Electro-mechanical tone oscillator having fast rise time

Claim 1

A TONE OSCILLATOR INCLUDING IN COMBINATION, AMPLIFIER MEANS HAVING INPUT AND OUTPUT CIRCUITS, A MECHANICALLY RESONANT VIBRATORY STRUCTURE RESPONSIVE AT A GIVEN FREQUENCY AND HAVING A PREDETERMINED REACTION TIME, INDUCTANCE MEANS COUPLED TO SAID VIBRATORY STRUCTURE AND INCLUDING A DRIVING COIL CONNECTED TO SAID OUTPUT CIRCUIT, SAID INDUCTANCE MEANS HAVING A PORTION CONNECTED TO SAID INPUT CIRCUIT TO APPLY THERETO SIGNALS DERIVED FROM THE VIBRATORY STRUCTURE TO THEREBY FORM AN OSCILLATING CIRCUIT, SAID AMPLIFIER MEANS INCLUDING A CONTROL CIRCUIT FOR CONTROLLLING THE GAIN OF SAID OSCILLATING CIRCUIT BETWEEN AN INITIAL RELATIVELY HIGH LEVEL AND A RELATIVELY LOW OPERATING LEVEL, AND SWITCH MEANS CONNECTED TO SAID CONTROL CIRCUIT AND OPERABLE TO CAUSE OPERATION OF SAID OSCILLATING CIRCUIT AT THE INITIAL LEVEL, SAID CONTROL CIRCUIT INCLUDING MEANS CONNECTED TO SAID SWITCH MEANS AND FORMING A DIRECT CURRENT PATH IN WHICH CURRENT FLOWS UPON OPERATION OF SAID SWITCH MEANS TO CAUSE SAID CONTROL CIRCUIT TO REDUCE THE GAIN OF SAID OSCILLATING CIRCUIT TO THE OPERATIVE LEVEL, SAID CONTROL CIRCUIT FURTHER INCLUDING DELAY MEANS TO DELAY THE REDUCTION IN THE GAIN OF SAID OSCILLATING CIRCUIT TO THE OPERATING LEVEL UNTIL AFTER A TIME DELAY WHICH IS GREATER THAN THE REACTION TIME OF SAID VIBRATORY STRUCTURE, WHEREBY SAID OSCILLATING CIRCUIT OPERATES AT THE INITIAL RELATIVELY HIGH LEVEL TO CAUSE FAST BUILD UP OF OSCILLATIONS WHEN SAID SWITCH MEANS IS OPERATED AND OPERATES AFTER SAID TIME DELAY AT THE RELATIVELY LOW OPERATING LEVEL TO CAUSE CONTINUED OSCILLATIONS.