This invention relates to audio learning and amusement systems.

In recent years a variety of audio and audiovisual teaching systems have been developed. In particular, interactive systems have been -developed which require the learner to answer a multiple choice question, indicating the answer with appropriate input means, with the apparatus then indicating audibly whether the selected answer was correct or not. Many such systems require dedicated integrated apparatus which increases the cost of such systems and restricts their use.

Various such systems have been described in the patent literature. Thus United States Patent Specification 3662078 describes a self teaching machine including a tape player and a tape with a sequence of problems set out on the tape. The problems correspond to printed material and the selection of the answer is effected by the user by touching a probe onto the printed material. If the correct answer is selected, the apparatus moves the tape forward to present the next question. If an

incorrect answer is selected, nothing happens and the user can make another attempt. Only when the user finds the correct answer does the tape move forward.

A more sophisticated audiovisual approach is described in United States Specification 3408749 which uses a film format with a plurality of picture and sound tracks. Answers are entered e.g. via a keyboard and if correct the film advances further. If incorrect the film is rewound and material presented to the student from a

"remedial track". Such a system is complex and expensive to manufacture. United States Specification 3693268 describes further developments of that system as does US Specification 3715811.

A dedicated "conversational toy" with a multi-track tape system is described in United States Specifications 3947972 and 4078316. The latter specification discloses the use of individual printed templates which can be used in connection with a robot like housing for the toy to designate the purposes of switches within the toy in correlation to the question and answer material on pre-recorded cassette.

A further approach is disclosed in GBA 2182190 which discloses apparatus for playing a programmed tape cassette with voice and data signals on it. The unit includes a keyboard. After each question, the apparatus has memorised (from the tape) correct answer data, and these are compared with the answer data put into the keyboard by the user. If the answers match, a visual indication of this is provided. If not, the user can try again. After a given number of incorrect tries, the correct answer may be displayed automatically.

Finally, United States Specification 4464124 describes a magnetic tape player with a stereo playback head for reproducing information from adjacent channels on a magnetic tape on which there is recorded a series of questions and answers in successive blocks. In the first portion of each block there is a question and a choice of answers, recorded on both channels of the tape, and this is followed by a second portion (during the running of which the question is meant to be being answered by the student) in which a coded indication of the correct answer to the question is recorded on one channel. The apparatus includes a plurality of answer buttons which enable the user to make a selection. Depending on the selection made, the user then hears an indication that the answer was correct, which is recorded on one channel of the tape (or that it was incorrect, from a message recorded.on the other channel) .

The apparatus described in all of these specifications tends to be bulky, dedicated to the particular use concerned, and accordingly expensive to produce.

We have now found that considerably greater flexibility can be achieved with substantially less outlay by the provision of apparatus responsive to coded answer information recorded on tape or other audio or audiovisual carrier e.g. a compact disc and having input selection means and being adapted to produce an indication of whether the selected input was correct or incorrect.

Thus in accordance with the first feature of the present invention there is provided audio learning and amusement apparatus adapted for use with audio equipment which

generates from an audio or audiovisual source audible intelligible signals and audible unintelligible or inaudible signals either sequentially and/or concurrently but independently of the audible intelligible signals; the audible intelligible signals including both questions and instructions to a user, and the inaudible or audible but unintelligible signals including control code data; and the apparatus including answer entry means, wherein the reaction of the audio learning and amusement apparatus to an answer entered by the user via the answer entry means is controlled by the control code data.

Preferably the apparatus comprises a control unit for detecting and decoding the control code data, entry means, a means for comparison of the decoded control code data and the answer entered via the answer entry means, and an output means for indicating the result of the comparison.

Preferably the output means provides an audible output, though it may provide a visual output or a combination of the two.

A major advantage of such apparatus is that it may be used in conjunction with standard unmodified reproduction apparatus e.g. a tape player, videotape player, CD player or even using a wireless or television broadcast as the source. In particular, the apparatus of the invention may be configured as an accessory which is to be inserted between standard apparatus adapted to produce an audio signal from a tape and means for rendering that audio signal audible, for example a loudspeaker or a pair of headphones. In particular, the apparatus may be configured as an accessory to portable tape playback

apparatus which is conventionally listened to by the use of headphones. Thus the accessory may plug into the headphone socket of a standard portable tape player, for example of the type sold under the trade mark WALKMAN, and the headphones may be plugged into the apparatus in accordance with the invention. Any other source with a composite single or a multiple audio channel may, of course, be used with the apparatus of the present invention.

