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EP0142733A2
Expired / Lapsed
EP
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Ultrasonic rangefinder
Assignee: Nissan Motor Co Ltd
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Filing: 1984-10-23
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Granted: —
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Expires: 2004-10-23
Abstract
Abstract An ultrasonicrangefinder which measures distance to the ground by transmitting ultrasonic waves toward the ground and measuring the time which elapses until the reflected wave is received is shown. In order to reliably prevent erroneous measurement due to ultrasonic waves which travel to the receiver directly without striking the ground, the distance calculation is based on the time which elapses aftertransmis- sion of the ultrasonic wave until the rate of change of the envelope of the received ultrasonic wave signal exceeds a prescribed value.
Inventors
- 👤 Kiyoshi Takeuchi
- 👤 Hiroshi Kobayashi
- 👤 Hiroaki Obayashi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 23:05
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/52; G01S7/523; G01S7/526; G01S15/00; G01S15/02; G01S15/06; G01S15/08; G01S15/10; G01S15/18; G01S7/527
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
148 words
A ultrasonic rangefinder comprising: an oscilator (1) generating a series of pulse signals (S 1 ); a transmitter microphone (2) which emits ultrasonic pulses toward a target object (10) on the basis of the pulse signals transmitted from said oscillator (1); a receiver microphone (3) which receives ultrasonic pulses reflected from said target object (10); a means (14) for differentiating by time the envelope of the output signals (S 2 ) of said receiver microphone (3) a means for detecting (6,7) the rise of the signal corresponding to the refrected pulse on the basis of the A output signal (S 3 ) of said differentiating means (16); a means for calculating a distance between said rangefinder and the object (10) on the basis of a delay time of the rise detected by said detecting means in relation to the pulse signal (S 1 ) from said oscillator (1)
Claim 2
Dependent Claim
148 words
A ultrasonic rangefinder comprising: an oscilator (1) generating a series of pulse signals (S 1 ); a transmitter microphone (2) which emits ultrasonic pulses toward a target object (10) on the basis of the pulse signals transmitted from said oscillator (1); a receiver microphone (3) which receives ultrasonic pulses reflected from said target object (10); a means (14) for differentiating by time the envelope of the output signals (S 2 ) of said receiver microphone (3) a means for detecting (6,7) the rise of the signal corresponding to the refrected pulse on the basis of the A output signal (S 3 ) of said differentiating means (16); a means for calculating a distance between said rangefinder and the object (10) on the basis of a delay time of the rise detected by said detecting means in relation to the pulse signal (S 1 ) from said oscillator (1)
Claim 3
Dependent Claim
42 words
An ultrasonic rangefinder of claim l.further comprising a means (8, 9) for eliminating the signals corresponding to the output (5 2 ) from said receiver microphone (3) during a prescribed period (c) after an emission of pulse from said transmitter microphone (3).
Claim 4
Dependent Claim
48 words
An ultrasonic rangefinder of claim2, wherein said detecting means comprises: a reference voltage generator (7) and a comparator (6) receiving the output signal from said differentiating means (16) and the output from said generator and allowing the output signal from said differentiating means to enter said calculating means.
Claim 5
Dependent Claim
75 words
An ultrasonic rangefinder of claim 3 wherein, said eliminating means comprises: a time delay circuit (8) receiving the pulse singnal (S 1 ) from said oscillator (1) and outputting a mask signal (S 5 ) which starts with the delay time (τ) of said prescribed period after the pulse signal (S 1 ) from said oscillator (1) an AND circuit receiving the output of said delay circuit (8) and the output of said comparator (6)
Claim 6
Dependent Claim
103 words
-5. An ultrasonic rangefinder of claim 4 further comprising: a clock (14); a counter (11) which starts its counting when it receives the pulse signal (S 1 ) from said oscillator (1); a latch circuit (12) which receives the output of said counter (11) and the output (S 6 ) of said AND circuit (9) and outputs the output of said counter when the output (S 6 ) of said AND circuit (9) is received; a time delay circuit which allows the output (S 6 ) of said AND circuit (9) to enter said counter (11) with delay time to reset said counter.
Claim 7
Dependent Claim
14 words
An ultrasonic rangefinder of claim 1 wherein; said envelope is differentiated for one time
Claim 8
Dependent Claim
13 words
An ultrasonic rangefinder of claim 1 wherein; said envelope is differentiated for multi-times
References Cited (Backward Citations)
No citation records indexed.
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