Patent US3804518A successfully refreshed from Google Patents.
US3804518A
Expired / Lapsed
US
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Measurement of the velocity of a body
Assignee: Hasler AG
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Filing: 1972-05-01
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Granted: 1974-04-16
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Expires: 1992-05-01
Abstract
Abstract A device for a moving body, to measure the speed of the moving body over a surface having local irregular features, having sources to illuminate local areas of the surface under a leading and a trailing photo-electric converter on the moving body which produce two sequences of electrical signals which correspond to the irregular feature of the surface at two points running in common with the body, that are spaced one from the other in the direction of movement. A delay unit with an adjustable delay for the signal output of the leading converter, a multiplication circuit for multiplying the delayed signals of the leading converter by the undelayed signals of the trailing converter, a low pass filter connected to the output of the multiplication circuit, a control circuit for adjusting the delay of the delay unit to a value which corresponds to a timely coincidence of the two consecutive signals obtained from the same point at the two inputs to the multiplication circuit, and an indicating device which on the basis of the delay time and the spacing of the two points indicates at any time the relative velocity of the moving body, so characterized that a filter is interposed in the connection between each photo-electric converter and the multiplication circuit, the frequency characteristics of which are different and so chosen that the valves obtained at the output of the low pass filter go through zero, when the delay time of the delay unit is equal to the time required to cover the said distance at the instant of the measurement.
Inventors
- 👤 H Meyr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:39
CPC Classifications
G; G01; G01P; G01P3/00; G01P3/64; G01P3/80; G01P3/806
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
281 words
A device for the measurement of the speed of a body which is moved parallel to a surface, which has a local irregular feature, comprising one leading and one trailing converter means spaced above the surface to produce two sequences of electrical signals which correspond with the feature of the surface at two points running together with the body, said leading and trailing converter means being spaced one from the other in the direction of movement, a delay unit with an adjustable delay for the signals emanating from the leading converter means, a multiplier circuit for the multiplication of the delayed signals of the leading converter means by the undelayed signals of the trailing converter means, a low pass filter connected to the output of the multiplier circuit, a control circuit connected to said low pass filter for the adjustment of the delay of said delay unit in dependence of the output of said multiplier circuit to a value which corresponds to a timely coincidence of the delayed and undelayed signals, and at least one indicating device, which on the adjusted basis of the delay of the delay circuit and the spacing of the points indicates the relative velocity and/or the path travelled onward from a given point, two filters, each interposed in the connection between one of said converter means and the multiplier circuit, and the said filters having different frequency characteristics which are so chosen that the value obtained at the output of the low pass filter is zero, when the delayed signal and the undelayed signal timely coincide, said control circuit adjusting the delay of the delay unit so that the output of said multiplier circuit is zero.
Claim 2
Independent Claim
281 words
A device for the measurement of the speed of a body which is moved parallel to a surface, which has a local irregular feature, comprising one leading and one trailing converter means spaced above the surface to produce two sequences of electrical signals which correspond with the feature of the surface at two points running together with the body, said leading and trailing converter means being spaced one from the other in the direction of movement, a delay unit with an adjustable delay for the signals emanating from the leading converter means, a multiplier circuit for the multiplication of the delayed signals of the leading converter means by the undelayed signals of the trailing converter means, a low pass filter connected to the output of the multiplier circuit, a control circuit connected to said low pass filter for the adjustment of the delay of said delay unit in dependence of the output of said multiplier circuit to a value which corresponds to a timely coincidence of the delayed and undelayed signals, and at least one indicating device, which on the adjusted basis of the delay of the delay circuit and the spacing of the points indicates the relative velocity and/or the path travelled onward from a given point, two filters, each interposed in the connection between one of said converter means and the multiplier circuit, and the said filters having different frequency characteristics which are so chosen that the value obtained at the output of the low pass filter is zero, when the delayed signal and the undelayed signal timely coincide, said control circuit adjusting the delay of the delay unit so that the output of said multiplier circuit is zero.
Claim 3
Dependent Claim
92 words
A device as set forth in claim 1, wherein said converter means produce continuous voltages and the frequency characteristics of said filters are so chosen that the Fourier transformations H1 ( omega ) and H2 ( omega ) respectively of the impulse response to an infinitely narrow input pulse of the two filters satisfy the following equation: H1 ( omega ) . H2 ( omega ) - H1 (- omega ) . H2 (- omega ) in which H1 identifies the conjugate complex value of H1 and omega is the angular frequency.
Claim 4
Dependent Claim
57 words
A device as claimed in claim 2, wherein the Fourier transformation of the impulse response of one of the two filters is H1 ( omega ) 1/1 + j omega RC and of the other of the two filters is H2 ( omega ) j omega RC/1 + j omega RC wherein RC is a time constant.
Claim 5
Dependent Claim
111 words
A device as set forth in claim 3, wherein each of said two filters contains an inverting operatiOnal amplifier the output of which is connected with the filter output, one filter having a first resistor connected between the input of the filter and the input of said amplifier, and a second resistor and a first capacitor in parallel with one another and connected between the input and the output of said amplifier, the other filter having a third resistor and a second capacitor in series between the input of the filter and the input of said amplifier, and a fourth resistor connected between the input and the output of said amplifier.
Claim 6
Dependent Claim
108 words
A device as set forth in claim 1, including first and second sampling means interposed respectively in the connection between one of said converter means and one of said filters for producing an impulse sequence with an impulse frequency f 1/Ta and corresponding to the amplitudes of the signals emanating from the converter means, and said filters are arranged for discrete values, of which the z-transforms H1 (z) and H2 (z) respectively of the impulse response are so selected that H1 (z) . H2 (1/z) H1 (1/z) . H2 (z) in which z e sT and s signifies the quantity sigma + j omega of the Laplace transformation.
Claim 7
Dependent Claim
110 words
A device as claimed in claim 5, wherein the value Y1 (k) is yielded from the first filter at any instant and is determined by the equation Y1 (k) qY1 (k-1) + X1 (k-1) + X1 (k) and the value Y2 (k) is yielded by the second filter at the same instant and is determined by the equation Y2 (k) q(Y2 (k-1) - X2 (k-1) + X2 (k)) , in which y1 and Y2 respectively signify the values of the input signal, X1 and X2 respectively the value of the output signal, and q a factor <1, while k-1 and k relate to two instants spaced by the time Ta.
Claim 8
Dependent Claim
15 words
A device as claimed in claim 5, wherein the delay unit is a shift register.
References Cited (Backward Citations)
GB964581A
Cited
US3689157A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-15 | 1977-10-15 | 1978-04-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-15 | 1981-10-15 | 1982-04-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-15 | 1985-10-15 | 1986-04-16 | $7700.00 | Window Closed / Lapsed |