WO1996011529A1 - Voice activated transmitter switch - Google Patents

Abstract

This invention comprises an improvement in radio microphone systems commonly found in emergency vehicles such as police, fire ambulance, etc. It entails automatically turning the microphone (10) on with the voice of the user thereby obviating the manual push to talk switch commonly found on such microphones (10). The best mode embodiment comprises use of two microphones (10) generally 180 degrees apart, the output of which is applied to plus and minus inputs of a differential amplifier (20). The output of the differential amplifier (20) is then passed through an A/D converter (30) and is then digitally processed to authenticate the speaker and/or the speech. The digital processor (50) authenticates by comparing speech envelopes and harmonics etc. before activating the transmission.

Description

VOICE ACTIVATED TRANSMITTER SWITCH

TECHNICAL FIELD This invention relates to the technical field of authenticated voice activated transmitter switches.

BACKGROUND This invention relates to an improvement in radio microphone systems commonly found in emergency vehicles such as police, fire ambulance etc. Many accidents have been caused in emergency vehicles while returning the microphone to its hold position because the driver could not locate the home position without taking the eyes off the road. This invention entails automatically turning the microphone on with the voice of the user thereby obviating the manual push to talk switch commonly found on such microphones. Two sets of voice commands are generated for each operator one to turn the transmission on and the other to turn the transmission off. For added security the voice print/signature of a few authorized people is stored in the system such that unauthorized people are not able to interrupt the system. The unit provides for the training of the system by each operator. The voice switch is interface and plug compatible with existing push to talk switch found on microphones in emergency vehicles.

PRIOR ART The prior art method of using the transmitter in an emergency vehicle requires the driver to use one hand to both hold the microphone and to push the PUSH-TO-TALK switch on the side of the microphone provided for this purpose to activate the transmitter. This leaves only one hand to operate the vehicle and to concentrate on where the hand microphone is and how to control its movement. This effectively reduces the driver's ability to operate the motor vehicle while concentrating on the more important task of handling the emergency. This in turn very substantially increases the risk of accident and injury to the driver and to other people in the area when the vehicle is in pursuit of another vehicle in high speed chase. When the emergency vehicle has an accident, two new emergency vehicles are dispatched one to handle the emergency vehicle and the other to handle the situation to which emergency vehicle was assigned to handle before the mishap. A preliminary prior art search was conducted and furthermore the inventor is intimately familiar with the problem and the prior art. There is plethora of prior art on speech and speaker recognition and hence the ability to automatically activate and deactivate electronic devices such as a camera, dictation recorder, telephone answering machine, the automobile etc etc. Following are typical examples of the closest U S patent as prior art arranged in the reverse chronological order. 12) U S Patent 5,267,323 granted to Toshiyuki Kimura on November 30, 1993 for "Voice Operated Remote Control System" 11) U S Patent 5,214,707 awarded to Fuji oto et al on May 25, 1993 for "Control System for Controlling Equipment provided inside a Vehicle Utilizing a Speech Recognition Apparatus". 10) U S Patent 5,008,954 bestowed upon Carl Oppendahl on April 16, 1991 for "Voice Activated Radio Transceiver". 9) U S Patent 4,961,177 granted to Kensuke Uehara on October 2, 1990 for "Method and Apparatus for Inputting A Voice through A Microphone" 8) U S Patent 4,905,270 earned by Hideyo Ono on February 27, 1990 for "Vehicular Hands Free Telephone System" 7) U S Patent 4,901,354 obtained by Goll ar et al on February 13, 1990 for "Method of Improving the Reliability of Voice Controls of function Elements and Device for Carrying Out this Method". 6) U S Patent 4,827,520 secured by Mark Zeinstra on May 2, 1989 for "Voice Actuated Control System for Use in a Vehicle" 5) U S Patent 4,797,924 granted to Schnars et al on January 10, 1989 for "Vehicle Voice Recognition Method and Apparatus" . 4) U S Patent 4,401,852 given to Noso et al on August 30, 1983 for Voice Response Control System". 3) U S Patent 4,119,797 conferred upon Walter C. Wollert on October 10, 1978 for "Voice Operated Switch Having an Activation Level which is Higher than its Sustaining Level" 2) U S Patent 3,746,789 awarded to Ernesto Alcivar on July 17, 1973 for "Tissue Conduction Microphone Utilized to Activate a Voice Operated Switch" . 1) U S Patent 3,730,995 bestowed upon Max Vernon Mathews on May 1, 1973 for Voice Switched Microphone Control System". The applicants are also aware that several companies such as Dragon Systems manufacture and market voice activated software systems for the end user. Prior art patents disclose the general concept of voice activated electronic devices even voice activated switches but not in the configuration of a voice activated radio microphone, let alone one meeting all of the objectives established by the inventor for this invention as disclosed above. The applicants are first to disclose a simple automatic replacement of the push to talk switch on radio microphones found in emergency vehicles. Unfortunately none of the prior art devices singly or even in combination meet all of the objectives established by the inventor for this voice activated radio microphone. OBJECTIVES 1. The main objective of this invention is to provide a simple, low cost, hands free operation of a two way radio such that the microphone push to talk switch function normally used in two way emergency mobile radios to turn the transmitter on and off is replaced by a recognized voice command. 2. Another objective of the invention is to prevent emergency vehicle accidents caused while accessing or returning the microphone to its hold position because driver is unable to handle the mike and the concomitant push-to-talk switch on the prior art emergency microphones without taking the eyes off the road. 3. Another objective of this invention is to provide a system where the need for push to talk switch in microphones is altogether obviated or used merely as a backup. 4. Another objective of this invention is to provide a low noise voice activated radio microphone switch that can operate reliably in high ambient noise. 5. Another objective of this invention is to provide an add on unit to existing radio microphone systems in emergency vehicles that can be easily interfaced. 6. Another objective of this invention is that it use little or no energy. 7. Another objective of this invention is that it can be used without detracting from the task of driving. 8. Another objective of this invention is that it be secure such that it recognizes the voice prints of a few authorized users in real time. 9. Another objective of this invention is that the system of this invention be compact, light weight and low cost. 10. Another objective of this invention is that the various components not interfere with the driver or the other components in the emergency vehicle.. 11. Another objective of this invention is that the invention use modular standard components easily interface- able to each other. 12. Another objective of this invention is that it be reliable such that it practically never fails and requires little or no maintenance. 13. Another objective of this invention is that it is easy to use even intuitive requires little training if any and does not expect the driver to do any thing different and unusual or even unnatural. 14. Another objective of this invention is that it be environmentally safe. 15. Another objective of this invention is that it be physically safe in normal environment as well as accidental situations. 16. Another objective of this invention is that it meet all federal, state, local and other private standards guidelines, regulations and recommendations with respect to safety, environment, energy consumption. 17. Another objective of this invention is that it provide both analog and digital outputs so that both digital and analog type transmitters can be activated with equal ease. 18. Another objective of this invention is that it be safe, fail-safe and fail-soft, stable, reliable secure and flexible. 19. Another objective of this system is that a stranger or any authorized person cannot accidentally turn on or off the microphone or enable or disable the system. 20. Another objective of this invention is that the driver or other authorized user cannot accidentally turn off the microphone or disable the system. 21. Another objective of this invention is that it use very little energy. 22. Another objective of this invention is that its design be streamlined and have a small footprint. 23. Another objective of this invention is that its design is aesthetic to blend with the decor of the emergency vehicle or other environment. 24. Another objective of this invention is that it not interfere with normal functions of the driver and the driving tasks. 25. Another objective of this invention is that it be adaptable for other primary and secondary uses without significant modifications. 26. Another objective of this invention is to facilitate and optimize under cover police work by obviating use of hand held mike and thereby making detection difficult if not impossible and reducing the chances of related injuries. 27. Another objective of this invention is to facilitate use of such radios and concomitant communications in ambulance cab section where hands of paramedic or other medical assistant are free to provide assistance to the patient without the use of hand held mike. Other objectives of this invention reside in its simplicity, elegance of design, ease of manufacture, service and use and even aesthetics as will become apparent from the following brief description of the drawing and detailed description of the best mode embodiment.

