An ultrasonic signal drive/sense circuitry is provided, which circuitry is adaptable to a variety of automated or manual fastener tightening operations. This circuitry operates for measuring tension in a fastener as a function of change in time of flight of an ultrasonic wave. A microcontroller directs...http://www.google.com/patents/US5216622?utm_source=gb-gplus-sharePatent US5216622 - Ultrasonic drive/sense circuitry for automated fastener tightening
