Patent GB-1281732-A (GB)
Title: Teaching machine
Inventor: LAPLUME JACQUES
IPC: G09B7/04
Filed: 1969-06-27
Abstract: 1281732 Teaching machines SOC D'ETUDES TECHNIQUES ET D'ENTREPRISES GENERALES 27 June 1969 [28 June 1968] 32596/69 Heading G5G An apparatus for use in conjunction with a teaching tape on which instructional items and questions have been recorded consists of means for automatically controlling the movements of the tape in response to students' answer selections. The apparatus includes a student keyboard for selecting answers, means for generating signals which identify the selected answers, means for comparing the selected answer identifying signals with predetermined correct answer signals, and means for moving the tape in such manner that the next item presented to the student is appropriately dependent on the comparison between his selection and the correct answer. The means for controlling the tape movement needs to receive signals indicating the extent of previous movement of the tape: these signals are derived from a device which rotates as the tape advances, the extent of tape movement being represented by a count of the number of rotations made by this device. Fig. 5 shows one form of such a device: a member which rotates with the tape, e.g. by being coupled with one of the idler pulleys 5 of Fig. 2, carries magnetic teeth 90 whose passage past a core 91 is sensed by a coil 92. In Fig. 6 (not shown) the rotating member has a diametral hole which, once per revolution, is aligned between a lamp and a photo-cell. The Fig. 6 form gives signals whose magnitudes are independent of the tape speed and is therefore preferable to the electromagnetic device of Fig. 5. The invention is particularly described with reference to a system in which a branched programme as depicted in Fig. 1 is recorded on several tracks of a tape. The main teaching sequence is information A followed by a question Aa, information B, question Ba &c. When incorrect answers are given, e.g. to question Aa, the student is "branched" e.g. to information A 1  followed by question Aa 1  and he only proceeds to B when he ultimately gives a correct answer to a question in one of the branches. The teaching tape also carries coded signals relating to the correct answers and to other machine control functions. The tape 3, Fig. 2, has two reading heads 1 and 2 positioned to scan different tracks on the tape. On starting, a first instructional item and a question on it are read from the tape by the head 1 and audibly reproduced at the student's headphones 14. The tape is automatically stopped when a filter unit 13 responds to an "end-of-item" signal on the tape. This response also energizes a relay 16 which switches the taperecorder output to a unit 18 just before the tape stops. The unit 18 is a decoder whose circuitry is depicted in Fig. 3 (not shown) and by which a frequency-coded input signal derived from the tape before it stops changes the state of one and only one of a set of five frequency-discriminative flip-flops. This identifies tne correct answer to the question posed at the end of the item. The student's response to the question is to depress one of the keys 41-45. If he selects the correct answer, the changed-state flip-flop provides an output voltage by which (a) a "correct-answer" counter 46 is advanced by one unit and (b) a unit 49 is energized, by which the contacts necessary to re-start the tape and to reed the next item on the track under reading head 1 are re-closed. If an incorrect answer is given, contacts 47 and 47a (which close automatically whenever any one of the buttons 41-45 is depressed) complete an input to the unit 49. Such input, in the absence of a voltage at the "correct-answer" input 51, produces an output (not given in the "correct-answer" situation) at terminal 50, and this output triggers a flip-flop 7 by which a relay 6 is energized to switch the earphone input from contact 8 and head 1 to contact 55 and head 2. Thus on the subsequent automatic re-starting of the tape a different track will be read, corresponding to a parallel item such as Aa-Aa 1  of Fig. 1. When the student eventually gives a correct answer, the next operation of the tape will be a fast re-wind back to the position of the item on the main (head 1) track at which he first failed. The means controlling the extent of rewind is a counter 28 which, having been set to zero before branching began, will since have been fed with pulses from one of the devices described above with reference to Figs. 5 and 6. It will therefore register a count indicative of how far beyond the branch point, e.g. B in Fig. 1, the tape now is. The fast rewind stops when the count has been reduced to zero.