Abstract: An externally-powerable sensor is described for detecting ultrasonic energy and for providing an accurate indication of the level of such energy to an external monitoring device over a wide dynamic range. A first electrical signal proportional to the detected ultrasonic energy is chopped by the output of a free-running multivibrator to generate a signal having a frequency differing from the frequency of the first signal by an amount within the audio frequency range. Such difference signal is selectively amplified to concentrate the spectral energy of the difference component in a lower portion of the audio range. A low pass filter extracts, from the so-concentrated difference signal, a modified audio signal whose frequency content is at the lower end, illustratively 0-6 KHz, of the spectrum of the concentrated difference signal. The output of the low pass filter is processed to generate a DC output current that is proportional to the detected ultrasonic energy level.

Abstract: An externally-powerable sensor is described for detecting ultrasonic energy and for providing an accurate indication of the level of such energy to an external monitoring device over a wide dynamic range. A first electrical signal proportional to the detected ultrasonic energy is chopped by the output of a free-running multivibrator to generate a signal having a frequency differing from the frequency of the first signal by an amount within the audio frequency range. Such difference signal is selectively amplified to concentrate the spectral energy of the difference component in a lower portion of the audio range. A low pass filter extracts, from the so-concentrated difference signal, a modified audio signal whose frequency content is at the lower end, illustratively 0-6 KHz, of the spectrum of the concentrated difference signal. The output of the low pass filter is processed to generate a DC output current that is proportional to the detected ultrasonic energy level.

Abstract: The invention provides a device that generates predictable and reproducible sounds. The device according to the invention serves as a standard to calibrate ultrasonic measuring equipment through either a gaseous medium or a solid medium. The device according to the invention is similar in basic shape to an hourglass or venturi (e.g., a sand-type egg-timer), but instead of using fine particles, such as sand, the device includes identical media particles (e.g., marbles, balls, beads, etc.) which drop from an upper chamber to a lower one. The media particles are pre-sorted so that those sealed within the hourglass structure are uniform. An impingement post (e.g., a bell or sounding plate) is positioned in the path of the falling media particles so that each will hit the sounding plate, resulting in a reverberating sound. The impingement post is cantilevered and supported from a side of a chamber of the hour glass structure.

Abstract: The invention provides a device that generates predictable and reproducible sounds. The device according to the invention serves as a standard to calibrate ultrasonic measuring equipment through either a gaseous medium or a solid medium. The device according to the invention is similar in basic shape to an hourglass or venturi (e.g., a sand-type egg-timer), but instead of using fine particles, such as sand, the device includes identical media particles (e.g., marbles, balls, beads, etc.) which drop from an upper chamber to a lower one. The media particles are pre-sorted so that those sealed within the hourglass structure are uniform. An impingement post (e.g., a bell or sounding plate) is positioned in the path of the falling media particles so that each will hit the sounding plate, resulting in a reverberating sound. The impingement post is cantilevered and supported from a side of a chamber of the hour glass structure.

Abstract: The invention provides a device that generates predictable and reproducible sounds. The device according to the invention serves as a standard to calibrate ultrasonic measuring equipment through either a gaseous medium or a solid medium. The device according to the invention is similar in basic shape to an hourglass or venturi (e.g., a sand-type egg-timer), but instead of using fine particles, such as sand, the device includes identical media particles (e.g., marbles, balls, beads, etc.) which drop from an upper chamber to a lower one. The media particles are pre-sorted so that those sealed within the hourglass structure are uniform. An impingement post (e.g., a bell or sounding plate) is positioned in the path of the falling media particles so that each will hit the sounding plate, resulting in a reverberating sound. The impingement post is cantilevered and supported from a side of a chamber of the hour glass structure.

Abstract: Leaks or thin spots in containers, as well as mechanical faults, e.g. worn bearings, are detected by an ultrasonic energy indicator that includes a modulator that heterodynes ultrasonic signals received by a transducer and creates an audio signal related thereto. The transducer includes a series arrangement of piezoelectric crystals feeding a field-effect transistor amplifier and the modulator operates in an amplitude modulation, suppressed-carrier mode which can be stabilized by a feedback loop. For indicating the presence of the audio signal, either headphones or a meter or both are employed. When leaks in a container are being detected, an ultrasonic generator is used which varies its output frequency slowly over a band of frequencies. The leak detection technique can be improved by applying a thin layer of a liquid to the container surface so that pressure introduced into the container causes the formation and bursting of bubbles in the liquid that results in the production of ultrasonic energy.