approximately 16 million colours to the animation objects output from the rto processor 12 the ramdac 14 converts the colours into analogue rgb signals 15 a suitable ramdac 14 which includes 4 1 multiplexed inputs is for example the inmos g300 or the brooktree bt458 the ramdac 14 is only required if the hdtv 1 is configured for the display of analogue signals if digital signals can be displayed there is no requirement for the ramdac 14 and a colour look up table clut is used in this case the analog switch 6 is replaced with a digital multiplexer the provision of the interactive animation system 7 into the hdtv set 1 affords a number of advantages not generally available this includes the ability of interactive animation in which interactive computer games can be down loaded from an isdn line and played on the hdtv set 1 furthermore for example periodicals such as magazines can be produced electronically and made available as isdn services using a standard 64 kilobit isdn line an entire magazine can be transferred for display in approximately one minute furthermore the system 7 can be used for connection to a cdrom which can provide input of graphic objects for animation purposes connection to teletext registered trade mark services can also be provided as the host processor 8 is not necessarily required exclusively for real time animation generation the system 7 provides high quality animated text and graphics including smooth motion smooth curves and.