METHODS AND APPARATUS FOR REDUCING NOISE ASSOCIATED WITH AN ELECTRICAL SPEECH SIGNAL

摘要

In a system for enhancing the signal-to-noise ratio of a speech signal a plurality of local energy maximums (402) associated with the speech signal are determined. Presumably, each of these local energy maximums (402) defines a speech pitch period. Because human speech typically includes more energy near the beginning of a pitch period than at the end of the pitch period, and background noise tends to remain relatively constant throughout the pitch period, the speech signal may be enhanced by increasing the energy associated (410) with the beginning of the pitch period and/or by decreasing the energy (412) associated with the end of the pitch period. Preferably, the amount of energy increase in the earlier portion of the pitch period is approximately equal to the amount of the energy reduction in the later portion of the pitch period. In this manner, the total energy remains the constant.