Timer start-pulse generator is fast series-transistor coincidence circuit. Slop-gate generator is one-shot mvbr that prevents 1N97A diode from passing blocking oscillator negative sync pulse until mvbr fires. Used to count number of sing-around cycles and measure total time in system for measuring ultrasonic velocity in liquids and solids. -R. L. F
orgacs, Precision Ultrasonic Velocity Measurements, Electronics, 33:47, p 98-100.