The reception of many different audio sources and the transmission of these to different audio zones, may require different audio clocks. The asynchronous Audio Sample Rate Converter (ASRC) module takes samples from one clock zone and moves them to another, while maintaining a high signal to noise ratio to ensure that the output quality is sufficient to meet the requirements for various high-end algorithms.
ASRC Overview Diagram is a simplified overview diagram of the ASRC module implementation within the device.
The ASRC module supports the following main features:
- High performance Asynchronous Sample Rate Converter with 140dB Signal-to-Noise (SNR)
- Up to 8 input and output stereo streams (16 audio channels)
- 4 input and output clock zones
- Support for input and output audio sample rates from 8 kHz to 216 kHz
- Automatically sensing/detection of input sample frequencies
- Attenuation of sampling clock jitter
- 16-, 18-, 20-, 24-bit data input/output
- Input/output sampling ratios from 16:1 to 1:16
- 128-sample input and 32-sample output FIFO for each channel with independently configurable thresholds
- Group mode, where multiple ASRC blocks use the same timing loop for input or output
- Linear phase FIR filter
- Controllable soft mute
- De-Emphasis supported for 48, 44.1 and 32 kHz sample rates
- Separate DMA events for input and output, for each channel and group
- Interrupts for input, output, and error for channels and groups of channels
- Independent clock generator for each input and output clock zone
- Channels belonging in an input/output clock zone may be configured and managed as a group or as individual streams
The ASRC module has the following main constrains:
- The ASRC output rate divided by input rate must be between 1/16 and 16
- Sample rate must be between 8 and 216 kHz
Note: ASRC is also known as AASRC