US3746849A
Expired / Lapsed
US
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Cordic digital calculating apparatus
Assignee: Gemalto Terminals Ltd
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Filing: 1971-08-12
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Granted: 1973-07-17
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Expires: 1991-08-12
Abstract
Abstract Digital calculating apparatus, comprising two shift register stores with each store connected in a recirculating circuit loop which includes means for changing a number in one store by an arithmetic progression, typically linear or exponential. Initial values are entered in both stores and successive recirculations of digital data are effected in each loop in a manner which causes one loop to undergo a plurality of N addition or subtracting cycles, and also causes the other loop to undergo a plurality of M recirculating cycles where M is equal to or less than N. Through recirculation in the manner described, one of the stores converges upon a predetermined final value and the desired answer in digital form may then be obtained from the other store.
Inventors
- 👤 C Bailey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:16
CPC Classifications
G; G06; G06F; G06F7/00; G06F7/38; G06F7/48; G06F7/544; G06F7/552; G06F7/5525; G06F1/00; G06F1/02; G06F1/03; G06F1/0307
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
205 words
Digital calculating apparatus comprising a first and a second shift register store; means for entering a respective number having a respective predetermined initial value in each store; a respective combining circuit associated with each store, each combining circuit being connected between opposite ends of its store to form a respective recirculation loop therewith, each combining circuit including means for carrying out a combining operation on the number in its store when the number is recirculated through the combining circuit, with successive combining operations serving to change the value of the number in the respective store in a predetermined progression as said number is successively recirculated through the respective combining circuit; and control means for successively recirculating the number in said first store through its respective combining circuit for a plurality of groups of N combining operations, where N is an integer greater than 0, to cause the number in said first source to converge to a predetermined final value, and for recirculating the number in said second store through its respective combining circuit for a group of M combIning operations for each group of N combining operations of the combining circuit associated with the first store, where M is an integer not greater than N.
Claim 2
Dependent Claim
205 words
Digital calculating apparatus comprising a first and a second shift register store; means for entering a respective number having a respective predetermined initial value in each store; a respective combining circuit associated with each store, each combining circuit being connected between opposite ends of its store to form a respective recirculation loop therewith, each combining circuit including means for carrying out a combining operation on the number in its store when the number is recirculated through the combining circuit, with successive combining operations serving to change the value of the number in the respective store in a predetermined progression as said number is successively recirculated through the respective combining circuit; and control means for successively recirculating the number in said first store through its respective combining circuit for a plurality of groups of N combining operations, where N is an integer greater than 0, to cause the number in said first source to converge to a predetermined final value, and for recirculating the number in said second store through its respective combining circuit for a group of M combIning operations for each group of N combining operations of the combining circuit associated with the first store, where M is an integer not greater than N.
Claim 3
Dependent Claim
92 words
Digital calculating apparatus as in claim 1 wherein the combining means in at least one of said recirculating loops perform combining operations serving to change the value in the respective store in an exponential progression, the last recited combining operations being selectively additions to the store contents and subtractions from the store contents of the store contents divided by Rp, wherein R is the radix of the number system of the number in the store and P is initially zero and is incremented by one for each group of N combining operations.
Claim 4
Dependent Claim
30 words
Digital calculating apparatus as in claim 2 wherein both combining means perform the same type of combining operations serving to change the numbers in their respective stores in exponential progressions.
Claim 5
Dependent Claim
16 words
Digital calculating apparatus as in claim 3 where M 1 and N is greater than 1.
Claim 6
Dependent Claim
13 words
Digital calculating apparatus as in claim 3 wherein M 1 and N 2.
Claim 7
Dependent Claim
13 words
Digital calculating apparatus as in claim 3 where M 1 and N 3.
Claim 8
Dependent Claim
58 words
Digital calculating apparatus as in claim 2 wherein one of said combining means perform combining operations serving to change the number in the respective store in a linear progression, the last recited combining operations being selectively additions to and subtractions from the contents of its store of terms which are different for each group of N combining operations.
Claim 9
Dependent Claim
47 words
Digital calculating apparatus as in claim 7, wherein said terms are the terms of the series log10 2, log10 (0.9), log 10 (1.01), . . . , with a successive term of said series being used as the term in each successive group of N combining operations.
Claim 10
Dependent Claim
53 words
Digital calculating apparatus as in claim 1 including register means for storing said final value, means for comparing the current contents of one of said stores with the contents of said register means, said control means controlling the combining operations in accordance with the results of the comparisons performed by said comparing means.
Claim 11
Dependent Claim
133 words
Digital calculating apparatus for performing the CORDIC algorithm comprising two registers, means for storing in said registers the values of two quantities, combining means connected to said two registers and operative in a succession of cycles for selectively adding to or subtracting from the contents of each register the contents of the other register multiplied, in successive pairs of cycles, by fractions R 1, R 2, R 3, in a number system having a predetermined Radix R, and means connected to the registers and to the combining means and operative following at least the first pair of said cycles for correcting the contents of the registers by subtracting from the contents of each register its own contents multiplied by the square of the fraction used in the multiplying of the immediately preceding cycle.
Claim 12
Dependent Claim
133 words
Digital calculating apparatus for performing the CORDIC algorithm comprising two registers, means for storing in said registers the values of two quantities, combining means connected to said two registers and operative in a succession of cycles for selectively adding to or subtracting from the contents of each register the contents of the other register multiplied, in successive pairs of cycles, by fractions R 1, R 2, R 3, in a number system having a predetermined Radix R, and means connected to the registers and to the combining means and operative following at least the first pair of said cycles for correcting the contents of the registers by subtracting from the contents of each register its own contents multiplied by the square of the fraction used in the multiplying of the immediately preceding cycle.
Claim 13
Dependent Claim
57 words
Digital calculating apparatus as in claim 10 wherein the last recited means include means responsive to the completion of the correcting subtraction for carrying out a correcting addition in which the contents of each register are corrected by adding thereto the register contents multiplied by the fourth power of the fraction utilized in the immediately preceding cycle.
Claim 14
Dependent Claim
13 words
Digital calculating apparatus as in claim 11 wherein the Radix R is 10.
References Cited (Backward Citations)
US3649821A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-16 | 1977-01-15 | 1977-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-16 | 1981-01-15 | 1981-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-16 | 1985-01-15 | 1985-07-17 | $7700.00 | Window Closed / Lapsed |