Patent US2040550A successfully refreshed from Google Patents.
US3680101A
Expired / Lapsed
US
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Distance measuring device
Assignee: Linde Sverige AB
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Filing: 1970-08-10
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Granted: 1972-07-25
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Expires: 1990-08-10
Abstract
Abstract A distance measuring device wherein the phase difference between a transmitted signal and the received reflection thereof is used to determine the distance the received signal has traversed. The device generates a pair of electromagnetic waves at two accurately known frequencies. The first frequency wave is transmitted and the other frequency wave is used to modulate the received reflected wave in the receiver to produce a difference frequency. A phase measuring circuit compares the phase of this difference frequency to the phase of a signal of the same difference frequency that has been generated locally within the device. To resolve the ambiguity in the resulting phase difference measurement obtained, a switching means is provided to reverse the roles of the generated waves by connecting the second frequency wave to the transmitter and connecting the first frequency wave to the modulatable receiver. This same switching means also changes the phase measuring circuit so that the phase difference associated with the modulated received second frequency is subtracted from the first phase difference. By providing a phase difference measurement at a difference frequency having an associated effective wave length larger than the distance to be measured any ambiguity regarding the number of wavelengths contained in the measured distance is eliminated.
Inventors
- 👤 Carl-Erik Granqvist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:49
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/32; G01S13/36; G01S13/38; G01S17/00; G01S17/02; G01S17/06; G01S17/08; G01S17/32
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
196 words
A distance measuring device of the type providing for the detection of the phase difference between a transmitted electromagnetic wave and the received reflection of said wave comprising: a modulatable transmitter; a modulatable receiver; a first frequency generator for producing an output of a first frequency; a second frequency generator for producing an output of a second frequency; a difference frequency producing means for producing a signal having a frequency equal to the frequency difference between said first and said second frequencies; a switching means for, in a first position, connecting the output from said first frequency generator to said modulatable transmitter to modulate the output thereof and connecting the output from said second frequency generator to said modulatable receiver to modulate the output thereof and for, in a second position, connecting the output from said second frequency generator to said modulatable transmitter to modulate the output thereof and connecting the output from said first frequency generator to said modulatable receiver to modulate the output thereof; and a phase measuring circuit responsive to the difference in phase between the output of said difference frequency producing means and the phase of the output of said modulatable receiver.
Claim 2
Dependent Claim
196 words
A distance measuring device of the type providing for the detection of the phase difference between a transmitted electromagnetic wave and the received reflection of said wave comprising: a modulatable transmitter; a modulatable receiver; a first frequency generator for producing an output of a first frequency; a second frequency generator for producing an output of a second frequency; a difference frequency producing means for producing a signal having a frequency equal to the frequency difference between said first and said second frequencies; a switching means for, in a first position, connecting the output from said first frequency generator to said modulatable transmitter to modulate the output thereof and connecting the output from said second frequency generator to said modulatable receiver to modulate the output thereof and for, in a second position, connecting the output from said second frequency generator to said modulatable transmitter to modulate the output thereof and connecting the output from said first frequency generator to said modulatable receiver to modulate the output thereof; and a phase measuring circuit responsive to the difference in phase between the output of said difference frequency producing means and the phase of the output of said modulatable receiver.
Claim 3
Dependent Claim
104 words
A distance measuring device in accordance with claim 1 wherein said phase measuring circuit comprises further switching means responsive to the first-mentioned switching means having first and second positions corresponding to the first and second positions of said first-mentioned switching means, said further switching means connecting the output of said modulatable receiver to the said phase measuring circuit such that the difference in phase between the output of said modulatable receiver in the first position of said first-mentioned switching means and the output of said modulatable receiver in the second position of said first-mentioned switching means can be determined by said phase measuring circuit.
Claim 4
Dependent Claim
88 words
A distance measuring device in accordance with claim 2 wherein said phase measuring circuit comprises phase delay means comprising a reversible phase delay device and a further phase delay device responsive to the output from said reversible phase delay device, said delay means producing an output corresponding to the difference between the phase of the output of said modulatable receiver for the first position of said first-mentioned switching means and the phase of the output of said modulatable receiver for said second position of said first-mentioned switching means.
Claim 5
Dependent Claim
63 words
A distance measuring device in accordance with claim 3 wherein said reversible phase delay device comprises a resolver connected to said further switching means such that the polarity of the output of said resolver for the first position of said further switching means is opposite to the polarity of the output of the resolver for the second position of Said further switching means.
Claim 6
Dependent Claim
25 words
A distance measuring device according to claim 3, comprising a null instrument connected between said difference frequency producing means and said reversible phase delay device.
Claim 7
Dependent Claim
27 words
A distance measuring device in accordance with claim 5 comprising a further null instrument, connected between said difference frequency producing means and said further phase delay device.
Claim 8
Dependent Claim
40 words
A distance measuring device in accordance with claim 1 wherein said first generator comprises a high precision generator and said second generator comprises an oscillator for producing an output responsive to a control signal derived from said high precision generator.
Claim 9
Dependent Claim
80 words
A distance measuring device in accordance with claim 7 wherein the means for producing the control signal comprises a mixer for producing an output of a frequency corresponding to the difference in frequency between the output of said precision generator and the output of said oscillator; a frequency dividing means for producing the difference frequency from the output of said precision generator; and a means for comparing the output from said frequency dividing means with the output from said mixer.
References Cited (Backward Citations)
US3200399A
Cited
US3333264A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-25 | 1976-01-24 | 1976-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-25 | 1980-01-24 | 1980-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-25 | 1984-01-24 | 1984-07-25 | $7700.00 | Window Closed / Lapsed |