摘要 |
A cellular phone includes a communication circuit, a control module, and a video module. The communication circuit is used to receive an image signal and transmit a radio-frequency (RF) signal via radio transmission. The control module includes a processor, a button, and a display panel. A microphone is used to receive an analog acoustic wave and convert the analog acoustic wave into an audio signal. The conversion circuit is used to convert the image signal into a video signal. The video signal includes an analog brightness signal. The output terminal is used to transmit the video signal to a television. The television includes a screen for displaying an image according to the brightness signal. The brightness of the image changes from bright to dark when a level of the brightness signal increases from a first level corresponding to the bright image to a second level corresponding to the dark image.
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