Pulse reflection type ultrasonic thickness meter

Claim 2

A pulse reflection type ultrasonic thickness meter comprising: a pulse oscillator means for producing a transmission signal; an ultrasonic transducer connected to said pulse oscillator means, producing an ultrasonic pulse wave, said ultrasonic pulse wave being transmitted to an object to be measured, and said transducer receiving an echo pulse train including a plurality of pulses from said object; a receiving amplifier with a variable gain control receiving the echo pulse train output of said ultrasonic transducer to control the height of a first echo pulse included in said echo pulse train; a pulse generator means connected to receive said transmission signal from said pulse oscillator means and said echo pulse train from said receiving amplifier and producing a pulse signal whose duration is proportional to the thickness of said object; and an automatic gain control means connected to the variable gain control of said receiving amplifier and receiving a first input from said pulse generator means and a second input from said receiving amplifier and having two output conditions which depend upon which of its two inputs are smaller and such that the smaller of its two inputs control its output condition for controlling the gain of said receiving amplifier.

Claim 3

A pulse reflection type ultrasonic thickness meter comprising: a pulse oscillator means for producing a transmission signal; an ultrasonic transducer connected to said pulse oscillator means and producing an ultrasonic pulse wave, said ultrasonic pulse wave being transmitted to an object to be measured, and said transducer receiving an echo pulses train including a plurality of pulses from said object; a receiving amplifier with a variable gain control receiving the echo pulse train output of said ultrasonic transducer to control the height of a first echo pulse included in said echo pulse train; a pulse generator means connected to receive said transmission signal from said pulse oscillator means and said echo pulse train from said receiving amplifier and producing a pulse signal whose duration is proportional to the thickness of said object; an automatic gain control circuit connected to the variable gain control of said receiving amplifier and receiving a first input from said receiving amplifier; an integration circuit receiving the output of said pulse generator means; and a peak hold circuit receiving the output of said integration circuit and supplying a second input to said automatic gain control circuit, said automatic gain control circuit having two output conditions which depend upon which of its two inputs are smaller and such that the smaller of its two inputs control its output condition for controlling the gain of said receiving amplifier.

Claim 4

A pulse reflection type ultrasonic thickness meter comprising: a pulse oscillator means for producing a transmission signal; an ultrasonic transducer connected to said pulse oscillator means and producing an ultrasonic pulse wave, said ultrasonic pulse wave being transmitted to an object to be measured, and said transducer receiving an echo pulses train including a plurality of pulses from said object; a receiving amplifier with a variable gain control receiving the echo pulse train output of said ultrasonic transducer to control the height of a first echo pulse included in said echo pulse train; a pulse generator means connected to receive said transmission signal from said pulse oscillator means and said echo pulse train from said receiving amplifier and producing a pulse signal whose duration is proportional to the thickness of said object; an automatic gain control circuit connected to the variable gain control of said receiving amplifier and receiving a first input from said receiving amplifier; an integration circuit receiving the output of said pulse generator means; and a peak hold circuit receiving the output of said integration circuit and supplying a second input to said automatic gain control circuit, said automatic gain control circuit having two output conditions which depend upon which of its two inputs are smaller and such that the smaller of its two inputs control its output condition for controlling the gain of said receiving amplifier.

Claim 5

A pulse reflection type ultrasonic thickness meter comprising: a pulse oscillator means for producing a transmission signal; an ultrasonic transducer connected to said pulse oscillator means and producing an ultrasonic pulse wave, said ultrasonic pulse wave being transmitted to an object to be measured, and said transducer receiving an echo pulse train including a plurality of pulses from said object; a receiving amplifier with a variable gain control receiving the echo pulse train output from said ultrasonic transducer to control the height of a first echo pulse included in said echo pulse train; a pulse generator means connected to receive said transmission signal from said pulse oscillator means and said echo pulse train from said object and producing a pulse signal whose duration is proportional to the thickness of said object; an automatic gain control circuit connected to the variable gain control of said receiving amplifier, a peak hold circuit receiving an input from said receiving amplifier; a converter receiving the output of said pulse generator means; a comparator receiving the output of said converter and a reference voltage input; and a gate receiving the outputs of said peak hold circuit and said comparator and supplying an input to said automatic gain control circuit from said peak hold circuit when the output of said comparator is less than said reference voltage.

Claim 6

A pulse reflection type ultrasonic thickness meter comprising: a pulse oscillator means for producing a transmission signal; an ultrasonic transducer connected to said pulse oscillator means and producing an ultrasonic pulse wave, said ultrasonic pulse wave being transmitted to an object to be measured, and said transducer receiving an echo pulse train including a plurality of pulses from said object; a receiving amplifier with a variable gain control receiving the echo pulse train output from said ultrasonic transducer to control the height of a first echo pulse included in said echo pulse train; a pulse generator means connected to receive said transmission signal from said pulse oscillator means and said echo pulse train from said object and producing a pulse signal whose duration is proportional to the thickness of said object; an automatic gain control circuit connected to the variable gain control of said receiving amplifier, a peak hold circuit receiving an input from said receiving amplifier; a converter receiving the output of said pulse generator means; a comparator receiving the output of said converter and a reference voltage input; and a gate receiving the outputs of said peak hold circuit and said comparator and supplying an input to said automatic gain control circuit from said peak hold circuit when the output of said comparator is less than said reference voltage.