Linearization methods in digital video signal transmission

In digital video signal transmission, many non-linear effects is occurring. For spectrum efficiency, amplifier linearity is needed. In the case of non-linear amplifier it is necessary to compensate this non-linearity with special additional units. This paper contains some methods trying to achieve this goal. The first group include methods where the power amplifier is fed with a signal having varying envelope that force amplifier to generate IMD. The IMD can be cancelled by shaping of the input signal or by isolating the IMD component and subtracted it from the amplifier output. Second group are methods that completely avoid the non-linear characteristic of the amplifier by feeding it with a signal having a constant envelope