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Publication numberUS2364357 A
Publication typeGrant
Publication dateDec 5, 1944
Filing dateMar 29, 1944
Priority dateSep 8, 1941
Publication numberUS 2364357 A, US 2364357A, US-A-2364357, US2364357 A, US2364357A
InventorsHalstead William S
Original AssigneeHalstead William S
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Signaling system
US 2364357 A
Abstract  available in
Images(7)
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Claims  available in
Description  (OCR text may contain errors)

Dem 1944- A w. s. HALSTEAD 2,364,357

SIGNALING SYSTEM Original Filed Sept. 8, 1941 7 Sheets-Sheet l 7' Ml AIIL J W/LL/AMS. HALSTEAD INVENTOR BY MW AT ORN/EY Dec. 5, 1944. w. s. HALSTEAD SIGNALING SYSTEM Original Filed Spc. 8, 1941 7 Sheets-Sheet 2 fu tflw I L- W A IIIIIIIII W/LL/AM J. HHLSTEAD INVENTOR Dec. 5, 1944. w s HALsTEAD 2,364,357

SIGNALING SYSTEM Original Filed Sept. 8, 1941 7 Sheets-Sheet 4 PLUG 8 JACK CONNECT/ON PLUG 8 -/ACk CONNECT/0N 'INVENTOR Dec. 5, 1944. w. s. HALSTEAD 2,364,357

SIGNALING SYSTEM Original Filed Sept. 8, 1941 7 Sheets-Sheet 5 umN lNVENTbR L/AMSHALSTEAD Patented Dec. 5, 1944 UNITED STATES PATENT OFFICE Original application September 8, 1941, Serial No. 410,069. Divided and this application March 29, 1944, Serial No. 528,633

12 Claims.

This invention relates in general to signaling systems and is more particularly concerned with automatic means for transmission of aural signaling intelligence by carrier wave energy to cooperating receivers located within a predetermined signaling zone.

In my co-pending application, Serial No. 410,069, filed September 8, 1941, now Patent No. 2,347,477, dated April 25, 1944, of which this ap plication is a division, a signaling system was disclosed in which a repeating signal-record storage device in combination with a carrier wave transmitter'having means for establishing electric wave signaling along lanes of traffic was employed in automatically transmitting pre-recorded aural intelligence for reception within the signaling zone.

The system of this invention is an improvement on that disclosed in the earlier application and likewise employs a repeating signalrecord device of magnetic-tape or other suitable type operating in conjunction with a carrier wave transmitter having means for establishing electric wave signaling to traffic within an effective signaling zone associated with the transmitting system, and includes switching means for automatically initiating repetitive transmission of a pre-recorded communication carried by the signal-record medium.

It is an object of the present invention to provide automatic means for the transmission of voice s gnals, coded impulses, and facsimile or teleprinter signals to vehicles as well as to fixed stations within the signaling zone associated with the carrier wave transmitter after the transmitting system has been placed in operation by the operation of an initiating device;

such as a call box or electric relay connected with a control circuit, subsequent reproduction of the signals at the receiving points being in aural or visual record form.

It is an additional object of the present invention to provide automatic means whereby pre-recorded voice signals, coded impulses, facsimile or teleprinter signals identifying the location of the point of origin of the signals may be automatically transmitted in repetitive manher without mutual interference to vehicles or fixed stat ons within a predetermined signaling zone. the signals being reproduced at receiving points in aural and visual form through selective operation of existing loudspeakers, punch recorders facsimile printers or teletypewriters.

Another object of the invention is to provide a signaling system having automatic means at matically reproduced in aural and visual record form.

A further object is to provide a signaling system employing a plurality of signal transmitting stations each including a signal storage means having a record of facsimile or aural intelligence impressed thereon, and a central receiving station for automatically receiving the transmitted facsimile or voice signals from any of the transmitting stations in the system to provide a reproduction of the transmitted facsimile and voice intelligence without employment of a facsimile transmitter at the signal transmitting stations, said signal storage means serving as a source of the transmitted facsimile and aural signals.

