A discrete time filter includes a plurality of sampling cells and a first dummy sampling cell. Each of the sampling cells performs a current mode sampling operation based on current input to an input terminal in response to a corresponding one of a plurality of sampling clock signals and is reset in response to a corresponding one of the plurality of sampling clock signals and a first dummy sampling clocks. The first dummy sampling cell alternately performs with the first sampling cell the current mode sampling operation based on current input to the input terminal in response to the first dummy sampling clock signal and is alternately reset with the first sampling cell in response to the first sampling clock signal.