Adaptive noise filtering and equalization for optimal high speed multilevel signal decoding

A system for processing digital signals comprising:

• a first filter stage comprising a first linear tapped-delay line filter tuned to a first time constant, the first time constant comprising a value that is less than a symbol period, for compensating for signal distortions tat occur within a single symbol period and for integrating over less than a symbol period in order to substantially reduce at least one of ringing, jitter, and noise;
• and
• a second filter stage comprising a second linear tapped-delay line filter tuned to a second time constant, the first time constant being smaller than the second time constant and the second time constant comprising value at least equal to a symbol period, the second filter stage for removing inter-symbol interference (ISI).

A system for processing digital signals comprising symbols propagated according to a period, the system comprising:

• a cascade of two linear filters, where each filter comprises a series of variable gain amplifiers connected by delay elements, each delay element for a respective filter having a same delay value, each linear filter equalizing a particular frequency band of a multilevel signal;
• the delay elements in the first filter being tuned to a fraction of the symbol period at which the symbols are propagated for compensating for signal distortions that occur within a single symbol period and for integrating over less than a symbol period in order to substantially reduce at least one of ringing, jitter, and noise;
• the delay elements in the second filter being tuned to a magnitude at least equal to the symbol period at which symbols are propagated for mitigating degradations that occur according to the period.