By the use of audibly intelligible signals, i.e. signals that form known words or distinctive sounds that have been taught to have a specific meaning, and audibly unintelligible control code data signals may need not be inaudible) and logic circuitry of appropriate configuration, a wide variety of educational or amusement units may be produced. An advantage of the present invention is that the control code data signals may run sequentially to or concurrently with the audible intelligible signals; this renders the control code data independent of the audible intelligible signals. In a preferred embodiment in which the control code data signals are rendered inaudible (e.g. by filtering them out from the signal the user hears) , this provides a particular advantage over known audio and audiovisual teaching systems in that the control code data transmission to the control unit is not limited to periods in which control code data signals may be integrated with the audible sound effects heard by the user.

The answer selection means may vary widely. For example the apparatus may have a small keypad or array of buttons with a plurality of keys or buttons on it which may be of

different colours or bear different identifying indicia with the recorded material providing the association between possible answers and individual keys or buttons. An alternative approach is for the apparatus to include means for indicating and answering in conjunction with printed material. Thus, for example, the apparatus may include an infra red reflectance sensor head and a discrimination circuit and be used with printed material showing a plurality of different areas which are distinguished from one another from their infra red reflectance. This technique is described in EP A 0099920. Analogous techniques using conductive or magnetic inks can also be used.

Alternatively, an input may be put in using visual material in conjunction with some sort of matrix or array associated with the visual material. A particularly attractive approach of this type is to have as input device a transparent window consisting of an array of switch cells each of which acts as a switch, i.e. becomes conductive when pressed. Such a window is laid over printed material and the learner decides where to press dependant upon the position of what he or she judges to be the correct answer on the page of printed material. Alternatively, a transparent or non-transparent switch array may be laid under printed material or a suitably flexible carrier such as paper or film, and used analogously.

If desired, apparatus according to the invention may include its own visual display means, for example one or more lamps or light emitting diodes or, in more complex versions, a dot matrix liquid crystal display screen or an LCD screen appropriately configured with icons and/or

alphanumeric indications.

The control data encoded in the audio signal when decoded by the apparatus is used to programme the logic control circuit in an appropriate fashion to suit the gameplay and expected switch input. The encoded signal and decoding circuit must provide a reliable data signal from a variable quality of unknown audio signal sources, with changes in amplitude, phase and frequency.

The data signal frequency is preferably chosen to be above the most significant audible range from 50Bz to 5kHz, but not beyond the human audible range, since such frequencies are not always reliably reproduced well by standard magnetic playback heads and other commercial audio signal sources.

It is intended to filter out the data signal from the audio output by providing appropriate standard filtering circuitry above typically 5kHz.

We have found a data signal of 6.5kHz is a convenient compromise between providing good quality and reliable signal data. The control signal which is preferably active continuously may be tracked reliably by a phase lock loop technique, together with compensation for possible amplitude and frequency/speed variations.

Alternatively two closely related frequencies may be used e.g. 6.5kHz and 7.0kHz on the same channel to provide continuous data and signal pulses, which can then be decoded extremely reliably by a comparator eliminating amplitude and phase variations, which are common problems at lower frequencies or when doing comparative signalling

between two separate audio channels.

A further method is the well known Dual Tone Multi Frequency technique used in telephone communications. These tones are normally at audible frequencies and used without filtering and therefore may interfere with the activity.

The apparatus of the invention may be configured to work with mono or stereo tape sound reproduction apparatus.

Stereo systems are preferred since the recorded material may then include, as disclosed in United States Specification 4464124, alternative messages between questions depending upon whether the preceding question was answered rightly or wrongly.

It is to be understood that the present invention extends also to records such as audio and audiovisual recordings and printed materials configured or adapted for use with apparatus according to the present invention.

The invention is illustrated by way of example with reference to the accompanying drawings in which:

Figure 1 is a schematic diagram of an accessory unit in accordance with the invention adapted for use with a portable tape player or other standard audio signal source.

Figures 2 A and B show two event/time diagrams, in each case for a period of time covering a single question, answering period and answer section for a single or double track magnetic tape respectively.

Figure 3 is a pictorial illustration of the apparatus using one form of answer input device;

Figure 4 is yet a further embodiment using a touch sensitive window.

Figure 5 is a pictorial illustration showing the use of an alternative answer input device using specially printed material, and

Figures 6, 7 and 8 are pictorial illustrations parallel to Figures 3 to 5 where the sound source is a loudspeaker or other sounder and not headphones.

Referring to Figure 1 this shows apparatus according to the invention which is adapted to be connected between the headphones 1 (only the headphone plug being shown) and player unit 2 (only the output socket being diagrammatically shown) of a standard portable tape player. The apparatus of the invention has a stereo jack plug 3 for plugging into the player unit and a stereo jack socket 4 for receiving the headphone plug 1.

Located between plug 3 and socket 4 is a solid state switch array 5 which is controlled by a logic unit 6.

