DS138F5

13

CS5330A/31A

3.1.11

Digital Filter

Figures 5 through 8 show the attenuation characteristics of the digital filter included in the ADC. The filter

response scales linearly with sample rate. The x-axis has been normalized to Fs, and can be scaled by

multiplying the x-axis by the system sample rate, i.e. 48 kHz.

0

-10

-20

-30

-40

-50

-60

-70

-80

-90

-100

-110

-120

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Normalized Input Frequency

2

0

-2

-4

-6

-8

-10

.46

.47

.48

.49

.50

.51

.52

.53

.54

Normalized Input Frequency

Figure 5. CS5330A/31A Digital Filter Stopband Rejection

Figure 6. CS5330A/31A Digital Filter Transition Band

0.05

0.04

0.03

0.02

0.01

0.00

-0.01

-0.02

-0.03

-0.04

-0.05

0

0.1

0.2

0.3

0.4

0.5

Normalized Input Frequency

0.0

-10.0

-20.0

-30.0

-40.0

-50.0

-60.0

-70.0

-80.0

-90.0

-100.0

0.40

0.45

0.50

0.60

0.65

0.70

Normalized Input Frequency

Figure 7. CS5330A/31A Digital Filter Passband Ripple

Figure 8. CS5330A/31A Digital Filter Transition Band