Other and further objects reside in the constructional and circuit arrangements for effecting automatic operation of signal record apparatus, transmission equipment, and cooperating receiving and recording apparatus as set forth in the specification herein following and by reference to the accompanying drawings in which:

Figure 1 is a front elevational view of an electric light pole showing attached thereto signal storage apparatus, a carrier wave transmitter, and a signal initiating device employed in placing the apparatus in operative condition for automatic transmission of pre-recorded intelligence to remote receiving points.

Figure 2 is a front elevational view of the interior of a metal case shown on the electric light pole of Figure l, the case containing repeating signal record and carrier wave apparatus employed in the system of the invention.

Figure 3 is aplan view of a preferred form of signal recording andreproducing machine of magnetic-tape type which is enclosed in the lower section of the case shown in Figure 2.

Figure 4 is a side elevational view of a downwardly disposed loudspeaker which is employed at the transmitting location for the purpose of receiving an acknowledgment from a central station of the reception of the automatic signal transmission.

Figure 5 is a plan view of a plurality of intersecting streets with an illustrative disposition of automatic transmitting stations of the system of the invention at street corners.

Figure 6 is a schematic block diagram illustrating the combination of carrier wave and repeating signal record apparatus, together with control equipment employed in the system of the invention.

Figure '7 illustrates in block diagram a signa record device having an associated carrier wave transmitter and antenna.

Figure 8 illustrates the same signal record device with independent pick-up head connected to a second carrier wave transmitter and antenna.

Figure 9 is a schematic block diagram illustrating an arrangement of apparatus employed in recording coded control impulses or voice signals on the recording device employed in the system.

Figure 10 illustrates the combination of units employed in recording facsimile or teleprinter signals on the recording device shown in Figure 9.

Figure 11 is a circuit diagram of a present preferred form of recording, reproducing and carrier wave transmitting apparatus employed in the system.

Figure 12 is a schematic block diagram showing the arrangement of reproducing and recording apparatus at a central receiving station cooperatively associated with the signaling system.

Figure 13 is a block diagram showing the arrangement of parts employed in a modification of the receiving system illustrated in Figure 12.

Figure 14 is a schematic diagram illustrating circuit connections employed in receiving aural signals and in recording signaling intelligence in permanent visual form at the central receiving station.

Referring to the drawings in detail wherein like reference characters indicate corresponding parts throughout the several views, a carrier wave transmitter I0, Figure 2, is disposed in a weatherproof case I8, located on an electric power pole l9, Figure 1. A signal record device, such as a magnetic tape machine H, is also enclosed in the same case as shown.

Carrier wave energy from the transmitter It! may be applied to an antenna IE, or to any conductor, such as the electric power lines or other cables extending throughout the signaling zone with which the carrier wave transmitter is associated. The transmitting equipment is preferably battery operated, as subsequently described,

in order that operation of apparatus may be unaffected by failures of commercial power circuits. In the particular arrangement of apparatus shown herewith, the storage battery l6 and associated trickle charger I! are enclosed in a weatherproof steel case imbedded in the ground at the foot of the pole.

A signal initiating device such as call box 30, of any well-known type, is connected in the storage battery circuit in such a manner that when the contacts of the initiating device are closed, power will be applied to the transmitting equipment, and pre-recorded intelligence, such as words or coded signals identifying-the point of origin of the transmission, will be automatlcally and continuously transmitted by carrier wave means to fixed stations, such as police or fire stations located within the signaling zone, and simultaneously to all radio-equipped patrol cars within the zone.

Thus, if a short message such as This is alarm 25, First National Bank, Forty-Fifth Street and Madison Avenue, has been pre-recorded in permanent form on the signal record carrier, these words will be repeated continuously at all police stations within the zone and in all patrol cars within the vicinity. Acknowledgment of reception of the signals may be provided by means of receiver l2, which is tuned to a municipal fre quency, and loudspeaker [3.

In order to control the operation of existing alarm devices located at police or fire headquarters, coded impulse signals within a predetermined audio-frequency range may be recorded on the same steel tape that is employed to carry the recorded voice signals. Facsimile or teletypewriter signals, with associated control signals may be pre-recorded on the steel tape to eifect automatic production of a permanent written record of the transmission at the receiving point.

