Abstract: An apparatus for remote distance measurement varies the decay time of an electronic transducer to measure the distance to objects that are close to the transducer. The decay time for the amplitude of the oscillations of the transducer is varied by changing the transmitting frequency of the transducer since the rate at which the transducer oscillations decay depends on the transmitting frequency. The frequency is changed using a circuit comprising an electroacoustic transducer, a generator, a receiving amplifier and a control circuit. The generator generates an oscillation signal having a constant transmitting frequency and constant amplitude for a given transmitting time that depends on the distance of the object from the transducer. The transmitting frequency is chosen to measure the distance to a close object so that the transducer amplitude decays so fast that the echo signal can be received and evaluated without interference.

Abstract: A method and an apparatus for determining a length of a pipe utilizing sound waves, which comprise: transmitting sound waves having a prescribed frequency and a prescribed transmission intensity toward the interior of a pipe at one end thereof by an oscillator; receiving the thus transmitted sound waves at the other end of the pipe by a receiver; measuring a propagation time required for the sound waves to pass through the air in the pipe from the one end to the other end thereof by a clock; and determining a length of the pipe by a length calculator on the basis of a predetermined propagation velocity of the sound waves in the air in the pipe and the thus measured propagation time of the sound waves.

Abstract: An interface circuit for use in connecting a high frequency piezoelectric transducer to an input stage of an echo ranging system is described. The circuit includes first, second and third control transistors which are selectively switched by a state controller to control the operation of the circuit. The first transistor is controlled to generate a coherent acoustical pulse at a first predetermined time. The second transistor is controlled to damp the transducer output at a second predetermined time following the first predetermined time. The third transistor serves to clamp the input stage of the echo ranging system to ground until the pulse signal has been effectively transmitted. This operation insures the transducer is in a condition to immediately receive an echo pulse despite the proximity of the transducer to the target whose range is being measured.

Abstract: A transmitter/receiver for suppling a pulse power to a transducer and receiving a signal from the transducer comprises a parallel connection of a first circuit including a first switch element connected in series with a power supply having one terminal thereof connected to a common potential point, a second circuit including a second switch element connected in series with a receiver having one end thereof connected to the common potential point, and a third circuit including the transducer having one end thereof connected to the common potential point.

Abstract: An ultrasonic ranging system includes transformer means with a transformer which is selectively energized to produce a transducer drive signal. An ultrasonic transducer transmits an ultrasonic pulse in response to the drive signal and develops an echo signal upon receipt of an echo pulse derived from the ultrasonic pulse; a shunt switch is connected across a winding of the transformer and is selectively closed to quickly damp the ringing following the transmission of an ultrasonic pulse to a level substantially below the level of the echo signal to permit close ranging.

Abstract: A circuit arrangement for separating high-frequency pulses produced successively in time at a piezoelectric transducer of an acoustic reflection lens arrangement. According to the invention, the transducer is preceded by a three-way pin switch, the common end of the wiper of which is connected to the acoustic lens, the other end of the wiper being alternately connected in a first position to the output of a transducer oscillator, in a second position to a 50-Ohm resistor, or in a third position to a measurement circuit.

Abstract: An acoustic transducer is connected to an electronically controllable time-dependent conductance so that energy may be rapidly applied to and extracted from the transducer and associated circuitry.

Abstract: A solid state transmit/receive switching circuit is provided by a system which, in accordance with the invention, comprises a solid state relay which, when energized, causes an optically controlled resistor connected to an input terminal of a preamplifier of the receiver to change its resistance and hence the sensitivity of the preamplifier according to the transmitter transmission state.

Abstract: A circuit for exciting an ultrasonic transducer element comprises a diode switch exhibiting a long reverse recovery time duration connected between an input and an output terminal. A transducer exciting signal varying in both positive and negative directions and applied to the input terminal is conducted to the output terminal through the diode switch.

