Digital modulator for a gsm/gprs/edge wireless plar rf transmitter

A polar RF transmitter within a radio transceiver for producing Phase Shift Keying (PSK) and Gaussian Minimum Shift Keying (GMSK) modulated communication signals, comprising:

• a baseband processor for producing transmission (TX) data and a TX control signal;
• a digital modulator that receives the TX data, that digitally modulates outgoing digital data to produce one of a PSK and GMSK modulated digital signal based upon the TX control signal, wherein the digital modulator further includes:
• a modulation switching control block that receives the TX control signal, producing a modulation control signal to select one of a PSK modulation and GMSK modulation mode;
• a PSK symbol mapper operably coupled to receive the TX data that produces in-phase and quadrature PSK symbols based on the TX data and further based on a first value of the modulation control signal and that produces logic zero signals based on a second value of the modulation control signal;
• a GMSK symbol mapper operably coupled to receive the TX data that produces binary GMSK symbols based on the TX data and further based on the second value of the modulation control signal and that produces logic zero signals based on the first value of the modulation control signal;
• a pulse shaping block for filtering the PSK and GMSK symbols, wherein the pulse shaping block produces filtered PSK symbols for the first value of the modulation control signal and produces filtered GMSK symbols for the second value of the modulation control signal;
• envelope path adjustment circuitry operably coupled to receive the filtered PSK symbols that produces an envelope signal;
• phase path adjustment circuitry operably coupled to received the filtered GMSK symbols and a PSK phase signal that produces a phase signal;
• first and second Digital-to-Analog converters (DACs) for converting the envelope signal and the phase signal, respectively, from digital signals to analog signals to produce analog envelope signal and analog phase signal;
• first and second low pass filters for filtering the analog envelope signal and the analog phase signal, respectively;
• translational loop operably coupled to receive the analog phase signal to up-convert the analog phase signal from an IF frequency to an RF frequency;
• and
• a power amplifier for producing a modulated RF signal based on the RF frequency and the analog envelope signal.