A technique for a substantial reduction of the quantization noise in the direct processing of delta-modulated signals

The quantization noise introduced by the direct arithmetic operations on delta modulated signals can be considerably reduced by a proposed technique. According to this technique, the arithmetic network of a digital filter is clocked at a rate higher than that of the delta modulation encoder. Thus, as it is proved, a considerable reduction of the maximum quantization error can be achieved. A simple network is properly used to restore the filter output rate to that of the delta modulation encoder. The experimental results prove that the output sequence quantization noise can be reduced so much that the remaining noise is very close to that of the input delta modulated signal of the filter.