Cirrus Logic AN168 - Manual (Page 9)

AN168
AN168REV2 9
Speaker Driver
Mic Preamp
Speaker
Microphone
Air
Coupling
ADC
AO
APO
DAC
1
2
3
CS6422
Figure 5. Three Common Sources of Acoustic Path Distortion
Speaker Driver
Mic Preamp
Speaker
Microphone
Air
Coupling
ADC
AO
APO
DAC
Acoustic Path = -9dB CS6422
Figure 6. Acoustic Coupling Design Target
Acoustic Coupling (dB)
-80
-70
-60
-50
-40
-30
-20
-10
0
0 500 1000 1500 2000 2500 3000 3500 4000
Frequency (Hz)
Figure 7. Example Acoustic Coupling Frequency Response