Digital signal generator with frequency-dependent corrections for DAC and analog non-idealities

A digital signal generator configured to generate a pre-distorted digital signal x[n] of a given sampling frequency Fs, comprising:

• a phase accumulator and first adder configured to output a modulated phase signal φ[n], where φ[n] denotes an instantaneous phase of each nth sample of the modulated phase signal φ[n];
• a second adder configured to sum the modulated phase signal φ[n] and a pre-distortion phase correction value to obtain a phase-corrected modulated phase signal φ′[n];
• a phase to amplitude converter configured to covert the phase-corrected modulated phase signal φ′[n] to a periodic output signal y[n];
• a multiplier configured to multiply the periodic output signal y [n] by a pre-distortion amplitude correction value to obtain the digital signal x[n],
• wherein the pre-distortion phase and amplitude correction values are frequency dependent, and wherein the digital signal generator is configured to determine an instantaneous frequency of the modulated phase signal φ[n] by computing a derivative of the modulated phase signal φ[n], and to address a memory table correlating the determined instantaneous frequency with the pre-distortion phase and amplitude correction values.

A digital signal generator, comprising

• a numerically controlled oscillator (NCO) configured to generate a phase-modulated signal, and to convert the phase-modulated signal to periodic output signal;
• and
• a pre-distortion module configured to adjust a phase of the phase-modulated signal prior to conversion to the periodic output signal, and to adjust an amplitude of the periodic output signal to obtain a pre-distorted digital output signal,
• wherein the phase and amplitude adjustments are frequency dependent, and wherein the pre-distortion module is configured to determine an instantaneous frequency of the NCO by computing a derivative of the phase-modulated signal, and to address a memory table correlating the determined instantaneous frequency with the phase and amplitude adjustments.