CMX649 View Datasheet(PDF) - CML Microsystems Plc
Part Name
Description
MFG CO.
'CMX649' PDF : 50 Pages View PDF
ADM Codec
CMX649
Estimator
Integrator Time
Constant
(Bits 7 – 5)
Allows selection of the estimator integrator time constant.
Bit 7
0
0
0
0
1
1
1
1
Bit 6
0
0
1
1
0
0
1
1
Bit 5
0
1
0
1
0
1
0
1
Decay Time Constant (ms),
Bit Rate in kbps
16/(3*Bit Rate)
24/(3*Bit Rate)
32/(3*Bit Rate)
48/(3*Bit Rate)
64/(3*Bit Rate)
96/(3*Bit Rate)
Bluetooth compatible when
running at 64kbps.
128/(3*Bit Rate
192/(3*Bit Rate)
Second Order
Estimator Time
Constant
(Bits 4 – 3)
Allows selection of the second order estimator time constant.
Bit 4
0
0
1
1
Bit 3
0
1
0
1
Loss Factor
N/A (selects first order estimator).
(Estimator Time Constant)/2
(Estimator Time Constant)/4
(Estimator Time Constant)/8
Zero Selection
(Bits 2 – 1)
When second order integration is used, a zero can be inserted to help stability.
Bit 2
0
0
1
1
Bit 1
0
1
0
1
Time Constant (ms), Bit Rate in kbps
N/A (select for first order estimator)
1.5/Bit Rate
2.5/Bit Rate
4.5/Bit Rate
Zero at ½ Bit
Rate
(Bit 0)
When decoding ADM, a zero at (bit rate)/2 can be enabled by setting this bit to
logic 1. When encoding or transcoding from PCM to ADM this bit should always be
set to a logic 0 to avoid instability of the ADM feedback loop.
© 2003 CML Microsystems Plc
33
D/649/2
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