A present preferred form of construction of the magnetic tape signal record machine is shown in Figures 2 and 3, in which rollers 20 and 2|, fabricated of Bakelite or other suitable material, are horizontally disposed between bearings in frame 22, Figure -3. In the illustrative arrangement of the recording device, two steel tapes or wires 23 and 23A, which serve as signal record carriers, are helically wound around the two rollers to form separate sections, as shown. The first and last loops of tape 23 are joined together by cross-over rollers 24 and 25 thereby forming an endless loop. The first and last loops of tape 23A are joined in similar manner, by cross-over rollers 24A and 25A. The pick-up heads, 26 and 26A, are disposed midway on the cross-over loop of tapes 23 and 23A, and are supported in position by bracket 21. Electric motor 28, Figure 2, drives roller 2| by means of a bolt or chain 29, thereby moving tapes 23 and 23A.

As shown in the block diagram of Figure 6, the pick-up head 26, of the magnetic tape machine is connected to the input circuit of radio transmitter It. The obliterating coil of the pick-up head is connected to a recording amplifier, 60, of which the circuit details are shown in Figure 11. The recording head, 16, is connected to the output circuit of recording amplifier 60, as also shown in Figure 11, to be described hereinafter in detail. The output circuit of transmitter l2, may be connected to a conductor, 50, extending along a lane of traflic, as shown in the street plan of Figure 5, or to an antenna 33, Figure 1. The magnetic tape machine, recording amplifler 60, and transmitter l2, are operated by electric power supplied by a source of power 40, such as the storage battery shown in Figure 1. The apparatus is normally maintained in inoperative condition, no power being applied to the apparatus from the power source 40. A call box 30, of any conventional type, or other initiating device may be employed adjacent to the transmitting location in order to apply electric power from power source 40 to the associated equipment. Radio receiver I0, is also connected in parallel with the power circuit of the magnetic tape machine and radio transmitter in such manner that the receiver is energized by power source 40 when the initiating device 30 is placed in Operation. Loudspeaker, [3, connected to the output circuit of receiver H), is employed to reproduce the receiving signaling energy. In normal operation the receiver is tuned to' the municipal frequency, differing from that employed by transmitter, l2. It will thus be observed that after the transmitter l2, has been placed in operation through actuation of the control circuit to the call box, or other initiating device, pre-recorded signaling intelligence, such as a police or fire alarm, identifying the location of. the point of origin of the signal, may be received at a central station within the signaling zone associated with the transmitter on any police or fire vehicles proceeding within the signaling zone. At the same time, by means of receiver H), and loudspeaker I3, central authorities may acknowledge the signal and provide advice to the person tuming in the alarm.

It is pointed out that in the majority of small municipalities, power lines customarily extend parallel to lanes of traffic, as represented by conductors 50 and 52 of Figure 5. These conductors ordinarily run in proximity to the police or fire stations, such as 54. Application 'of carrier wave energy to one of the power line conductors. such 35, Figure 1, or to any other conductor, 50 and 52, Figure 5, will produce an effective electromagnetic field extending longitudinally along the conductor for a distance of several miles, or for the length of a desired signaling zone, and laterally for a short distance. In practice it has been determined that the lateral extent of the electromagnetic field surrounding a power line or other conductor disposed parallel to a trafiic lane is sufficient to be effective throughout the width 01 a highway or citystreet. If a suitable radio receiver is installed within vehicles, the electromagnetic field may be utilized effectively in conveying signaling intelligence to the occupants of vehicles proceeding along traffic lanes, such as 5| and 55. By the same transmission means, the carrier wave energy may be guided to a central receiving station, 54, where suitable receiving and recording apparatus may be located. In this manner, through utilization of existing roadside conductors, the signaling system of the invention may be employed without the use of antennas or space-radiated wave energy/ However, in muconducted at the location where the transmitting equipment is installedpor the audio-frequency control signals may be pre-recorded on a phonograph disc or other record-bearing medium at any desired point and subsequently transferred from this record to the steel tape employed in the transmitting equipment. A plug and jack connection 12, is provided in the input circuit of recording amplifier 60, as shown in detail in Figure 11. to facilitate connections at the transmitting point. A microphone 15, may also be connected by means of plug and jack [4, to the input circuit of the recording amplifier.

