US4853884A
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US
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Random number generator with digital feedback
Assignee: Motorola Solutions Inc
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Filing: 1987-09-11
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Granted: 1989-08-01
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Expires: 2007-09-11
Abstract
Abstract A zener diode random number generator circuit is described which produces a random binary number output having a statistical distribution exhibiting a controlled degree of randomness determined in response to an input control signal. A microprocessor feedback circuit monitors the random number output and produces the input control signal in response to the difference between the degree of randomness of the output signal and that of a pre-determined statistical distribution. The digital feedback automatically adjusts the zener diode biasing point and the limiter threshold such that part-to-part tolerance, component aging, temperature variations, or voltage fluctuations will not adversely affect the randomness of the bit stream output. In the preferred embodiment, the microprocessor tests the ratio of ONES bits to ZERO bits of the random number such that a desired 1:1 ONES/ZERO ratio is approximated.
Inventors
- 👤 Daniel P. Brown
- 👤 Carl M. Danielsen
- 👤 Ezzat A. Dabbish
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:42
CPC Classifications
G; G06; G06F; G06F7/00; G06F7/58; G06F7/588
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
115 words
A random number generator having a controlled degree of randomness comprising: noise source means for producing an analog noise signal having a statistical distribution exhibiting a particular degree of randomness determined in response to an input control signal; pulse shaping means for generating random binary data in response to said analog noise signal; feedback means for monitoring said random binary data and for producing said input control signal in response to the difference between the degree of randomness of said binary data and that of a predetermined statistical distribution; and control means for outputting said random binary data only when it is within prescribed limits of said degree of randomness of said predetermined statistical distribution.
Claim 2
Dependent Claim
115 words
A random number generator having a controlled degree of randomness comprising: noise source means for producing an analog noise signal having a statistical distribution exhibiting a particular degree of randomness determined in response to an input control signal; pulse shaping means for generating random binary data in response to said analog noise signal; feedback means for monitoring said random binary data and for producing said input control signal in response to the difference between the degree of randomness of said binary data and that of a predetermined statistical distribution; and control means for outputting said random binary data only when it is within prescribed limits of said degree of randomness of said predetermined statistical distribution.
Claim 3
Dependent Claim
49 words
The random number generator according to claim 1, wherein said noise source means includes a zener diode having a bias point at the knee of the avalanche breakdown region of its characteristic curve so as to generate random noise, said bias point being responsive to said input control signal.
Claim 4
Dependent Claim
42 words
The random number generator according to claim 1, wherein said pulse shaping means includes a limiter device having an input switching threshold defined in response to its supply voltage, and wherein said feedback means includes means for varying said limiter supply voltage.
Claim 5
Dependent Claim
28 words
The random number generator according to claim 3, wherein both said analog noise signal and said limiter supply voltage are responsive to changes in said input control signal.
Claim 6
Dependent Claim
45 words
The random number generator according to claim 1, wherein said feedback means includes a microprocessor which produces said input control signal in a digital format, and further includes a digital-to-analog converter which produces a variable bias voltage in response to said digital input control signal.
Claim 7
Dependent Claim
28 words
The random number generator according to claim 1, wherein said predetermined statistical distribution exhibits a ratio of ONES bits to ZEROS bits which is approximately equal to 1:1.
Claim 8
Dependent Claim
129 words
A circuit for generating random binary numbers which meet a given criteria for randomness comprising: circuit means for producing a bias voltage in response to a control signal; noise source means for producing an analog noise signal having a random noise component and an average DC component, both of which are responsive to said bias voltage; pulse shaping means for amplifying and limiting said analog noise signal to product a digital pulse stream having randomness properties defined by both said random noise signal; and controller means for sampling said digital pulse stream for a particular time interval to provide a random binary number, and for producing said control signal in response to the difference between desired randomness criteria of said random binary number and said given criteria for randomness.
