US 3710313 A
Communications warning apparatus of the type wherein a transmitter is mounted in an emergency vehicle and one or more frequency-adaptive receivers are mounted in other vehicles. This system utilizes an FM transmitter coupled with recorder and play back mechanism in the emergency vehicle so that transmission can be effected in any of three modes, i.e. modulated C-W, voice transmission or repetitive recorded voice message, and transmission is effected at such frequency that all surrounding vehicles having a required receiver instrument will receive such warning or message preferentially over a receiver instrument or modular adapter utilized with a standard car radio.
Description (OCR text may contain errors)
United State Kimball et al. 14 1 Jan. 9, 1973 [s41 EMERGENCY WARNING SYSTEMS 3,461,423 8/1969 Trumble ..340 33  Inventors: Pleasent P. Kimball, 583 Market g g et al Street, San Francisco, Calif. 94105; 3 er Robert H. Ha e Malcolm J.
Macaulay both North Vina Primary Exammer.lohn W. Caldwell Apt 23 Oklahoma City Okla: Assistant Examiner-Robert J. Mooney 731 16 Attorney-Dunlap, Laney, Hessin & Dougherty  Filed: Jan. 13, 1971 57 ABSTRACT  Appl. No.: 106,170 Communications warning apparatus of the type wherein a transmitter is mounted in an emergency 52 US Cl ..340/33, 179/1 VE, 179/100.1 (2, vehicle and one or more frequerwy-adaptive receivers 325/64, 325/131 are mounted in other vehicles. This system utilizes an  Int. Cl. ..G08g 1/00 FM n mi r pl wi h re order and play back  Field of S earch..340/33, 34; 179/1 VE, 100,1 C; mechanism in the emergency vehicle so that transmis- 325/64 sion can be effected in any of three modes, i.e. modulated C-W, voice transmission or repetitive recorded  References Cited voice message, and transmission is effected at such frequency that all surrounding vehicles having a UNITED STATES PATENTS required receiver instrument will receive such warning 2,994,765 8/1961 Adam ..340/33 or message preferentially over a receiver instrument 2,799,731 7/1957 Straub ..179/100.1 C or modular adapter utilized with a standard car radio. 3,387,101 6/1968 Skiles 3,014,199 12/1961 Dill et a1 ..340/33 7 Claims, 7 Drawing Figures n/ 19 f M H /a A FM M00 UM TPA/VSM/TTE'E MODE- /?4 SELLC 7' 0? TOMA 50 semen/r02 L 2550205? EMERGENCY WARNING SYSTEMS BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates generally to emergency vehicle warning systems and, more particularly, but not by way of limitation, it relates to improvements in radio frequency transmission systems as used for intercommunication between motor vehicles and the like.
2. Description of the Prior Art The Prior Art includes various types of radio energy transmission systems of the general type which serve to effect a selective transmission from an emergency vehicle, i.e. ambulance, fire truck, police car, etc., for the purpose of generating a warning transmission for reception by various other vehicles which may be in the immediate path of the emergency vehicle. Receivers of the forerunner systems have been adapted to provide such as a warning buzzer or dash-light indication to normal traffic drivers in their vehicles an response to such emergency vehicle transmission, and some receiver instruments have been adapted to exercise preferential transmission selection or override reception of emergency warning information on the standard vehicle receiver. Systems have also been designed wherein transmission from an emergency vehicle or the like can provide output energy at a preselected frequency for the purpose of effecting charge of oncoming traffic lights to green along the route of travel. These systems too are primarily a modulated FM frequency transmitter propagating a characteristic frequency adapted or selected for reception and operational control by a suitable device associated with the traffic light switching system.
SUMMARY OF THE INVENTION The present invention contemplates an emergency warning transmission system wherein the emergency vehicle transmitter instrument is capable of plural mode transmission operation to enable selection of one of several types of warning transmission. In a more limited aspect, the invention consists of a transmitter assembly in the emergency vehicle which includes an associated record-playback apparatus which enables the emergency vehicle operator to transmit at any of several modes, i.e. modulated C-W transmission, direct voice transmission, automatic repetitive voice warning as effected by the play back instrument. One or more vehicles, preferably all surrounding vehicles, are then outfitted with receiver instruments which are sensitive to the characteristic frequency transmission to pick up such emergency transmissions for reproduction to the driver of the vehicle or vehicles in the immediate vicinity to audibly reproduce a suitable warning message as to approach of an emergency vehicle, accident ahead, icy bridge condition, etc.
