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US3731300A
Expired / Lapsed
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Digital to sin/cos converter
Assignee: TDK Micronas GmbH
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Filing: 1971-08-13
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Granted: 1973-05-01
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Expires: 1991-08-13
Abstract
Abstract In a radar system, an arrangement for converting digital information representative of the rotational (azimuthal) position of the radar antenna to sine and cosine of azimuth waveforms for use in a display such as a plan position indicator. Azimuth change pulses indicative of the antenna''s rotation and azimuth reference pulses indicating the 0* reference direction are applied to a first counter, the individual outputs of each stage of which are in turn coupled to a comparator arrangement. The state of the first counter is compared with that of a second counter which is fed by a pulse source standard. The output of the last stage of the second counter is treated and filtered to provide a pure sinusoidal reference waveform to be sampled in a sample/hold detector arrangement. From the comparator arrangement sampling pulses are derived in accordance with the rotational position of the antenna relative to the digital reference as represented by the count in the second counter, with these sampling pulses then being applied to the sample/hold detector in order to produce a sine of azimuth waveform. A cosine of azimuth waveform is also derived via an adder stage in conjunction with the comparator arrangement, which adder counts the equivalent of 90* from the first derived sine sampling pulse to produce the priming condition for a cosine sampling pulse.
Inventors
- 👤 W Greutman
- 👤 I Studebaker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:58
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/66; H03M1/82; H03M1/68
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
219 words
A digital to sin/cos converter comprising: a. first means for digitally representing, by way of a plurality of outputs, positional information in response to equivalent input digital positional information applied thereto; b. second means for digitally representing, by way of a plurality of outputs, digital reference information, said second means further providing a symmetrical sinusoidal reference waveform and including a generator having a predetermined output frequency, a first n-stage counter arrangement coupled to said frequency generator and providing in response thereto n parallel outputs, and third means, coupled to the nth and with ones of said parallel outputs, which outputs constitute respectively a first desired pulse frequency output in accordance with the predetermined frequency generator input to said first n-stage counter and a pulse frequency output substantially twice that of said nth output, for generating in response to said nth and n-1th outputs said symmetrical sinusoidal reference waveform; c. fourth means for comparing said plurality of outputs of said first means and second means and for providing sampling pulses responsive to the phase relationship of said first and second means outputs; and d. detecting means coupling said sinusoidal reference waveform and said sampling pulses, for providing a resultant sinusoidal output equivalent to the digital information input in response to a sampling of said reference waveform by said sampling pulses.
Claim 2
Dependent Claim
219 words
A digital to sin/cos converter comprising: a. first means for digitally representing, by way of a plurality of outputs, positional information in response to equivalent input digital positional information applied thereto; b. second means for digitally representing, by way of a plurality of outputs, digital reference information, said second means further providing a symmetrical sinusoidal reference waveform and including a generator having a predetermined output frequency, a first n-stage counter arrangement coupled to said frequency generator and providing in response thereto n parallel outputs, and third means, coupled to the nth and with ones of said parallel outputs, which outputs constitute respectively a first desired pulse frequency output in accordance with the predetermined frequency generator input to said first n-stage counter and a pulse frequency output substantially twice that of said nth output, for generating in response to said nth and n-1th outputs said symmetrical sinusoidal reference waveform; c. fourth means for comparing said plurality of outputs of said first means and second means and for providing sampling pulses responsive to the phase relationship of said first and second means outputs; and d. detecting means coupling said sinusoidal reference waveform and said sampling pulses, for providing a resultant sinusoidal output equivalent to the digital information input in response to a sampling of said reference waveform by said sampling pulses.
Claim 3
Dependent Claim
102 words
The converter according to claim 1 wherein said third means includes a monostable multivibrator arrangement coupled to said n-1th output for producing a pulse output of predetermined duration in response to the input thereto, steering and flip-flop logic means, coupled to the output of said multivibrator arrangement and to said nth output from said first counter, for generating in response to the inputs thereto a symmetrical square wave output reference, and filter means coupled to said square wave reference for providing a symmetrical sinusoidal reference waveform which is to be sampled by the dual output sampling pulses provided by said fourth means.
Claim 4
Dependent Claim
50 words
The convertor according to claim 2 wherein said third means includes adjustment means for adjusting the phase of the sinusoidal reference waveform relative to the digital input positional information in order to provide output sine and cosine waveforms accurately corresponding to the position which the digital input positional information represents.
Claim 5
Dependent Claim
63 words
The converter according to claim 1 wherein said first means include a second n-stage counter providing n parallel outputs in dependence upon the digital positional information input thereto, and wherein the input information is in the form of a series of rotational change pulses, the outputs of said second n-stage counter at any given time thereby representing collectively the digital input rotational position.
Claim 6
Dependent Claim
91 words
The converter according to claim 4 whereiN said fourth means includes fifth means, comparing the respective parallel outputs of said first and second n-stage counters, for providing in response thereto a first pulse output whenever the state of said first and second counters is the same, and sixth means for generating a second pulse having a 90* phase relationship with said first pulse, said fourth means thereby providing dual pulse outputs having a relative phase of 90* for sampling the generated reference sinusoidal waveform in accordance with the digital input information.
Claim 7
Dependent Claim
101 words
The converter according to claim 5 wherein said fifth means includes a m-bit comparator coupled to the first m (m least significant) outputs of each n-stage counter and a first r-bit comparator coupled to the output of said m-bit comparator and to the remaining r outputs of each n-stage counter, and said sixth means includes a 90* adder stage coupled to said r outputs of one of said n-stage counters and a second r-bit comparator coupled to the outputs of said adder stage and said m-bit comparator and further input-coupled to said r outputs of the other of said n-stage counters.
Claim 8
Dependent Claim
49 words
The convertor according to claim 4 further including gating means coupled to the pulse outputs of said fourth means for providing output sampling pulses free from spurious pulses which may arise from the switching of the logic contained in said counters in response to the input information applied thereto.
References Cited (Backward Citations)
US3349230A
Cited
US3371334A
Cited
US3488653A
Cited
US3493965A
Cited
US3514775A
Cited
US3609320A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-30 | 1976-10-30 | 1977-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-30 | 1980-10-30 | 1981-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-30 | 1984-10-30 | 1985-05-01 | $7700.00 | Window Closed / Lapsed |