448 



MECHANICAL AND ACOUSTICAL SENSES 



Figure 18 Tunable ultrasonic telemetry receivers designed for use either in 

 boat or by divers underwater. Top: DuKane model N15A235A (DuKane 

 Corp., Ultrasonics Div., St. Charles, 111. 60174). Bottom: Burnett Model 512 

 (Burnett Electronics Lab., Inc., 7917 Balboa Ave., San Diego, Calif. 92111). 

 Both units tune from 30 to 45 kHz. 



