MEJORAS EN SISTEMAS DE TELEVISIoN

摘要

650,666. Colour television. STANDARD TELEPHONES & CABLES, Ltd. Nov. 26, 1945, No. 31820. Convention date, Jan. 13. [Class 40 (iii)] In a colour television system, the framesynchronizing pulses corresponding to frames of any one component colour differ in width from the synchronizing pulses corresponding to frames of a different component colour. It is also stated that the pedestals of the framesynchronizing pulses may be used to carry further pulses conveying additional information, e.g. the accompanying sound channel, by modulation of the timing of these pulses with respect to the leading edges of the synchronizing pulses. Transmitter. A generator delivers a pulse f, Fig. 2, at the commencement of each complete colour cycle. In a tricolour system, the pulse f is applied to three delay networks, each of which delays the pulse by the amount appropriate to its respective colour channel to produce pulses g, i, k. These are applied to trigger circuits which produce pulses h, j, l of predetermined and differing widths. These signals are combined in a mixer with the three colourcomponent video signals from a television camera. The horizontal-synchronizing and vertical-pedestal. signals are also introduced into the mixer, the composite output signal, which is as shown at a, Fig. 4, being passed to a transmitter. Receiver. The signal a, Fig. 4, is limited, as at b, differentiated, as at c, and limited again to produce pulses d which are used for horizontal synchronization. The signal b is also applied to three width discrimination circuits, as described in Specification 592,789. The outputs of these circuits shown at e, f, g are applied in pairs, i.e. ef, fg, ge, to three trigger circuits which produce pulses h, i, j respectively. Each of these is applied, together with signal a, to a separate mixer, each of which produces a signal such as is shown at k. The mixer outputs are limited to give the signals l, m, n, so that the received signal is separated into three channels corresponding to the channels at the output of the camera. The Specification as open to inspection under Sect. 91 also states that the lines of successive frames are so interlaced that in nine successive frames each line of three adjacent line positions is used once only for each primary colour. This subject-matter does not appear in the Specification as accepted.