Window Active Noise Control System with Virtual Sensing Technique

In the window ANC system based on the feedforward structure, error microphones are located in the room. Although the noise reduction of whole room depends on the locations of error microphones, microphones will be obstacle if they are put on the center of the room. A solution to this problem is to apply a virtual sensing technique. This technique can achieve the maximum noise reduction at the desired locations. Currently, two classes of algorithms have been developed for this technique. The first class does not require offline training to obtain some system models to compensate the relationship between the physical microphone location and the desired location, but requires a microphone array to estimate the sound pressure and its gradient at the desired locations. However, there are some constraints between the microphones and then this class is unsuitable for the window ANC system. We therefore focus on the second class, which requires the system models. In this class, physical microphones are placed at the desired locations and the transfer functions between the error microphones and virtual microphones are estimated in advance. We demonstrate the effectiveness of the window ANC system with the virtual sensing technique through some simulation and experimental results.