Digital modulator and digital-to-analog conversion techniques associated therewith

A transmitter, comprising:

• a baseband processor to provide a multi-bit representation of a frequency control word and I- and Q-data;
• a cordic to convert the I- and Q-data into polar data which includes a phase component, θ(t), and an amplitude component, r(t);
• a digital polar modulator to provide a digital modulated RF signal based on both the polar data and the multi-bit representation of the frequency control word;
• a digital-to-analog converter (DAC) coupled to an output of the digital polar modulator and configured to generate an analog modulated RF signal based on the digital modulated RF signal;
• and
• a resonant circuit coupled to an output of the DAC, the resonant circuit to filter undesired frequency components from the analog modulated RF signal.

A circuit that includes a digital modulator, the digital modulator comprising:

• a differentiator to receive successive phase values at a sampling rate and provide differentiated phase values based on the phase values;
• an adder to provide successive instantaneous phase offset values at the sampling rate based on both the differentiated phase values and a frequency control word;
• a phase accumulator to provide successive instantaneous phase values at the sampling rate based on the instantaneous phase offset values;
• and
• an angle-to-amplitude converter to convert the instantaneous phase values to a multi-bit representation of a phase modulated wave at the sampling rate.

A method of generating a radio-frequency (RF) signal in a transmitter, comprising:

• providing a multi-bit representation of a frequency control word, where the frequency control word is associated with a carrier frequency;
• providing a multi-bit representation of data in polar format according to a sampling rate;
• providing a multi-bit digital polar modulated RF signal based on both the multi-bit representation of data in polar format and the multi-bit representation of the frequency control word;
• converting the multi-bit digital polar modulated RF signal into an analog RF signal;
• removing unwanted frequency components from the analog RF signal by using a resonant circuit.