Spectral Translation/Folding in the Subband Domain
    42.
    发明申请
    Spectral Translation/Folding in the Subband Domain 有权
    子带域中的光谱翻译/折叠

    公开(公告)号:US20100211399A1

    公开(公告)日:2010-08-19

    申请号:US12703553

    申请日:2010-02-10

    IPC分类号: G06F17/00

    摘要: The present invention relates to a new method and apparatus for improvement of High Frequency Reconstruction (HFR) techniques using frequency translation or folding or a combination thereof. The proposed invention is applicable to audio source coding systems, and offers significantly reduced computational complexity. This is accomplished by means of frequency translation or folding in the subband domain, preferably integrated with spectral envelope adjustment in the same domain. The concept of dissonance guard-band filtering is further presented. The proposed invention offers a low-complexity, intermediate quality HFR method useful in speech and natural audio coding applications.

    摘要翻译: 本发明涉及使用频率转换或折叠或其组合来改进高频重建(HFR)技术的新方法和装置。 所提出的发明适用于音频源编码系统,并提供显着降低的计算复杂度。 这通过在子带域中的频率转换或折叠来实现,优选地与同一域中的频谱包络调整集成。 进一步提出了不一致保卫带滤波的概念。 所提出的发明提供了一种在语音和自然音频编码应用中有用的低复杂度,中等质量的HFR方法。

    Low delay modulated filter bank
    44.
    发明授权
    Low delay modulated filter bank 有权
    低延迟调制滤波器组

    公开(公告)号:US08880572B2

    公开(公告)日:2014-11-04

    申请号:US13201572

    申请日:2010-02-17

    申请人: Per Ekstrand

    发明人: Per Ekstrand

    IPC分类号: G06F7/00 H03H17/02

    摘要: The document relates to modulated sub-sampled digital filter banks, as well as to methods and systems for the design of such filter banks. In particular, the present document proposes a method and apparatus for the improvement of low delay modulated digital filter banks. The method employs modulation of an asymmetric low-pass prototype filter and a new method for optimizing the coefficients of this filter. Further, a specific design for a (64) channel filter bank using a prototype filter length of (640) coefficients and a system delay of (319) samples is given. The method substantially reduces artifacts due to aliasing emerging from independent modifications of subband signals, for example when using a filter bank as a spectral equalizer. The method is preferably implemented in software, running on a standard PC or a digital signal processor (DSP), but can also be hardcoded on a custom chip. The method offers improvements for various types of digital equalizers, adaptive filters, multiband companders and spectral envelope adjusting filterbanks used in high frequency reconstruction (HFR) or parametric stereo systems.

    摘要翻译: 该文件涉及调制的次采样数字滤波器组,以及用于设计这种滤波器组的方法和系统。 特别地,本文件提出了一种用于改进低延迟调制数字滤波器组的方法和装置。 该方法采用非对称低通原型滤波器的调制和用于优化滤波器系数的新方法。 此外,给出了使用(640)系数的原型滤波器长度和(319)个样本的系统延迟的(64)信道滤波器组的具体设计。 该方法基本上减少了由于子带信号的独立修改引起的混叠所产生的伪像,例如当使用滤波器组作为频谱均衡器时。 该方法优选地以在标准PC或数字信号处理器(DSP)上运行的软件实现,但也可以在定制芯片上被硬编码。 该方法为各种类型的数字均衡器,自适应滤波器,多频带压缩器以及用于高频重构(HFR)或参数立体声系统的频谱包络调整滤波器组提供了改进。