Table 6. Soft Ramp Rates; Table 7. Noise Gate Bit Depth Settings - Cirrus Logic CS4244 Manual

tracking and always produce a constant ramp rate. To accomplish this, set the
DELAY[2:0] values to match the
The envelope counter time out period which defines the boundary between the two soft-ramping behav-
iors depends on the base rate. It is equal to approximately 100,000/Fs.
The MUTE DELAY[1:0],
of the base period between volume steps of
resolution of the volume control engine. Consequently the soft-ramp rate can be expressed in ms/dB as
shown in Table
Ramp Rate
1 x Base
2 x Base
4 x Base
8 x Base
16 x Base
32 x Base
64 x Base
128 x Base
Full-scale ramp is 96 dB (-90 dB to +6 dB)
4.6.5.3 Noise Gate
The CS4244 is equipped with a Noise Gate feature that mutes the output if the signal drops below a given
bit depth for 8192 samples. While the enabling or disabling of the Noise Gate feature is done for the entire
DAC1-4 output path, each of the channels within the path have separate monitoring circuitry that will trig-
ger the Noise Gate function independently of the other channels. For instance, if the Noise Gate were en-
abled for and one of the channels were to exhibit a pattern of more than 8192 samples of either all "1's"
or all "0's", the output for that particular channel would be muted (and subsequently unmuted), inde-
pendently of the other channels. To enable the Noise Gate feature, set the DAC1-4 NG[2:0] bits to the
desired bit depth. The available bit depth settings are shown in
DS900F2
MUTE DELAY[1:0]
MIN DELAY[2:0], and
6.
Fs = 48 kHz or 96 kHz (Base = 48 kHz)
Time to Ramp
Time to Ramp
to Full Scale
6 dB (ms)
(ms)
21.33 1.33
42.67 2.67
85.33 5.33
170.67 10.67
341.33 21.33
682.67 42.67
1365.33 85.33
2730.67 170.67

Table 6. Soft Ramp Rates

DAC1-4 NG[2:0] Setting
000
001
010
011
100
101
110
111

Table 7. Noise Gate Bit Depth Settings

setting.
MAX DELAY[2:0] bits specify a delay equal to a multiple
6.02
/ dB, which is approximately 0.1 dB. This is the internal
64
Fs = 32 kHz or 64 kHz (Base = 32 kHz)
Time to Ramp
ms/dB to Full Scale
(ms)
0.22 32
0.44 64
0.89 128
1.77 256
3.54 512
7.09 1024
14.17 2048
28.35 4096
Table
Channel is muted after "x" bits
Upper 18 Bits (-102 dB)
Upper 24 Bits (-138 dB)
MIN DELAY[2:0]
Time to Ramp
6 dB (ms)
2
4
8
16
32
64
128
256
7.
Upper 13 Bits (-72 dB)
Upper 14 Bits (-78 dB)
Upper 15 Bits (-82 dB)
Upper 16 Bits (-90 dB)
Upper 17 Bits (-94 dB)
Noise Gate Disabled
CS4244
and MAX
ms/dB
0.33
0.66
1.33
2.66
5.32
10.63
21.26
42.52
41