ACS422A68TAGZBX8 IDT, ACS422A68TAGZBX8 Datasheet - Page 16

• Manufacturer Part Number: ACS422A68TAGZBX8
• Description: Interface - CODECs
• Manufacturer: IDT

Specifications of ACS422A68TAGZBX8

• Rohs: yes
• Part # Aliases: IDTACS422A68TAGZBX8

ACS422x68
LOW-POWER, HIGH-FIDELITY, INTEGRATED CODEC
©2011 INTEGRATED DEVICE TECHNOLOGY, INC.
DATA IN
3.4.1.
eq_prescale
Prescaler & Equalizer Filter
The Equalizer Filter consists of a Prescaler and 6 cascaded 6-tap IIR Filters. The Prescaler allows
the input to be attenuated prior to the EQ filters in case the EQ filters introduce gain, and would thus
clip if not prescaled.
IDT provides a tool to enable an audio designer to determine appropriate coefficients for the equal-
izer filters. The filters enable the implementation of a 6-band parametric equalizer with selectable fre-
quency bands, gain, and filter characteristics (high, low, or bandpass).
The figure below shows the structure of a single EQ filter. The a(0) tap is always normalized to be
equal to 1 (400000h). The remaining 5 taps are 24-bit twos compliment format programmable coeffi-
cients. (-2 coefficient  +2).
x(n)
x(n)
Filter 0
Z
Z
Z
Z
EQ
-1
-1
-1
-1
b(0) *2
b(1) *2
b(0)
b(1)
b(2)
b(2)
Filter 1
Figure 5. 6-Tap IIR Equalizer Filter
EQ
Figure 4. Prescaler & EQ Filters
Filter 2
EQ
16
Filter 3
EQ
a(1) *2
a(1)
a(2)
a(2)
Filter 4
EQ
Z
Z
Z
Z
-1
-1
-1
-1
y(n)
y(n)
Filter 5
EQ
DATA OUT
ACS422X68
V1.6 01/13