In similar manner, facsimile or teleprinter signals may berecorded on the steel tape employed at the transmitting point. One arrangement of apparatus to effect this purpose is illustrated schematically in the block diagram of Figure 10. A source of facsimile carrier signals 80, such as a facsimile scanner, not illustrated, may be connected to the input circuit of the recording amplifier 60, to effect recording of the facsimile signicipalities to which radio frequencies have been i assigned for communications purposes, the space radiation method employing an antenna 33, may be preferable, particularly in extensivemetropolitan areas.

In order that a printed record of a received signal may be provided at central station 54, control signals for operation of a punch register, facsimile recorder, or teletypewriter may be recorded on the same tape employed to carry the recorded voice signals. In order to control the operation of a punch register, 307, Figure 14, audio-frequency signals having a frequency below 200 cycles may be employed to provide selective actuation of the visual recording device at the receiving station without interfering with intelligent reception of voice signals transmitted on the same carrier wave frequency.

In the arrangement of apparatus for recording control signals on the steel tape, as illustrated in Figure 9, an audio-oscillator H, is employed as a source of low frequency f 200 cycle) signal energy. Any well-known keyin device I0. may be employed to apply the audio-frequency energy to the input circuit of recording amplifier in accordance with a desired keying sequence or coding arrangement. This recording operation may be nals on the steel tape 23. The audio-frequency facsimile carrier signal may be limited to a predetermined band-width by means of a band pass filter 8| connected between the signal source and the recording amplifier. The frequency of the facsimile carrier signal may, for example, be in the neighborhood of 7,000 cylces, with side-bands extending over a frequency range of 2,000 cycles.

If desired, the facsimile signals may be recorded on the same steel tape employed to carry a magnetic record of voice and coded pulse signals. By virtue of their frequency-separation, the three types of signals may be transmitted and received simultaneously, without appreciable mutual interference, provided that suitable audio-frequency filters, such as band pass filters 32L 326 and 328, Figure 13, are employed to sep-- arate the various signals at the receiving point. However, it may be desirable to record the facsimile signals on a separate tape, such as 23A, Figures 3 and 8, having individually associated therewith transmitter 12A operating on a frequency different from that employed by transmitter l2. In this case effective separation of the facsimile and voice signals will require the use of separate/receivers 30! and 3| I, Figure 12.

Referring to the circuit diagram of the recording and transmitting system, as shown in Figure 11, in which is shown a present preferredarrangement of parts, battery 40, is employed as a source of power. charged condiiton by means of a rectifier H, which is connected across the low voltage winding of transformer 310 having a primary circuit connected to a source of commercial power. A voltage reducing register 3!! is employed in series between the rectifier and storagebattery to provide the correct charging voltage. A call box 30. is connected in serie between storage battery 40, and the circuits of the transmitting equipment as shown. Vibrator 3H. is disposed in the primary circuit of transformer 232, the vibrator being placed in actuation by the operation of call box 30. A secondary winding, BIG, on

transformer 3l2. supplies alternating current energy of desired frequency to motor 28 of the magnetic tape machine and recording timer motor 237. Another secondary winding of tranformer 232, as shown, provides operating voltage for the heater of the rectifier 233. .An additional winding provides high voltage to the anodes of rectifier 333. The high voltage provided by the rectifier is filtered by means of chokes 234 and con- The battery is kept in a r densers 235. transmitting tubes are battery, as indicated.

The source of motive power, 28, continuously moves steel tape 23 through the pick-up heads and recording heads, consisting of pick-up coils 242, recording coils 24l, and obliterating coils 243. The magnetic variations in the steel tape cause corresponding fluctuations in voltage in pick-up coils 242 when the tape is moving past the pole piece associated with the coils, and these electrical variations are impressed upon an amplifying and modulating circuit, which will hereinafter be more completely described. By means of recording coils 24l, magnetic variations corresponding to speech variations are impressed upon the tape in the recording process. Coil 243 is employed to obliterate any magnetic variations from the tape when it is desired to change a message recorded thereon.

The switch members, 245 and 246, of relay 3!,

The heaters of all amplifying and directly energized by the are normally connected to impress the signal voltages generated in pick-up coil 242, upon the modulating circuit. In the recording position, the switch members 245 and 246 disconnect the transmitting circuits and apply signal energy from input jack 25! to the recording coils 24! after having passed through the associated amplifier circuits.

