| This thesis presents a robust programmable analog Gaussian noise generator suitable for mixed-signal test applications. Unlike conventional methods, noise generators employing a linear feedback shift register (LFSR) or resistor thermal noise amplification techniques, the user has full control over the characteristics of the Gaussian signal. Indeed, the frequency band, the mean, and the variance of the distribution are fully programmable over the voltage range within the supply rails. The method consists of digitally encoding the specified Gaussian signal in a random access memory (RAM), using pulse-density modulation, followed by filtering the output bit stream using an analog low-pass filter. It is demonstrated that the quality of the generated noise signal is independent of the quality of the filter used; hence, making the noise source highly robust. The output of the noise generator accurately models a real Gaussian signal, even at high sigma values; thus, making it a very effective and predictable dithering signal. Two applications of the proposed Gaussian noise source are demonstrated: histogram testing of analog-to-digital converters (ADCs) and high-resolution digitization. In addition, a high-voltage automotive test instrument that supports the high-resolution digitization process proposed is outlined. |