Abstract: A circuit is provided for supplying a transmission oscillator voltage suitable for a piezoelectric sound source transducer in which the transducer also serves as a receiving transducer. The circuit contains an electrical series resonant circuit having a capacitor C and an inductor L withL.multidot.C=(1/2 .pi. f.sub.0).sup.2,wherein the electrical series resonant circuit is matched to the series resonant frequency f.sub.0 of the transducer and is connected parallel to the transducer. The circuit further contains a pair of diodes, connected anti-parallel to one another, and connected in parallel to either the inductor L or to the capacitor C, with the output of the receiver being connected to the capacitor C or to the inductor L.

Abstract: An ultrasonic signal transducer is characterized in that the piezoelectrically active element has a first unitary electrode over the entire surface of one face and a matrix of a plurality of individual electrodes on the opposite face. In the receive mode, such an arrangement effectively constitutes a plurality of individual transducers arranged in the matrix array while maintaining the efficacy of a unitary structure. The signals from the individual electrodes are individually amplified, full-wave rectified, and combined additively to produce a composite signal which eliminates the phase cancellation of the ultrasonic pulses distributed over the face of the transducer assembly.

Abstract: A multiplexer for an ultrasonic ranging device for a vehicle having a resettable digital counter is disclosed herein. The digital counter receives a plurality of pulses from an oscillator and provides a counter output signal indicative of the stored count of the number of pulses. A plurality of logic gates are connected to the digital counter for control thereby. A plurality of ultrasonic transducers are connected to the logic gates, the logic gates sequentially energizing the transducers in response to the stored count in the digital counter.

Abstract: An echo sounder including a unit for transmitting, into a medium, acoustic signals at two slightly differing high frequencies and in the form of pulses, resulting in the creation of an acoustic signal in the medium at a low frequency equal to the difference between the two high frequencies, and a receiving unit including a receiving transducer for receiving echoes of acoustic signals at the difference frequency and a display device for recording the echo signals in accordance with their travel times, the display device having a signal input which is connected with the low frequency receiving transducer, is further provided with a second receiving transducer responsive to high signal frequencies for receiving echoes of acoustic signals at at least one of the two transmitting frequencies, and a member connecting the second receiving transducer to the signal input of the display device.

Abstract: The invention relates to a transmit/receive switching unit for use between a transmit/receive converter and the transmission line of a transmit/receive device having a voltage source. The unit has transmitting and receiving channels with the receiving channel having a signal amplifier. An energy storage element such as a capacitor stores a part of the transmission energy on a continuing basis for operating the signal amplifier in the receiving channel. This scheme saves having to provide a separate line from a voltage source to the amplifier.

Abstract: Each receiving or transmitting circuit for a respective transducer element includes an individually controllable buffer amplifier which is so operated as to avoid detrimental switching transients. For example, the buffer amplifiers in the receiving circuit may have input switches closed immediately after a transmit pulse and prior to the actual receiving phase. Then output switches of the buffer amplifiers to be activated are closed in the receiving phase, but transients so produced are blocked by the high reverse attenuation of the buffer amplifiers. The input switches may be actuated prior to activation of the transducer elements in receive mode and may serve to simultaneously supply operating voltage to the respective associated buffer amplifiers, the buffer amplifiers all being switched off during transmit mode to block transmit energy from non-active transducers.

Abstract: A charging circuit for a helicopter dipped sonar system in which a single ble conducts sonar and command signals in either direction along with a DC charging current from the helicopter to a storage battery in a submersible sensor unit. A multiplexer and power supply in the helicopter respectively provide simultaneous transmission of command data and charging current over a common conductor to the sensor unit. A filter and demultiplexer positioned in the sensor unit passes only the data for control of a sonar transmitter. The storage battery is charged directly from the conductor and a battery charge indication as well as hydrophone information is combined by a multiplexer at the sensor and returned to the helicopter by the common conductor for data display and power supply control.