Coding apparatus for digital signal
First Claim
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1. An apparatus for compressing a digital input signal, the apparatus comprising:
- a deriving mans for deriving from the digital input signal plural spectral components in the frequency domain, the spectral components being divided into blocks corresponding to critical bands;
means for dividing one of the blocks of spectral components corresponding to critical bands in frequency into sub blocks;
peak value determining means for determining a peak value for each sub block;
comparing means for determining a difference in the peak values of the sub blocks; and
block floating means for applying block floating processing to the sub blocks individually when the difference from the comparing means is above a fixed value.
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Abstract
An apparatus for compressing a digital signal in which a block of a spectral components in the frequency domain is divided in frequency into at least two sub blocks. The peak value for each sub block is determined, and the difference between the peak values is determined. Block floating is applied to each sub block individually when the difference between the peak values is above a fixed value. This prevents quantizing noise from being heard when the input signal is highly tonal.
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Citations
15 Claims
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1. An apparatus for compressing a digital input signal, the apparatus comprising:
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a deriving mans for deriving from the digital input signal plural spectral components in the frequency domain, the spectral components being divided into blocks corresponding to critical bands; means for dividing one of the blocks of spectral components corresponding to critical bands in frequency into sub blocks; peak value determining means for determining a peak value for each sub block; comparing means for determining a difference in the peak values of the sub blocks; and block floating means for applying block floating processing to the sub blocks individually when the difference from the comparing means is above a fixed value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for compressing a digital input signal, the apparatus comprising:
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a deriving mans for deriving plural spectral components from the digital input signal, the plural spectral components being divided into blocks, each block corresponding to a critical band; block dividing means for dividing one of the blocks of spectral components into two sub blocks; tonality signal generating means for generating a tonality signal indicating when part of the input signal represented by the spectral components in the block is tonal; and a block floating means for applying block floating processing to both sub blocks using a common scale factor, the block floating means applying block floating to each sub block individually in response to the tonality signal. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification