Patent ID: 8619847

Claim:
A reconditioning equalizer filter for use with non-constant envelope signals to enhance the performance of a transmitter, the reconditioning equalizer filter comprising: a delay-and-gain-adjustment block that operates on a main input baseband signal to produce a primary delay-and-gain-adjusted main baseband signal; a peak reduction filter that operates on the main input baseband signal to produce a peak-reduced main baseband signal; a feedforward loop that injects an in-band-and-out-of-band-adjusted baseband signal into the main baseband signal, wherein the feedforward loop comprises: a delay adjustment block that delays the main baseband signal, a first gain adjustment block that gain-adjusts the delayed main baseband signal to produce a second delay-and-gain-adjusted main baseband signal, a first digital signal processing block that subtracts the second delay-and-gain-adjusted main baseband signal from the peak-reduced main baseband signal, a second digital signal processing block that correlates the main baseband signal and the result of the subtraction of the second delay-and-gain-adjusted main baseband signal from the peak-reduced main baseband signal to calculate the amount of the delay adjustment in the delay adjustment block and the amount of gain adjustment in the gain adjustment block, a low pass filter that filters the result of the subtraction of the second delay-and gain-adjusted main baseband signal from the peak-reduced main baseband signal to adjust in-band and out-of-band components in the baseband signal, a second gain-adjustment block that adjusts the gain of the filtered subtraction of the second delay-and-gain-adjusted main baseband signal from the peak-reduced main baseband signal for injection into the primary delay-and-gain-adjusted main baseband signal, and a digital signal processing summing block that adds the primary delay-and-gain-adjusted main baseband signal and the low-pass-filtered and gain-adjusted subtraction of the second delay-and-gain-adjusted main baseband signal from the peak-reduced main baseband signal to produce a modified main baseband signal; a third gain adjustment block that adjusts the gain of the modified main baseband signal to produce an output of the reconditioning equalizer filter; and a controller that uses the main baseband signal, the output of the low pass filter, the output of the reconditioning equalizer filter, and external input to provide control signals to the peak reduction filter, the correlation block, the delay-and-gain-adjustment block, and the second gain-adjustment block.