Therefore, it is an object of the present invention to provide an emergency warning system having greater capability through increasing the number of modes of operation to satisfy requirements of all exigencies.
It is also an object of the invention to provide emergency warning apparatus which will provide emergency warning to all vehicles in the vicinity despite tightly sound-p roofed autos, air conditioner noise within individual autos, and other hindrances to the audibility of siren-type warnings as presently employed.
It is yet another object of the invention to provide a warning system which is cable of delivering a voice message in repetitive form automatically without requiring constant attention from the operator of an emergency vehicle.
Finally, it is an object of the present invention to provide an emergency warning system of the type utilized in radio energy transmission which is of very low cost and high reliability and which enables plural operating modes for maximum effect warning operation as between an emergency vehicle or warning station and the general or normal flow of vehicle traffic.
Other objects and advantages of the invention will be evident from the following detailed description when which illustrate the invention.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a radio transmitter as employed in the system of the invention;
FIG. 2 is a suitable form of front panel layout of one form of vehicle-mounted transmitter instrument as may be employed in the invention;
FIG. 3 is a block diagram of the recorder portion of the FIG. 1 transmitter circuitry;
FIG. 4 is a block diagram of a suitable form of receiver instrument for use in the present invention;
FIG. 5 is an elevation view of a suitable form of front panel lay out as might be employed with a receiver instrument;
FIG. 6 is a plan view illustrating an alternative usage of the present invention; and
FIG. 7 is a block diagram of an alternative form of receiver structure.
DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1, the transmitter 10 includes such as a signal input circuitry 12 providing input to a modulator 14. The modular 14 is then connected in conventional manner to apply modulating signal to an FM transmitter 16 which, in turn, provides output to an antenna 18 for propagation of the radio frequency energy. The FM transmitter 16 may be such as a standard solid state FM transmitter of the continuous wave type and including design allowances for the specific amplification functions. It is contemplated that production considerations will result in the use of modularized or encapsulated circuits.
Transmitter 16 should transmit energy at a frequency as assigned or selected by the FCC. Propagation from antenna 18 should be concentrated in the forward direction. It is probably sufficient that the transmitter operate with an input of between 1 and 25 watts average power so as to limit the range of reception of the transmitter to approximately 1 mile. Further, the frequency of transmission should be high enough to be directional so that the energy can be transmitted from the front of the emergency vehicle, by means of a suitable form of antenna instrument (not specifically shown) and yet the frequency should be low enough to eliminate line of sight limitations such that adequate coverage is assured for downtown business or high building areas.
The antenna 18 should be designed to propagate the radio energy in a major lobe approximately between half power points and directed forwardly of the emergency vehicle. Minor side lobes and other lobing effects may be sufficiently minimized utilizing well known antenna design considerations that should not necessitate expensive fixtures. The antenna 18 may be permanently affixed atop or on the front of an emergency vehicle or emergency warning station along a highway since the antenna is highly specialized in form and function.
The input circuitry 12 includes a microphone 20 connected to provide voice input upon depression of key 21 via connector cable 22 to a mode selector 24. The mode selector 24 may be such as a ganged, plural contact switch, e.g. a plural circuit rotary wafer switch, for receiving input signals relative to various modes of operation. A tone generator 26 serves to generate a suitable constant frequency tone for modulated C-W operation. Tone generator 26 provides such as a 1,000 cycle tone as output via lead 28 for application to mode selector 24.
A recorder 30 may be a conventional form of recordplayback instrument as connected via leads 32 and 34 to mode selector 24 to provide yet another mode of operation, as will be further described below. Thus, mode selector 24 may select any of (a) voice communication as input at microphone 20, (b) C-W tone modulation as generated by tone generator 26 or (c) a selected recorded message as recorded on recorder 30 for selected playback and transmission.
FIG. 2 illustrates the front panel of one form of instrument which may be mounted in the emergency vehicle. Thus, a transmitter instrument 36 may include a front panel 38 with connections being made at sidemounted receptables. Supply voltage from the system battery or the like may be applied via lead 40 through the ignition system 42 and lead 44 to an input jack 46, and voice input from microphone 20 is effected through a cable 48 and input jack 50.
Front panel 38 may include a loudspeaker grille 52 and an indicator dial light 54 to denote equipment ON condition. A screwdriver adjust 56 may be included to enable permanent setting of modulation and volume levels. A two position switch 58, e.g. a conventional toggle-type switch, may be utilized to provide ON-OFF control or application of the supply voltage.
A mode selector switch 60, here shown in the modulated C-W or alert position 62, may be operated to any of additional positions 64, 66 and 68 to select voice transmission, tape message transmission and tape message record mode, respectively. Thus, tape record position 68 enables the operator of the emergency vehicle to speak a message through microphone 20 for recording on the recorder 30 (as will be further described below), whereupon placement of the mode switch 60 to tape transmit position 66 will then enable repetitive play back and transmission of the taped message. A time meter 69 enables the operator to observe elapsed record time visually during recording so that the message is better fitted into available time. It is probably preferrable that time meter 69 only be energized during the Tape Record position 68 of mode switch 60.
FIG. 3 illustrates the mode selector 24 and recorder 30 in greater detail. Thus, a suitable form of recordplayback mechanism 70 is utilized to provide recording capability, e.g. 20 to 30 seconds of record time. While record-playback mechanism may be any of various commercially available units, considerations of cost, reliability and preferable function have prompted the selected of an endless record type of record-playback apparatus. Thus, an endless record, e.g. a tape or wire record, is driven around a drive pulley 74 and an idler pulley 76 across a transducing position 78 wherein recording and playback are effected. Drive pulley 74 is driven by means of a drive control 80 as indicated by dash-line linkage 82. Drive control 80 is controlled via electrical connection 84 from mode selector switch 24.
Input audio information from mode selector 24 is applied via lead 86 through a suitable form of input amplifier 88 and lead 90 to a recording head 92. Recording head 92 then engages endless tape 72 at the transducing position 78 to effect recording of the input audio message. Playback from endless tape 72 may be cf fected by a transducer 94 with signal output on a lead 96 for input to an audio amplifier 98 whereupon amplified audio energy is available on lead 34 for input to mode selector 24. A head selector 100, e.g. a suitable solenoid control, receives energization via lead 102 from mode selector 24 to engage one or the other of the record head 92 or play back 94, as indicated generally by the connecting linkage 104. While the record-playback transducing heads 92 and 94 are indicated as separate implements, it should be understood that there are many choices regarding this structure and it may be most desirable to employ a combined-type of head which effects both playback and reproduction without the necessity for physical movement. In addition it should also be understood that the record head 92 containing suitable erase windings supplied by an erase bias amplifier to effect erasure of any previously recorded message on the tape immediately before recording a new message.
A receiver suitable for use in the emergency warning system is illustrated in FIG. 4. Incoming radio energy received by an antenna 112 is applied to an FM receiver 114. FM receiver 114 may be such as an FM crystal-controlled receiver of solid state design which is tuned to receive the frequency or frequencies at which the system transmitter in one or more emergency vehicles is operating. A simple form of test oscillator 116 may be included for test purposes and the output energy may be coupled as by a winding 118 about the antenna input.
The F.M. receiver 114 may be a standard, modular form of receiver including discriminator circuitry for generating an output via lead 120 for audio amplification in amplifier 122 and output through loudspeaker 124. Either modulated C-W tone frequency or voice message may be reproduced through loadspeaker 124. It is also contemplated that the receiver output via lead 126 may be applied to energize a relay circuit 128, e.g. a semi-conductive controlled relay. The output from the energized relay circuit 128 will then energize a suitablee flasher 130 and dash-mounted warning indicator 132. The relay circuit 128 may be reset by a reset circuit 136, e.g. in the case of the semi-conductive controlled rectifier it may be merely a momentary open switch connected to open the rectifier cathode circuit upon actuation.
FIG. 5 illustrates one form of front panel 140 which may be utilized with the receiver 110. Supply voltage from the vehicle system may be applied via lead 142 through ignition 144, input cable 146 and an input jack 148. The front panel 140 includes a speaker grille 150 providing audible sound output and a volume control 152 may be utilized to set the audio output in accordance with each operators preference. A dial indicator light 154 denotes the ON-OF F condition of the receiver 110 and a Test-Reset switch 156 is used to effect the designated functions. Test-Reset switch 156 would preferably be a toggle-type switch of the spring return type wherein it is normally in its off or central position with momentary make at either side to effect the respective test or reset functions.
In operation, the driver of an emergency vehicle or an attendant at a road way warning station can select his mode of transmission to mode selector switch 60 (FIG. 2). In position 62 as shown, operation is in modulated C-W wherein tone generator 26 (FIG. 1) provides an output tone of a predetermined number of cycles through mode selector 24 for modulation in modulator 14 and FM transmitter 16. In the voice position 64 of mode selector switch 60, the emergency vehicle operator or station attendant can speak into microphone whereupon mode selector 24 and modulator 14 effect voice modulation of transmission energy from FM transmitter 16.
When it is desired to tape a recorded message, the selector switch 60 is placed on tape record position 68 whereupon mode selector 24 serves to receive voice input from microphone 20 and line or cable 22 (See FIG. 3) to apply such audio frequency energy through amplifier 88 and record head 92 for recording on endless record 72. The endless record 72 may be of any pre-set time length, e.g. 20 seconds message length per revolution of endless record 72. After recording of a desired message, mode selector switch 60 is switched to the tape transmit position 66 whereupon the selected message is i played back repeatedly for transmission without further attention from the emergency vehicle or road way station operator. Thus, in the tape transmit position 66 energization via lead 102 energizes head selector 100 to enable playback head 94 such that audio playback from endless record 72 is amplified through amplifier 98 for application through mode selector 24 to modulator 14. The modulator 14 then effects modulation of FM transmitter 16 so that energy conveying the repetitive recorded message is propagated from antenna 18.
Output from the discriminator stage of FM receiver 114 should preferably be such that relay circuit 128 will be energized in response to reception of either modulated C-W or a voice transmission so that flasher 130 and indicator light 132 will be energized whenever some form of emergency warning is received. Each individual operator is able to test his receiver by placing the Test-Reset switch momentarily in the test position (switch 156) whereupon test oscillator 116 of FIG. 4'is energized to couple output energy from the oscillator through coupling coil 118 into the RF stages of FM receiver 114 such that a characteristic output will indicate proper operational capability to the operator.
In addition to the primary or normally applied use of the emergency warning system, it is also contemplated that the system as described herein could be adapted in a highway information system such as that shown in FIG. 6. Thus, a plurality of transmit-receive stations a, 170k through 170n could be positioned at designated intervals along such as the specialized access of four lane highway 172. The individual transmitter-receiver stations 170a through n may each function to cover a certain information zone wherein all cars passing therethrough would be advised of roadway conditions,- weather reports, or other selected information. Alternatively, transmitted energy from transmiterreceivers 1700 through 170n could also be used to energize predetermined sign notices on visual notice boards stationed at selected intervals along highway 172.
Each of the transmitter-receivers 170a through 170n would include a transmitter system similar to that of FIGS. 1 and 3, i.e. including a record-playback unit, and the stations would also include an associated receiver which could efiect message recording and enabling of playback from a central remote station 176. The central station 176 may include a suitable form of microphone or voice input stage 178 operating through a modulator 180 to modulate carrier output from a central transmitter 182 and antenna 184. The antenna 184 may be omni-directional or highly directional as placed in line along the roadway but, in any event, it should radiate sufficient power to transmit to all transmitter-receiver stations 170a through l70n. A pulse code as selected at a pulse code input stage 186 provides further pulse input to modulator 180 for the purpose of providing an interrogation output from central transmitter 182 for the purpose of interrogating only selected ones of transmitter-receivers 170a through 170n to effect recording of their designated repetitive voice message. Thus, the system will have the capability of sending voice messages for recording on all or only selected ones of transmitter-receiver stations 170a through l70n.
Transmitter output power at the stations 1700 through 11 would probably be limited to a short, minimum range power output utilizing directional antenna as directed along highway 172. If a vehicle operator did not care to further listen to such bulletins or weather information, road warnings, traffic hazards, notices, general information to motorists and the like, he has the option of controlling his receiver through volume control; however, emergency vehicle attention can still be communicated by means of the dash warning light. For example, and referring again to FIG. 4, the warning light 132 could be energized to blink and to continue to blink until reset by the reset switch 136, i.e. to open the relay circuit 128 sufficiently long for quenching of the semiconductive controlled rectifier.
FIG. 7 indicates still another alternative form of receiver structure wherein existing circuitry of the standard operating receiver 190 may be utilized in the emergency vehicle warning system. Thus, emergency warning transmission received via antenna 192 may be amplified through a suitable frequency selector stage 194 for discrimination in discriminator stage 196. Discriminated output is then applied through an amplifier 198 for input to the audio amplifier stages 200 to give visual message or audible indication through the radio receiver loudspeaker 202. A visual indicator 204 may still be utilized as it can receive output direct from amplifier 198 in a manner as aforedescribed. The automobile receive 190, as well as the frequency selector 194 and discriminator 196, could be maintained in standby energization whenever the auto ignition key is on since transistorized structures used in the modern receiver art require little or no power for operation.
The foregoing describes an emergency vehicle Waming system of a type which is highly reliable and can be constructed at minimum cost to enable a simple and adaptable warning system of highly automatic function. The system utilizes low powered radio frequency energy transmission of relatively directive propagation although it is contemplated that certain systems may utilize a selectively energized second omni-directional antenna which could be utilized in special circumstances such as congested downtown areas. While the system is described primarily with respect to moving emergency vehicles, it should be understood that present usage in many major applications may include radio warning, information or control systems for use along a highway right-of-way. Such special adaptations, although in some cases requiring particular selection of transmission and reception equipment, can easily be carried out using the same general system design.
Changes may be made in the combination and arrangement of elements as heretofore set forth in the specification and shown in the drawings; it being understood that changes may be made in the embodiments disclosed without departing from the spirit and scope of the invention as defined in the following claims.
What is claimed is:
1. An electronic warning system for use in apprising one or more vehicle operators of information relating to or emanating from an emergency vehicle, comprising:
frequency modulated transmitter means including a directional antenna mounted on said emergency vehicle to propagate radio frequency energy essentially forward of said emergency vehicle; modulator means disposed in said emergency vehicle to modulate the transmitted output of said frequency modulated transmitter means;
mode selector means consisting of plural position switch means having first, second and third inputs and first and second outputs connected to select one of plural inputs of audio frequency signal for conduction via either a first output to said modulator means or a second output;
microphone means providing a first audio signal input to said mode selector means first input;
tone generator means generating a constant frequency second audio frequency signal for input to said second input of said mode selector means;
record-playback means connected to said mode selector means second output and being actuatable to receive voice input from said microphone means for recording on an endless record of preset length, said recorder-playback means being actuable to playback said recorded message to provide a third audio frequency signal output to said third input of the mode selector means; and
one or more receiver means disposed at one or more vehicle gositions to receive said frequency modulated ra to frequency energy to provide an output in the form of a visible and/or audible warning to said vehicle operator. 2. An electronic warning system as set forth in claim 1 which is further characterized to include:
time indicating means actuated to commence time count upon actuation of said record-playback means for recording. 3. An electronic warning system as set forth in claim 2 which is further characterized in that:
said time indicating means total count duration is synchronized with one revolution of said recordplayback means endless record. 4. An electronic warning system as set forth in claim 1 wherein said record-playback means comprises:
a loop of magnetic recording tape; tape transport means receiving said tape loop; drive means providing drive output to said tape transport means; transducing means affixed in operative position engaging said tape loop; and control means controlling said transducing means for record or playback of audio frequency signal. 5. An electronic warning system as set forth in claim 4 which is further characterized to include:
time indicating means actuated to commence time count upon actuation of said record-playback means for recording. 6. An electronic warning system as set forth in claim 1 wherein said receiver means each include:
test oscillator means actuatable to produce an alternating electrical signal output; and inductive means coupling said alternating electrical signal output to said respective receiver means. 7. An electronic warning system as set forth in claim 4 wherein said plural position switch means comprises:
switch means for selectively connecting said microphone means first audio signal to said modulator means, or said microphone means first audio signal to said record-playback means, or said tone generator means second audio signal to said modulator means, or said record-playback means third audio signal to said modulator means.