Analysis The Research And Implementation Of Mobile Audio Fault Detection

According to the investigation in several domestic well-known mobile phone manufacturers, it is learned that the current process of defect detection on assembled mobile phones, which is the last step before the mobile phones leave the factory, is mostly done by hand, other than automation. Specifically, the detection process mainly include checking on the overall appearance of the handsets, like screens and keyboards, and testing on the audio loops when the handsets are in headset mode, discrete mode and playback mode. However, there are a range of issues for manual testing, such as high cost, low efficiency, high error rates and un-conduciveness to pipeline production, and so on. Therefore, how to achieve the automation of this testing process becomes one of the problems the mobile phone manufacturers should solve urgently.This thesis focuses on the handset audio loop test and aims at addressing the key issues in the transition of the test from hand to automation. The handset audio loop test includes three scenarios:headset mode, discrete mode and playback mode. Based on the test, the main research work of this thesis are as follows:First of all, the architecture of the handset audio loop test circuit is analyzed and audio data acquisition technologies are studied. The occurrence of self-excited howling between the handset’ s microphone and speaker is deeply discussed and a corresponding solution is proposed in this part.Secondly, we studied how to build an audio data acquisition system via the computers’sound card. Here, based on the fundamentals of the computer sound card, we can capture audio data from it in real time, which is done by calling the underlying API interfaces on the windows operating system. In addition, the direct connection between the computer’ s sound cart and the handset’s headset is implemented with analog circuit, which contributes to the isolation from the environmental noise.Next, the design ideas for handset audio loop test are proposed. The main ideas of this design include two aspects:first, the audio data acquisition system based the computer’ s sound card is used for controlling the I/O of handset audio loop, substituting people’ s ears; second, the difference of the audio signals is decided based on the audio frame’ s feature, which can improve the test accuracy in a great extent.And then, handset audio loop test based on Support Vector Machine (SVM) is discussed at length. In this part, we deeply studied the SVM concepts, principles and applications etc; afterwards, the handset audio loop test method based on SVM is presented.In the end, the SVM method is deployed on the100handsets in headset mode and discrete mode, which are modeled ALCATEL-203X. The result shows that a high correct test rate up to96%can be achieved with this method.