BRIEF DESCRIPTION OF THE DRAWING The objects, features and advantages of the present invention and its application will be more readily appreciated when read in conjunction with the accompanying drawing , in which:

a) FIG 1 is a system interface block diagram of the voice activated transmitter switch of this invention. b) FIG 2 is a detailed block diagram of the voice activated transmitter switch of this invention. c) FIG. 3 is a flow-chart of the voice activated transmitter switch of this invention.

DETAILED DESCRIPTION OF THE BEST MODE EMBODIMENT As shown in the drawings wherein like numerals represent like parts throughout the several views, there is generally disclosed in Figure 1 a pair of microphones 10 generally 180 degrees apart, the out put of which is applied to plus and minus inputs of a differential amplifier 20. The Output of the differential amplifier is then passed through an A/D converter 30 and is then digitally processed in a digital processor 50 to include phrase recognition such as "Key Mike" to engage and activate the transmission and "Over" to disengage and deactivate the transmitter 100. Also included are such features as phrase learning and training, auto time out and intelligibility processing. Digital processor 50 also has on-board memory 55 to store sample voice prints as signatures of the authorized personnel. The speech recognition, conditioning and comparison circuit 110 of the processor 50 verifies by comparing envelopes and harmonics etc before activating the transmitter 100. It should be noted that transmitters with digital interface receive the output of the digital process directly. The entire invention comprising the pair of microphones 10, differential preamplifier 20, Codec 35 (which performs the functions of A/D converter 30 and D/A converter 40), and digital processor 50 is plug and interface compatible with the single existing microphone and the existing transmitter 100. The analog signal from the mike 10 via differential preamplifier 20 can go directly to the transmitter 100 and the input to the A/D circuitry 30 (or codec 35) tapped off of it without severing the existing connection 22 between the microphone 10 (via differential preamp 20) and the transmitter 100. Alternatively the connection 22 between the microphone 10 and the transmitter 100 can be severed and then is either reconverted back to analog via D/A converter 40 (or via codec 35) or directly fed to a digital input of a transmitter with that capability. In either case additional digital processing via digital processor 50 is done to effect bandwidth spectrum balance, to alter intensity ratios, to improve intelligibility or other desired signal characteristics. As shown in detailed block diagram Fig. 2 the invention comprises a pair of electret microphones 10 with differential pre-amps 20 to condition the signals for analog to digital converter 30 or codec 35 which is a linear codec commonly used in digital telephone systems. The data is then processed through a digital signal processor 50 which performs the voice recognition conditions and comparison function 110. All this is under the control of a controller 120 which is a single CMOS microprocessor chip with plurality of I/O lines for interface as well as external address and data buses. The program 150 for the controller 50 and the program routines 152 for the DSP 50 are stored in PROM 52. All the indicators 80 and switches 90 are also under the control of controller 120. For convenience all of said components are mounted on a single throw-away board, which allows the use of automated assembly techniques to used for fabrication and mass production. All of the actions taken by the speech recognition circuit are accomplished under the control of the controller 120, which monitors the external switches 90 and controls the indicators 80 as well as the transmitter 100. The controller 120 further initialize the speech recognition circuits, initialize and monitors all of the registers of the microprocessor or DSP 50 for whatever function is being requested by the user through said switch 90. The controller 120 can also select either conditioned speech, processed through the speech conditioning circuit or the analog audio from the microphone 10 can be patched directly to the transmitter 100. As shown in Fig. 3 voice activated transmitter switch flow-chart after initialization 200 comprises plurality of decision blocks a) Is stored command valid? - 210 b) Is switch pushed? - 220 c) Is calibration complete? - 230 d) Is calibration switch pushed? - 240 e) Is transmitter active? - 250 f) Does voice on command match? - 260 g) Does voice off command match?- 270 h) Has the voice time period exceeded? - 280 If the answer to the decision blocks 220 (Is button pushed?) and 240 (Is calibration switch pushed) is in the affirmative then capture patter function 222 and store captured data 224 are performed. If the answer to the decision block 240 (Is calibration switch pushed?) is in the negative then check switch status function 242 is performed. If the answer to the decision block 260 (Does voice ON command match?) is in the affirmative then transmitter 100 is turned on via function 262. Similarly if the answer to the decision block 270 (Does voice off command match?) is in the affirmative then transmitter 100 is turned off via function 272. In the preferred embodiment the inventor used microphones 10 Panasonic model WM-54BT. Differential pre-amps were implemented using single supply quad OP AMP LM324 which is an industry standard, which provides proper gain and conditioning for proper levels for codec 35 for which U-LAW/A-LAW PCM codec AT&T T-7500 was used. For speech recognition function the inventor employed AT&T DSP16A1. The controller 120 was 8 bit Hitachi HD6305 and RAM Module was SRAM Hitachi HN62256. Both of these and other components can be used by a person of average skill in the art with equal facility.

OPERATION The installation use and operation of this device is simple and even intuitive. The pair of microphones is mounted in the vehicle facing opposite of each other 180 degrees apart with a nominal distance of 10 to 12 inch space between the mouth of the driver and the microphones. The system is then trained with the On and off voice commands for each operator. The example of an ON command is "KEY-MIKE" An example of the OFF command is OVER. By speaking the phrase taught for transmitter ON the turns on the transmitter and likewise by speaking the phrase taught for transmitter off, the transmitter turns off. Any speech that does not conform to the command phrases is ignored. Even command phrases by a different person are ignored. The command phrases by the same person having some change in voice due to cold etc are not ignored.

To facilitate training the system a plurality of switches 90 and plurality of indicator lights 80 are provided which are self explanatory as follows: a) Active/Inactive switch 92 b) Learn Transmit On Command Switch 94 c) Learn Transmit OFF Command 96 d) Test Voice Command switch 98 e) LED Indicator Transmitter Active 82 f) LED Ready Indicator 84 g) LED Test/Learn Indicator 86 The first time a particular operator driver other user uses the unit, it has to be taught the phrases for ON and OFF in the voice of this particular driver, operator or other user. Obviously the operator must push the appropriate learn transmit switch 94 for On and 96 for OFF command. When said switch is pushed the test/learn indicator 86 begins to blink along with the transmitter active light 82. After the operator, driver or other user has spoken the phrase, the ready indicator 84 is lit to indicate that the operator, driver or other user should repeat the phrase. When the phrase is repeated, the light turns off for a short period of time and then come back ON indicating that the phrase needs repeating again. The minimum number of utterances required. Once the unit recognizes the calibration is satisfactory, the test/learn indicator 86 and the transmitter active indicator 82 is turned off and the READY indicator 84 begins to blink to indicate that the learning process is not complete until the transmitter OFF command has been taught to the unit. The same procedure is used to train the transmitter off command. When all this is done, READY indicator 84 goes steady instead of blinking and all the other indicators 82,86 are turned off. The switch 98 allows the user to test and verify the training without activating the transmitter 100. In this mode the test/learn indicator 86 is turned on steady (not blinking) and the transmitter indicator 82 responds to the voice commands without keying the transmitter 100. The inventor has given a non-limiting description of the concept. Many changes may be made to this design without deviating from the spirit of the concept of this invention. Examples of such contemplated variations include the following. a) A boom mike with very close coupling to the mouth of the user may be employed. b) Some of the software functions may be employed by hardware. c) Non-obvious enhancements may be made to the flow-chart described here. d) The voice activated transmitter switch of this invention may be adapted for other applications such as the Citizen Band Radio. e) The invention may be adapted for physically challenged. f) A different type of energy source such as NICAD battery or solar energy source may be employed. g) Complementary functions such as synthesized voice output instead of LED indicators may be used. h) Different types of switches may be used. i) An infra-red or RF3 link to the transmitter may be used which would also allow the maximum natural noise rejection and the use of relatively inexpensive standard VOX energy detectors to be used. j) Logical operations to monitor activity in the emergency vehicle for the safety of the driver and others may be incorporated.

Other changes such as aesthetic and substitution of newer materials as they become available which substantially perform the same function in substantially the same manner with substantially the same result without deviating from the spirit of this invention may be made.

Following is a listing of the components and procedural steps used in this embodiment arranged in ascending order of the reference numerals for ready reference of the reader. 10 = A pair of microphones such as PANSONIC WM-54BT. 20 = Differential Pre-amplifier such as LM324 22 = Connection between microphone 10 and transmitter 100 via pre-amp 20 30 A/D converter 35 Codec U-LAW/A-LAW PCM such as AT&T T7500 40 D/A convertor 50 DSP such as AT&T DSP16A1 52 PROM 55 Memory 32 x 8 SRAM such as Hitachi HN62256 60 = Transmitter on/off control device 62 Transmitter Key Signal 70 = Transmitter Level shifting interface 72 - Audio speech signal to transmitter modulator 80 = Indicators 82 = Transmitter active indicator 84 = Ready indicator 86 = Test/Learn indicator 90 = Switches 92 = Active/Inactive Switch 94 = Learn Transmit On Command switch 95 = Three way speech, conditioned speech and inactive switch 96 Learn Transmit Off Command Switch 98 = Test voice command switch 100 = Transmitter 110 = Speech recognition, conditioning and comparison 120 = Controller 8 Bit such as Hitachi HD6305 150 = voice activated transmitter switch flow-chart/program 152 = Program routines.

200 = Program initialization function

210 = Decision Block - Is stored command valid?

220 = Decision Block - Is switch pushed?

222 = Capture pattern function

224 = Store captured data

230 = Decision Block - Is calibration complete?

240 = Decision Block - Is calibration switch pushed?

242 = Check calibration switch status function

250 = Decision Block - Is transmitter active?

260 = Decision Block - Does voice on command match?

262 = Turn on transmitter 100 function

270 = Decision Block - Does voice off command match?

272 = Turn off transmitter 100 function

280 = Decision Block - Has the no voice time period exceeded?

DEFINITIONS

While exacting care has been taken to avoid terms of art and use words with their conventional dictionary meaning the following definitions are included for clarification of the specification and its interpretation.

CPU - Central processing unit of a computer capable of performing all the timing, control, logic associated with running a computer program. Driver - a software interface to match two or more dissimilar entities to make them compatible. Interface - Matching or two or more dissimilar entities however realized LED - Light emitting diode - a type of visual indicator CODEC - Coder decoder performs the same function as A/D convertor + D/A converter. Program - A computer program executable in a given computing environment.

While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the invention will be apparent to person skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications, embodiments as fall within the true scope of the invention.

Claims

The inventors claim: 1. A voice activated transmitter switch comprising: a) a voice input means; b) a differential amplifier connected to said voice input means; c) an analog to digital convertor connected to said differential amplifier; d) a digital signal processor connected to said analog to digital convertor; e) a digital to analog convertor connected to said digital signal processor and to the transmitter recited in the preamble; and f) a transmitter key circuit connected to said digital processor and said transmitter.

2. The voice activated transmitter switch of claim 1 wherein said voice input means comprises a plurality of microphones.

3. The voice activated transmitter switch of claim 1 where in said voice input means comprises a pair of microphones 180 degrees apart the output of which is connected to plus and minus inputs of said differential amplifier.

4. The voice activated transmitter switch of claim 1 where in said voice input means comprises a single electret microphone and where in said analog to digital convertor and said digital to analog convertor functions are realized by a codec.

5. The voice activated transmitter switch of claim 1 wherein said digital processor performs inter alia the following functions: a) speech recognition; b) speech conditioning; c) speech storage; and d) speech comparison.

6. A voice activated transmitter switch particularly adapted for use in an emergency vehicle communication system having a transmitter comprising: a) a voice input means; b) a differential amplifier connected to said voice input means; c) a codec also known as a coder decoder which performs analog to digital and digital to analog functions; d) a digital signal processor connected to said codec; e) a transmitter key circuit connected to said digital processor and said transmitter. f) a controller connected to said digital signal processor; g) a plurality of switches connected to said controller; and h) a plurality of indicators connected to said controller.

7. The voice activated transmitter switch of claim 6 where in said voice input means comprises a pair of microphones 180 degrees apart the output of which is connected to plus and minus inputs of said differential amplifier.

8. The voice activated transmitter switch of claim 6 wherein said digital processor performs inter alia the following functions: a) speech recognition; b) speech conditioning; c) speech storage; and d) speech comparison.

9. The voice activated transmitter switch of claim 6 wherein said plurality of switches includes: a) an active/inactive switch; b) a learn transmit on command switch; c) a learn transmit off command switch; and d) a test voice command switch;

10. The voice activated transmitter switch of claim 6 wherein said plurality of indicators include: a) an LED indicator for indicating transmitter is active; b) an LED ready indicator; and c an LED test/learn indicator.

11. A voice activated transmitter switch particularly adapted for use in an emergency vehicle communication system having a transmitter comprising: a) a voice input means; b) a differential amplifier connected to said voice input means; c) a codec also known as a coder decoder which performs the analog to digital and digital to analog functions; d) a microprocessor connected to said codec; e) a memory connected to said microprocessor; f) a controller connected to said microprocessor; g) a transmitter key circuit connected to said microprocessor and said transmitter; h) a transmitter level shifting interface connected to said transmitter and said codec; and i) a plurality of switches and indicators connected to said controller.

12. The voice activated transmitter switch of claim 11 wherein said microprocessor performs inter alia the following functions: a) speech recognition; b) speech conditioning; c) speech storage; and d) speech comparison.

13. The voice activated transmitter switch of claim 11 wherein said plurality of switches and indicators includes: a) an active/inactive switch; b) a learn transmit on command switch; c) a learn transmit off command switch; d) a test voice command switch; e) an LED indicator for indicating transmitter is active; f) an LED ready indicator; and g) an LED test/learn indicator.

14. The voice activated transmitter switch of claim 13 wherein said microprocessor is programmed to sense and make the following decisions: a) Is stored command valid?; b) Is switch pushed?; c) Is calibration complete?; d) Is calibration switch pushed?; e) Is transmitter active?; f) Does voice on command match?; g) Does voice off command match?; and h) Has the voice time period exceeded?.

15. The voice activated transmitter switch of claim 11 wherein said transmitter is turned on upon recognition of a pre-recorded phrase from a given speaker and turned off by recognition of a different prerecorded phrase from the same speaker.

16. The process of automatically activating a transmission in an emergency vehicle without the use a prior art push-to-talk microphone switch comprising the steps of: a) recording and storing a first command for turning said transmission on; b) recording and storing second and different command for turning said transmission off; c) turning said transmission on when said first command is given; and d) turning said transmission off when said second and different command is given.

17. The process of automatically activating a transmission in an emergency vehicle of claim 16 wherein a micro-processor is programmed to sense and make the following decisions: a) Is stored command valid?; b) Is switch pushed?; c) Is calibration complete?; d) Is calibration switch pushed?; e) Is transmitter active?; f) Does voice on command match?; g) Does voice off command match?; and h) Has the voice time period exceeded?.