Preliminary Technical Data

WM8972L

w

PTD Rev 2.2 June 2004

43

-10

-8

-6

-4

-2

0

0

5000

10000

15000

20000

Frequency (Fs)

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0

5000

10000

15000

20000

Frequency (Fs)

Figure 38 De-emphasis Frequency Response (44.1kHz)

Figure 39 De-emphasis Error (44.1kHz)

-10

-8

-6

-4

-2

0

0

5000

10000

15000

20000

Frequency (Fs)

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0

5000

10000

15000

20000

Frequency (Fs)

Figure 40 De-emphasis Frequency Response (48kHz)

Figure 41 De-emphasis Error (48kHz)

HIGHPASS FILTER

The WM8972L has a selectable digital highpass filter in the ADC filter path to remove DC offsets. The filter response is

characterised by the following polynomial:

Figure 42 ADC Highpass Filter Response

H(z) =

-15

-10

-5

0

0

0.0005

0.001

0.0015

0.002

Frequency (Fs)