WM8940CGEFLSLASHV datasheet(27/91 Pages) WOLFSON

27 / 91 page

Production Data

WM8940

PD, Rev 4.3, November 2011

The notch filter coefficients are calculated as follows:

)

tan(

)

tan(







)

cos(

)

(







Where:









fc = centre frequency in Hz, fb = -3dB bandwidth in Hz, fs = sample frequency in Hz

The actual register values can be determined from the coefficients as follows:

NFn_A0 = -a0 x 2

NFn_A1 = -a1 x 2

To configure Notch Filter 3 as a 1

st order low pass filter, set the NF3_LP bit to 1 and calculate the

coefficients as follows:

0 

)

tan(

)

tan(







Where:





fc = cutoff frequency in Hz, fs = sample frequency in Hz

The actual register values can be determined from the coefficients as follows:

NF3_A0 = 0

NF3_A1 = -a1 x2

DIGITAL ADC VOLUME CONTROL

The output of the ADCs can be digitally attenuated over a range from –127dB to 0dB in 0.5dB steps.

The gain for a given eight-bit code X is given by:

Gain = 0.5 x (x–255) dB for 1

 x  255, MUTE for x = 0

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R15

ADC Digital

Volume

7:0

ADCVOL

[7:0]

11111111

( 0dB )

ADC Digital Volume Control

0000 0000 = Digital Mute

0000 0001 = -127dB

0000 0010 = -126.5dB

... 0.5dB steps up to

1111 1111 = 0dB

Table 19 ADC Volume

WM8940CGEFL/V 데이터시트(PDF) 27 Page - Wolfson Microelectronics plc

WM8940CGEFL/V 데이터시트(HTML) 27 Page - Wolfson Microelectronics plc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91

데이터시트 다운로드

링크 URL