An apparatus comprising: a linear amplification using non-linear components, Linc, processing system configured to receive an input signal (x(t)) and decompose the input signal into two vector signals (x 1 (t), x 2 (t)) to be amplified by a pair of power amplifiers (116(a), 116(b), 216(a), 216(b), 316(a), 316(b)) and combined; and an envelope restoration, ER, processing system configured to calculate an idealized wide bandwidth envelope gain (G ER (t)) and generate an actual band-limited envelope gain (G' ER (t)) at an output of the ER processing system to modulate a supply voltage of each power amplifier of the pair of power amplifiers (116(a), 116(b), 216(a), 216(b), 316(a), 316(b)) of the Linc processing system; the Linc processing system comprises a clipped Linc generator configured to receive the input signal and decompose the input signal into the two vector signals, the clipped Linc generator comprises an out-phasing generator (211.4, 311.4) configured to generate an out-phasing angle for each of the two vector signals and comprises a limiting device (211.2, 311.2) and the Linc processing system comprises a power combiner configured to combine the two vector signals (x 1 (t), x 2 (t)) after amplification; and the ER processing system comprises an envelope gain generator configured to generate the idealized wide bandwidth envelope gain (G ER (t)) and an envelope amplifier configured to amplify the idealized wide bandwidth envelope gain (G ER (t)) and output the actual band-limited envelope gain (G' ER (t)); and characterised by: a feedback path from the output of the ER processing system to the Linc processing system configured to provide information about the actual band-limited envelope gain (G' ER (t)) to the Linc processing system, the feedback path comprising a bandwidth limit estimator configured to generate, based on the idealized wide bandwidth envelope gain (G ER (t)), the actual band-limited envelope gain (G' ER (t)) and using a non-linear model, an estimate of the actual band-limited envelope gain (G ^ ' ER (t)) and provide said estimate of the actual band-limited envelope gain (G ^ ' ER (t)) to the out-phasing generator (211.4, 311.4), wherein the out-phasing generator (211.4, 311.4) is configured to generate the out-phasing angle of each of the two vector signals based on the estimate of the actual band-limited envelope gain (G ^ ' ER (t)). a linear amplification using non-linear components, Linc, processing system configured to receive an input signal (x(t)) and decompose the input signal into two vector signals (x 1 (t), x 2 (t)) to be amplified by a pair of power amplifiers (116(a), 116(b), 216(a), 216(b), 316(a), 316(b)) and combined; and an envelope restoration, ER, processing system configured to calculate an idealized wide bandwidth envelope gain (G ER (t)) and generate an actual band-limited envelope gain (G' ER (t)) at an output of the ER processing system to modulate a supply voltage of each power amplifier of the pair of power amplifiers (116(a), 116(b), 216(a), 216(b), 316(a), 316(b)) of the Linc processing system; the Linc processing system comprises a clipped Linc generator configured to receive the input signal and decompose the input signal into the two vector signals, the clipped Linc generator comprises an out-phasing generator (211.4, 311.4) configured to generate an out-phasing angle for each of the two vector signals and comprises a limiting device (211.2, 311.2) and the Linc processing system comprises a power combiner configured to combine the two vector signals (x 1 (t), x 2 (t)) after amplification; and the ER processing system comprises an envelope gain generator configured to generate the idealized wide bandwidth envelope gain (G ER (t)) and an envelope amplifier configured to amplify the idealized wide bandwidth envelope gain (G ER (t)) and output the actual band-limited envelope gain (G' ER (t)); and characterised by: a feedback path from the output of the ER processing system to the Linc processing system configured to provide information about the actual band-limited envelope gain (G' ER (t)) to the Linc processing system, the feedback path comprising a bandwidth limit estimator configured to generate, based on the idealized wide bandwidth envelope gain (G ER (t)), the actual band-limited envelope gain (G' ER (t)) and using a non-linear model, an estimate of the actual band-limited envelope gain (G ^ ' ER (t)) and provide said estimate of the actual band-limited envelope gain (G ^ ' ER (t)) to the out-phasing generator (211.4, 311.4), wherein the out-phasing generator (211.4, 311.4) is configured to generate the out-phasing angle of each of the two vector signals based on the estimate of the actual band-limited envelope gain (G ^ ' ER (t)).