US3735110A
Expired / Lapsed
US
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Digital sine/cosine generator
Assignee: Thales Nederland BV
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Filing: 1971-10-14
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Granted: 1973-05-22
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Expires: 1991-10-14
Abstract
Abstract In a sine/cosine generator the angular value written into an angle register, is directly supplied to a memory (ROM), if either the sine of an angle located in the first or third quadrant, or the cosine of an angle in the second or fourth quadrant must be determined. The value is supplied in inverted form to the memory, if either the sine of an angle located in the second or fourth quadrant, or the cosine of an angle located in the first or third quadrant must be determined. The memory contains the sine values of a discrete number of angular values to be offered by the angle register. Furthermore, the sine/cosine generator comprises various logic circuits to minimize the memory capacity to be used, and to place the sine and cosine values, obtained by the memory and provided with a sign bit, in a register which is part of an output circuit.
Inventors
- 👤 C Lecomte
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:05
CPC Classifications
G; G06; G06F; G06F1/00; G06F1/02; G06F1/03; G06F1/035; G06F1/0353
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
229 words
A digital sine/cosine generator, comprising an angle register and a memory which contains in digital form the sine values of a discrete number of angular values to be offered by said register, a control unit to which, in the first instance, are fed the contents of that part of the angle register in which two most significant bits are stored, and to which, in the second instance, signals are supplied indicating whether the sine or the cosine of the angular value contained in said register should be determined, said control unit having switching means for ensuring that the contents of the angle register decreased by the two most significant bits are fed directly to the memory, if either the sine of an angle located in the first or third quadrant, or the cosine of an angle located in the second or fourth quadrant must be determined, said contents being fed in an inverted form to said memory if either the sine of an angle located in the second or fourth quadrant, or the cosine of an angle located in the first or third quadrant should be determined, and an output circuit having at least a register in which, under the control of a signal supplied by said control unit, provides a sine value supplied by said memory, with a sign bit corresponding with said sine or cosine value, respectively.
Claim 2
Dependent Claim
229 words
A digital sine/cosine generator, comprising an angle register and a memory which contains in digital form the sine values of a discrete number of angular values to be offered by said register, a control unit to which, in the first instance, are fed the contents of that part of the angle register in which two most significant bits are stored, and to which, in the second instance, signals are supplied indicating whether the sine or the cosine of the angular value contained in said register should be determined, said control unit having switching means for ensuring that the contents of the angle register decreased by the two most significant bits are fed directly to the memory, if either the sine of an angle located in the first or third quadrant, or the cosine of an angle located in the second or fourth quadrant must be determined, said contents being fed in an inverted form to said memory if either the sine of an angle located in the second or fourth quadrant, or the cosine of an angle located in the first or third quadrant should be determined, and an output circuit having at least a register in which, under the control of a signal supplied by said control unit, provides a sine value supplied by said memory, with a sign bit corresponding with said sine or cosine value, respectively.
Claim 3
Dependent Claim
65 words
A digital sine/cosine generator according to claim 1, wherein the memory contains 2m 2 sine values the magnitude of which can be denoted by sin(n-1/2) delta with n 1, 2, . . . , 2m 2, where m represents the number of bits from which the total contents of the angle register are composed, and delta represents the angular value of the least significant bit.
Claim 4
Dependent Claim
128 words
A digital sine/cosine generator according to claim 1, wherein the register in the output circuit comprises a parallel adder, said adder having a number of elements corresponding to a number of bits composed by the sine values supplied by the memory said elements increased by a sign bit, and wherein the signal coming from the control unit and supplied to the output circuit ensures that a sine value supplied by the memory is directly supplied to said adder, if said sine or cosine value is positive, said value being supplied in an inverted form, if said sine or cosine is negative, whereby the above signal derived from the control unit is also supplied to the parallel adder in order to increase the contents of the adder by 1.
Claim 5
Dependent Claim
29 words
A digital sine/cosine generator according to claim 2, wherein of each of the sine values expressed in k bits only k-1 least significant bits are stored in the memory.
Claim 6
Dependent Claim
182 words
A digital sine/cosine generator according to claim 4, wherein the register in the output circuit is formed by a parallel adder consisting of k+1 elements, said generator comprising switching means for feeding the signal coming from the control unit to the output circuit, said switching means ensuring that the number supplied by the memory, and consisting of k-1 bits, is directly fed to the first k-1 elements of the adder, if said sine or cosine, respectively, is positive, and wherein said number is supplied in an inverted form, if said sine or cosine, respectively, is negative, said sine/cosine generator further comprising a logic circuit for determining the contents of the kth element of the parallel adder after the most significant bit supplied by the memory has been supplied to it, and wherein a signal coming from the control unit, functioning as a sign bit, determines the contents of the (k+1)th element of the parallel adder and is fed to said adder in order to increase the contents of said adder by 1 in case the desired sine or cosine, respectively, is negative.
Claim 7
Dependent Claim
128 words
A digital sine/cosine generator according to claim 1, wherein the memory comprises a first and a second part memory whereby the first part memory contains 2m 4 sine values whose magnitude can be denoted by sin(4n - 7/2) delta with n 1, 2, . . . , 2m 4, where m represent the number of bits constituting the total contents of the angle register, and delta the angular value of the least significant bit, and whereby of each coarse sine value expressed in k-1 bits, only the k-2 least significant bits are stored in the first part memory, and further wherein sine increment values, 2m 2, are contained in the second part memory and are expressed in 2 bits form as a refinement of the coarse sine values.
Claim 8
Dependent Claim
167 words
A digital sine/cosine generator according to claim 6, wherein the register contained in the output circuit is constituted by a parallel adder consisting of k+1 elements, whereby under the control of a signal supplied by the control unit, a coarse sine value supplied by the first part memory is placed into the second to the (k-1)th element of the adder, and a sine increment value supplied by the second part memory is fed to the first two elements of the adder and is added to the coarse sine value, the sine/cosine generator further comprising a logic circuit by means of which, after the most significant bit supplied by the first part memory and controlled by signals coming from the angle register and control unit has been supplied to it, the contents of the kth element of the parallel adder are determined, and further wherein the signal coming from the control unit functions as a sign bit for determining the contents of the (k+1)th element of the adder.
Claim 9
Dependent Claim
119 words
A digital sine/cosine generator according to claim 7, wherein the signal coming from the control unit, using first switching means available for this purpose in the output circuit, ensures that the number consisting of k-2 bits supplied by the first part memory is fed directly to the parallel adder if the desired sine or cosine, respectively, is positive, and the number is fed in an inverted form if the desired sine or cosine, respectively, is negative, whereby at the same time either a 0 or a 1 is fed to the least significant element of the parallel adder, and added to the contents of said adder depending on whether the desired sine or cosine, respectively, is positive or negative.
Claim 10
Dependent Claim
102 words
A digital sine/cosine generator according to claim 7 wherein the signal coming from the control unit ensures, using second switching meAns available for this purpose in the output circuit, that the two bits supplied by the second part memory are directly fed to the parallel adder if said sine or cosine, respectively, is positive, and said bits are fed in an inverted form if said sine or cosine, respectively, is negative, and further wherein a correction circuit is available, which for the purpose of sine or cosine determination of small angular values corrects the increment values supplied by the second part memory.
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) | 1976-05-21 | 1976-11-20 | 1977-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-21 | 1980-11-20 | 1981-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-21 | 1984-11-20 | 1985-05-22 | $7700.00 | Window Closed / Lapsed |