| 摘要 |
In a bilingual television signal processor which is capable of automatically controlling a bandpass filter for detecting a pilot signal included in a bilingual signal received in a television receiver having a bilingual function without an external adjustment, an improvement including a microcomputer for outputting an on-screen display message indicating a bilingual broadcasting and scanning the locked information of the pilot signal outputted from the PLL detector in a predetermined voltage range and step and outputting a corresponding pulse width modulated (PWM) signal, and a digital/analog (DA) converter for converting the PWM signal outputted from the microcomputer into an analog signal and outputting a corresponding DC voltage to set the bandpass filter, can achieve the effect that it can be controlled without an external adjustment since the voltage for adjusting the center frequency of the bandpass filter is scanned in an appropriate range, and as a result, the shift in the center frequency of the bandpass filter due to the variation of the temperature and the applied voltage can be prevented, and consequently, the exact setting of the center frequency and the detectability of the pilot signal can be significantly enhanced.
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