Method of expanding a frequency range of a digital audio signal

Details Method of expanding a frequency range of a digital audio signal Method of expanding a frequency range of a digital audio signal

1997-03-31

1999-04-06

Dorvil, Richemond

Data processing: speech signal processing, linguistics, language

Audio signal bandwidth compression or expansion

Delay line

704205, G10L 700

Patent

active

058930680

ABSTRACT:
A frequency range of a digital audio signal is expanded without increasing a sampling frequency f.sub.5. The digital audio signal has a frequency range with an upper frequency defined by a frequency f.sub.5 /2, and also has noise components induced when being digitized. Firstly, the digital audio signal is split into first and second audio signals. The noise components of the first audio signal are shifted up to a predetermined frequency higher than f.sub.5 so as to leave a first frequency range between the first audio signal and the noise components. Following this, the first audio signal is delayed by a predetermined time duration. On the other hand, the second audio signal is band-pass filtered such as to have a second frequency range defined by frequencies f.sub.1 and f.sub.2 wherein 0<f.sub.1 <f.sub.2 <f.sub.5. Subsequently, the second audio signal is Fourier transformed, after which the spectrum of the second frequency range is processed so as to be expanded over new spectrum. Thereafter, the second audio signal with the new spectrum is subjected to reverse-Fourier transformation. The delayed first digital audio signal is combined with the second audio signal which has been reverse-Fourier transformed, in a manner which incorporates the second audio signal into the first frequency range.

REFERENCES:
patent: 4182930 (1980-01-01), Blackmer
patent: 4614934 (1986-09-01), Kobayashi et al.
patent: 4700390 (1987-10-01), Machida
patent: 4855894 (1989-08-01), Asahi et al.
patent: 5075880 (1991-12-01), Moses et al.
patent: 5267095 (1993-11-01), Hasegawa et al.
patent: 5454011 (1995-09-01), Shimoyoshi

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