Cirrus Logic CS4234 - Manual (Page 40)

DS899F1 40
CS4234
The de-emphasis feature is included to accommodate audio recordings that utilize 50/15 s preemphasis
equalization as a means of noise reduction.
De-emphasis is only available in Single-speed Mode.
4.6.4 Low-Latency Path
A low-latency path is provided to allow four user selectable data signals to be routed around the group
delay block and interpolation filters of the DAC1-4 path. These four signals can be present in any of the
32 slots on the two TDM streams on SDIN1 and SDIN2.
The Low-Latency path also includes a global mute bit and individual channel invert bits. The signals from
the low latency path are summed with the DAC1-4 path after the master volume control. Changes to the
master volume control setting do not affect the low-latency-path signals. For details concerning the oper-
ation of the volume control, please see
Section 4.6.6 Volume Control .
Gain
dB
-10dB
0dB
Frequency
T2 = 15 µs
T1=50 µs
F1 F2
3.183 kHz 10.61 kHz
Figure 25. De-emphasis Curve
Gain / Volume
AIN4 (±)
AIN3 (±)
AIN2 (±)
AIN1 (±)
Interpolation
Filter
Channel Volume ,
Mute, Invert,
Noise Gate
Multi-bit 
Modulators
AOUT1 (±)
AOUT2 (±)
AOUT3 (±)
AOUT4 (±)
I 2 C Control
Data
Control Port
Level Translator
VL
1.8 to 5.0 VDC
RST INT SDIN1 SDOUTx



 Group
Delay
0-500uS
Master Clock In
Frame Sync
Clock / LRCK SDIN 2
Serial Clock
In / Out
LDO Analog Supply 2.5 V
VA
5.0 VDC
VD
2.5 VDC
Low -Latency
Demux
5 th DAC
Input Advisory
DAC &
Analog
Filters
Tracking
SMPS
Enable
Sample
& Hold
Mute, Invert,
Noise Gate
Master
Volume
Control
Serial Audio Interface
AOUT 5 (±)
(SMPS Control )
DAC &
Analog
Filters
Master
Vol . Cntrl
Select
Master Volume
0 dB
TPS
GAIN
Filter
Select X Interpolation Filter
Sample & Hold
Max
Detect
Envelope
Tracking
Mute, Invert,
Noise Gate
DAC
Volume Multi-bit 
Modulators
Mode
Select
Full Scale Code 
X
DC Offset
Digital Filters
Multi-bit
 ADC
-2
X
Gain
S elect
-1
Figure 26. Low-latency Path