| 摘要 |
PURPOSE: An AC-3 audio system for PCM(Pulse Code Modulation) audio signals is provided to downmix the audio signal converted with 5.1 channels and output the result as a digital signal. CONSTITUTION: An AC-3 audio system for pulse width modulation audio signals includes an AC-3 audio decoder(10), a downmixer(20), a selector(50), a digital output format(40), and a controller(60). The AC-3 audio decoder(10) compresses the input audio bit stream signals into an AC-3 it stream signals, and decodes the result audio bit stream signal with 5.1 channel signal. The downmixer(20) combines two channels of the 5.1 channel signals, and outputs the overall digital audio signal combining all 5.1 channel signals. The selector(50) selects one of the overall digital audio signal and a compressed AC-3 bit stream signals. The digital output format(40) converts the selected signal into a digital format. The controller(60) controls the selector to select the signal of user's preference.
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