GB1329946A - Monochannel audio teaching device - Google Patents

Abstract

1329946 Educational appliances DATAPLEX SYSTEMS Inc 25 Jan 1972 3384/72 Heading G5G [Also in Division H4] Audio teaching apparatus of the type wherein multiple units of information are transmitted is provided with frequency and time multiplexing arrangements so that several related units of information, e.g. a multiple choice question and statements regarding four selectable answers, may be carried on only a single channel, e.g. having a passband of 9 KHz, such as single track magnetic tape. As shown, the apparatus comprises a source of five audio signals AS1-AS5 representing a question and four answers; a tone generator TG for generating three control signals of 9 KHz, one control signal being associated with the question signal, a second control signal being associated with first and second choice answer signals, and a third control signal being associated with third and fourth choice answer signals; a multiplexer AM for frequency-multiplexing the first and second choice answer signals to form one multiplexed signal, e.g. in a band from 0-3 KHz, and for forming a multiplexed signal e.g. in a band from 3-6 KHz, from the third and fourth choice answer signals, means for serially transmitting on a single line FAM the question signal and the control signal associated therewith, and thereafter the frequency multiplexed signals and their associated control signals; and a tape recorder TR which records the transmitted information on a single track tape. The recording of the information is effected by a director operating a control panel CP associated with the tone generator TG and switching circuits SKS and the tape may be played back by a student provided with a tape player associated with de-multiplexer and choice-selecting circuits, Fig. 2 (not shown).