Method for digitally measuring the peak value of ultrasonic test pulses

摘要

These pulses have a predetermined pulse repetition rate. After amplification, the input signal to be measured is supplied to a window comparator (3), the window size of which corresponds to one voltage step of a reference voltage which is variable in steps and is supplied by a D/A converter (11), and the output of which is connected, within a predetermined periodically generated time slot for the time interval in which the signal is expected, to a memory which is reset at the beginning of the time slot. The D/A converter is controlled by a digital counter (10), the direction of counting of which is controlled in dependence on the memory content and which is stopped in the case of equality between the received signal within the time slot and the respective reference voltage. The indication is derived from the final count. The clock signal for the digital counter has the same frequency as the time slot and is derived from it. <IMAGE>