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BTM8670 DATASHEET

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4.2.2

A D C

Figure 3 shows the CSR8670 consists of 2 high-quality ADCs:

Each ADC has a second-order Sigma-Delta converter

Each ADC is a separate channel with identical functionality

There are 2 gain stages for each channel,1 of which is an analogue gain stage and

the other is a digital gain stages

4.2.3

ADC Sample Rate Selection

Each ADC supports the following pre-defined sample rates, although other rates are

progrmmable,e.g.40kHz:

8kHz

11.025 kHz

16kHz

22.050kHz

24kHz

32 kHz

44.1kHz

48 kHz

4.2.4

ADC Digital Gain

A digital gain stage inside the ADC varies from -24dB to 21.5dB,see as below, there is

also a fine gain interface with 9-bit gain setting allowing gain changes in 1/32 steps.

The Firmware controls the audio input gain.