1. An apparatus for applying pitch features in automatic speech recognition, comprising: a distribution evaluation module configured to evaluate the global distribution of pitch features of voiced frames in speech signals, and the global distribution of random values for unvoiced frames in speech signals; a normalization module configured to normalize the global distribution of random values for unvoiced frames based on the global distribution of pitch features of voiced frames; and a random value adjusting module configured to adjust random values for unvoiced frames based on the normalized global distribution, so that the adjusted random values are assigned to unvoiced frames in speech signals as pitch features of the unvoiced frames.