APPARATUS AND METHOD FOR MODULATING AND DIGITALLY PREDISTORTING A SIGNAL IN MULTIPLE MODULATION SCHEMES
摘要
A programmable modulator (100) is programmable to operate in either of a GMSK or 8PSK mode. When operating in a GMSK mode, a signal modulating circuit 105 receives (210) a bit stream (110), maps the bit stream (110) to a phase value in complex I, Q form and applies a progressive rotation to the phase value according to GMSK specifications. The output (140) is filtered by a filter circuit (135), preferably using a complex Finite Impulse Response (FIR) filter using the standard coefficients for an 8PSK modulation to create (215) an approximate GMSK output (165). A GMSK correction circuit (150) determines a correction term that is added to the filter circuit output (165) so as to correct amplitude variations to allow the output to conform to GSM/EDGE standards. The same modulator (100) may be programmed to operate in an 8PSK mode with linear predistortion.
申请公布号
WO2006124165(A3)
申请公布日期
2007.05.18
申请号
WO2006US13999
申请日期
2006.04.14
申请人
MOTOROLA, INC.;AMAN, ASAD, U.;KUNDMANN, THOMAS, J.;NASH, GREGORY, T.
发明人
AMAN, ASAD, U.;KUNDMANN, THOMAS, J.;NASH, GREGORY, T.