The Specification of Error Amplifiers for use in Feedforward Transmitters

The performance of a feedforward amplifier, in terms of the linearity improvement which can be achieved, is investigated mathematically. The improvement in linearity is shown to depend on the gain and phase matching throughout the system, and two methods are demonstrated whereby this may be predicted using sensitivity analysis. Finally, the result is used to examine the trade-offs involved in the design of the error amplifier in a feedforward system.