Extending test signal generation using sigma-delta encoding beyond the voltage/amplitude domain

This thesis extends signal generation techniques using sigma-delta encoding principles for synthesizing test signals of all types. In fact, sigma-delta encoding is used to generate repeatable and programmable noise-like signals; phase domain signals such as accurate phase offsets, sinusoidal and Gaussian jitter; and frequency domain signals used for accurate frequency synthesis.;Moreover, a novel bit-to-bit mapping algorithm that converts digital signals to either phase or frequency, is proposed. A digital-to-time conversion (DTC) algorithm is used to convert a digital signal to the phase domain; likewise, a digital-to-frequency conversion (DFC) algorithm is used to convert a digital signal to the frequency domain. The DTC or DFC conversion algorithm is implemented in software together with the sigma-delta encoding process in order to digitally encode a phase or frequency domain signal. The resulting bit sequence with the desired phase or frequency signal is then captured and applied cyclically to an analog time/frequency-mode reconstruction filter. The time/frequency-mode filtering is realized by a PLL structure with the desired phase/frequency domain transfer function.;All signal generation schemes (amplitude, noise, phase and frequency) consist of a digital bit-stream with the desired signal encoded and a reconstruction filtering device in the appropriate domain. Using the proposed techniques and circuits, robust, programmable, repeatable, and portable test signals in the amplitude, phase, and frequency domains can be synthesized at low-cost. Although the techniques are demonstrated in a production test environment using a commercial mixed-signal tester, the methodology can be implemented in any testing environment: production test, characterization test, design-for-test (DFT), or built-in self-test (BIST).;For the synthesis of noise-like signals, a Gaussian noise with the desired frequency characteristic is encoded in the voltage/amplitude domain in software using sigma-delta modulation. The resulting sequence of bits is then captured and applied cyclically to an analog filter to reconstruct the noise-like signal with the desired frequency spectrum (e.g. spectrum with a notch for noise-power ratio test).