Claim 9
Dependent Claim
129 words
A circuit for generating random binary numbers which meet a given criteria for randomness comprising: circuit means for producing a bias voltage in response to a control signal; noise source means for producing an analog noise signal having a random noise component and an average DC component, both of which are responsive to said bias voltage; pulse shaping means for amplifying and limiting said analog noise signal to product a digital pulse stream having randomness properties defined by both said random noise signal; and controller means for sampling said digital pulse stream for a particular time interval to provide a random binary number, and for producing said control signal in response to the difference between desired randomness criteria of said random binary number and said given criteria for randomness.
Claim 10
Dependent Claim
39 words
The circuit according to claim 7, wherein said controller means produces said control signal in a digital format, and wherein said circuit means includes a digital-to-analog converter for varying said bias voltage in response to said digital control signal.
Claim 11
Dependent Claim
46 words
The circuit according to claim 7, wherein said noise source means includes a zener diode having a bias point at the knee of the avalanche breakdown region of its characteristic curve so as to generate random noise, said bias point being determined by said bias voltage.
Claim 12
Dependent Claim
40 words
The circuit according to claim 7, wherein said pulse shaping means includes a limiter device having an input switching threshold defined in response to its supply voltage, and wherein said controller means includes means for varying said limiter supply voltage.
Claim 13
Dependent Claim
25 words
The circuit according to claim 10, wherein both said analog noise signal and said limiter supply voltage are responsive to changes in said bias voltage.
Claim 14
Dependent Claim
52 words
The circuit according to claim 7, wherein said controller means is a microprocessor which determines the acceptability of said random binary number with respect to the desired randomness criteria of a predetermined statistical distribution and outputs said random binary number only if it is within prescribed limits of said desired randomness criteria.
Claim 15
Dependent Claim
28 words
The circuit according to claim 7, wherein said desired randomness criteria is the difference between the number of ONES bits and ZEROS bits of said random binary number.
Claim 16
Dependent Claim
26 words
The circuit according to claim 13, wherein said predetermined statistical distribution exhibits a ratio of ONES bits to ZEROS bits which is approximately equal to 1:1.
Claim 17
Dependent Claim
43 words
The circuit according to claim 13, wherein said controller means determines the acceptability of said random binary number by testing whether the difference between the number of ONES bits and ZEROS bits of said random binary number is less than a predetermined limit.
Claim 18
Independent Claim
173 words
A method of generating random binary numbers which meet a desired criteria for randomness comprising the steps of: generating an analog noise signal having a random noise component and an average DC component, both of which are responsive to a variable bias voltage; amplifying and limiting said analog noise signal to produce a digital pulse stream having randomness properties defined by both said random noise component and said average DC component of said analog noise signal; sampling said digital pulse stream for a particular time interval to provide a random binary number; measuring desired randomness criteria of said random binary number; determining the acceptability of said random binary number with respect to the desired randomness criteria of a predetermined statistical distribution; outputting said random binary number only if it is within prescribed limits of said desired randomness criteria; and varying said bias voltage in a manner to direct the randomness properties of said digital pulse stream to approach said desired randomness criteria if said random binary number is not within said prescribed limits.
Claim 19
Independent Claim
173 words
A method of generating random binary numbers which meet a desired criteria for randomness comprising the steps of: generating an analog noise signal having a random noise component and an average DC component, both of which are responsive to a variable bias voltage; amplifying and limiting said analog noise signal to produce a digital pulse stream having randomness properties defined by both said random noise component and said average DC component of said analog noise signal; sampling said digital pulse stream for a particular time interval to provide a random binary number; measuring desired randomness criteria of said random binary number; determining the acceptability of said random binary number with respect to the desired randomness criteria of a predetermined statistical distribution; outputting said random binary number only if it is within prescribed limits of said desired randomness criteria; and varying said bias voltage in a manner to direct the randomness properties of said digital pulse stream to approach said desired randomness criteria if said random binary number is not within said prescribed limits.
Claim 20
Dependent Claim
50 words
The method according to claim 16, wherein said noise signal generating step is performed by a zener diode having a bias point at the knee of the avalanche breakdown region of its characteristic curve so as to generate random noise, said bias point being determined by said variable bias voltage.
Claim 21
Dependent Claim
30 words
The method according to claim 16, wherein said limiting step is performed by a limiter device having an input switching threshold which is also responsive to said variable bias voltage.