The transmitter employed in the system may preferably be of the crystal control type, as illustrated in Figure 11, and may consist of an oscillator tube 252, the frequency of which is controlled in conventional manner by crystal 253. The required grid-biasing potential is secured by means of resistor 254, and its associated by-pass condensers 255. The output of the oscillator is coupled from the anode thereof, by means of condenser 256, and resistor 258, to the grid of a power amplifier 251, which, as illustrated, is a beam power tube. The power amplifier may be of the well-known Class C type, and the modulation of the carrier wave is effected within this amplifier.

During the transmission of a signal pre-recorded upon the steel tape the fluctuating voltage developed within pick-up coil 242 is transferred to the grid of a conventional amplifier 261, which is illustrated herein as a pentode. The anode circuit of this pentode is connected to the source of direct current through the load resistor 262.

The amplified signal is then coupled by means of condenser 263, and volume control 264, to a control grid 265, of another amplifying tube 260, which is illustrated herein as a duplex triode. Another control grid 261, of this tube is joined through volume control 21! to recording jack 25!, in which a microphone or other source of signal energy may be connected. As indicated, both anodes of the duplex type are joined together and thus the signal appearing across load resistor 212, will depend upon the signals impressed upon both grids. Switching members 245 and 246 insure that when signals are impressed upon one gridthe other is at ground potential or otherwise inoperative.

The anodes of the amplifying tube 266 are joined to the direct current source through load resistor 212, and, as indicated, through a decoupling filter 213. The amplified signal is coupled by means of condenser 214, and resistor 215 to the control grid of an amplifier 216, which provides in the output thereof a signal of sufficient amplitude to modulate the carrier current originating at the oscillator.

The anode circuit of amplifier 216 is electrically joined to the source of direct current through transformer 211, the secondary coil of which is divided and contains a plurality of taps for reasons which will be more fully described. One end of section 218 of the secondary coil of transformer 211, connects with a grid of the Class C power amplifier 251 through resistor 28L and is in addition joined to the anode of tube 251 through a radio-frequency choke coil 282, and through the inductance 283, of the transmitting tank circuit. The other end of this section of the secondary coil is joined to one contact of the switching member 246. The radiofrequency choke 282, serves as filtering means to aid in P enting feed-back of radio frequency energy in the power and amplifier circuits.

The second section 285, of the secondary coil is joined to one pole of the switching member 245, and in addition to the source of high voltage through resistor 286. The opposite end of section 285 of the secondary and the center tap thereof are in addition joined to poles of switching member 246.

Also joined to contacts of switching member 245, are both grids of amplifier tube 266, and the direct current source. The direct current source is connected to a pole of switch 245 as shown. The recording coils 24!, are joined through an equalizing network 29l, to a contact of switching member 246.

When switching member 245, is moved to the left, as viewed in Figure 11, and the switching member 246, is moved to the right, the system will be in transmitting position, the voltage generated in the pick-up coil 242, will be amplified by amplifier 26l, and impressed upon the grid 265, of amplifier 266, while grid 261 of this tube will be grounded through a contact of switching member 245. Accordingly, the signal recorded upon the tape will be amplified by tube 266, and again by the beam power tube 216, and will be impressed on the secondary of the modulating transformer, 211.

Switching member 246, when in the position mentioned, inter-connects both sections of the secondary coil of modulating transformer 211, and switching member 245, connects one end of the secondary to the source of direct current. The transformer 211, will function when the switching members are thus oriented to modulate the carrier current supply by oscillator 252.

The anode circuit of the Class C amplifier 251, contains the tank inductance 283, and variable tuning condenser 292, and through condenser 293 the modulated carrier is coupled to the conductor associated with the antenna 33, Figure 1, or cable 50, Figure 5.

When it is desired to record on steel tape 23, switching member 245 is displaced to the right and switching member 246 to the left, as viewed in Figure 11. This orientation of the switching members grounds grid 265, of the duplex type 266, and thus voltage fluctuations in pick-up coil 242 are not amplified nor passed on to succeeding amplifying stations. On the other hand, grid 261 is no longer grounded and thus electrical variations entering through jack 25I will be imp essed upo grid 261 and amplified by duplex tube 266. In the movement of switching memher 245 from the left to the right as described. the resistor 286, is inserted in series between the anodes of tubes 251 and 252 and the source of 25l, are amplified by tubes 266 and 216, and are impressed upon the recording coils 24 l It is obvious that the type 23, must pass through the obliterating coils 243, prior to its passage through the recording coil, in order that the message previously recorded thereon may be obliterated.

