| 摘要 |
A digital communication transmitter serves as a signal path ( 10 ) which uses an adaptive equalizer ( 18 ) in a predistortion role. The adaptive equalizer ( 18 ) pre-distorts a complex digital communication signal ( 12 ) that need not exhibit any distortion. Subsequent analog distortion-introducing segments ( 24, 30, 36, 42 ) then distort a predistorted signal ( 22 ) output from the adaptive equalizer ( 18 ). An error signal ( 46 ) is formed from a reference signal ( 52 ) and a return signal ( 54 ). The equalizer ( 18 ) implements an adaptation algorithm that adjusts filter ( 68 ) coefficients to minimize correlation between one of the reference and return signals ( 52, 54 ) and the error signal ( 46 ). The equalizer ( 18 ) generates four sets of coefficients for four different filters. Consequently, the equalizer ( 18 ) exhibits four degrees of freedom in introducing predistortion into a complex signal to counter the distortion subsequently introduced in the signal path ( 10 ) by the distortion-introducing segments ( 24, 30, 36, 42 ).
|
