First-order reconfigurable reconnection-less filters using modified current differencing unit

This paper presents simple electronically reconfigurable and reconnection-less filtering applications based on useful modification of current differencing unit (CDU). Modified CDU improves its controllable features and bring some other advantages. Three examples of first-order filtering structure in voltage- and current-mode were studied and compared. The last presented solution providing all-pass, inverting high-pass and low-pass (and theoretically also direct transfer) responses was investigated by PSpice simulations using complex behavioral model of the modified CDU, based on commercially available devices. It confirmed theoretically expected behavior.