of a peak value of the received signal is within the window formed by the two comparators;
• and
• processing a digital signal of a final count from the digital counter to provide a data output representing the measured digital peak value of the ultrasonic test pulses.