Detection apparatus
Abstract
Abstract ULTRASONIC DETECTION APPARATUS FOR DETECTING THE PRESENCE OR ABSENCE OF AN OBJECT WHICH COMPRISES SPACED ULTRASONIC TRANSMITTING AND RECEIVING TRANSDUCERS CONNECTED WITH AN AMPLIFIER TO FORM A REGENERATIVE FEEDBACK LOOP ADAPTED TO PRODUCE CONTINUOUS-WAVE OSCILLATIONS WHEN THE PATTH BETWEEN THE SPACED TRANSDUCERS IS IN AN ACOUSTICALLY TRANSMITTING CONDITION, SAID CONTINUOUS-WAVE OSCILLATIONS CEASING WHEN THE PATH IS IN ITS NONACOUSTICALLY TRANSMITTING CONDITION, AND MEANS CONNECTED TO THE AMPLIFIER TO INDICATE THE PRESENCE OR ABSENCE OF SAID OSCILLATIONS. THE TRANSDUCERS AND AMPLIFIER HAVE A RELATIVELY NARROW PASSBAND FOR THE REGENERATIVE LOOP OSCILLATIONS, THE AMPLIFIER GAIN AND SAID NARROW PASSBAND BEING CORRELATED TO MAINTAIN A CLOSED LOOP POWER GAIN OF AT LEAST UNITY THROUGHOUT A VARIATION OF C/L WHICH PRODUCES AT LEAST TWO CONSECUTIVE ONE-WAVELENGTH CHANGES IN THE NUMBER OF ACOUSTIC WAVELENGTH BETWEEN THE TRANSDUCERS WHEN THE PATH THEREBETWEEN IS IN ITS ACOUSTICALLY TRANSMITTING CONDITION, WHERE C IS THE VELOCITY OF PROPAGATION OF THE ULTRASONIC ENERGY AND L IS THE PATH LENGTH BETWEEN THE TRANSDUCERS.
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Bibliographic Details
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-15 | 1977-04-16 | 1977-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-15 | 1981-04-16 | 1981-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-15 | 1985-04-16 | 1985-10-16 | $7700.00 | Window Closed / Lapsed |