ROBUST TRANSMIT/FEEDBACK ALIGNMENT

摘要

A system (100) performs digital predistortion (DPD) for widely spaced narrowband signals, such as used in multi-carrier GSM using a polynomial curve for values of a cross-correlation function (above a predetermined threshold) to determine a delay estimate. A transmit processor (102) and digital signal processor (104) generate in-phase (I) and quadrature (Q) components for a baseband signal (BB). The components (I, Q) are provided to digital-to-analog converters (106, 108) and converted to analog signals. A modulator (110) (which uses a local oscillator 120) converts the analog signal to an RF signal which is amplified by amplifiers (112, 114) and transmitted by an antenna (116). A mixer (118) (which also uses local oscillator 120), a buffer (120) and an analog-to-digital converter (122) provide feedback to the transmit processor (102) to compensate for errors and nonlinearities.