Patent ID: 6999523
Filing Date: 2006-02-14
Classification: H03F,H04B,H04L

Abstract:
1. A multi frequency carrier transmitter comprising: input means for receiving a plurality of different digital signals to be transmitted, said different digital signals to be transmitted on different carrier frequencies; digital modulators for modulating said different digital signal at respective modulation frequencies; digital to analog converter means for converting a composite digital signal comprising said different digital signals at the respective carrier frequencies to analog form, thereby generating a composite analog signal; amplifier means for receiving and amplifying said composite analog signal; and predistortion means for predistorting said plurality of different digital signals during or after modulation of said different digital signals by said digital modulators and prior to amplification of the composite analog signal by said amplifier means, said predistortion provided by said predistortion means being subsequently altered in dependence on differences between each of said different digital signals and the output at said amplifier means.