A New Non-Uniform ADC: Parallel Digital Ramp Pulse Position Modulation

This work introduces a new non-uniform Analog-to-Digital Converter (ADC) architecture. The architecture partitions the amplitude axis into P non-overlapping partitions that sample the analog input at input signal driven instances resulting into a greatly reduced sampling rate and ADC implementation complexity for a given input signal bandwidth. It is shown that for an arbitrary random process, this new architecture automatically satisfies the Nyquist requirement on average (Beutler's condition) and results in a random additive sampling architecture that is alias free (Shapiro-Silverman condition). The architecture does not require a pseudo-random sequence for reconstruction or otherwise, as the sampling instants are largely signal driven. Additionally, it is shown that the architecture geometrically reduces the slew rate requirement within each partition, effectively compressing the amplitude of each digital sample. As this is a new architecture, a comprehensive design paradigm is presented; circuits to affect the desired response, the format of the encoded digital samples and the signal to quantization noise are introduced.