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CC8530: CC8530 24-Bit Word Length Support

Part Number: CC8530

What exactly is the capability of the PurePath wireless line with regard to 4 channel 24-bit audio?  Is it only capable of compressed 24-bit audio or is lossless 24-bit possible?  The CC8530 datasheet references uncompressed 24-bit capability, but the user guide does not show a streaming format that supports it.  The user guide only offers the SLAC streaming format for 4 channel 24-bit audio, but this is compressed and lossy and results in less than 2 mbps of bandwidth (928 kbps average for 4 channels).  However, the CC853X line is capable of 5 mbps of bandwidth so 4 channels of lossless 24-bit audio would easily fit (4.4 megabits). Is this possible and if so, what streaming format should be selected in the configurator to facilitate this? If not, what is the point of 5 mbps capability?

  • Hi Stuart,

    There is only support for 4 channels with SLAC compression. There is no support for 24-bit lossless.

    There is not support for 5 Mbps of audio data because:
    - We need over-capacity in order to support retransmissions
    - We need a good balance between average retransmission capacity, and number of attempts per audio sample block. For each retransmission attempt there is significant overhead:
    o Timeslot planning and other processing that must be completed between start of packet reception and transmission (with safe margins), in parallel with radio turnaround time
    o Base overhead for each packet (transmitted from master and received from all slaves), including preamble+sync, packet headers, network information, audio slice headers etc.
    o Audio slice acknowledgment (one packet from each slave)
    - The protocol supports also remote control, volume control, data side channel etc.

    4 x PCME24 can be achieved by using two masters that are synchronized through a single wire.

    Cheers,
    Fredrik
  • Thank you.  It would be great if TI offered a true wireless uncompressed 24-bit 96 kHz device.  I guess for now we'll continue pursuing the Avnera devices.