Cirrus Logic CS42L55 - Manual (Page 65)

DS773F1 65
CS42L55
6.32.2 Noise Gate Enable
Configures the noise gate.
6.32.3 Noise Gate Threshold and Boost
THRESH sets the threshold level of the noise gate. Input signals below the threshold level will be attenu-
ated to -96 dB. NG_BOOST configures a +30 dB boost to the threshold settings.
6.32.4 Noise Gate Delay Timing
Sets the delay time before the noise gate attacks.
Note: The Noise Gate attack rate is a function of the sampling frequency, Fs, and the DIGSFT ( “Digital
Soft Ramp” on page 46 ) setting unless the disable bit ( “ALCx Soft Ramp Disable” on page 65 ) is enabled.
6.33 ALC and Limiter Soft Ramp, Zero Cross Disables (Address 28h)
6.33.1 ALCx Soft Ramp Disable
Configures an override of the analog soft ramp setting.
6.33.2 ALCx Zero Cross Disable
Configures an override of the analog zero cross setting.
NG Noise Gate Status
0 Disabled
1 Enabled
THRESH[2:0] Minimum Setting (NG_BOOST = ‘0’b) Minimum Setting (NG_BOOST = ‘1’b)
000 -64 dB -34 dB
001 -67 dB -36 dB
010 -70 dB -40 dB
011 -73 dB -43 dB
100 -76 dB -46 dB
101 -82 dB -52 dB
110 Reserved -58 dB
111 Reserved -64 dB
NGDELAY[1:0] Delay Setting
00 50 ms
01 100 ms
10 150 ms
11 200 ms
7 6 5 4 3 2 1 0
ALCBSRDIS ALCBZCDIS ALCASRDIS ALCAZCDIS LIMSRDIS Reserved Reserved
ALCxSRDIS ALC Soft Ramp Disable
0 OFF; ALC Attack Rate is dictated by the DIGSFT ( “Digital Soft Ramp” on page 46 ) setting
1 ON; ALC volume changes take effect in one step, regardless of the DIGSFT setting.
ALCxZCDIS ALC Zero Cross Disable
0 OFF; ALC Attack Rate is dictated by the ANLGZC ( “Analog Zero Cross” on page 46 ) setting
1 ON; ALC volume changes take effect at any time, regardless of the ANLGZC setting.