CMX649 CML Microcircuits, CMX649 Datasheet - Page 33

• Manufacturer Part Number: CMX649
• Description: ADM Codec
• Manufacturer: CML Microcircuits

ADM Codec
Estimator
Integrator Time
Constant
(Bits 7 – 5)
Second Order
Estimator Time
Constant
(Bits 4 – 3)
Zero Selection
(Bits 2 – 1)
Zero at ½ Bit
Rate
(Bit 0)
2003 CML Microsystems Plc
Allows selection of the estimator integrator time constant.
Allows selection of the second order estimator time constant.
When second order integration is used, a zero can be inserted to help stability.
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.
Bit 2
Bit 7
0
0
1
1
Bit 4
0
0
0
0
1
1
1
1
0
0
1
1
Bit 1
Bit 6
0
1
0
1
0
0
1
1
0
0
1
1
Bit 3
0
1
0
1
33
N/A (select for first order estimator)
1.5/Bit Rate
2.5/Bit Rate
4.5/Bit Rate
Bit 5
Time Constant (ms), Bit Rate in kbps
0
1
0
1
0
1
0
1
N/A (selects first order estimator).
(Estimator Time Constant)/2
(Estimator Time Constant)/4
(Estimator Time Constant)/8
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)
Decay Time Constant (ms),
Loss Factor
Bit Rate in kbps
CMX649
D/649/2