Random number generator with digital feedback

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.

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.

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.

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.