Processing the handsfree call

The QNX CAR acoustic processing module uses reference signals, and processes input and output signals to improve the sound quality and intelligibility of handsfree calls.

The figure below shows a simplified view of handsfree acoustic echo cancellation through the QNX acoustic processing module:
  1. On the near-side (in the vehicle), one or more microphone signals are input for send-signal processing.
  2. The audio signal received from the far-side of the conversation is processed to improve sound quality before it is output to the local system.
  3. The send-signal processing produces an echo-free and noise-reduced output signal, which is sent to the remote system.
Figure 1. Input and output signals in handsfree telephony