Signal filtering

A filter for providing a filtered output signal from a received input signal, the filter comprising

• an input for receiving an input signal;
• an output for transmitting an output signal;
• a first plurality of multipliers, each connected to receive the input signal from the input and a respective coefficient, and operable to produce respective output signals in dependence upon the input signal and the coefficient;
• a second plurality of adding means connected to receive respective multiplier output signals as a first input thereto, the second plurality equalling the first plurality, the adder means being arranged in a series such that each adding means of the series, except the first in the series, receives the output of the previous adding means of the series as a second input thereto, the first adding means of the series receiving the output of the last adding means of the series as a second input thereto,
• wherein each adding means receives its second input via a delay line element, and the output of the last adding means in the series provides the output of the filter.