Sonar calibrator

Claim 1

AN ECHO-RANGING SYSTEM CALIBRATOR COMPRISING IN COMBINATION, A TRANSDUCER, SAID TRANSDUCER BEING ADAPTED TO TRANSMIT AND RECEIVE WAVE ENERGY OF A PREDETERMINED FREQUENCY RANGE, AN OSCILLATOR GENERATOR CONNECTED TO SAID TRANSDUCER ADAPTED TO GENERATE SIGNALS WITHIN SAID PREDETERMINED FREQUENCY RANGE, A RECEIVER CONNECTED TO SAID TRANSDUCER ADAPTED TO RECEIVE SIGNALS WITHIN SAID PREDETERMINED FREQUENCY RANGE, SAID OSCILLATOR GENERATOR AND SAID RECEIVER INCLUDING A COMMON TRANSISTOR AMPLIFIER, MEANS CONNECTED TO SAID OSCILLATOR GENERATOR AND SAID RECEIVER FOR INDICATING THE MAGNITUDE OF THE SIGNALS TRANSMITTED AND RECEIVED THEREBY RESPECTIVELY, MEANS COUPLED TO SAID OSCILLATOR GENERATOR, RECEIVER, AND COMMON TRANSISTOR AMPLIFIER FOR SUPPLYING ELECTRICAL POWER THERETO, A THERMISTOR INTERCONNECTING THE TRANSISTOR AMPLIFIER COMMON TO SAID OSCILLATOR GENERATOR AND RECEIVER AND SAID INDICATOR MEANS FOR TEMPERATURE COMPENSATION THEREOF, THEREBY SUBSTANTIALLY ELIMINATING INDICATING ERRORS DUE TO VARYING AMBIENT TEMPERATURES, SELECTOR MEANS COUPLED TO SAID OSCILLATOR GENERATOR AND SAID RECEIVER FOR ACTIVATING ONE AND DEACTIVATING THE OTHER AS DESIRED, ADJUSTABLE MEANS INTERCONNECTING SAID TRANSDUCER AND SAID SELECTOR MEANS FOR APPROPIATELY BIASING SAID AMPLIFIER WHEN SAID RECEIVER IS ACTIVATED, AND MEANS COUPLED BETWEEN SAID POWER SUPPLY MEANS AND THE AFORESAID INDICATING MEANS FOR RESPECTIVELY ENERGIZING AND DEENERGIZING SAID OSCILLATOR GENERATOR AND RECEIVER MEANS SIMULTANEOUSLY.