WM8510GEDS/V Wolfson Microelectronics, WM8510GEDS/V Datasheet - Page 52

• Manufacturer Part Number: WM8510GEDS/V
• Description: Audio CODECs VoIP Mono CODEC
• Manufacturer: Wolfson Microelectronics

Specifications of WM8510GEDS/V

• Operating Supply Voltage: - 0.3 V to + 7 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SSOP-28
• Minimum Operating Temperature: - 25 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

WM8510
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Table 43 Companding Control
Companding involves using 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):
F(x) = ln( 1 + µ|x|) / ln( 1 + µ)
A-law (where A=87.6 for Europe):
F(x) = A|x| / ( 1 + lnA)
F(x) = ( 1 + lnA|x|) / (1 + lnA)
The companded data is also inverted as recommended by the G.711 standard (all 8 bits are inverted
for µ-law, all even data bits are inverted for A-law). The data will be transmitted as the first 8 MSB’s
of data.
Companding converts 13 bits (µ-law) or 12 bits (A-law) to 8 bits using non-linear quantization. The
input data range is separated into 8 levels, allowing low amplitude signals better precision than that
of high amplitude signals. This is to exploit the operation of the human auditory system, where
louder sounds do not require as much resolution as quieter sounds. The companded signal is an 8-
bit word containing sign (1-bit), exponent (3-bits) and mantissa (4-bits).
Table 44 8-bit Companded Word Composition
R5
Companding
control
SIGN
BIT7
REGISTER
ADDRESS
0
2:1
4:3
BIT
EXPONENT
BIT[6:4]
LOOPBACK
ADC_COMP
DAC_COMP
LABEL
-1 ≤ x ≤ 1
} for x ≤ 1/A
} for 1/A ≤ x ≤ 1
0
0
0
DEFAULT
Digital loopback function
0=No loopback
1=Loopback enabled, ADC data output is
fed directly into DAC data input.
ADC companding
00=off
01=reserved
10=µ-law
11=A-law
DAC companding
00=off
01=reserved
10=µ-law
11=A-law
MANTISSA
BIT[3:0]
DESCRIPTION
PD, Rev 4.5 ,September 2008
Production Data
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