Excitation signal generation in bandwidth spreading and signal reconstruction method and apparatus

Abstract

The invention discloses a method for generating exciting signals in bandwidth extension, which processes narrow-band low frequency signals via frequency spectrum folding and synthesis to generate required high frequency exciting signals. The invention further provides a reconstruction method for the high frequency signals in bandwidth extension and a device thereof. The technical scheme utilizes low frequency signals to generate high frequency signals, and is based on the harmonic characteristic of low and high frequency spectrums of the signals, therefore, the method can extend speech and music signals effectively, and the frequency spectrum folding method can confirm the signal frequency spectrum continuity of high and low frequencies at joint part. Tests prove that the technical scheme is suitable for extending ultra wideband signals of 7 to 14 kHz.

Description

technical field [0001] The invention relates to the technical field of bandwidth expansion, in particular to a method for generating an excitation signal in bandwidth expansion, a method for reconstructing a high-frequency signal, and a corresponding device. The invention is particularly suitable for ultra-wideband bandwidth expansion. Background technique [0002] BandWidth Extension (BWE: BandWidth Extension) technology is a technology that expands a signal with a narrower frequency range to a wider frequency range by selecting an appropriate parameter model, thereby improving the quality of the perceived audio signal. [0003] Usually under the conditions of limited coding rate, such as mobile and network environments, based on the auditory characteristic that the human ear is more sensitive to low-frequency signals, in order to achieve better coding effects, most of the available bits are generally allocated to low-frequency signals. signal, but because the high-frequenc...

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Problems solved by technology

[0037] In the process of proposing the present invention, the inventors found that the excitation generation at the decoding end of the above-mentioned bandwidth extension technology is generated using a method similar to the binary excitation generation method in the speech generation model, which is suitable for coding speech signals, while the coding effect for music-like signals is better. Poor; and the experiment proves that under the above-mentioned excitation generation method, if the bandwidth extension technology is used for 7-14kHz ultra-wideband extension, the noise will be large and the coding effect will be poor, indicating that this technology is not suitable for application in ultra-wideband extension

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