Ultrasonic received signal insertion point definition circuit - examines RAM contents with regard to signal period and corrects cycle length value

摘要

The circuit defines the insertion time point of an ultra sonic received signal in which the signal is input to two voltage comparators (6, 7) with different thresholds. A cycle signal and a period signal are produced which act as a gating signal for a cycle (21) and period length counter (16). The cycle length counter (21) output addresses a RAM (22) in which is stored a binary value for the received signal. After the cycle length is measured, the contents of the RAM (22) are examined with regard to the period of the signal, and the cycle length value is corrected accordingly. USE/ADVANTAGE - For ultra sonic measuring devices where only minimal temporal error in relation to sound wave length is permissable. No need for special command to transducer or special operation of transmitter or receiver.