Datasheet

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SBAS291C − AUGUST 2003 − REVISED DECEMBER 2004
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Register 4: Attenuation Control Register – Channel 4
BIT 7 (MSB) BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 (LSB)
AT47 AT46 AT45 AT44 AT43 AT42 AT41 AT40
This register controls the digital output attenuation for Channel 4.
Default: AT4[7:0] = 255, or 0dB
Let N = AT4[7:0].
For N = 16 to 255, Attenuation (dB) = 0.5 x (255 – N)
For N = 0 to 15, Attenuation (dB) = Infinite (Muted)
Register 5: Function Control Register
BIT 7 (MSB) BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 (LSB)
MUT4 MUT3 MUT2 MUT1 ZDM PHASE DEM1 DEM0
This register controls various D/A converter functions, including de-emphasis filtering, output phase reversal, zero data
mute, and per-channel soft muting.
DEM[1:0] Digital De-Emphasis
De-emphasis is available for Single Rate mode only.
De-emphasis is disabled for Dual and Quad Rate modes.
DEM1
DEM0 De-Emphasis Selection
0 0 De-emphasis disabled (default)
0 1 De-emphasis for f
S
= 48kHz
1 0 De-emphasis for f
S
= 44.1kHz
1 1 De-emphasis for f
S
= 32kHz
PHASE Output Phase
PHASE Output Phase
0 Noninverted (default)
1 Inverted
ZDM Zero Data Mute
ZDM Zero Mute
0 Disabled (default)
1 Enabled
MUT[4:1] Soft Mute
MUTx D/A Converter Output
0 On (default)
1 Muted
NOTE: x = channel number.