US3696407A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital to synchro converter
Assignee: ENVIROMENTAL TECHNOLOGIES GROUP Inc
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Filing: 1969-08-21
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Granted: 1972-10-03
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Expires: 1989-08-21
Abstract
Abstract Disclosed is a D to S converter for converting a binary input digital code to an analog output suitable for driving a synchro or resolver. The encoder comprises a plurality of electronic angle vector rotators including cross coupled sine and cosine channels for modifying the input to each stage by an amount equal to plus or minus a known angle. Each stage produces rotation by half the angle of the previous stage. The converter includes a first stage forming a quadrant selector and angle rotation for bits of lesser significance are approximated by a resistance ladder linear interpolator. The output drives a resolver directly or passes through a Scott transformation stage for application to the windings of a synchro.
Inventors
- 👤 Mckenny W Egerton Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:52
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/66; H03M1/665
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
182 words
A digital to analog converter comprising sine and cosine channels, means for impressing a reference voltage on both said sine and cosine channels, a vector rotator comprised of a plurality of electronic vector rotator stages coupled to said channels for producing an output from said sine channel representative of the sine of a known angle and from said cosine channel an output representative of the cosine of a known angle, each stage of said rotator including means for cross coupling to respective channels signals representative of either positive or negative quantities of the signal in the other channel, the cross coupled quantities of successive stages being related in accordance with the tangent of a binarily decreasing angle, and means coupled to said successive stages for applying to them the successive bits of a digital input code wherein each stage of said vector rotator comprises an operational amplifier in each channel having an inverting input and a non-inverting input, and means for cross coupling a signal from each channel to both the inverting and non-inverting inputs of the amplifier in the other channel.
Claim 2
Dependent Claim
182 words
A digital to analog converter comprising sine and cosine channels, means for impressing a reference voltage on both said sine and cosine channels, a vector rotator comprised of a plurality of electronic vector rotator stages coupled to said channels for producing an output from said sine channel representative of the sine of a known angle and from said cosine channel an output representative of the cosine of a known angle, each stage of said rotator including means for cross coupling to respective channels signals representative of either positive or negative quantities of the signal in the other channel, the cross coupled quantities of successive stages being related in accordance with the tangent of a binarily decreasing angle, and means coupled to said successive stages for applying to them the successive bits of a digital input code wherein each stage of said vector rotator comprises an operational amplifier in each channel having an inverting input and a non-inverting input, and means for cross coupling a signal from each channel to both the inverting and non-inverting inputs of the amplifier in the other channel.
Claim 3
Dependent Claim
57 words
A converter according to claim 1 including a switch coupled to each amplifier, said switch when closed acting to short out a corresponding input of its respective amplifier, means coupling an input bit to the switch of one channel, and means coupling the input bit complement to the switch in the other channel of the rotator stage.
Claim 4
Dependent Claim
20 words
A converter according to claim 2 wherein said switches couple the respective non-inverting inputs of said amplifiers to system ground.
Claim 5
Dependent Claim
181 words
A digital to analog converter comprising sine and cosine channels, means for impressing a reference voltage on both said sine and cosine channels, a quadrant selection stage forming a part of each of said channels, means coupled to said quadrant selection stage for applying to it the two most significant bits of an input binary code representative of an angle of from 0* to 360*, a plurality of electronic vector rotator stages coupled to said quadrant selection stage for producing an analog output from said sine channel representative of the sine of said angle and from said cosine channel an analog output representative of the cosine of said angle, each stage of said rotator including means for cross coupling to respective channels signals representative of either positive or negative quantities of the signal in the other channel, the cross coupled quantities in the successive rotator stages being related in accordance with the tangent of a binarily decreasing angle, and means coupled to the successive stages of said vector rotator for applying to them corresponding successive remaining bits of said input code.
Claim 6
Dependent Claim
181 words
A digital to analog converter comprising sine and cosine channels, means for impressing a reference voltage on both said sine and cosine channels, a quadrant selection stage forming a part of each of said channels, means coupled to said quadrant selection stage for applying to it the two most significant bits of an input binary code representative of an angle of from 0* to 360*, a plurality of electronic vector rotator stages coupled to said quadrant selection stage for producing an analog output from said sine channel representative of the sine of said angle and from said cosine channel an analog output representative of the cosine of said angle, each stage of said rotator including means for cross coupling to respective channels signals representative of either positive or negative quantities of the signal in the other channel, the cross coupled quantities in the successive rotator stages being related in accordance with the tangent of a binarily decreasing angle, and means coupled to the successive stages of said vector rotator for applying to them corresponding successive remaining bits of said input code.