Claim 22
Dependent Claim
43 words
The method according to claim 16, wherein said determining step determines the acceptability of said random binary number by testing whether the difference between the number of ONES bits and ZEROS bits of said random binary number is less than a predetermined limit.
Claim 23
Dependent Claim
132 words
A random number generator having a controlled degree of randomness comprising: noise source means for producing an analog noise signal having a statistical distribution exhibiting a particular degree of randomness determined in response to an input control signal, said noise source means including a zener diode having an adjustable bias point near the knee of the avalanche breakdown region of its characteristic curve so as to generate random noise, said adjustable bias point being responsive to said input control signal; pulse shaping means for generating random binary data in response to said analog noise signal; and feedback means for monitoring said random binary data and for producing said input control signal in response to the difference between the degree of randomness of said binary data and that of a predetermined statistical distribution.
Claim 24
Dependent Claim
132 words
A random number generator having a controlled degree of randomness comprising: noise source means for producing an analog noise signal having a statistical distribution exhibiting a particular degree of randomness determined in response to an input control signal, said noise source means including a zener diode having an adjustable bias point near the knee of the avalanche breakdown region of its characteristic curve so as to generate random noise, said adjustable bias point being responsive to said input control signal; pulse shaping means for generating random binary data in response to said analog noise signal; and feedback means for monitoring said random binary data and for producing said input control signal in response to the difference between the degree of randomness of said binary data and that of a predetermined statistical distribution.
Claim 25
Dependent Claim
36 words
The random number generator according to claim 20, wherein said pulse shaping means includes means for limiting said analog noise signal to provide said random binary data, said limiting means having an adjustable input switching threshold.
Claim 26
Dependent Claim
29 words
The random number generator according to claim 21, wherein said feedback means includes means for adjusting both said zener diode bias point and said limiting means input switching threshold.
Claim 27
Dependent Claim
146 words
A random number generator having a controlled degree of randomness comprising: noise source means for producing an analog noise signal having a statistical distribution exhibiting a particular degree of randomness determined in response to an input control signal; pulse shaping means for generating random binary data in response to said analog noise signal, said pulse shaping means including means for limiting said analog noise signal to provide said random binary data, said limiting means having an adjustable input switching threshold responsive to said input control signal, wherein said random binary data has a statistical distribution exhibiting a particular degree of randomness determined in response to said input control signal; and feedback means for monitoring said random binary data and for producing said input control signal in response to the difference between the degree of randomness of said binary data and that of a predetermined statistical distribution.
Claim 28
Dependent Claim
146 words
A random number generator having a controlled degree of randomness comprising: noise source means for producing an analog noise signal having a statistical distribution exhibiting a particular degree of randomness determined in response to an input control signal; pulse shaping means for generating random binary data in response to said analog noise signal, said pulse shaping means including means for limiting said analog noise signal to provide said random binary data, said limiting means having an adjustable input switching threshold responsive to said input control signal, wherein said random binary data has a statistical distribution exhibiting a particular degree of randomness determined in response to said input control signal; and feedback means for monitoring said random binary data and for producing said input control signal in response to the difference between the degree of randomness of said binary data and that of a predetermined statistical distribution.
Claim 29
Dependent Claim
74 words
The random number generator according to claim 23, wherein said noise source means includes a zener diode having an adjustable bias point near the knee of the avalanche breakdown region of its characteristic curve so as to generate random noise, said adjustable bias point being responsive to said input control signal, wherein said analog noise signal has a statistical distribution exhibiting a particular degree of randomness determined in response to said input control signal.
Claim 30
Dependent Claim
59 words
The random number generator according to claim 23, wherein said feedback means includes means for determining the acceptability of said random binary data with respect to the desired randomness criteria of said predetermined statistical distribution, and for outputting said random binary data only when it is within prescribed limits of said degree of randomness of said desired randomness criteria.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-31 | 1993-01-30 | 1993-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-31 | 1997-01-30 | 1997-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-31 | 2001-01-30 | 2001-08-01 | $7700.00 | Window Closed / Lapsed |