US 4,056,761 AGranted

Sonic transducer and drive circuit

AssigneeQuintron, Inc.

InventorsBenjamin Franklin Jacoby, Marvin E. Monroe

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Abstract

A sonic transducer, having a drive electromechanical transducing element and a pickup electromechanical transducing element or a single transducing element electronically operating as both, is excited through suitable power amplifiers by a voltage controlled oscillator. A phase comparator connected to these transducing elements detects the phase difference between stress and strain in the transducer. Its output is connected to an integrator circuit means which integrates the phase difference signal and applies the integrated signal to control the voltage controlled oscillator. The maximum and minimum values of the voltage which is applied to control the oscillator are independently limited by a pair of diodes connected to sources of two different voltages. An adjustably fixable phase shift circuit is interposed between the pickup transducing element and the phase comparator to permit calibration of the system for optimal operation. Amplifier and clipper circuitry interposed between the phase shift circuit and the phase comparator circuit make the oscillator output signal independent of the amplitude of the vibrations of the sonic transducer.

Claims13

Dependent claims

A sonic tool comprising:

a. a sonic transducer including electromechanical transducing means for the application of a periodic electronic drive signal thereto to produce a mechanical stress for driving said transducer and for generating an electronic pickup signal which is proportional to mechanical strain;
b. a phase comparator having an output signal proportional to the phase difference of a pair of periodic signals at a pair of inputs, one input connected to receive the electronic drive signal applied to said transducing means and the other input connected to receive the electronic pickup signal from said transducing means;
c. integrator circuit means having its input connected to the output of said phase comparator;
d. an electronic signal controlled oscillator having its input control terminal connected for control by the output of said integrator circuit means and its output connected for exciting said transducing means with said drive signal;
e. limiter circuit means connected to the input control terminal of said oscillator for limiting the escursions of the control signal to confine it within a selected range;
and
f. an adjustable phase shift network means and amplitude limiting circuit means electrically interposed in cascade between said transducing means and said phase comparator for introducing a selected phase shift in said pickup signal and for making the input pickup signal applied to said phase detector independent of the amplitude of the pickup signal from said transducing means.

4 more elements

A sonic tool comprising:

a. a sonic transducer including electromechanical transducing means for the application of a periodic electronic drive signal thereto to produce a mechanical stress for driving said transducer and for generating an electronic pickup signal which is proportional to mechanical strain;
b. a phase comparator having an output signal proportional to the phase difference of a pair of periodic signals at a pair of inputs, one input connected to receive the electronic drive signal applied to said transducing means and the other input connected to receive the electronic pickup signal from said transducing means;
c. integrator circuit means having its input connected to the output of said phase comparator;
d. an electronic signal controlled oscillator having its input control terminal connected for control by the output of said integrator circuit means and its output connected for exciting said transducing means with said drive signal;
wherein said transducing means comprises a transducing element and time sharing means for applying a driving signal from said oscillator during a minor part of each cycle and for applying said pickup signal from said transducing element to said phase comparator during another part of each cycle.

2 more elements

Dependencies are inferred from the claim text.