Method and apparatus for generating numbers
First Claim
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1. A method of generating a non-repeating sequence of numbers having a substantially uniform distribution, the method comprising:
- shifting digits out of a shift register;
using successive digits from a continuous sequence thereof to replace said digits shifted out of the shift register; and
using the contents of at least one stage of the shift register to control whether the contents of the shift register are replaced by their complement, so that the shift register has changing contents which can be used to derive said non-repeating sequence.
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Abstract
A non-repeating sequence of numbers having a substantially uniform distribution is obtained from a shift register whose contents are shifted, with the shifted digits being replaced by digits from a continuous sequence. The contents of the shift register are also replaced by their complement in dependence for the value of the most significant bit, so that the operations performed on the contents are represented by a tent map, thereby providing uniform distribution of the numbers. A randomising subsystem can be used to convert the output sequence into a random sequence.
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Citations
15 Claims
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1. A method of generating a non-repeating sequence of numbers having a substantially uniform distribution, the method comprising:
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shifting digits out of a shift register;
using successive digits from a continuous sequence thereof to replace said digits shifted out of the shift register; and
using the contents of at least one stage of the shift register to control whether the contents of the shift register are replaced by their complement, so that the shift register has changing contents which can be used to derive said non-repeating sequence. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15)
combining the digits shifted out of the shift register with substantially random numbers.
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12. The method as claimed in claim 11, further comprising:
producing the random numbers with a non-deterministic source.
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13. The method as claimed in claim 12, wherein said step of producing the sequence of random numbers with a non-deterministic source comprises:
producing the sequence of random numbers with a thermal noise source.
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14. The method of claim 11, further comprising:
producing both the continuous sequence of digits and the random numbers with a common source.
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15. The method of claim 14, wherein the combination of numbers from the non-repeating sequence with the random numbers is performed by exclusive OR-ing each bit of the random number with a respective bit of a number from the non-repeating sequence.
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10. A method of generating a non-repeating sequence of numbers having a substantially uniform distribution within a predetermined interval, the method comprising:
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providing a sequence of digits and repeatedly doubling a value of a group of said sequence of digits to produce a result; and
replacing the result by its complement in dependence on said value, wherein said step of providing includes successively replenishing the group with digits from said sequence.
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Specification