Elimination of idle tones by a second order 2-bit adaptive sigma delta modulation system

We investigate the operation and implementation aspects of a second order 2-bit adaptive sigma-delta modulation system that offers complete elimination of the idle tones without dithering as needed by various other adaptive and simple sigma delta schemes. Performance comparisons made by computer simulation indicate that this advantageous feature together with the enhanced performance stability is due to the combination of both "memory" and "look-ahead" estimation of the employed step-size adaptation algorithm. © Springer Science+Business Media, LLC 2009

A 2-bit adaptive delta modulation system with improved performance

A 2-bit adaptive delta modulation system with improved performance is proposed in this paper. Its main characteristic is a new adaptation algorithm that incorporates both memory and look-ahead instantaneous step-size estimation and leads the modulator into generating a 2-bit output codeword. As shown by computer simulation results, the proposed system offers reduced overshoot and fast response to signal variations in comparison to other similar systems

Elimination of idle tones by a 2-bit adaptive sigma-delta modulation system

The operation of a first-order 2-bit adaptive sigma-delta modulation system is described and discussed in this paper. The system operation is based on the combination of both "memory" and "look-ahead" estimation in the employed step-size adaptation algorithm of the basic quantizer. In comparison to simple systems and other adaptive sigmadelta systems, computer simulation results show that these features of the described system are responsible for the high SNR values and the extended dynamic range achieved for AC signals as well as the noise power reduction of almost 10 dB and the complete elimination of the idle tones for DC signals. However, such an advantageous performance requires the least possible multiplicative error accumulation, and this cannot be achieved without analog circuits of the highest possible accuracy