TV 마이크로포닉 현상에 관한 연구

A tudy on the TV Microphonic Phenomenon

The microphonic phenomenon in TV(television) is a phenomenon that a stained pattern locally appears in the screen or moves like waves. This can be observed when audio signal of TV has specific frequencies under loud volume of sound. In this study, microphonic phenomenon has been investigated, and two practical ways of circumventing this has been proposed. Based on modal analysis of several TV parts(Cathod Ray Tube, shadowmask, etc.), it was proved that the microphonic phenomenon is caused by the resonance of the shadow mask. One of the proposed ways to circumvent this phenonenon is increasing the thickness of the frame, the other is removing the middle welding points between the frame and the shadow mask. The effects of these modifications are evaluated by the finite element analysis, and the results show that the magnitude of vibration of shadow mask reduced by 10 - 20dB, which is large enough to provent microphonic phenomenon even under maximum level of sound volume.