
1
2
0
1
2
15
1
2
1
2
N
2 N z
N z
H(z)
2
2 D z
D z
-
+
+
=
-
-
(5-5)
5.6.1.4 DAC Interpolation Filter Characteristics
TSC2117
Low-Power Audio Codec With Embedded miniDSP, Stereo Class-D
Speaker Amplifier, and Smart Four-Wire Touch-Screen Controller
SLAS550A – APRIL 2009 – REVISED JUNE 2009
www.ti.com
5.6.1.3.2 Biquad Section
The transfer function of each of the biquad filters is given by
Table 5-27. DAC Biquad Filter Coefficients
Filter
Coefficient
Left DAC Channel
Right DAC Channel
Default (Reset) Values
Biquad A
N0
Page 8/registers 2–3
Page 8/registers 66–67
0x7FFF (decimal 1.0 – LSB value)
N1
Page 8/registers 4–5
Page 8/registers 68–69
0x0000
N2
Page 8/registers 6–7
Page 8/registers 70–71
0x0000
D1
Page 8/registers 8–9
Page 8/registers 72–73
0x0000
D2
Page 8/registers 10–11
Page 8/registers 74–75
0x0000
Biquad B
N0
Page 8/registers 12–13
Page 8/registers 76–77
0x7FFF (decimal 1.0 – LSB value)
N1
Page 8/registers 14–15
Page 8/registers 78–79
0x0000
N2
Page 8/registers 16–17
Page 8/registers 80–81
0x0000
D1
Page 8/registers 18–19
Page 8/registers 82–83
0x0000
D2
Page 8/registers 20–21
Page 8/registers 84–85
0x0000
Biquad C
N0
Page 8/registers 22–23
Page 8/registers 86–87
0x7FFF (decimal 1.0 – LSB value)
N1
Page 8/registers 24–25
Page 8/registers 88–89
0x0000
N2
Page 8/registers 26–27
Page 8/registers 90–91
0x0000
D1
Page 8/registers 28–29
Page 8/registers 92–93
0x0000
D2
Page 8/registers 30–31
Page 8/registers 94–95
0x0000
Biquad D
N0
Page 8/registers 32–33
Page 8/registers 96–97
0x7FFF (decimal 1.0 – LSB value)
N1
Page 8/registers 34–35
Page 8/registers 98–99
0x0000
N2
Page 8/registers 36–37
Page 8/registers 100–101
0x0000
D1
Page 8/registers 38–39
Page 8/registers 102–103
0x0000
D2
Page 8/registers 40–41
Page 8/registers 104–105
0x0000
Biquad E
N0
Page 8/registers 42–43
Page 8/registers 106–107
0x7FFF (decimal 1.0 – LSB value)
N1
Page 8/registers 44–45
Page 8/registers 108–109
0x0000
N2
Page 8/registers 46–47
Page 8/registers 110–111
0x0000
D1
Page 8/registers 48–49
Page 8/registers 112–113
0x0000
D2
Page 8/registers 50–51
Page 8/registers 114–115
0x0000
Biquad F
N0
Page 8/registers 52–53
Page 8/registers 116–117
0x7FFF (decimal 1.0 – LSB value)
N1
Page 8/registers 54–55
Page 8/registers 118–119
0x0000
N2
Page 8/registers 56–57
Page 8/registers 120–121
0x0000
D1
Page 8/registers 58–59
Page 8/registers 122–123
0x0000
D2
Page 8/registers 60–61
Page 8/registers 124–125
0x0000
5.6.1.4.1 Interpolation Filter A
Filter A is designed for an fS up to 48 ksps with a flat pass band of 0 kHz–20 kHz.
Table 5-28. Specification for DAC Interpolation Filter A
Parameter
Condition
Value (Typical)
Unit
Filter-gain pass band
0
… 0.45 f
S
±0.015
dB
Filter-gain stop band
0.55 fS… 7.455 fS
–65
dB
Filter group delay
21/fS
s
APPLICATION INFORMATION
50