Decoder for digital information T.V. signal

Claim 1

In a television system including input means (40) for receiving a demodulated television signal carrying, during picture-free periods thereof, a set of pages of information represented by serial binary signals provided in a repeated cycle and at least some of the binary signals representing coded instructions, the form of the cycle being such that the binary signals for the set of pages received are in groups, which groups are received each in a different one of said periods and the whole of the information for the set of pages is received during each occurrence of the cycle; a parallel binary memory device (41) connected with the input means (40) for storing binary signals representing a page of information; processing means (45) for controlling the system and connected with the input means and the parallel binary memory device; selector means (42) connected with the processing means for generating a desired page address code and activating the processing means to effect storage of the binary signals representing the page; further storage means (47) connected with the processing means and the parallel binary memory device (41) for storing a plurality of routines for use by the processing means; the processing means being arranged to access a received coded instruction in the parallel binary memory device and accessing the further storage means in order to carry out the required instruction; signal generator means (44) connected with the parallel binary memory device (41) for processing the signals stored in the parallel binary memory device to produce output signals for visual display; and display means (30) connected with the signal generator means (44) for visual display of the signals produced by the signal generator, the improvement comprising: (a) a timer means (45a) connected with said processing means (45) for enabling the same to control the timing of the processing of the incoming coded instructions; (b) inhibiting means (44a) connected with said signal generator means (44) and said processing means (45) and operable by said processing means to prevent operation of the said signal generator; and (c) auxiliary storage means (48) connected with said signal generator means (44), said parallel binary memory device (41), said further storage means (47) and the said processing means (45) for receiving signals representing a visual image from at least one of the processing means, signal generator means and the parallel binary memory device, said processing means (45) and timer means (45a) being arranged to effect and control the input of signals from said at least one of the processing means (45), signal generator means (44) and parallel binary memory device to the auxiliary storage means (48), said auxiliary storage means (48) having an output connected with said display means (30), thereby to display the contents of said auxiliary storage means.