Product Preview

WM8569

w

PP Rev 1.1 December 2005

31

ADC FILTER RESPONSES

-80

-60

-40

-20

0

0

0.5

1

1.5

2

2.5

3

Frequency (Fs)

-0.02

-0.015

-0.01

-0.005

0

0.005

0.01

0.015

0.02

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

Frequency (Fs)

Figure 23 ADC Digital Filter Frequency Response

Figure 24 ADC Digital Filter Ripple

ADC HIGH PASS FILTER

The WM8569 has a selectable digital high pass filter to remove DC offsets. The filter response is characterised by the

following polynomial.

1

1

9995

.

0

1

1

)

(

−

−

−

−

=

z

z

z

H

DIGITAL DE-EMPHASIS CHARACTERISTICS

-10

-8

-6

-4

-2

0

0

2

4

6

8

10

12

14

16

Frequency (kHz)

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

0

2

4

6

8

10

12

14

16

Frequency (kHz)

Figure 25 De-Emphasis Frequency Response (32kHz)

Figure 26 De-Emphasis Error (32kHz)