-•~
`,
`
`..
`
`PCT
`INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`WORLD INTELLECTUAL PROPER1Y ORGANIZATION
`International Bureau
`
`(51) International Patent Classification 5 :
`
`(11) International Publication Number:
`
`WO 94/03020
`
`H04Q9/00
`
`Al
`
`(43) International Publication Date:
`
`3 February 1994 (03.02.94)
`
`(21) Intemational Application Number:
`
`PCT/US93/06627
`
`(22) International Filing Date:
`
`15 July 1993 (15.07.93)
`
`(81) Designated States: AU, CA, JP, KR, European patent (AT,
`BE, CH, DE, DK, ES, FR, GB, GR, IE, IT, LU, MC,
`NL, PT, SE).
`
`Published
`With international search report.
`Before the expiration of the time limit for amending lhe
`claims and to be republished in the event of the receipt of
`amendments.
`
`(30) Priority data:
`915,112
`
`17 July 1992 (17.07.92)
`
`us
`
`(71) Applicant: VOICE POWERED TECHNOLOGY INTER­
`NATIONAL, INC. [US/US]; 19725 Sherman Way,
`Suite 295, Canoga Park, CA 91306 (US).
`
`; TURNER,
`(72) Inventors: BISSONNETTE, W., Michael
`Douglas, L. ; 19725 Sherman Way, Suite 295, Canoga
`Park, CA 91306 (US).
`
`(74)Agents: SCHERLACHER, John, P. et al.; Spensley Horn
`Juhas & Lubitz, 1880 Century Park East, Fifth Floor, Los
`Angeles, CA 90067 (US).
`
`(54)Title: VOICE OPERATED REMOTE CONTROL DEVICE
`
`1"
`
`20
`
`-
`
`-0�
`
`II
`
`·.-
`•,,
`
`,J
`
`(57) Abstract
`
`A voice operated remote control device (figure SA, 5B) accepts voice commands spoken by the user (301, 307, 310), per­
`forms voice recognition pattern matching on the spoken word comparing the same against pretrained templates to determine the
`appropriate corresponding command (308, 311), determines the specific IR remote control code or set of IR codes that represent
`the function corresponding to the command and transmits the IR remote control codes to the electronic equipement to be con­
`trolled (309, 313). The voice operated remote control device can be operated by multiple users either by voice or by manual con­
`trol of the selected function of the remote control. The voice commands can represent either real time commands, which are trans­
`mitted immediately after the determination of the voice command, or programmed delay events which delay the transmission of
`the_ remote control codes or set of remote control codes for a preset period of time specified by the user.
`
`Page 1 of 65
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`

`

`..
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`. '
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`FOR THE PURPOSES OF INFORMATION ONLY
`
`Codes used to identify States party to the PCT on the front pages of pamphlets publishing international
`applications under the PCT.
`
`AT
`AU
`BB
`BE
`BF
`BG
`BJ
`BR
`BV
`CA
`CF
`cc
`CH
`Cl
`CM
`CN
`cs
`CZ
`DE
`DK
`ES
`Fl
`
`Austria
`Australia
`Barbados
`Belgium
`Burkina Faso
`Bulgaria
`Benin
`Bra:t.il
`Belarus
`Canada
`Central African Republic
`Congo
`Switzerland
`Cote d'Ivoire
`Cameroon
`China
`Czechoslovakia
`Czech Republic
`Germany
`Denmark
`Spain
`Finland
`
`FR
`GA
`CB
`GN
`CR
`HU
`IE
`IT
`JP
`KP
`
`KR
`KZ
`LI
`LK
`LU
`LV
`MC
`MC
`ML
`MN
`
`France
`Oabon
`United Kingdom
`Guinea
`Greece
`Hungary
`Ireland
`Italy
`Japan
`Democratic People's Republic
`or Korea
`Republic of Korea
`Ka,.akhstan
`Liechtenstein
`Sri Lanka
`Luxembourg
`Latvia
`Monaco
`Madagascar
`Mali
`Mongolia
`
`MR
`MW
`NE
`NL
`NO
`NZ
`PL
`PT
`RO
`RU
`SD
`SE
`SI
`SK
`SN
`TD
`TG
`UA
`us
`uz
`VN
`
`Mauritania
`Malawi
`Niger
`Netherlands
`Norway
`New Zealand
`Poland
`Portugal
`Romania
`Russian Federation
`Sudan
`Sweden
`Slovenia
`Slovak Republic
`Senegal
`Chad
`Togo
`Ukraine
`United States of America
`Uzbekistan
`Viel Nam
`
`Page 2 of 65
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`WO94/03020
`
`PCT /US93/06627
`
`1
`
`VOICE OPERATED REMOTE CONTROL DEVICE
`
`FIELD OF THE INVENTION
`The present invention is directed to a remote
`control apparatus and in particular to a portable
`universal remote control which is voice operated.
`
`BACKGROUND OF THE INVENTION
`Voice recognition has long been accepted as one of
`the more user friendly interfaces between man and
`machine. Nevertheless, a number of impediments have
`prevented voice recognition from being more widely used
`in applications where portability is a significant
`factor. These impediments can be broken down generally
`into software and hardware limitations inherent in
`prior art voice recognition techniques. For example,
`many companies as well as government agencies such as
`DARPA have invested years of research and resources in
`developing complex voice recognition software
`algorithms, but such algorithms ultimately require the
`performance of a large personal computer (PC) or
`mainframe to implement. Voice recognition algorithms
`also typically require sophisticated hardware in the
`form of either digital signal processors (DSPs) or 16
`bit microprocessors. This hardware is expensive,
`requires numerous support devices, is bulky and
`consumes a significant amount of power. These
`considerations explain why voice recognition has
`traditionally been confined to larger computer-based
`environments. For example, published U.K. Patent
`Application No. GB 2220290A (Harvey) uses voice
`recognition for control of equipment, but again the
`voice recognition is implemented on a large and bulky
`PC based platform which is not suited for portable
`applications.
`There are, nevertheless, many portable low cost
`applications where voice recognition would be
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`PCT /US93/06627
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`2
`
`desirable. For example, it is often desirable to
`remotely control home entertainment electronic
`components, such as a video cassette recorder (VCR),
`television, cable box, satellite dish controller, or
`stereo with a portable remote control. These
`components typically include their own separate remote
`controls. These remote controls typically use
`transmitted infra-red (IR) or radio-frequency (RF)
`signals to effectuate control of the various electronic
`components. Since each component has its own separate
`remote control, the number of separate remote controls
`can soon become unwieldy and cluttersome.
`In order to
`reduce the number of separate remote controls, a
`universal remote control must be used which transmits
`the equivalent signals of each of the separate remote
`controls. But, as explained above, the limitations of
`the available voice recognition systems preclude such
`systems from being used in smaller, portable
`environments. While the prior art includes remote
`control devices, these typically lack voice recognition
`capability for the reasons mentioned above. An example
`of such a typical prior art remote control device can
`be seen in U.S. Patent No. 4,856,081 (Smith).
`Accordingly, an objective of the present invention
`is to provide a portable, low-power voice-operated
`remote control device. The term "portable" as used
`throughout the specification generally means that the
`present invention is easily carried but this does not
`mean that the teachings of the present invention could
`not be used in a compact embodiment that is mounted on
`a wall for example.
`
`SUMMARY OF THE INVENTION
`In accordance with one exemplary embodiment of the
`present invention, there is provided a portable remote
`control device operated by a voice command for
`controlling one or more electronic components each
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`3
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`which in turn is responsive to a set of respective
`remote control codes. This device includes a voice
`input circuit for receiving the voice command and
`generating a voice signal based on the voice command;
`an analog to digital converter coupled to the input
`circuit for converting the voice signal into a first
`digital voice signal; a reference memory (a RAM) for
`storing a plurality of reference digital voice
`templates and the remote control codes; a program
`memory (a ROM) for storing a control program; a
`processor coupled to the reference memory, converter
`and program memory for converting the first digital
`voice signal into a first voice template and for
`executing the control program to determine whether the
`first voice template is substantially equivalent to one
`of the reference voice templates, and for selecting one
`of the remote control codes based on the first voice
`template; and finally, a remote control code
`transmitter coupled to the processor for transmitting
`the selected remote control code.
`In addition, an input capture circuit may be
`coupled to the processor and used for capturing the
`remote control codes from the separate remote
`controllers. A keyboard with a plurality of control
`keys is also coupled to the processor. When a key is
`depressed by the user, the processor selects an
`appropriate remote control code to be output.
`In this
`manner, the device can be controlled manually as well
`as by voice command. Furthermore, a liquid crystal
`display (LCD) is provided for displaying the voice
`command to the user
`As used herein, the term "component system" (or
`system of components) is used generally to refer to a
`home entertainment system comprised of at least two
`separate electronic components such as a TV, VCR, cable
`box, satellite receiver, etc. A "component function"
`refers generally to functions that require control of
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`WO 94/03020
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`
`4
`
`only a single electronic component, such as a "channel"
`function, which should only affect one component in the
`component system. When a component command is entered
`by the user (either by voice or by means of a keyboard)
`the component function is generated by outputting IR
`remote control codes to the particular component. A
`"system function" conversely refers generally to
`functions that require control of more than one of the
`electronic components in the component system, such as
`the "record" function described above, which requires
`that the VCR as well as the cable box be controlled.
`When a system command is entered by the user (again
`either by voice or by means of a keyboard) the system
`function is generated by outputting a specific sequence
`of IR remote control codes to two or more components.
`As mentioned, a typical component system includes a
`television, a videocassette recorder which can be
`programmed to perform a record operation to record
`information on a videocassette, and a cable box
`converter. Often, these components share one or more
`functions in common (such as a channel select for
`example). The present device, in response to a user's
`voice command to perform one of the functions which the
`components share in common, selects and outputs one or
`more remote control codes to only one of the electronic
`components to effectuate the requested functional
`operation.
`In this manner, for example, only the cable
`box channel would be changed in response to a "channel"
`voice command. Furthermore, the present device also
`includes means to intelligently select, in response to
`a user's voice command to perform a record operation, a
`sequence of whichever remote control codes are
`necessary to transmit to the electronic components to
`effectuate a system command, such as a record
`operation.
`In this manner, for example, a "record"
`voice system command would cause the present invention
`to output a sequence of remote control codes to cause a
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`WO94/03020
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`PCT/US93/06627
`
`5
`
`VCR to perform a record operation, but also to cause a
`remote control code to be sent to either the VCR or
`cable box converter for purposes of setting the
`recorded channel.
`Finally, in accordance with a more specific
`embodiment of the present invention, the user may also
`enter, as part of the system command, programmed
`sequence timing data to effectuate remote control of
`the system components or single components at a later
`time, such as, for example, to record a future TV
`broadcast on a VCR. The present invention then
`generates the necessary sequence of remote control
`codes at the later time based on the timing data. For
`a future record operation, for example, a first portion
`of the sequence of remote control codes is generated at
`a first time based on the timing data (for example at
`the start time) while a second portion of the sequence
`of remote control codes is generated at a second time
`based on the timing data (such as at the stop time).
`Thus, the present invention provides a simple way
`for a user to control a number of home entertainment
`electronic components by means of a voice-operated,
`hand-held, portable, battery-operated universal remote
`control device. While the present invention is
`described in connection with electronic components used
`in a home entertainment system, it will become apparent
`to skilled artisans that the invention is applicable
`for any number of environments requiring control of
`separate electronic components.
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`WO94/03020
`
`PCT /US93/06627
`
`6
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`Other objects, features and advantages of the
`present invention will become evident from the ensuing
`"Detailed Description of the Invention" when read in
`conjunction with the accompanying drawings in which:
`FIG.l is a block diagram of a voice operated remote
`control device in accordance with the present
`invention;
`FIG.2 is a flow diagram detailing the setup mode
`software routine implemented in a control program
`forming part of a program ROM;
`FIG.3 is a flow diagram describing the voice
`operation mode software routine implemented in the
`control program forming part of a program ROM;
`FIG.4 is a flow diagram describing the manual
`operation mode software routine implemented in the
`control program forming part of a program ROM;
`FIGs. SA and SB show a housing which may be used to
`enclose the present invention, including casing,
`keyboard keys, sliding door and LCD;
`FIGs. 6A and 6B show the LCD used in the present
`invention;
`FIG. 7 is a flow diagram describing the channel
`control configuration software routine implemented in
`the control program forming part of a program ROM;
`FIG. 8 is a flow diagram describing the volume
`control configuration software routine implemented in
`the control program forming part of a program ROM;
`FIG. 9 is a flow diagram describing the playback
`and stop control configuration software routine
`implemented in the control program forming part of a
`program ROM.
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`WO94/03020
`
`PCT /US93/06627
`
`DETAILED DESCRIPTION OF THE INVENTION
`
`7
`
`A.
`
`STRUCTURE OF THE VOICE CONTROLLER
`The hardware of the present invention consists of
`several functional sections as shown in Figure 1. As
`can be seen therein, a Voice Controller 1 embodying the
`present invention consists generally of an Analog Voice
`Input 2, a Keyboard 3, a Battery Circuit 4, IR Input 5,
`a ROM Code Library 7, an External DRAM 8, a Shift
`Register 9, an LCD 10, a Piezo Beeper 11, an IR output
`12 and a Microcontroller 20. These circuits are
`described in detail below.
`Looking at Figure 1 and proceeding
`counterclockwise, the first functional block is IR
`Input 5. This circuit is used to capture IR remote
`control codes for later control of each unit of the
`user's equipment, such as their TV, VCR, cable box,
`satellite dish receiver and the like. The present
`invention includes sufficient RAM capacity to learn and
`store the IR codes from several separate remote control
`units. While the present embodiment is directed to an
`infrared (IR) remote control signal capturing circuit,
`it will be apparent to the skilled artisan that a
`radio-frequency (RF) capturing circuit could easily be
`used instead for learning RF codes from RF remote
`controllers. Moreover the IR or RF capturing circuit
`could easily consist of a direct electrically connected
`interface between the user's remote controller and the
`present invention in lieu of the present wireless
`embodiment.
`IR Input 5 is comprised of well-known IR remote
`control capture circuits. A typical example of such a
`circuit can be found in U.S. Patent No. 4,857,898
`(Smith) which is hereby incorporated by reference as if
`fully set forth herein.
`In the present invention, this
`circuit consists of a conventional input photodiode and
`a transistor amplifier (not shown).
`IR Input 5 is
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`WO94/03020
`
`PCT /US93/06627
`
`8
`
`activated to capture IR remote control codes when
`placed into the "SETUP" mode by the user as described
`below. This section of the hardware is normally
`powered down to minimize power consumption from the
`battery. To learn the IR remote control codes from the
`user'~ remote controllers, the user points the
`transmitting end of the remote controller to be learned
`at the input IR window (not shown) of IR Input 5. The
`IR code from the teaching remote control passes through
`the IR window to a photodiode in IR Input 5 which
`converts the IR signal to an electrical signal. The
`output of the IR Input 5 photodiode is signal
`conditioned by a conventional two transistor amplifier
`which converts the analog electrical signal to a
`digital electrical signal.
`IR Input 5 handles IR
`remote control codes with carrier frequencies from 20
`KHz to 70 KHz and IR pulse codes with long and short
`"on" times. The digital signal translated from the IR
`code from the user's remote control is input into an
`interrupt input of the Microcontroller 20 which reads
`the code, converts the code to a particular format and
`stores the converted code in RAM 23 which is a
`reference memory for later use to control the separate
`components (TV, VCR and cable box) of the user's
`systems. While one embodiment of IR Input 5 has been
`shown, it would be apparent to one skilled in the art
`that a number of acceptable alternatives which capture
`remote control codes could be used in place of the
`circuit shown.
`The IR remote control codes from the user's
`separate remote controllers are stored by the
`Microcontroller 20 until such time as the user desires
`to control one of the separate components in their
`system. The IR remote control codes are output by IR
`output 12.
`IR output 12, as with IR input 5, is also
`conventional, and consists of a well-known circuit
`including three (3) infra-red light emitting diodes
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`WO94/03020
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`PCT /US93/06627
`
`9
`
`(LEDs) driven by two transistors which in turn are
`driven from an output port of the Microcontroller 20.
`A representative example of the state of the art in
`such circuits can be seen in the Smith patent referred
`to above, and also in U.S. Patent No. 4,425,647
`(Collins et. al.) which is also hereby incorporated by
`reference.
`In the present invention, three (3) light emitting
`diodes provide the coverage needed for operation in the
`various physical positions that the present invention
`may be used. Two LEDs are positioned at 90 degree
`angles from each other, while the third light emitting
`diode is positioned at the center of the 90 degree
`angle, 45 degrees from the two end diodes. The IR
`diodes used are model No.· QED243 by Quality Technology,
`which are known for their ability to provide a wide
`dispersion IR beam of light. The axial dispersion of
`the 3 IR LEDs are 130 degrees with relatively full
`coverage in-between the diodes
`In operation, the 3 LEDs, which are in series with
`each other, are driven in a well-known circuit
`configuration as explained earlier. A first series
`pass transistor (not shown) is also in series with the
`diodes and is driven directly from an unregulated
`battery voltage from Battery Circuit 4. The LEDs are
`configured in the circuit to provide their own current
`limiting. A second transistor (not shown) buffers the
`output port of the Microcontroller 20, driving the base
`of the first series pass transistor thus driving the
`LEDs. The drive circuit to the LEDs also provides
`protection to ensure that the LEDs will not remain on
`all the time in the event Microcontroiler 20 fails to
`toggle its I/O line to turn the LEDs off.
`While one embodiment of IR Output 12 has been
`shown, a number of equivalent circuits which output IR
`remote control codes could be used in place of the
`circuit shown. Moreover, as with the remote control
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`10
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`capture circuit described above, the remote control
`output circuit (IR Output 12) of the present invention
`could also easily be implemented by a skilled artisan
`to accommodate RF rather than IR signals. Moreover, IR
`Output 12 could easily output the remote control codes
`to the user's separate electronic components via wire
`rather than through wireless air transmission.
`The present invention may be operated by way of
`voice commands as explained further below. An Analog
`Voice Input 2 converts the audio information in the
`user's voice to an analog electrical signal and also
`conditions this electrical signal for processing by
`Microcontroller 20. The present invention may be
`enclosed in a plastic casing (Fig. 5A). Referring to
`Figure 1 again, in a preferred embodiment of the
`present invention, Analog Voice Input 2 includes a
`microphone that is mounted against the front of the
`casing with a small opening through the plastic located
`at the center of the microphone. The microphone is
`physically mounted to a printed circuit board
`containing the present invention with a rubber grommet
`(not shown). This grommet not only provides a means to
`physically mount the microphone to the printed circuit
`board but also provides mechanical isolation required
`between the hardware and the microphone. This
`mechanical isolation isolates the microphone from any
`mechanical noise induced within the unit when the user
`depresses the voice switch as well as mechanical noise
`when holding the plastic.
`In operation, the voice signal output of the
`microphone is fed into an analog input section of
`Analog Voice Input 2. The signal is ~hen conditioned
`by well known electronic circuits that amplify and
`filter the voice input signal from the microphone prior
`to going to an analog to digital converter (ADC) 24 in
`Microcontroller 20. An example of a typical prior art
`speech recognition amplifying and conditioning circuit
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`11
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`can be seen in U.S. Patent No. 4,054,749 (Suzuki et.
`al.) which is incorporated by reference herein.
`In a
`preferred embodiment, Analog Voice Input 2 consists of
`three stages of gain and filtering. A first stage
`provides a signal gain of 40 with frequency emphasis
`characteristics of 6 db per octave at the upper end of
`the band pass. The frequency emphasis is used to
`amplify the voice information at the upper end of the
`frequency spectrum which has been determined by the
`inventors to enhance the voice recognition capability
`of the present invention. A second stage of Analog
`Voice Input 2 consists of an amplifier circuit that
`provides for analog band pass filtering. This
`filtering band passes maximum useful voice information
`while filtering out unwanted noise outside the band
`pass. The band pass section of this analog circuit has
`minimal gain with a frequency response roll off
`characteristic of 18 db per octave. The overall
`frequency response of the analog section is 300 to 4800
`Hz. A third and final stage of Analog Voice Input 2
`provides for analog gain control (AGC) of the voice
`input signal. Microcontroller 20 can adjust the level
`of the ADC input signal for maximum signal to noise
`ratio, thus enhancing recognition performance. The AGC
`compensates for variations in audio levels as the user
`speaks and also compensates volume variations which can
`result from the user speaking from various distances
`into the microphone. To maximize on battery life,
`Analog Voice Input 2 is also powered up only when the
`user activates one of three voice keys described below
`to speak into the unit. While one embodiment of Analog
`Voice Input 2 is shown herein, it wouid be apparent to
`one skilled in the art that any equivalent circuit for
`conditioning audio voice information could be used in
`lieu thereof.
`The output of Analog Voice Input 2 feeds into an
`8-bit ADC 24 within Microcontroller 20 which samples
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`the data at 9.6 Khz. ADC 24 then outputs a digital
`signal representing the input analog voice signal from
`Analog Voice Input 2. Microcontroller 20 then
`processes the digital voice signal by means of
`microprocessor 21 and a voice recognition software
`routine that is part of a control program stored in ROM
`22. The digital voice signal is converted into a voice
`template that is compared against previously stored
`voice templates of the user's voice. The program then
`decodes the voice templates as explained further below.
`Because of its compact and efficient design the
`present invention consumes minimal electrical power and
`can be powered entirely by conventional batteries.
`Batteries, however, eventually lose their charge, and
`can render the device inoperable. The present
`invention also includes a mechanism for informing the
`user at an early stage when the power level of the
`batteries is running low. As can be seen in Figure 1,
`Battery Circuit 4 provides an analog output to the
`20 Microcontroller 20 level that is read by the software
`program in ROM 22 to determine when the present
`invention is operating below a preset first voltage
`value.
`In a preferred embodiment, the first value is
`set to 5.2 volts. The output of Battery Circuit 4 is a
`digital signal driven by a operational amplifier
`configured as a comparator and read through a second
`analog to digital converter port of the Microcontroller
`20.
`If the output of the analog to digital converter
`read by the software in ROM 22 is below the specified
`battery voltage, Microcontroller 20 outputs a warning
`message to the user on LCD 10.
`When the battery voltage falls below a second
`preset value, a second output designated "change
`battery" is output to Microcontroller 20. This output
`indicates that the battery level has fallen below 4.9
`volts. A latched output signal produced by a voltage
`regulator within Battery Circuit 4 prevents the present
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`invention from going into and out of the "change
`battery" mode each time the system is operated. This
`could happen, for example during operation when IR
`Output 12 photodiodes are transmitting, causing the
`battery voltage typically to drop lower than when
`sitting in an idle or clock mode. Without the latch
`mode and accompanying hysteresis, the battery voltage
`would momentarily go low then high causing
`Microcontroller 20 to go into and out of the "change
`battery" condition. Again, while one embodiment of the
`Battery Circuit 5 has been described, a number of
`alternatives that provide battery information to the
`user could be implemented instead.
`Next, it is often desirable to provide audible
`feedback to the user of the present invention, such as
`when the device has finished learning a specific IR
`remote control code from one of the user's separate
`remote controllers. For this reason, the present
`invention also includes a Piezo output circuit 11 for
`providing audible feedback. The Piezo Output 11
`consists of a simple single transistor circuit driving
`a piezo beeper from an output port of the
`Microcontroller 20. The output port of the
`Microcontroller 20 outputs a 4 KHz signal with an on
`time controlled by the software program in ROM 22.
`Finally, the majority of the electronic data
`processing and control is performed by 8-bit CMOS
`Microcontroller 20 which has several input and output
`ports interfacing to the various hardware sections
`described above. As explained earlier, included within
`Microcontroller 20 is a microprocessor 21 with an
`associated program read-only memory (ROM) 22 and an
`reference random access memory (RAM) 23 which perform
`voice recognition and other functions described herein.
`For this purpose, ROM 24 contains a 24 kbyte control
`program consisting of microcode instructions executed
`by Microprocessor 21 to effectuate the aforementioned
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`functions. An additional 1.5 kbytes of reference
`memory is found in RAM 23 for temporary storage and is
`used by Microprocessor 21 for computing and for storage
`of information needed frequently. Microcontroller 20
`also includes ADC 24 explained above for converting
`analog voice signals from Analog Voice Input 2 into
`digital voice signals. Microcontroller 20 also
`controls all input/output (I/O) in the present
`invention (such as Keyboard 3, IR input and output 5
`and 12) and drives liquid crystal display {LCD) 10 as
`described below.
`In a preferred embodiment,
`Microcontroller 20 is a Panasonic integrated circuit
`part no. NN 1872410, but it is apparent that any number
`of acceptable Microcontrollers and or Microcomputers
`could be used instead.
`Microcontroller 20 runs off of two standard
`crystals: a first 32.768 KHz crystal for the clock mode
`which is used to maintain the real time clock while
`consuming minimal power {150 microamps) from the
`battery supply and a second crystal running at 8.38 MHz
`for performing voice recognition and transmitting IR
`remote control codes.
`In the higher speed mode the
`power consumption from the battery increases to
`approximately 5 milliamps.
`The input ports of Microcontroller 20 thus include:
`a voice data port for receiving the analog voice signal
`from Analog Voice Input 2; a key strobe port for
`reading the Keyboard 3; an interrupt input (IRQ) for
`reading the IR remote control codes from IR Input 5; a
`memory data port for reading data from ROM Code Library
`7 and External DRAM 8, and low battery ports for
`reading the status of the Battery Circuit 5 for low
`battery and change battery conditions. The output
`ports of Microcontroller 20 then include: an LCD driver
`port to drive a 200 segment LCD 10; an IR port for the
`IR remote control code transmission by IR Output 12; a
`piezo port for the Piezo Output 11; an AGC output to
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`Analog Voice Input 2; and a key strobe port for driving
`keyboard decode lines on Keyboard 3.
`Microcontroller 20 also has access to 1 MEG of
`External DRAM 8 for additional storage of information
`where larger memory capacity is desired.
`In a
`preferred embodiment, External DRAM 8 is a pseudo
`static 1 MEG DRAM which consumes lower power to operate
`then conventional DRAMs and at the same time has a
`smaller foot print and is far less expensive then
`static RAMS.
`To address the External DRAM 8, an 8-bit
`Shift Register 9 ls used between Microcontroller 20 and
`External DRAM 8 to minimize the number of I/O ports
`used to address External DRAM 8.
`In other words, using
`Shift Register 9 allows use of only two output port
`lines to address External DRAM 8 instead of the normal
`8 address lines. A clock output port line from the
`Microcontroller 20 controls the data clock input of
`Shift Register 9, and a second output port serial
`address line provides the address data to be shifted
`into Shift Register 9. The 8 output lines of Shift
`Register 9 provide the RAS and CAS address lines to
`External DRAM. Because the address lines are shifted
`into Shift Register 9 in a serial manner, External DRAM
`8 access time is significantly longer. Thus,
`25 Microcontroller 20 works out of its high speed internal
`memory RAM 23 any operations requiring high speed
`memory access such as for voice recognition or IR code
`capture or transmission.
`In addition to External DRAM 8 the present
`invention accommodates an additional ROM Code Library 7
`to support a code library of known manufacturer IR
`remote control codes. ROM Code Library 7 allows the
`user to select an IR code associated with their
`equipment without having to learn the remote control
`code through IR Input 5. To address ROM Code Library
`7, a second 8-bit shift register is used in the same
`manner used to address External DRAM 8 allowing two I/O
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`port lines to be used instead of eight. ROM Code
`Library 7 provides 8 kbytes of additional IR remote
`control code storage.
`Figures 5A and 5B are depictions of the exterior of
`the casing which can physically incorporate the
`