US3684375A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital distance measuring instrument
Assignee: A AG AB
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Filing: 1970-09-28
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Granted: 1972-08-15
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Expires: 1990-09-28
Abstract
Abstract A distance measuring instrument comprising a high-frequency reference source for emitting a modulated light signal and from which a first and second oscillation of 1 kHz is derived in a first and a second periodic counter, respectively. A phase control means locks the phase of the emitted signal to the first oscillation. A heterodyne frequency representing the transmitter phase is applied to transpose the received signal down to 1 kHz and a second phase detector compares the phase of this signal with the second oscillation and causes additional pulses to be supplied to the first or the second counter depending on the polarity of the phase difference so as to reduce it to zero. A forward-backward counter responds in one direction to additional pulses supplied to one periodic counter and to the opposite direction to those supplied to the other periodic counter to provide a digital indication of the phase difference corresponding to the distance.
Inventors
- 👤 Carl-Erik Granqvist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:39
CPC Classifications
G; G01; G01S; G01S17/00; G01S17/02; G01S17/06; G01S17/08; G01S17/32
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
216 words
A distance measuring instrument comprising, in combination: a source of high-frequency reference pulses of a predetermined frequency, a first periodic counter responsive to said source for producing a first oscillation of a submultiple of said predetermined frequency, a second periodic counter responsive to said source for producing a second oscillation of said submultiple frequency, a transmitter for emitting a signal of a phase representative of said reference pulses, a receiver for receiving said signal after said signal has traversed the distance to be measured, the phase of said received signal representing the distance to be measured, and for deriving from said received signal a secondary signal of the frequency of said second oscillation and representing said phase, a first phase control means for controlling the phase of said emitted signal relative to the phase of said first oscillation, means for modifying the number of pulses supplied to said second counter relative to the number supplied to said first counter, a second phase control means responsive to the phase difference between said secondary signal and said second oscillation for controlling said modifying means to establish phase equality between said second oscillation and said secondary signal, and a forwardbackward counter responsive to said modifying means for indicating the phase difference between said fiRst oscillation and said secondary oscillation.
Claim 2
Dependent Claim
216 words
A distance measuring instrument comprising, in combination: a source of high-frequency reference pulses of a predetermined frequency, a first periodic counter responsive to said source for producing a first oscillation of a submultiple of said predetermined frequency, a second periodic counter responsive to said source for producing a second oscillation of said submultiple frequency, a transmitter for emitting a signal of a phase representative of said reference pulses, a receiver for receiving said signal after said signal has traversed the distance to be measured, the phase of said received signal representing the distance to be measured, and for deriving from said received signal a secondary signal of the frequency of said second oscillation and representing said phase, a first phase control means for controlling the phase of said emitted signal relative to the phase of said first oscillation, means for modifying the number of pulses supplied to said second counter relative to the number supplied to said first counter, a second phase control means responsive to the phase difference between said secondary signal and said second oscillation for controlling said modifying means to establish phase equality between said second oscillation and said secondary signal, and a forwardbackward counter responsive to said modifying means for indicating the phase difference between said fiRst oscillation and said secondary oscillation.
Claim 3
Dependent Claim
63 words
An instrument as claimed in claim 1, in which said modifying means comprises a first switch for supplying additional pulses to said first counter, and to said forward-backward counter for actuating said forward-backward counter in the forward direction and a second switch for supplying additional pulses to said second counter, and to said forward-backward counter for actuating forward-backward counter in the backward direction.
References Cited (Backward Citations)
GB953048A
Cited
US3446971A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-15 | 1976-02-14 | 1976-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-15 | 1980-02-14 | 1980-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-15 | 1984-02-14 | 1984-08-15 | $7700.00 | Window Closed / Lapsed |