Datasheet

Low-pass
filter
Digital
modulator
Randomizer
High-pass
filter
Audiointerface
DAC
032-028
Low-pass
filter
Digital
modulator
Randomizer
High-pass
filter
Voiceinterface
DAC
032-029
TPS65950
SWCS032E–OCTOBER 2008–REVISED JANUARY 2011 www.ti.com
Table 6-10. MCPC and USB-CEA Carkit Audio Downlink Electrical Characteristics (continued)
Parameter Conditions Min Typ Max Unit
Phone speaker amplifier output impedance at 1 kHz USB-CEA (DP/DM) 200 Ω
MCPC (RXAF) 200
6.1.8 Digital Audio Filter Module
Figure 6-15 shows the digital audio filter downlink full path characteristics of the audio interface.
Figure 6-15. Digital Audio Filter Downlink Path Characteristics
The HPF can be bypassed.
Table 6-11 lists the audio filter frequency responses relative to reference gain at 1 kHz.
Table 6-11. Digital Audio Filter RX Electrical Characteristics
Parameter Conditions Min Typ Max Unit
Passband 0.42 F
S
Passband ripple 0 to 0.42F
S
(1)
–0.25 0.1 0.25 dB
Stopband 0.6 F
S
Stopband attenuation F = 0.6F
S
(1)
to 0.8F
S
(1)
60 75 dB
Group delay 15.8/F
S
(1)
μs
Linear phase –1.4 1.4 °
(1) F
S
is the sampling frequency (8, 11.025, 12, 16, 22.05, 24, 32, 44.1, or 48 kHz).
6.1.9 Digital Voice Filter Module
Figure 6-16 shows the digital voice filter downlink full path characteristics of the voice interface.
Figure 6-16. Digital Voice Filter Downlink Path Characteristics
The global HPF or only the third-order HPF can be bypassed (when the third-order HPF is skipped, the
first-order HPF remains active).
80 Audio/Voice Module Copyright © 2008–2011, Texas Instruments Incorporated
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