Patent ID: 7796195

Claim:
A circuit for eliminating abnormal sound, mounted in a display device connected to a digital video/audio player for playing a digital video/audio stream having a video signal and an audio signal, the circuit comprising: a video/audio processor connected to an output end of the digital video/audio player for receiving the digital video/audio stream to perform decoding, wherein the video signal is transformed into an analog video signal, and the audio signal is transformed into a digital audio signal; a digital to analog converter connected to the video/audio processor for transforming the digital audio signal into an analog audio signal; a front-stage mute circuit connected to an output end of the digital to analog converter; a changing delay device connected between the output end of the digital to analog converter and the input end of the front-stage mute circuit for delaying the changing of analog audio signal outputted by the digital to analog converter so as to use the front-stage mute circuit to filter out noise in the digital audio signal; a front-stage amplifier connected to an output end of the front-stage mute circuit for outputting the analog audio signal of the front-stage mute circuit; a back-stage amplifier connected to the output end of the front-stage amplifier; a back-stage mute circuit connected to the back-stage amplifier and the micro control unit; and a micro control unit connected to the video/audio processor and the back-stage mute circuit for controlling the back-stage mute circuit; wherein, as the digital video/audio stream begins changing of the video/audio processor, the video/audio processor sends an interrupt control signal to the micro control unit, and the micro control unit controls the back-stage mute circuit via interrupt for disabling the back-stage amplifier so as to enter in the mute mode.