ACS422A68TAGZBX8 IDT, ACS422A68TAGZBX8 Datasheet - Page 30

• 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.
.
3.10. Psychoacoustic Bass Enhancement
One of the primary audio quality issues with small speaker systems is their inability to reproduce significant amounts of
energy in the bass region (below 200Hz). While there is no magic mechanism to make a speaker reproduce frequen-
cies that it is not capable of, there are mechanisms for fooling the ear into thinking that the bass material is being
heard.
The psychoacoustic bass processor relies on a psychoacoustic principle called “missing fundamental”. If the human
ear hears a proper series of harmonics for a particular bass note, the listener will hear the fundamental of that series,
even if it is not present.
A processing algorithm using this principle allows for improving the apparent low frequency response of an audio sys-
tem below what it is actually capable of. Below is a diagram of the implementation of this algorithm.
This implementation is composed of 5 major components:
1. If the material common to the two channels is removed, then the speakers will sound more 3-D.
2. If the material for the opposite channel is presented to the current channel inverted, it will tend to
Note: 3D_Mix specifies the amount of the common signal that is subtracted from the left and right
channels. This number is a fractional amount between 0 and 1. For proper operation, this value is typically
negative.
cancel any material from the opposite channel on the current ear. For example, if the material
from the right is presented to the left ear inverted, it will cancel some of the material from the
right ear that is leaking into the right ear.
Extract
Filter
Right
Left
NLF
Figure 10. 3-D Channel Inversion
Figure 11. Bass Enhancement
Limit
Filter
30
Right
Left
Cutoff Filter
ACS422X68
V1.6 01/13