Sequency Filters Based on Walsh Functions

The theory of filters based on sine and cosine functions leads to frequency filters. They can be implemented almost ideally by coils and capacitors. The arrival of integrated circuits imposes new requirements that are hard to meet by frequency filters: coils are undesirable, and no tuning and no temperature compensation should be required. It is reasonable to look for a theory of filters based on other functions that are more suitable to the demands of integrated circuits, rather than to try to adapt frequency filters to the new technological requirements. Sequency filters based on Walsh functions can be implemented by integrated circuits about as ideally as frequency filters by coils and capacitors.