| 摘要 |
1,225,683. Colour television. NIPPON ELECTRIC CO. Ltd. 11 March, 1968 [11 March, 1967], No. 11766/68. Heading H4F. [Also in Division G5] The luminance component of a colour television signal is recorded in oblique tape tracks by rotating magnetic heads, while the two chrominance components are recorded longitudinally of the tape by a stationary magnetic head or heads. The system is applicable to Y, I, Q or Y, X, Z standards. The video signal 22 is divided into its various components and the Y-signal frequency modulated 25 and recorded by heads 5a, 5b driven by motor 44. The Y-signal is monitored through the receiver at terminal 53a via switch 35a, limiter 36 and demodulator 37 and the vertical sync. pulses separated at 38 and used to generate 60 c/s. pulses in generator 39. These pulses are multiplexed with the chrominance I- and Q-signals, frequency modulated 29, 30 and recorded by stationary heads 18a, 18b as well as being fed via switches 48a, 49a and demodulators 50, 51 to monitoring terminals 53b, 53c. The pulses are also fed via switch 40a to a comparator 41 controlling the motor speed in accordance with speed detector 45. The signals are reproduced with the various switches in position b, the Y-signals being fed through a switching circuit 34 synchronized with the rotation of the heads 5a, 5b, and the I- and Q-signals being fed through demodulators 50, 51, the former feeding a sync. separator 52 used to control the motor speed. The stationary head assembly includes two erase and three record/playback heads for the chrominance and audio signals and the various heads are screened from one another (Fig. 3, not shown). In a modification, the outputs from modulators 29, 30 are fed to a gate operated by horizontal sync. pulses separated from the video signal to generate a sequence of alternate I- and Q-signals, I 1 Q 2 I 3 Q 4 ... which are frequency modulated and recorded in a single track. The reproduced signal is fed to two inputs of a switching device, one input being delayed, to generate separate I- and Q-channels, each consisting of alternate fields repeated once, I 1 I 1 I 3 I 3 ... and Q 2 Q 2 Q 4 Q 4 ... which are subsequently demodulated. Slow motion colour and still black-and-white pictures are obtained by adjusting the tape speed and placing the switches in a neutral position. |
