wm8903 Wolfson Microelectronics plc, wm8903 Datasheet - Page 85

• Manufacturer Part Number: wm8903
• Description: Ultra Low Power Codec For Portable Audio Applications
• Manufacturer: Wolfson Microelectronics plc

Pre-Production
w
Companding uses a piecewise linear approximation of the following equations (as set out by ITU-T
G.711 standard) for data compression:
μ-law (where μ=255 for the U.S. and Japan):
A-law (where A=87.6 for Europe):
Figure 52 μ-Law Companding
Figure 53 A-Law Companding
F(x) = A|x| / ( 1 + lnA)
F(x) = ( 1 + lnA|x|) / (1 + lnA)
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F(x) = ln( 1 + μ|x|) / ln( 1 + μ)
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u-law Companding
A-law Companding
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Normalised Input
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} for -1 ≤ x ≤ 1
} for x ≤ 1/A
} for 1/A ≤ x ≤ 1
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PP, Rev 3.1, August 2009
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WM8903
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