Phase Accuracy Specification Note for APX-BT-WB Module

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Created on 2012-11-27 19:35:00

The APX-BT-WB Bluetooth hardware module includes support for the mSBC codec in addition to the existing SBC, aptX, and CVSD codecs.

The mSBC codec firmware provided by our chip vendor causes a potential ± 1 sample phase error in the A2DP mode. This issue cannot be corrected for by APx’s middleware. Research is ongoing with our vendor to fix the root cause, but meanwhile, users should be aware of this small potential inaccuracy in phase measurements.

  1. In A2DP Source or Sink mode, the module can exhibit a potential ± 1 sample phase error.
  2. The error randomly occurs approximately 15% of the time and affects results sensitive to phase, such as the time domain signal monitor, the group delay result, and the interchannel phase result.
  3. The measurements made in HFP and HSP profiles are unaffected as they are single channel measurements and have no phase component.

The APX-BT module (which supports SBC, aptX, and CVSD, but not mSBC) is still available and does not exhibit this error.