| 摘要 |
<p>1,193,020. Colour television. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 5 Nov., 1968 [8 Nov., 1967], No. 52407/68. Heading H4F. In an arrangement for deriving the colour sub-carrier from the burst signal in a colour television receiver, the burst signal is applied to a passive integrator circuit 71 to regenerate the sub-carrier which is passed to an amplifier 81, the gain of which is controlled by the amplitude of the sub-carrier from a high pass filter 105, 107. The input and output phases of the combination of units 71 and 81 are compared in a phase detector 75 which provides an error signal at an input of integrator 71. The amplitude of the regenerated sub-carrier at terminal 83 is detected by 92, 93 and 95 and passed to the high-pass filter specified above and also to a low-pass filter 99 and 101 to provide an average amplitude thereof which controls the gain of an amplifier 17 in the chrominance signal path. The burst signal is separated from the chrominance signal in a burst separator 23. The gaincontrolled sub-carrier at terminal 83 is fed to the chrominance demodulator and matrix circuit 49 from whence the colour difference signals are applied to the picture reproducer 13.</p> |
