3 Audio Subsystem

The input and output audios have different stages and each stage can be programmed to vary the gain response characteristics. For microphone, both single-ended inputs and differential inputs are supported. To maintain a high quality signal, a stable bias voltage source to the condenser microphone’s Field-Effect Transistor (FET) is provided. The DC blocking capacitors can be used at both positive and negative sides of an input. Internally, this analog signal is converted to 16-bit, 8 kHz/16 kHz/44.1 kHz/48 kHz linear PCM data.

The following figure shows the audio subsystem.