The logic unit 6 is powered by an appropriate power supply e.g. battery cells and has connected to it an input device of some appropriate kind. The input device schematically indicated as 7 may take the form of a keyboard or it may be an analogue input port to the logic unit or some other input device.

The apparatus may, in other embodiments, be adapted to be

connected between other types of audio equipment and headphones or a loud speaker which may be integral with the apparatus. The apparatus may be further adapted to receive mono output.

Figures 2 A and B show two event time diagrams, the "Audio signal" section of which may be thought of as corresponding with the relative positions of data signals on a length of magnetic tape. This also shows the timing relationship between audible sounds from the pre-recorded information, the control code data, electronic sounds generated by the apparatus control logic to indicate the status of a keyboard input and the user input. Figure 2A corresponds to a tape with a single mono channel of information recorded on it and Figure 2B has two channels as indicated. In both cases, control code data signals are impressed at an appropriate frequency to provide signals which can be processed in the logic unit e.g. codes A, B, C and a continuous background signal HF. We have found that a 6.5 kilohertz digital signalling tone code may easily be incorporated without disturbance to the recorded message. Even if the presence of the signal and its signal level are such that the presence of a coded signal is aurally detectable by the user, all the user hears may be a warbling tone or the like from which the user is unable usefully to detect any information.

In operation, the tape is moved past the playback head in the tape player apparatus and, reading the tape as time progresses e.g. from left to right as shown in the diagram, first a question is asked and there is then some sort of "go" sound recorded on the tape. This is followed by an answer period which may be a period of silence but which is preferably recorded with some sort

of audible indication that the apparatus is waiting for an answer to be input, for example a ticking noise, and at the end of a given period, determined by the length of the tape, an end of question answering period sound is provided, for example a bell noise. At around the same time as the bell noise, an encoded signal code B is recorded on tape which tells the logic unit 6 to carry out an appropriate comparison and e.g. give an indication of whether the answer given was correct or incorrect. In the case of the stereo tape system, the logic can then select which channel the user hears for the next period of time, thus enabling either a congratulatory message to be given on tape or a helpful and corrective message which, if appropriate, gives the correct answer. The pointβ at which an answer is inserted by the user are indicated by the 'BIP' inputs. The input is evaluated at the end of the answer period.

At the end of the period, in the case of a stereotape system an encoded "reset" signal code C goes to the control logic to reset it for the next question and answer on the tape. The use of a reset signal in this way is optional - one can simply leave the apparatus in "mono" mode. However, stereo systems are generally preferred, particularly as they allow both correct and incorrect answers to be given side-by-side, which the user hears being determined by the user's success at answering.

Figure 3 shows a unit configured with six buttons marked A, B, C, D, tick and cross. These last may be replaced if desired by other indicators with which a "true or false" type of question may be answered. The answer is given simply by pressing the appropriate button.

In the apparatus shown in Figure 4, printed material 40 is supplied for use with the apparatus and the apparatus includes a transparent window 41 which is divided up into an array of cells 42. Each cell consists of two sheets of transparent plastics film spaced slightly apart and having a conductive coating on their facing surfaces. The conductive coatings are connected in columns on one plastics film and rows on the other and may be made to come into contact by finger pressure. Thus if the window 41 is laid over the printed material 40, the user simply selects the answer using a finger and pressing onto the selected printed answer visible through the window 42. The logic units sorts out, from the position of the cell in which contact is made and from encoded information previously received by it, whether the selected answer was correct or not. Correctness may be indicated e.g. by a light 44 set in the window fraβe lighting up (or by one of two lights, e.g. a red and a green light, lighting) and/or e.g. by an appropriate "correct" noise being generated by the logic circuit and input to the headphones. Analogously, apparatus may use a (non-transparent) membrane keyboard slipped under the sheet of printed material 40.

Figure 5 shows a similar system but in which the correct answer is selected by pressing an infra red reflectance sensitive head 50 onto the desired one of a series of printed patches 52 in a book 53. Although the patches 52 are visually indistinguishable, one of them is considerably more infra red absorptive than others. The technique used for this is described in detail in European Patent Specification 0099920.

Figures ^' 6, 7 and 8 show systems analogous to those shown

in Figures 3, 4 and 5 respectively, but in which instead of headphones, loudspeakers 60 or other sound generating devices are incorporated. In Figure 7, the keyboard 41 is a standard membrane keyboard and a pack of overlay cards 62 is provided, each of which may be laid over the keyboard 41 when the device is in use.

As illustrated in Figures 3 to 8, the apparatus of the present invention consists of a 'personal stereo' or like tape player together with accessory means. It is, of course, possible to configure the apparatus as a single, purpose-built unit, and in such a case, more sophisticated control of the tape running motor may be employed, even including reversal modes to enable repeated attempts at questions to be made.