Sigma delta analog to digital converters with adaptive quantization

The signal to noise ratio (SNR) of conventional sigma delta analog to digital converter (/spl Sigma//spl Delta/ADC) reduces with input signal strength. The existing concept of adaptive quantization is applied to the design of /spl Sigma//spl Delta/ADCs to improve SNR in situations involving nonstationary signals with a high dynamic range. An adaptive algorithm that is suited particularly well to analog to digital converters and that can be implemented using little additional circuitry is proposed. Simulation results indicate that SNR can be made nearly independent of the signal strength, as expected.