| 摘要 |
PURPOSE:To settle radically the flare disturbance and to obtain a high-contrast projection picture, by providing a filter having the characteristics to suppress the low band frequency component compared with the high band frequency component of a picture signal to a transmission line through which the picture signal is supplied to a picture display tube. CONSTITUTION:An input picture signal is supplied to a flare disturbance eliminating circuit 5, and the proper signal processing is carried out to eliminate the flare disturbance of the picture signal. This picture signal is supplied to a projection type cathod-ray tube (CRT) 2 via a driving circuit 1 and projected on a screen 4 via a lens 3. The circuit 5 consists of a modulator 13, an SAW filter 14 and a demodulator 15. The modulator 13 applies the double side band amplitude modulation to the input picture signal with a carrier signal of a proper frequency, and the carrier picture signal is applied to a filter 14. Then the low band frequency component is suppressed compared with the high band frequency component of the picture signal by the characteristic of the filter 14. Then the carrier picture signal passed through the filter 14 is demodulated by a demodulator 15 and then supplied to the CRT, and a picture of a high contrast is projected on the screen 4. |
