| 摘要 |
A random number generator comprising a sigma-delta modulator, the sigma-delta modulator having a modulation unit comprising: a summation unit arranged to receive an analogue input signal that varies due to noise over a first voltage range, the summation unit being arranged to sum the analogue input signal with an adjustment signal to form a summation output signal; a loop filter arranged to receive the summation output signal and form a filtered output signal dependent thereon; and a quantiser arranged to receive the filtered output signal, compare the filtered output signal with a quantiser threshold and form a digital output signal by selecting between one of two predetermined voltage levels for the digital output signal in dependence on the comparison; and the sigma-delta modulator further comprising: a feedback loop arranged to receive the digital output signal and form the adjustment signal in dependence on the digital output signal such that at any given time instant the absolute difference between an amplitude of the summation output signal and the quantiser threshold is less than the first voltage range, the random number generator thereby being capable of forming a digital output signal derived from the analogue input signal and having a high degree of entropy. ® KIPO & WIPO 2009
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