Claim 7
Dependent Claim
23 words
A converter according to claim 4 including a synchro coupled to receive the outputs from said sine and cosine channels of said converter.
Claim 8
Dependent Claim
20 words
A converter according to claim 5 including a Scott transformation device coupling said sine and cosine channels to said synchro.
Claim 9
Dependent Claim
22 words
A converter according to claim 6 wherein said Scott transformation device is a Scott transformation stage including a pair of operational amplifiers.
Claim 10
Dependent Claim
65 words
A converter according to claim 4 including a linear interpolator coupled to receive the sine and cosine signal outputs from the last stage of said vector rotator, said interpolator including a plurality of stages, and means coupled to the successive stages of said interpolator for applying to them corresponding successive bits of said code of lesser significance than are applied to said vector rotator stages.
Claim 11
Dependent Claim
14 words
A converter according to claim 8 wherein said interpolator comprises a resistance ladder netWork.
Claim 12
Dependent Claim
32 words
A converter according to claim 9 wherein said interpolator includes sine and cosine channels, and a pair of amplifiers cross coupled between said channels ahead of the first stage of said interpolator.
Claim 13
Dependent Claim
67 words
A converter according to claim 10 wherein each stage of said interpolator comprises a pair of sine channel resistors and a first switch coupled between the junction of said sine channel resistors and ground, and a pair of cosine channel resistors and a second switch coupled between the junction of said cosine channel resistors and ground, the resistors of successive interpolator stage being binarily related in value.
Claim 14
Dependent Claim
22 words
A converter according to claim 11 including a pair of current summing amplifiers terminating the sine and cosine channels of said interpolator.
Claim 15
Dependent Claim
168 words
An electronic angle vector rotator comprising sine and cosine channels, means for coupling a signal representative of sine theta to the input of said sine channel and representative of cosine theta to the input of said cosine channel, where theta is a first angle to be rotated through a second known angle phi , an operational amplifier in each channel, each said amplifier having an inverting input coupled to receive said sine theta and cosine theta signals respectively and each having a non-inverting input, a first pair of resistors R1 each coupling the input signal in one of said channels to the inverting input of the amplifier in the other channel, a second pair of resistors R2 each coupling the input signal in one of said channels to the non-inverting input of the amplifier in the other channel, and a pair of switches coupling said non-inverting inputs to ground, said resistor having resistance values according to the relationship R1 cot phi and R2 cot phi - 1/2 .
Claim 16
Dependent Claim
168 words
An electronic angle vector rotator comprising sine and cosine channels, means for coupling a signal representative of sine theta to the input of said sine channel and representative of cosine theta to the input of said cosine channel, where theta is a first angle to be rotated through a second known angle phi , an operational amplifier in each channel, each said amplifier having an inverting input coupled to receive said sine theta and cosine theta signals respectively and each having a non-inverting input, a first pair of resistors R1 each coupling the input signal in one of said channels to the inverting input of the amplifier in the other channel, a second pair of resistors R2 each coupling the input signal in one of said channels to the non-inverting input of the amplifier in the other channel, and a pair of switches coupling said non-inverting inputs to ground, said resistor having resistance values according to the relationship R1 cot phi and R2 cot phi - 1/2 .
Claim 17
Dependent Claim
50 words
An angle vector rotator according to claim 13 including a flip-flop, one output of said flip-flop being coupled to one of said switches and the other output being coupled to the other of said switches whereby said switches are ganged such that when one is open the other is closed.
Claim 18
Dependent Claim
53 words
An angle vector rotator according to claim 13 including a pair of input resistors R coupling said sine theta and cosine theta inputs to the inverting inputs of said amplifiers, said resistors having resistance values according to the relationships R R, R1 R cot phi , and R2 R(cot phi - 1/2 ).
Claim 19
Dependent Claim
50 words
An angle vector rotator according to claim 15 including a pair of feedback resistors for said amplifiers each having a resistance value R, and a resistor in parallel with each of said switches coupling the respective non-inverting amplifier inputs to ground, said parallel resistors each having a resistance value R.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-03 | 1976-04-03 | 1976-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-03 | 1980-04-03 | 1980-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-03 | 1984-04-03 | 1984-10-03 | $7700.00 | Window Closed / Lapsed |