Speech filtering
A method and filter for filtering a speech signal for speech encoding in a communications network. The method comprises: determining a cut off frequency for a filter, wherein a component of the speech signal in a frequency range less than the cut off frequency is to be attenuated by the filter; receiving the speech signal at the filter S402; determining at least one parameter of the received speech signal, the at least one parameter providing an indication of the energy of the component of the received speech signal that is to be attenuated; and adjusting the cut off frequency in dependence on the at least one parameter S408, thereby adjusting the frequency range to be attenuated S410; wherein the at least one parameter comprises a pitch frequency of the speech signal which is determined from the determined pitch lag S406, and wherein the cut off frequency is adjusted to be no greater than the determined pitch frequency.