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Block long selecting arrangement of adaptation block long transform coding
Block long selecting arrangement of adaptation block long transform coding
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机译：自适应块长变换编码的块长选择布置
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摘要
PURPOSE: To provide the detection capable of reducing a hardware scale and with the precise rise in signal change by calculating the envelope of a sample value, detecting an envelope changing point in a prescribed length and selecting a block length according to the position, the number and the change and etc., of the changing point. CONSTITUTION: In a method for calculating an envelope using FFT, IFFT and the Fourier transformation Xi is obtained by FFT processing a signal Xi by the longest block length N. Then, Xi is doubled for 1=i=N/2 equivalent to a positive frequency and Zi making Xi for N/2=iN equivalent to a negative frequency zero is obtained to FFT (F -1) process. At this time, a signal waveform is obtained in a real number part and a Hilbert variable is obtained in an imaginary number part and an absolute value Zi is calculated as the envelope. In a changing point detection part 3, the longest block length in the block length being a selective object is divided equally, the envelope sum of divided partial blocks and a ratio between adjacent blocks are obtained and these values are compared with a threshold value by a selection part 4 to decide the block length.
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机译：目的：通过计算样本值的包络，以规定的长度检测包络变化点，并根据位置，数量选择块长度，以提供一种能够减少硬件规模并精确改变信号变化的检测以及变化点的变化等。构成：在一种使用FFT计算包络的方法中，通过对信号Xi进行最长块长度N的FFT处理，获得了IFFT和傅立叶变换Xi。然后，将Xi倍增至等于通过FFT（F -1）处理，获得N / 2 ＜＝ i ＜N的正频率和Zi使得Xi等于负频率零。此时，在实数部分中获得信号波形，并且在虚数部分中获得希尔伯特变量，并且计算绝对值Zi作为包络。在变化点检测部3中，将作为选择对象的块长中的最长的块长均等地分割，求出分割后的部分块的包络和以及相邻块之间的比率，将这些值与阈值进行比较。选择部分4决定块长度。
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