An apparatus comprising: a signal input configured to receive a source signal comprising a plurality of source symbols; an encoder module (207a-m) configured to receive the source signal and to encode the source signal to generate a corresponding encoded signal; a modulator module (209a-m) configured to receive the encoded signal and to modulate the encoded signal by mapping each source symbol to a respective signal constellation point of an applied signal constellation to generate a modulated signal; a pre-distorter module (210a-m) configured to receive the modulated signal and to pre-distort the modulated signal based on a distortion estimate to generate a pre-distorted signal; a filter module (211a-m) configured to receive the pre-distorted signal and to filter the pre-distorted signal to generate a filtered signal; and a transmitter module (213a-m) configured to receive the filtered signal and to frequency translate and amplify the filtered signal to generate a transmission signal for transmission to a satellite via an uplink channel (223a-m) of a satellite communications system; characterized in that to increase system throughput, the source signal is processed through the apparatus and the resulting transmission signal is generated with one or more of a faster than Nyquist symbol rate 1/τ that is grater than one and a minimized roll-off factor, wherein the pre-distorter module (210a-m) is configured to pre-compensate for distortion to which the source signal would be subjected as a result of one or more of processing through the apparatus for transmission via the uplink channel (223a-m) to a satellite. a signal input configured to receive a source signal comprising a plurality of source symbols; an encoder module (207a-m) configured to receive the source signal and to encode the source signal to generate a corresponding encoded signal; a modulator module (209a-m) configured to receive the encoded signal and to modulate the encoded signal by mapping each source symbol to a respective signal constellation point of an applied signal constellation to generate a modulated signal; a pre-distorter module (210a-m) configured to receive the modulated signal and to pre-distort the modulated signal based on a distortion estimate to generate a pre-distorted signal; a filter module (211a-m) configured to receive the pre-distorted signal and to filter the pre-distorted signal to generate a filtered signal; and a transmitter module (213a-m) configured to receive the filtered signal and to frequency translate and amplify the filtered signal to generate a transmission signal for transmission to a satellite via an uplink channel (223a-m) of a satellite communications system; characterized in that to increase system throughput, the source signal is processed through the apparatus and the resulting transmission signal is generated with one or more of a faster than Nyquist symbol rate 1/τ that is grater than one and a minimized roll-off factor, wherein the pre-distorter module (210a-m) is configured to pre-compensate for distortion to which the source signal would be subjected as a result of one or more of processing through the apparatus for transmission via the uplink channel (223a-m) to a satellite.