The message to be recorded upon the tape 23, must be of a predetermined length to correspond approximately with the time required for the tape to complete one cycle of rotation. A small timing motor, 231, is employed to initiate the recording cycle when desired, and terminate the same automatically at the end of the recording period. As illustrated, the timing motor 231, is started by momentarily depressing push-button 305. This will start the movement of the cam 400, which is fastened to the driftshaft of the timing motor. Movement of the cam will close the circuit of switching member 300, which serves to apply energizing voltage to relay coil 30!, placing switching members 245 and 246 in the recording position. The circuit of switching member 306 is also closed by operation of the cam, which shunts push-button switch 305, thereby closing the motor circuit and permitting the operator to release push-button 305. Upon the completion of the pro-determined recording cycle, the motor 231 is automatically halted inasmuch as switch 306 by means of the cam arrangment, is opened at the termination at each revolution of the cam. Likewise, the circuit through electro-magnetic relay 30l, is automatically opened by means of switching member 300. The switching members 245 and 246 then assume the normal position required for thetransmission of the signals recorded upon the tape.

The output circuit of the transmitter described hereinabove is such that it may be connected to an antenna or to a conductor of any length. A series circuit in which condenser 293, and inductance 3|3, are employed, provides a coupling means between tank coil 263 and an antenna or other conductor, to which a connection is made at any desired point through single conductor 3l5. It should now be apparent that the recording of audio-frequency signals on the tape will provide a means by which subsequent transmission of the signals may be effected at any time upon operating call box 30, Figure 11. The transmitting system will remain in operation for a given period, or as long as the power is applied to the transmitting units.

Referring to Figure 12, in which a receiving system for utilizing the signals is described, antenna 302 will provide a means for intercepting the transmitting signals on the frequency to which the receiver, 30I, is tuned. Low-pass filter 303, connected to the output circuit of receiver 30l, discriminates in favor of that portion of the received audio-frequency signal lying below 200 cycles. Thus low frequency control signals, such as pulses for actuation of punch register 301, or gong 306, pass through filter 303 and signal rectifier 304, with sufficient energy to actuate relay 305, thereupon energizing the aural alarm, such as gong 306, and the visual recording device, such as punch register 301. a A

Received audio-frequencies above 200 cycles consisting, forexample, of voice signals, are accepted by the high-pass filter 300, also connected to the output circuit 30l, and energize loudspeaker 309. It is pointed out that the voice signals which lie primarily in the audio-frequency range between 300 and 2,000 cycles, are effectively accepted by the high-pass filter, whereas the low frequency control signals, such as those having frequencies less than 200 cycles, are substantially attenuated by the high-pass filter. The resultant voice signals as reproduced by the loudspeaker contain little or no aural interference from the coded signals. Likewise, the gong and punch register circuits are free from interference from voice signal energy, which is substantially attenuated by low-pass filter, 303.

In the arrangement of Figure 12, a second receiver, 31 I, is employed to selectively actuate a facsimile recorder or teletypewriter. The output circuit of receiver 3 is connected to a rectifier, 3(2, as illustrated in detail in Figure 14. The rectifier applies a rectified motor control voltage to the motor relay 313 when a synchronizing pulse of low frequency is received. Closure of motor relay 3l3, automatically starts motor 3l5, which operates the facsimile printer or teletype machine 3I4. It is pointed out that motor 3l5 is normally inoperative and the recording mechanism associated with facsimile printer 3 l 4 is normally idle. Upon reception of the low frequency synchronizing control signal, which is also recorded upon the steel tape employed in the automatic transmitting device, motor relay 355 applies power to the motor and starts the recording process as will be explained hereinafter. In the arrangement of units shown in Figure 13 the same general function employed in Figure 12 is provided to cause reproduction of voice signals and in the operation of an aural alarm, punch register, or facsimile printer. In this case, how.-

ever, a band-pass filter 32l, is utilized to select low frequency control signals lying below 200 cycles and pass them on through the signal rectifier to relay 323, which serves to actuate the gong 324, and punch register 325. A second bandpass filter, 326, is also connected to the output circuit of the same receiver 320, the filter serving to pass audio-frequencies lying within the range of 300 to 2,000 cycles, for subsequent reproduction by loudspeaker 321. A third band-pass filter, 320, also connected to the output circuit of receiver 320, is employed toiipass audio-frequencies lying in the range from 6,000 to 8,000 cycles, which signals are subsequently amplified by signal amplifier 329, and thereupon applied to facsimile signal rectifier 330, which, as described above, serves to control the operation of motor 333 and facsimile printer 332.

