US Patent 7218263 Generating bit-streams with higher compression gains

A system (10) and method that generate bit-streams that result in higher compression gains. The system is akin to a normal 1-bit SDM. Internally, the system (10) tries to find the best possible bit sequence by tracing N possible solutions at every time instant. In an implementation, the system has N>I trellis path structures (20). Every path is used to track a possible output bitstream. The quality of a bitstream is determined by measuring the (frequency weighted) difference between input and output; it is this measure that is reduced or minimized.