Abstract: A method of reducing sinusoidal artifact generation in a vocoder. In one embodiment, the present invention first receives a determined input energy threshold value. The input energy threshold value is the value below which it is believed that a suspected noise-inducing codebook excitation vector will be generated by the vocoder. Next, provided that an input signal is received having an energy value lower than the input energy threshold value, the present invention uses a codebook excitation vector selection process to prevent the suspected noise-inducing codebook excitation vector from being continuously generated. In one embodiment, the codebook excitation vector selection process is a randomization codebook excitation vector selection process. In so doing, the present embodiment prevents the creation of harmonics during zero or low-energy input periods.