In this manner, by use of a plurality of bandpass filters, three separate signals may be electrically separated in such manner that they do not cause mutual interference at the receiving point.

' Referring to the circuit details of illustrative receiving equipment as shown in Figure 14, transformer 350 having its primary winding connected to the output circuit receiver 301, is connected in such manner that signal energy in its secondary winding is applied to low-pass filter section 303, and high-pass filter section 308. Low-frequency signals passed by filter 303 are applied to rectifier 304, the direct current output of which is applied to relay 305. Closure of relay 305 serves to operate gong 303 and punch register 301. Signal energy passed by the high-pass filter section 308 is applied to the low filter circuit 309, as indicated.

Transformer 35l connected in the output circuit of receiver 3| I, is connected in such manner that the signal voltage in the secondary winding is applied to the anodes of a full wave rectifier, 3l2. The center tap of the transformersecondary is grounded, as shown. Switching member 353,, associated with an illustrative facsimile recording machine such as the Finch autosynchronous type, shown herewith, is normally held in the position shown in the illustration. As will be observed from reference to the diagram, a frequencydiscriminating condenser 352, is normally shunted across one half the secondary winding of transformer 35l, when the switching member 353 is in the illustrated position. A low-frequency control signal such as a synchronizing pulse will be effectively rectified by rectifier tube 3l2, and the resultant direct-current voltage will be applied to solenoid 354. Simultaneously, the rectified voltage is applied to the coil of motor relay 355, of latch type, thereupon starting the motor. Clutch arm 356 will be actuated by solenoid 354, allowing cam 35! to turn,

thereby causing the contact cam 358, and driving cam 359, to rotate as all cams are on a common drift shaft. Rotation of cam 358 will cause switching member 253 to move, thereby applying rectified facsimile marking signal energy to the recording stylus 360. Subsequent operation of the facsimile recorder follows wellknown procedure, the facsimile recording stylus producing a reproduction of printed intelligence originally scanned and translated into electrical equivalents which subsequently were recorded on the steel tape at the transmitting location. In this manner, by entirely automatic means, the facsimile machine may be placed in operation by an incoming signal of predetermined control frequency, and a printed record such as alarm 25, 1st National Bank, 45th Street and Madison Avenue will be repeatedly produced in the facsimile machine as long as the remote transmitting unit remains in operation, or until an operator at the receiving station releases the latch relay 355, thus taking the facsimile recording machine out of service.

While in the foregoing description a specific application of the system has been outlined, it is understood that the same automatic signaling system may be employed in a number of fields, particularly in connection with communications services in which it is required that intelligence be transmitted to moving vehicles proceeding through established signaling zones.

It will be recognized that'the illustrated sys tems described herein are capable of considerable modification and rearrangement without departing from the spirit and scope of the invention, and it is therefore to be understood that the following claims embrace all such modifications .and equivalent arrangements as may fairly be construed to fall Within the scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a receiving system for simultaneously receiving a multiplicity of control signals, a normally-on carrier wave receiver, filter means connected to an output circuit of said receiver, a

Signal rectifier connected to an output circuit of said filter, relay means connected to an output circuit of said signal rectifier, said relay being responsive to rectified control signals of predetermined frequency as passed by said filter, visual signal indicating means upon energization of said relay, a second filter means connected to an output circuit of said receiver, and aural signal reproducing means connected with an output circuit of said last-mentioned filter, said signal reproducing means being responsive to audio frequency signal energy within a predetermined frequency band as passed by said last-mentioned filter.

