| 摘要 |
1,110,984. Colour television receivers. GRUNDIG E.M.V. ELEKTRO - MECHANISCHE VERSUCHSANSTALT INH. MAX GRUNDIG. 29 Nov., 1966 [29 Nov., 1965], No. 53406/66. Heading H4F. In a colour television receiver which responds to a signal which includes synchronizing " bursts," the phases of which differ in alternate lines, and in which the reference oscillator is synchronized to the " bursts " with the aid of a phase detector 1 which produces a saw-tooth signal at half the line frequency in the presence of " bursts " and a direct voltage in the absence of " bursts," a tuned amplifier 2 is provided to derive from the saw-tooth signal a sinusoidal signal which is rectified and filtered in a circuit 4 to produce a direct voltage which controls the colour amplifier 5, whereby the receiver is caused to produce a colour picture when " bursts " are received and a monochrome picture when " bursts " are not received or are inadequate for proper colour operation. The sinusoidal signal also controls a multivibrator of a colour switcher 3 which changes over the phase of one of the modulation components of the colour signal. The direct voltage produced by phase detector 1 in the absence of " bursts " may be applied over lead 6 to block amplifier 2. |
