US6122602A
Expired / Lapsed
US
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Method and arrangement for electromagnetic wave distance measurement by the pulse transit time method
Assignee: Endress and Hauser SE and Co KG
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Filing: 1998-04-13
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Granted: 2000-09-19
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Expires: 2018-04-13
Abstract
Abstract For electromagnetic wave distance measurement by the pulse transit time method, short electromagnetic transmission pulses are emitted at periodic transmission instants. The signals received in selected transmission cycles after the respective transmission instants are sampled for obtaining in each of these transmission cycles a sample at a sampling instant in a respective sampling time interval, each sampling instant having a delay dictated by a sampling function relative to the respective transmission instant. The sampling instants exhibit differing delays relative to the respective transmission instant so that the samples in sequence produce an image of the sampled received signal extended in time. The sampling function dictating the delays is generated by a computing circuit, preferably a microcomputer, thus making it possible to make use of any sampling function and to modify sampling of the received signals in any way. More particularly, it is possible to measure the applied delays and to correct them to maintain predetermined design values. One sampling function which can be put to use to advantage in this method is a staircase function, each step of which has the length of several sampling time intervals.
Inventors
- 👤 Bernhard Michalski
- 👤 Kenneth L. Perdue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 00:27
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/28; G01S7/285; G01F; G01F23/00; G01F23/22; G01F23/28; G01F23/284; G01S13/00; G01S13/02; G01S13/0209; G01S13/06; G01S13/08; G01S13/10; G01S13/103
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
130 words
A method for electromagnetic wave distance measurement by a pulse transit time method, wherein short electromagnetic transmission pulses are emitted at periodic transmission instants and signals received in selected transmission cycles after the respective periodic transmission instants are sampled for obtaining, in each of the selected transmission cycles, a sample at a sampling instant in a respective sampling time interval, each of the sampling instants having a delay dictated by a sampling function relative to the respective periodic transmission instant so that the sampling instants exhibit differing delays relative to the respective periodic transmission instants, and wherein an evaluation of the samples for determining the distance to be measured is done in a computing circuit and the computing circuit generates the sampling function dictating the delays of the sampling instants.
Claim 2
Independent Claim
130 words
A method for electromagnetic wave distance measurement by a pulse transit time method, wherein short electromagnetic transmission pulses are emitted at periodic transmission instants and signals received in selected transmission cycles after the respective periodic transmission instants are sampled for obtaining, in each of the selected transmission cycles, a sample at a sampling instant in a respective sampling time interval, each of the sampling instants having a delay dictated by a sampling function relative to the respective periodic transmission instant so that the sampling instants exhibit differing delays relative to the respective periodic transmission instants, and wherein an evaluation of the samples for determining the distance to be measured is done in a computing circuit and the computing circuit generates the sampling function dictating the delays of the sampling instants.
Claim 3
Dependent Claim
23 words
The method as set forth in claim 1, wherein the computing circuit evaluating the samples and generating the sampling function is a microcomputer.
Claim 4
Dependent Claim
21 words
The method as set forth in claim 2, wherein said sampling function is generated by an algorithm stored in said microcomputer.
Claim 5
Dependent Claim
17 words
The method as set forth in claim 2, wherein said sampling function is mapped in said microcomputer.
Claim 6
Dependent Claim
17 words
The method as set forth in claim 1, wherein said sampling function is a linear ramp function.
Claim 7
Dependent Claim
50 words
The method as set forth in claim 1, wherein said sampling function is a staircase function, the steps of which have a length of several sampling time intervals so that the sampling instants in several consecutive sampling time intervals have the same delay relative to the respective periodic transmission instants.
Claim 8
Dependent Claim
21 words
The method as set forth in claim 6, wherein the samples obtained during a step of said staircase function are integrated.
Claim 9
Dependent Claim
61 words
The method as set forth in claim 1, wherein a measurement value of the delay exhibited by the sampling instant relative to the respective periodic transmission instant in the same transmission cycle is measured, the measurement value is compared to a design value in the computing circuit and should a deviation exist, the sampling function is corrected to eliminate the deviation.
