摘要 |
An objective of one embodiment of the present invention is to perform infrared communications without error by reducing abrupt noise included in a data signal when a light source of a display device is driven by PWM drive. When a control portion is provided with a drive setting signal for determining whether to drive lamps of a liquid crystal television by pulse width modulation drive or by continuous drive, the control portion sets a threshold in a register for a frequency filter portion based on the provided drive setting signal. Furthermore, upon reception of infrared light from the lamps, the threshold being set is reviewed based on an occurrence frequency for abrupt noise provided by a waveform analysis portion. Thereafter, abrupt noise included in a data signal transmitted from a cell phone is reduced by the frequency filter portion, and then the data signal is transmitted to the liquid crystal television.
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