Patent GB-1454417-A (GB)
Title: Audiovisual information storage system
IPC: G06F3/023
Filed: 1973-12-19
Abstract: 1454417 Information storage and retrieval INTERNATIONAL BUSINESS MACHINES CORP 19 Dec 1973 [26 Dec 1972] 58933/73 Heading G5R [Also in Division H4] An audiovisual information storage apparatus stores video signals and audio signals, which are time compressed so as to occupy the same bandwidth as the video signals, in analogue form in an analogue store VF, and has a switching arrangement for connecting the store to any selected one of a plurality of display devices. The information in store VF may be recorded on magnetic discs and/or a read operation may involve fetching a requested document and positioning it in front of a television camera. The apparatus includes: an additional store file (DB), Fig. 1 (not shown), containing the necessary elements to locate documents in store VF and additional information which may be combined with that from store VF before transmission to the requesting station; a central processing unit (CPU) which processes the information from both stores VF, (DB); and a switching network controlled by a centralized control unit (CTL) to set up a transmission path between the stores and a requesting terminal. The (CTL) unit and switching components of an audio network (AN) and of a video network (VN) may be included in a centrally controlled PBX. An operator at any terminal uses the dial of a telephone set or a keyboard to transmit the references of desired documents. The PBX directs the enquiry to the (CPU) which initiates a search of the addresses of the documents in store VF and determines the order of readout, the (CPU) performing a look-up operation in store (DB) to do this. The (CPU) loads the required addresses in a central file address register VF.AD.REG, the outputs 6 of a decoder of which pass to store VF. The requested document is then read from store VF into a main analogue buffer store VBP having a control section VBP CTRL including a clock generating pulses on line SYN to synchronize all operations. If the information read into VBP is video, the (CPU) opens gate A1 and closes gate A<SP>1</SP>l and the contents of VBP are transferred into one of the N secondary analogue buffer stores VB1 to VBN selected by the (CTL) via register ADVB. The above process can then be repeated to transfer further data from VF via VBP to others of stores VB1 to VBN. The contents of each of stores VB1 to VBN are then sent independently to the requesting terminal via the switching network wherein a network NTWN comprises a matrix of N lines, each connected to the output of a respective one of VB1 to VBN, and N columns, each connected to a respective junctor J1 to JN which are also connected to respective ones of the N lines of matrix NTWB having n columns connected to respective video terminals. Appropriate crossing points in networks NTWN, NTWB and appropriate junctors J1 to JN are closed under the control of unit (CTL) via address register NTR to transfer the data in VB1 to VBN to a visual display unit (TV) at the requesting station. Audio data read from store VF is similarly transferred via store VBP into stores AB1 to ABN, the outputs of which are processed in audio network (AN) in a similar manner to the outputs from VB1 to VBN and sent to the requesting telephone set after being expanded in time. Text may be added to video information read from store VF by means of a text memory TM and character generator CG, the text passing to store VBP via OR gate OR1. Text may also be added to data in one of stores VB1 to VBN by passing the output therefrom via one of AND1 to ANDN and thence OR2 and OR1 back into VBP, the video data and text being added in mixer ADD.