Interference canceller and signal quantizer

Interference canceller for improving the signal-to-noise ratio of a weak signal corrupted by a larger additive noise signal comprising:

• analog-to-digital converter for quantizing said weak signal plus said noise signal into a word of greater than 3 states;
• memory means connected to the analog-to-digital converter for storing a finite string of said quantized weak signal plus noise;
• first digital processor means connected to the analog-to-digital converter for determining the discrete probability law of said noise;
• second digital processor means connected to the first digital processor means and the memory means, said second digital processor means comprising:
• means for determining an optimum discrete function based on said probability law of said noise;
• means for quantizing said optimum discrete function to two or three states;
• and
• means for operating on said string of quantized weak signal plus noise by said quantized optimum discrete function;
• whereby the signal to noise ratio of said weak signal is improved and said string of quantized weak signal plus noise is represented by 2- or 3-bit words.