| 摘要 |
PURPOSE:To ensure good tuning reception without using the inductance tuning by eliminating the disturbance of the base band video signal of the desired channel of the carrier chrominance and carrier sound signals of lower adjacent channels. CONSTITUTION:The input signal supplied from a high frequency input part undergoes a synchronous wave detection through a synchronous wave detectors 10 and 11 of a costus loop and then undergoes a low band filtering through LPF12 and 13 having a frequency range of a base band video signal and a low band range of frequency of a sound IF signal. Thus the greater part of energy is eliminated for the carrier video signals of lower adjacent channels. Furthermore the video signal undergoes a comb- shaped filtering with frame frequency intervals through an LPF39 of the time direction. Thus the greater part of disturbance is eliminated to the desired base band video signal of carrier chrominance and carrier sound signals of lower adjacent channels, and a video output 41 is delivered after D/A conversion 40. Then the sound signal undergoes frequency discrimination 23, and a demodulated signal is delivered 42 with sounds. |
