| 摘要 |
962,203. Colour television. FERNSEH G.m.b.H. Jan. 25, 1963 [Jan. 27, 1962], No. 3211/63. Heading H4F. In a vecterscope apparatus for use with colour television signals, a plurality (two as illustrated) of N.T.S.C.-type subcarrier signals are applied in cyclic succession via gate stages 9, 10 controlled by a gatepulse generator 19 to a pair of synchronous detectors 14, 15 whose outputs are applied to deflect a cathode-ray tube 18, the arrangement being characterized by means to apply the reference subearrier oscillation 21 (derived if desired from a subcarrier synchronizing " burst ") to the synchronous detectors via separate channels controlled by gates 23, 26 in synchronism with the operation of gates 9, 10, an adjustable phase shifter 24 being included in one channel which may be adjusted to allow for any phase displacement between the signals applied to gates 9 and 10. The invention is of use where it is desired to compare a reference signal with the same signal after passage through apparatus under test where it may be subject to delay. By appropriate adjustment of phase shifter 24 the reference subcarrier oscillation may be subjected to the same delay, whereby in the resulting cathode-ray display Fig. 4, the traces due to the reference and test subcarrier are in rotational alignment and may be compared more readily. Gate-pulse generator 19 may control a blanking stage 31 to suppress the cathode-ray beam during change-over from one subcarrier signal to another. |
