in the preferred embodiment , tones in the audible range are broadcast to communicate information through the audio output of an ordinary television or radio receiver to an apparatus for playing a game . fig1 illustrates how tones of the audible range , such as touch - tones ( 697 - 1477 hz ), can be added to the audio - video tape 44 of a regular program . the tones are created by a studio engineer using a touch - tones generator 40 . this is done at the same time as the engineer creates the program &# 39 ; s usual sound effects with a sound effects generator 42 , or later . the tones and the usual sound effects are added at appropriate places to the audio - video tape 44 of the program using a tape recorder 46 . there are other ways to ensure that an appropriate tone is included in the audio portion of a television or radio broadcast . for example , an engineer watching the program as it is recorded or as it is broadcast live could use a touch - tone generator 40 to create the tones appropriate to the action of the program , thereby causing the tones to be included in the initial audio tape or to be broadcast as part of a live transmission . alternatively , the tones can be permanently put on a tape with the related sound effects so that the tones are always automatically generated at the appropriate time . the touch - tone generator 40 could also be permanently wired into sound effects generator operating automatically when a button is pushed . preferentially , the tone lasts two television frames ( about one - fifteenth of a second ), is masked by the usual sounds of the program played at the same time or otherwise temporally adjacently , and has less volume than a show &# 39 ; s normal sound effects . in this manner , the touch - tone are substantially indiscernible to the listener . despite this , a touch - tone decoder as used in this embodiment can reliably detect and decode such touch - tones . as known in the art , a decoder &# 34 ; listens &# 34 ; for a very specific pair of frequencies for each tone . the tones have no harmonic or subharmonic relationship to any of the others , and the two tones of each pair must be of substantially the same duration as each other . in the present invention , the controller 54 listens for pairs of specific duration , and only pairs of that duration will be employed to encode information . it will be apparent to anyone skilled in the art that any set of tones can be utilized to communicate game control information . this communication can take place at any time during the broadcast , and the tones can be assigned different meanings depending on the show and how the home game is to be played . each touch - tone is assigned a pair of frequencies according to the &# 34 ; dtmf &# 34 ; (&# 34 ; dual tone multi - frequency &# 34 ;) system known in the art . there are sixteen pairs recognized by touch - tone decoder 106 . the following example is one illustration , based on a home game designed for playing along with a television game show , the &# 34 ; family feud .&# 34 ; the touch - tones corresponding to the given buttons on a telephone and given pairs of frequencies as assigned the following meanings in this example : ______________________________________ telephonefrequencies ( hz ) button meaning assigned______________________________________697 and 1209 1 begin round one697 and 1336 2 begin round two770 and 1209 4 begin &# 34 ; fast money &# 34 ; round part one770 and 1336 5 begin &# 34 ; fast money &# 34 ; round part two941 and 1477 0 reset941 and 1477 # yes941 and 1209 * no______________________________________ the &# 34 ; zero &# 34 ; button tone is added to the beginning of the audio - video tape 44 of the &# 34 ; family feud show &# 34 ; by the touch - tone generator 40 and tape recorder 46 , to tell the home game to reset . it is masked by the buzzer sound effect ordinarily played while the master of ceremonies ( m . c .) explains the rules of the game show . the tone can be masked by having it occur just before or after or during the buzzer sound effect . the tone is very short in duration and not as loud as the buzzer . after the master of ceremonies reads the first survey question , there is a bell that rings as soon as the first participant pushes his answer button . concomitant with this bell , the engineer adds a &# 34 ; one &# 34 ; tone to the tape 44 . this signifies the start of round one of the show . the studio participant suggests a likely response to the survey question . if he is correct that his answer was a popular response by those previously surveyed , a chime will sound , and a &# 34 ;#&# 34 ; tone is included on the audio - video tape 44 . if incorrect , a buzzer goes off , and a &# 34 ;*&# 34 ; tone is made on the audio - video tape . at the beginning of the second round of &# 34 ; family feud &# 34 ;, a bell rings when a participant first pushes an answer button , making a &# 34 ; two &# 34 ; tone to signify the beginning of round two . similarly , a &# 34 ; four &# 34 ; tone will accompany the beginning of the final &# 34 ; fast money &# 34 ; round , and a &# 34 ; five &# 34 ; tone signifies part 2 of &# 34 ; fast money &# 34 ;. in the &# 34 ; fast money &# 34 ; round , to be considered correct in the game of the present invention and therefore be signalled by a &# 34 ;#&# 34 ; tone , the participant &# 39 ; s answer must match at least 25 % of the survey response . otherwise , a &# 34 ;*&# 34 ; tone will be added to the audio - video tape 44 . when the program audio - video tape 44 is broadcast , the audio portion of the signal includes not only the usual sound effects , music , and dialogue of the program , but also includes coded information in the form of touch - tones . these tones are part of the usual in - band transmission , yet convey more information . when received , each tone in the signal is substantially indiscernible by humans since it is very brief , masked by usual sound effects , and relatively quiet . in fig2 an encoded signal is received by an ordinary unmodified television 48 . the television is tuned to the proper station to receive the program with the encoded signal . the audio portion of the show emanates from the television speaker 50 as usual . since the tape 44 includes brief , quiet touch - tones , these emanate from the speaker 50 but are substantially indiscernible to humans . the game device 52 has a controller 54 , however , which detects the tones if placed within the listening area of the speaker 50 . answer buttons 56 , 58 , 60 , and 62 are wired to the controller 54 . these buttons allow the player or players of the home game to input their response to the action of the program they are observing on the television 48 . in this example , the players listen to the survey question and the television contestant &# 39 ; s response . if the home player thinks that the contestant &# 39 ; s answer is correct ( appears in the survey results ), he pushes his &# 34 ; yes &# 34 ; button 64 , 66 , 68 or 70 . otherwise , he pushes his &# 34 ; no &# 34 ; button 72 , 74 , 76 or 78 . these responses can be accompanied by sound effects produced by the controller 54 , through its speaker 79 , or through speakers on the answer buttons 56 , 58 , 60 and 62 . for instance , the first &# 34 ; no &# 34 ; response will be accompanied by a low , descending sound . subsequent &# 34 ; no &# 34 ; responses will cause correspondingly lower sounds . the first &# 34 ; yes &# 34 ; response will be attended by a higher , ascending tone . subsequent &# 34 ; yes &# 34 ; responses will generate even higher ascending noises . the controller 54 detects and decodes the touch - tones described above , and locks out further response from the players &# 39 ; answer buttons 56 , 58 , 60 and 62 when it detects a &# 34 ;#&# 34 ; yes signal or a &# 34 ;*&# 34 ; no signal which informs it whether the studio contestant was correct . then the controller 54 compares this to responses received from the home players . the controller 54 tallies the score depending on which round is being played ( round two scores are doubled , and round three scores are tripled ) and whether the answer was correct . the controller 54 causes various information to be displayed . digital readouts 80 , 82 , 84 and 86 display the current score for each player . indicator lights 88 , 90 , 92 and 94 show what answer each player has given . indicator lights 95 , 96 , 97 and 98 show which player was first , second , third , or fourth to input his response . of course , other information could be displayed in a number of ways apparent to one skilled in the art . the displays could be part of the controller 54 or the individual answer buttons 56 , 58 , 60 and 62 . several seconds later , the controller 54 releases the lockout and once again accepts responses from the home players to the next question on the show . the game device 52 is powered by a power cord 99 attached to a wall outlet 100 . alternatively , the device 52 can be powered by batteries . the controller 54 is shown in greater detail in fig3 . the touch - tones are detected by a microphone 101 . this signal is processed through a band - pass filter 102 and an amplifier 104 . each of these components can be a single stage op - amp such as a standard national semiconductor l . m . 741 . alternately , the two can be combined in a double stage op - amp . the signal is then decoded by a touch - tone decoder 106 , which can be a mitel 8870 or ssi 202 . the touch - tone decoder 106 only accepts frequency pairs of the same length , and can be used to accept only touch - tones of a given length . to accomplish this , the touch - tone decoder 106 is crystal controlled via a crystal 107 . this is a standard 3 . 579545 mhz color television crystal . the crystal 107 provides a stable time reference for the touch - tone decoder 106 . when the decoder 106 detects a touch - tone , it provides a signal representing the tone on wires 108 , 110 , 112 and 114 . these four wires carry the four bits needed to distinctly indicate one of sixteen possible touch - tones . the central processing unit ( cpu ) 116 can be a mc6870545 semiconductor chip . it has 2k bytes rom storage , 128k bytes ram storage , and a 3 . 579545 mhz crystal 117 . the cpu 116 continuously polls the decoder 106 via a signal on a wire 118 through an a port 119 approximately every 3 milliseconds to determine whether the decoder 106 has detected a touch - tone . if the polling is defective , the decoder 106 sends a signal via a wire 120 to an interrupt 121 of the cpu 116 . upon receiving the interrupt signal , the cpu 116 immediately polls the decoder 106 again . if the decoder 106 has detected a touch - tone , the cpu 116 sends a signal over wires 122 and 123 to enable the decoder 106 to transmit the identity of the detected tone to the cpu 116 . this transmission is sent via decoder output wires 108 , 110 , 112 and 114 as discussed above , connected to cpu input wires 124 , 126 , 128 and 130 . for instance , when the four bit code for the &# 34 ; zero &# 34 ; tone is reported to the cpu 116 , it resets its memory to initial conditions to prepare for a new game . the enable wire 122 simultaneously disables the input buffer / isolator 132 via a wire 134 . the buffer / isolator 132 can be a standard 74ls245 . this disabling prevents input switches 136 from interfering with the communication of the decoder 106 with the cpu 116 . when the &# 34 ; one &# 34 ; tone is reported to the cpu 116 via decoder output wires 108 , 110 , 112 and 114 , the cpu 116 prepares for round one of the game . the cpu does this by disabling the decoder 106 via wire 123 and enabling the buffer / isolator 132 by wire 134 , from a signal on wire 122 . once the master of ceremonies reads the first question to the studio contestant and the contestant gives a response , the home players will indicate their agreement or disagreement with that response on their answer buttons 56 , 58 , 60 or 62 . these buttons are used as input switches 136 to the controller 54 . the yes and no signals are fed through an input debounce circuit 138 , which can be a mps a14 . the debounce levels off the fall and rise of the signals to emit even signals to the buffer / isolator 132 . since this example involves four players and two possible responses each , the buffer / isolator 132 uses eight lines 124 , 126 , 128 , 130 , 140 , 142 , 144 and 146 to communicate the responses to the d port 148 of the cpu 116 . the players can input a response until the continuous polling via wire 118 reports to the cpu 116 that the decoder 106 has received another tone from the game show revealing a &# 34 ;#&# 34 ; yes or &# 34 ;*&# 34 ; no correct answer . when this occurs , the cpu 116 disables the buffer / isolator 132 in order to lock out further responses by the players and enables the decoder 106 to communicate the correct answer to the cpu 116 as described above . the cpu 116 compares the correct answer to the responses given by the home players via input switches 136 . each player that was correct is awarded some number of points . alternatively , the first player to have responded correctly could be awarded more points than the later correct responses . incorrect responses could result in subtraction of points . the cpu 116 causes the scoring information to be displayed via its b port 150 . after an examination of the present application , various methods to display the information available from this port will be apparent to those skilled in the art . some of these methods are described in electronic display devices by richard perez , published by tab books in 1987 , especially pp . 176 - 178 . for example , illustration 5 - 35 of that book depicts a seven segment display as shown in fig3 . wires 200 , 202 , 204 , and 206 are connected from the b port 150 to the digit selector 152 . these wires carry a four - bit binary code representing which digits of the score displays 80 , 82 , 84 or 86 or indicator lamps 88 , 90 , 92 , 94 , 95 , 96 , 97 or 98 should get power to enable them to receive scoring information . the wire 212 enables the digit selector 152 to receive a new instruction from the cpu 116 . the digit selector 152 is a 72 hc 4514 multiplexer and is attached to the digit current sources 154 via the 16 wires 208 . at a given time , only one of these 16 wires will be &# 34 ; on &# 34 ;, and the other 15 will be &# 34 ; off &# 34 ;. the one that is &# 34 ; on &# 34 ; will correspond to one of the 16 wires 210 of the digit current sources 154 that will enable the correct digit of the score displays 80 , 82 , 84 , or 86 or indicator lamp 88 , 90 , 92 , 94 , 95 , 96 , 97 , or 98 to receive scoring information . for example , when wire 211 is selected , the hundreds digit of score display 80 is enabled . after a digit or lamp is enabled , the cpu 116 disables the digit selector 152 via wire 212 . then , the cpu 116 causes the scoring information to be available at the b port 150 in binary code . the enabled digit or lamp receives this information via wires 212 , 214 , 216 , 218 , 200 , 202 , 204 , and 206 and is updated accordingly . for example , when the scoring information from the cpu 116 is that the first digit of a score display 80 is to be changed to a &# 34 ; 1 &# 34 ;, wires 214 and 206 are &# 34 ; on &# 34 ; and wires 212 , 216 , 218 , 200 , 202 , and 204 are &# 34 ; off &# 34 ;. wire 214 tells the first segment 220 of the first digit of display 80 to glow . likewise , wire 206 informs the second segment 222 that it should glow . when segments 220 and 222 flow , they form a &# 34 ; 1 &# 34 ; in the hundreds place of score display 80 . sound effects can easily be generated by one skilled in the art from the output of the a port 119 . fig3 shows one way . some methods of accomplishing this are described in motorola &# 39 ; s user manual for its complex sound generator microchip sn 76495 . wires 160 and 162 provide information to two analog multiplexers ( mc14052 ) 164 to decide which external programming elements 166 to select . these elements are preferentially resistors and capacitors as shown but may also be diodes or other devices . the selected elements are connected from the ground 167 through the multiplexers 164 to the complex sound generator ( motorola microchip sn76495 ) 168 via wires 224 , 226 , 228 and 230 . depending on which of elements 166 are selected , the elements modify the operation of the oscillators contained in the complex sound generator 168 . the complex sound generator 168 is a large scale integrated microchip containing various oscillators summed , cascaded or sequenced to form the sound . the generated sounds emanate from the speaker 170 , with the volume being controlled by the variable resistor 172 . for developmental purposes , an eight position dip switch 174 acts as a program select connected to the c port 176 . it simulates various input conditions of the d port 148 in order to test the device &# 39 ; s reaction to the cpu 116 output from the a port 119 and b port 150 . the encoded communication need not involve a game show . it can represent any information that can be communicated with a discrete number of coded terms . for example , it can represent events in a sporting contest , where the home players predict plays or events . it can represent weather predictions , winning lottery numbers , &# 34 ; secret &# 34 ; messages on children &# 39 ; s shows requiring a special decoder , or many other things . since the communication is encoded in - band in tones of the audible range , the broadcast signal can be taped with the encoded information still available for later or repeated use . since the device detects the information by &# 34 ; listening &# 34 ; to the receiver &# 39 ; s audio output , the device needs no connection to the receiver . it can be placed anywhere in the room or listening area . the device can be placed at any orientation to the receiver ; it need not be aimed or placed next to the receiver .
this invention involves a system of communicating information using audio signals . in one embodiment , the information is encoded in touch tones on the sound track of a television game show . the information relates to the action of the show , and is broadcast in - band with the audio portion of the show . the show , and thus the information encoded in its audio portion , is received by an ordinary home television . a device for playing a game &# 34 ; listens &# 34 ; to the television speaker and decodes the information . the device allows home viewers to play a game based on the action of the show . the touchtones are substantially indiscernible to humans because they are quieter than most of the audio portion of the show , they are very brief , and they are masked by the show &# 39 ; s usual sound effects .