Improving Adaptive Resolution of Analog to Digital Converters Using Least Squares Mean Method

This paper presents an adaptive digital resolution improvement method for extrapolating and recursive analog-to-digital converters (ADCs). The presented adaptively enhanced ADC (AE-ADC) digitally estimates the digital equivalent of the input signal by utilizing an adaptive digital filter (ADF). The least mean squares (LMS) algorithm also determines the coefficients of the ADF block. In this scheme, the input bandwidth is limited to the Nyquist-rate. This scheme has the ability of enhancing its resolution by one bit through doubling the gain of a low-quality amplifier circuit. Behavioral simulation results are also provided for a 10-bit AE-ADC to verify the usefulness of the approach. Simulation results indicate that the spurious-free dynamic range (SFDR) and signal-to-noise-and-distortion-ratio (SNDR) are 68.8 dB and 55.5 dB, respectively.