BC352239A Datasheet, PDF (75/116 Pages) List of Unclassifed Manufacturers – BlueCore 3-Multimedia External

Device Terminal Descriptions
8.8.5 DAC
The DAC consists of two second order Sigma Delta converters allowing two separate channels that are identical
in functionality as shown in Figure 8..
8.8.6 DAC Sample Rate Selection and Warping
Each DAC supports the following samples rates:
! 48kHz
! 44.1kHz
! 32kHz
! 24kHz
! 22.050kHz
! 16kHz
! 11.025kHz
! 8kHz
Like the ADC, one of the main concerns for the DAC used in stereo wireless music applications is, the ability to
keep sample rates for the CODECs at both ends of the wireless link in synchronisation. A VM function adjusts the
sample rate using a ‘warping’ function to tune the sample rate to the required value. The DAC warp function
allows the sample rate to be changed by ±3%, in steps of 1/2¹⁷, or 7.6 ppm. The warp function preserves the
signal quality – the distortion introduced when warping the sample rate is negligible.
8.8.7 DAC Gain
The DAC contains two gain stages for each channel, a digital and an analogue gain stage.
The digital gain stage has a programmable selection value in the range of 0 to 15 with associated DAC gain
settings summarised by Table 8.3.
Gain Selection Value
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
DAC Digital Gain Setting (dB)
0
3.5
6
9.5
12
15.5
18
21.5
-24
-20.5
-18
-14.5
-12
-8.5
-6
-2.5
Table 8.3: DAC Digital Gain Rate Selection
BC352239A-ds-001Pc
© Cambridge Silicon Radio Limited 2004
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