Implementation technique for linear phase equalization in multi-mode RF transmitters

A multi-mode RF polar transmitter, comprises:

• digital modulator operable to produce phase-shift keying (PSK) filtered symbols and filtered Gaussian Minimum Shift Keying (GMSK) phase signals;
• envelope path adjustment circuitry coupled to received the PSK filtered symbols and operable to produce an envelope signal;
• and
• phase path adjustment circuitry, comprising:
• phase differentiator coupled to receive a phase signal from the envelope path adjustment circuitry and operable to differentiate phase information produced in the phase path adjustment circuitry for a PSK modulation to produce differentiated phase signals to the envelope path adjustment circuitry wherein, for a GMSK modulation, when phase accumulated in the phase path adjustment circuitry, neutralizes phase accumulation of the phase signal received from the envelope path adjustment circuitry;
• summing node operably coupled to sum the differentiated PSK phase signals and GMSK phase signals to produce summed phase signals;
• phase magnitude and group delay equalizer operably coupled to receive the summed phase signals to produce phase output signals with a phase error less than or equal to a specified value;
• phase accumulator for accumulating the phase output signals to produce accumulated phase output signal;
• direct digital frequency synthesizer (DDFS) coupled to receive the accumulated phase output signal to produce I and Q components of the accumulated phase output signal;
• and
• phase signal interpolator for producing an up-converted RF phase accumulated signal based upon the I and Q component accumulated phase output signal.