Distance measuring system arranged to limit false indications of distance measurements
First Claim
1. A method of determining the status of a distance measuring device having a transducer configuration that generates ringing signals, the method comprising the steps of:
- (a) generating a probe signal at said transducer configuration;
(b) detecting for a ringing signal within a time period of substantially one millisecond from the generation of the probe signal by said transducer configuration;
(c) detecting for the end of said ringing signal within a time period of substantially three milliseconds from the generation of the probe signal; and
(d) detecting for an echo of said probe signal from an external object.
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Accused Products
Abstract
A distance measuring system includes a device for detecting ringing signals (false echoes) generated by ultrasonic transducers used to generate probe signals and detect echoes of the probe signals to determine the distance of an external object from the measurement system. The absence or duration of ringing signals are determined, and the display of the distance measuring system is operated accordingly. False indications of distance measurements are limited by storing a number of distance measurements in a memory, and selecting the measurement most likely to indicate the presence of an object from which the distance to the measuring system is determined.
215 Citations
26 Claims
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1. A method of determining the status of a distance measuring device having a transducer configuration that generates ringing signals, the method comprising the steps of:
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(a) generating a probe signal at said transducer configuration; (b) detecting for a ringing signal within a time period of substantially one millisecond from the generation of the probe signal by said transducer configuration; (c) detecting for the end of said ringing signal within a time period of substantially three milliseconds from the generation of the probe signal; and (d) detecting for an echo of said probe signal from an external object. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for measuring distance between a measuring device and an object external to said measuring device, said measuring device including a transducer configuration for emitting probe signals and sensing echoes of said probe signals, the method comprising the steps of:
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(a) sending a probe signal from said transducer configuration; (b) receiving an echo of said probe signal at said transducer configuration and de-activating said transducer configuration for purposes of receiving until a subsequent probe signal is transmitted; (c) converting said echo into an electrical signal; (d) deriving a current distance value from said electrical signal; (e) placing said current distance value in a memory containing a plurality of a prior distance values; (f) selecting a greatest distance value from among said stored distance values in said memory; and (h) displaying said selected greatest distance value. - View Dependent Claims (10, 11, 12, 13, 14, 15, 26)
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9. A distance measuring system arranged to use ringing signals to determine system status, said system comprising:
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(a) a transducer configuration for emitting a probe signal and generating ringing signals; (b) means for detecting a ringing signal; (c) means for timing a detected ringing signal; and (d) display means responsive to time duration of a detected ringing signal.
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16. A distance measuring system, comprising:
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(a) a first transducer for emitting a probe signal; (b) a second transducer, associated with said first transducer, for receiving an echo of said probe signal and converting said echo into an electrical signal; (c) processing means responsive to said electrical signal for determining a distance value between said second transducer and an object reflecting said probe signal from said first transducer; (d) memory means for storing a plurality of the four most recent distance values determined by said processing means; (e) selection means for selecting a greatest one of said plurality of most recent distance values in said memory means; and (f) display means for displaying said selected distance value. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification