The use of adaptive filters in the suppression of interference on signal lines

Adaptive active filters can be successfully used to filter out interference on power and signal lines, where passive filters have great limitations especially if interference is at low frequency and is known to drift slowly. Three possible solutions of adaptive filters are examined. Conventional LMS filters generate intermodulation products, which in some cases are not acceptable. The novel solution of training phase LMS (least mean square) filter, which has the best filtering characteristics, is described and simulated.