An apparatus (10, 60a, 110) for encoding an audio signal including a plurality of frames, the apparatus comprising: a first estimator configured to obtain a first estimate (14, T 1), the first estimate being an estimate of a pitch lag for a current frame, wherein the first estimate is obtained as the lag (T 1) that maximizes a first correlation function associated to the current frame; a second estimator configured to obtain a second estimate (16, T 2), the second estimate being another estimate of a pitch lag for the current frame, wherein the second estimator is conditioned by the pitch lag (51, 19") selected at the previous frame so as to obtain the second estimate (16, T 2) for the current frame, wherein the second estimator is configured to obtain the second estimate (16, T 2) by searching the lag which maximizes a second correlation function in a second subinterval which contains the pitch lag (51, 19") selected for the previous frame, a selector configured to choose a selected value (19, T best) by performing a selection between the first estimate (14, T 1) and the second estimate (16, T 2) on the basis of a first and a second correlation measurements (23, 25), wherein the selector is configured to perform a comparison between: a downscaled version of a first normalized autocorrelation measurement associated to the current frame and obtained at a lag corresponding to the first estimate (14, T 1); and a second normalized autocorrelation measurement associated to the current frame and obtained at a lag corresponding to the second estimate (16, T 2), so as to select the first estimate (14, T 1) when the second normalized autocorrelation measurement is less than the downscaled version of the first normalized autocorrelation measurement, and/or to select the second estimate (16, T 2) when the second normalized autocorrelation measurement is greater than the downscaled version of the first normalized autocorrelation measurement. a first estimator configured to obtain a first estimate (14, T 1), the first estimate being an estimate of a pitch lag for a current frame, wherein the first estimate is obtained as the lag (T 1) that maximizes a first correlation function associated to the current frame; a second estimator configured to obtain a second estimate (16, T 2), the second estimate being another estimate of a pitch lag for the current frame, wherein the second estimator is conditioned by the pitch lag (51, 19") selected at the previous frame so as to obtain the second estimate (16, T 2) for the current frame, wherein the second estimator is configured to obtain the second estimate (16, T 2) by searching the lag which maximizes a second correlation function in a second subinterval which contains the pitch lag (51, 19") selected for the previous frame, a selector configured to choose a selected value (19, T best) by performing a selection between the first estimate (14, T 1) and the second estimate (16, T 2) on the basis of a first and a second correlation measurements (23, 25), wherein the selector is configured to perform a comparison between: a downscaled version of a first normalized autocorrelation measurement associated to the current frame and obtained at a lag corresponding to the first estimate (14, T 1); and a second normalized autocorrelation measurement associated to the current frame and obtained at a lag corresponding to the second estimate (16, T 2), a downscaled version of a first normalized autocorrelation measurement associated to the current frame and obtained at a lag corresponding to the first estimate (14, T 1); and a second normalized autocorrelation measurement associated to the current frame and obtained at a lag corresponding to the second estimate (16, T 2), so as to select the first estimate (14, T 1) when the second normalized autocorrelation measurement is less than the downscaled version of the first normalized autocorrelation measurement, and/or to select the second estimate (16, T 2) when the second normalized autocorrelation measurement is greater than the downscaled version of the first normalized autocorrelation measurement.