Filter

A method of processing a transmit signal for transmission from a transmitter, the method comprising:

• generating a scaling factor from the transmit signal using a function which is dependent upon the value of the transmit signal and a threshold value, the threshold value indicating a maximum value to which the transmit signal is to be limited;
• filtering the scaling factor to create a filtered scaling factor by applying the scaling factor to a delay line having a plurality of taps, applying respective weighting coefficients of a windowing function to outputs from the plurality of taps to thereby generate a plurality of weighted outputs, and repeatedly selecting the weighted outputs with the highest value;
• and
• applying the filtered scaling factor to the transmit signal such that the transmit signal does not exceed the maximum value indicated by the threshold value.

A filter for filtering a signal comprising:

• a delay line having a plurality of taps, the delay line being arranged to receive the signal;
• weighting means for applying respective weighting coefficients of a windowing function to outputs from the plurality of taps to thereby generate a plurality of weighted outputs;
• and
• selecting means for repeatedly selecting for output the weighted outputs with the highest value to create selected outputs.