초록 ▼

A system for enhancing low frequency spectral content of a digitized signal which identifies a fundamental frequency component in the signal and selectively boosts signals within a predetermined range thereof. In the illustrative embodiment, the digitized signal is a frequency domain transformed spe

A system for enhancing low frequency spectral content of a digitized signal which identifies a fundamental frequency component in the signal and selectively boosts signals within a predetermined range thereof. In the illustrative embodiment, the digitized signal is a frequency domain transformed speech signal. The invention amplifies the low frequency components of the speech signal. The speaker unique fundamental frequency of the speech is computed using pitch delay information and is thus dynamic from frame to frame and also speaker to speaker. This fundamental frequency defines the center point of a gain window which is applied to select frequency components. Only such fundamental frequency components which exhibit a large enough signal to noise ratio have the amplification function applied. Thus, this function can be applied directly following a noise suppression system which has knowledge of the signal quality in each frequency bin. The gain window is ramped up and hanged over to smooth the amplification function between successive frames.

대표청구항 ▼

[ We claim:] [1.]1. A system for enhancing low frequency spectral content of a signal comprising:a preprocessor for receiving a digitized signal;a fundamental frequency estimator for identifying a fundamental frequency component in said digitized signal; anda signal-to-noise estimator for determinin

[ We claim:] [1.]1. A system for enhancing low frequency spectral content of a signal comprising:a preprocessor for receiving a digitized signal;a fundamental frequency estimator for identifying a fundamental frequency component in said digitized signal; anda signal-to-noise estimator for determining a signal-to-noise ratio of the digitized signal within a predetermined range of said fundamental frequency;a gain adjuster for selectively boosting signals within said predetermined range of said fundamental frequency, wherein selection is based on the signal-to-noise ratio of the digitized signal within the predetermined range of said fundamental frequency.