Patent GB-1370127-A (GB)
Title: System for correcting or processing so-called diagnostic tests of multiple choice type
IPC: G06K17/00
Filed: 1971-08-10
Abstract: 1370127 Diagnostic test system STUDENTLITTERATUR AB 10 Aug 1971 [17 Aug 1970] 37409/71 Heading G4M  Diagnostic multiple choice answer test system has a test card (Fig. 2) with a field for data identifying the student and test, en clair, a field 12 reproducing the test in coded form, a field 13 having three columns containing squares in which answers are marked and a field 14 divided into two portions one either side of the card and containing clock track data. The card and a duplicate are completed by the student and the original is fed by hand to a reader having two sets of spaced rollers, the latter set after the read head moving slightly faster than the set before the read head to stretch the card across the head (Figs. 14, 15, not shown). The read head has an array of photo-electric sensors arranged across the card and disposed to read the clock tracks and the data in the columns, each sensor 26 being situated in a light guide 27 below a source 28 and arranged in a suitably apertured trough so that light from the source is carried by the guide and reflected by the paper to the source. The squares on the form are arranged unsymmetrically so that if the form is inserted in the reader the wrong way round the sensors scan the spaces between squares and not the squares. Each photo-cell in the reader (17 for the card shown) feeds an amplifier and a comparator and is stored in a register under the control of clock pulse markings K11. The clock signals K11, K12 feed a control network and a decoder fed by the register and the control network supplies signals to a punch. A parity generator is also provided (Fig. 3, not shown). The clock pulses are arranged so that a K12 and a K11 pulse are detected together at the start of the card. Five K11 pulses are counted and a signal "fresh form" is generated and punched and during the following K11 signals data is read. If the signals K11, K12, which apart from the first and last are displaced, are detected together the form is askew and an error signal is produced and punching is prevented. If an incorrect number of K11 pulses are detected, due to dirt or erasure chips an error signal prevents punching. If forms overlap then either the correct number of clock pulses are not counted or the corresponding K12, K11 pulses are not detected by being covered, or are detected early at the beginning of the later card and an error signal is produced. After a line is read the data is decoded and the answer given is punched out on to tape so that copies for, e.g. the course designer, teacher &c. may be later provided. The tape is also used for transfer to a computer to be processed. After punching an interval allowing the punch to recover is provided and the next decoding phase for the next question in the second group of markings occurs and is punched out. After a pause the third group is decoded and punched and then the next line is read. The duplicate is placed on a machine (Figs. 18, 19, not shown) and correct answers are printed or punched for the use of the student.