The disadvantage with the above solutions is in the generation of thermal noise, where the methods are not well suited for digital CMOS technology. Also, no protection of the noise generators from interference is provided. The solutions according to the known prior art utilize operational amplifiers, wherein the sizing of the amplifiers is not designed for high noise/interference ratio, but rather for conventional sizing parameters, such as current, driving capability, inherent noise etc.
Two 50-ohm n-well input resistors are used to generate a predictable level of thermal noise. Noise from a noise source device comprising a noise source, a low pass filter and a 1/f filter is amplified and fed to the input of a sample and hold circuit, via a limiter, and finally to a current controlled oscillator generating random output. Alvin Conelly, discloses a random number generator.
#RANDOM SEQUENCE GENERATOR GENERATOR#
"A Noise-Based 1C Random Number Generator for Applications in Cryptography", IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications, 47(5): 615-621, May 2000, Craig S. The comparator will generate a digital random output based on the noisy input signals. coupled to an operational amplifier for amplifying the weak noise, wherein the amplified noise signal is fed to the noninverting input of a comparator, and to the inverting input of the comparator via a low-pass filter to remove DC and low frequency components. Is utilized as a thermal noise generator. Dowlatabadi, discloses an analog/random noise source. "An Integrated Analog/Digital Random Noise Source", IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications, 44(6) : 521-528, June 1997, by W. The oscillators are typically relaxation based or ring oscillators, because of their inferior frequency stability. The thermal noise is derived from either a high-ohmic resistor or a reverse-biased PN junction (where some breakdown mechanism is often exploited). Noise devices typically consist of an amplified thermal noise source, a noisy oscillator or a chaotic feedback circuit. By combining the thermal noise source with a shift register and employing further signal processing a better result can be obtained. Due to circuit imperfections, the thermal noise will contain cycles, such as spurious signals and clock feed-through, rendering it less than optimal for stand-alone use as a random generator. thermal noise, which in principle is random.
#RANDOM SEQUENCE GENERATOR CODE#
By seeding the PN generator with a truly random value, the PN code will have better statistical properties. Such a PN sequence is deterministic and cyclic, but with a long enough cycle it appears to be random when taking a snap-shot at a random time interval. Random numbers or bits are usually of the pseudorandom (PN) type, generated by feedback shift registers. More specifically, the' invention relates to an oscillating means being protected from interfering signals so as to provide a truly random sequence of bits when fed by a noise signal. The present'invention relates to a device for generating a random bit sequence.
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