Claim 10
Dependent Claim
30 words
The method as set forth in claim 8, wherein correction values established for correcting the sampling function are memorized in the computing circuit and made use of in subsequent samplings.
Claim 11
Dependent Claim
32 words
The method as set forth in claim 8, wherein the measurement value of the delay is used in the computing circuit as a reference value for determining the distance to be measured.
Claim 12
Dependent Claim
24 words
The method as set forth in claim 10, wherein the computing circuit modifies the sampling function in dependence on the evaluation of the samples.
Claim 13
Dependent Claim
67 words
The method as set forth in claim 8, wherein each respective sampling time interval has a duration of several transmission cycles so that sampling occurs in each case only in one of several consecutive transmission cycles, and wherein measurement of the delay is also done in transmission cycles in which no sampling occurs, and the measurement values of the delay obtained between two consecutive samplings are integrated.
Claim 14
Dependent Claim
30 words
The method as set forth in claim 12, wherein said computing circuit permits emission of transmission pulses and sampling of received signals only in transmission cycles in which sampling occurs.
Claim 15
Dependent Claim
193 words
An arrangement for electromagnetic wave distance measurement by a pulse transit time method comprising a transceiver assembly for emitting short electromagnetic transmission pulses at periodic transmission instants and for furnishing received signals containing reflected echo pulses, a transmission pulse generator for generating said short electromagnetic transmission pulses, a transmission clock generating a periodic transmission clock signal supplied to said transmission pulse generator and dictating said periodic transmission instants, a sampling circuit in which samples are taken from said received signals in consecutive transmission cycles with control by sampling pulses, a sampling pulse generator generating one sampling pulse at a sampling instant in each one of all or of selected transmission cycles, said sampling instant having a delay dictated by a sampling function relative to one of said transmission instants, a delay control circuit receiving said periodic transmission clock signal and a function signal representing said sampling function and furnishing to said sampling pulse generator a sampling control signal dictating said sampling instants, and a computing circuit evaluating said samples for determining the distance to be measured and generating said function signal on the basis of said sampling function generated in said computing circuit.
Claim 16
Dependent Claim
193 words
An arrangement for electromagnetic wave distance measurement by a pulse transit time method comprising a transceiver assembly for emitting short electromagnetic transmission pulses at periodic transmission instants and for furnishing received signals containing reflected echo pulses, a transmission pulse generator for generating said short electromagnetic transmission pulses, a transmission clock generating a periodic transmission clock signal supplied to said transmission pulse generator and dictating said periodic transmission instants, a sampling circuit in which samples are taken from said received signals in consecutive transmission cycles with control by sampling pulses, a sampling pulse generator generating one sampling pulse at a sampling instant in each one of all or of selected transmission cycles, said sampling instant having a delay dictated by a sampling function relative to one of said transmission instants, a delay control circuit receiving said periodic transmission clock signal and a function signal representing said sampling function and furnishing to said sampling pulse generator a sampling control signal dictating said sampling instants, and a computing circuit evaluating said samples for determining the distance to be measured and generating said function signal on the basis of said sampling function generated in said computing circuit.
Claim 17
Dependent Claim
15 words
The arrangement as set forth in claim 14, wherein said computing circuit is a microcomputer.
Claim 18
Dependent Claim
63 words
The arrangement as set forth in claim 14, including a time difference measuring circuit which at a first input receives the periodic transmission clock signal and at a second input receives the sampling control signal and which furnishes at its output a time difference signal representing a time difference between these two signals, said time difference signal being supplied to said computing circuit.
Claim 19
Dependent Claim
43 words
The arrangement as set forth in claim 16, wherein in said computing circuit the time difference represented by said time difference signal is compared to a design value and in case of a deviation said function signal is modified to remove said deviation.
Claim 20
Dependent Claim
35 words
The arrangement as set forth in claim 16, wherein in said computing circuit the time difference represented by said time difference signal is used as a reference value for determining the distance to be measured.
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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) | 2003-09-19 | 2004-03-20 | 2004-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-09-19 | 2008-03-20 | 2008-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-09-19 | 2012-03-20 | 2012-09-19 | $7700.00 | Window Closed / Lapsed |