2. In a receiving system for simultaneously receiving a multiplicity of control signals, a normally-on carrier wave receiver, filter means connected to an output circuit of said receiver, a signal rectifier connected to an output circuit of said filter, relay means connected to an output circuit of said signal rectifier, said relay being responsive to rectified control signals of predetermined frequency as passed by said filter, visual signal indicating means operably connected with said relay to effect energization of said visual signal indicating means upon energization of said relay, a second filter means connected to an output circuit of said receiver, aural signal reproducing means connected with an output circuit of said last-mentioned filter, said signal reproducing means being responsive to audio frequency signal energy within a predetermined frequency band as passed by said last-mentioned filter, a third filter means connected to an output circuit of said receiver, an amplifier means connected to an output circuit of said third filter, a facsimile signal rectifier connected to an output circuit of said amplifier, and facsimile recording means connected to an output circuit of said facsimile signal rectifier.

3. In a, receiving system for simultaneously receiving a multiplicity of control signals, a normally-on carrier-wave receiver, filter means connected to an output circuit of said receiver, a signal rectifier connected to an output circuit of said filter, relay means connected to an output circuit of said signal rectifier, said relay being responsive to rectified control signals of predetermined frequency as passed by said filter, visual signal indicating means operably connected with said relay to effect energization of said visual signal indicating means upon energization of said relay, a second filter means connected to an output circuit of said receiver, aural signal reproducing means connected with an output circuit of said last-mentioned filter, said signal reproducing means being responsive to audio frequency signal energy within a predetermined frequency band as passed by said last-mentioned filter, a third filter means connected to an output circuit of said receiver, an amplifier means connected to an output circuit of said third filter, a facsimile signal rectifier connected to an output circuit of said amplifier, facsimile recording means connected to an output circuit of said facsimile signal rectifier, said facsimile recording means including a motor for driving said facsimile printer. and a relay connected to an output circuit of said facsimile signal rectifier for placing said motor in operative condition when said relay is energized by signal energy from said facsimile signal rectifier,

4. In a receiving system for receiving facsimile signals, a carrier wave receiver, an amplifier circuitously connected to an output circuit of said receiver, a facsimile signal rectifier connected to an output circuit of said amplifier, a facsimile recorder connected to an output circuit of said facsimile signal rectifier, a relay also connected to an output circuit of said facsimile signal rectifier, a normally-off motor connected with said relay, said motor being connected with said facsimile recorder for driving same upon energization of said motor by operation of said relay.

5. In a receiving system for receiving graphic and aural intelligence, a carrier wave receiver, a filter connected to an output circuit of said receiver, said filter passing graphic signal intelligence within a predetermined frequency range, a signal rectifier circuitously connected to an output circuit of said filter, a graphic signal recorder and a relay connected to an output circult of said signal rectifier, a normally-off motor electrically connected with said relay, said motor being connected with said graphic recorder for driving same upon operation of said relay, a second filter means connected to an output circuit of said receiver and an aural signal reproducing device connected to an output circuit of said second filter for reproducing aural intelligence passed by said second filter.

6. In a receiving system, a plurality of carrier wave receiving means each responsive to carrier wave energy within a predetermined frequency band, each of said carrier wave receiving means having an output circuit individual thereto, a facsimile signal rectifier connected to the output circuit of one of said carrier wave receiving means, a normally-off facsimile recorder means connected to an output circuit of said facsimile signal rectifier, 'and aural signal reproducing means connected to an output circuit of the other of said carrier wave receiving means for reproducing aural intelligence, said facsimile recorder means and said aural signal reproducing means being individually responsive to signal energy passed by the respective carrier .wave receiving means.

'7. In a carrier wave receiving system for receiving an audible alarm including carrier wave receiving means, a relay circuitously connected to an output circuit of said carrier wave receiver means, an aural alarm signal circuitously connected to said relay and responsive to operation thereof, and a second alarm signal circuitously connected to said relay, both of said alarm signals operating simultaneously in response to said relay operation, one of said alarm signals being a recorded signal for verification of said aural alarm signal.

8. In a facsimile receiving system, a carrier wave receiver, a signal rectifier connected to the output circuit of said receiver, an electro-mechanical clutch having a winding thereof connected to the output circuit of said signal rectifier and responsive to signal energy within a predetermined frequency band, a lock-in relay also electrically connected to the output circuit of said signal rectifier and responsive to signal energy within said frequency band, a motor electrically connected with said lock-in relay, said motor being connected with a facsimile recorder, said motor being placed in operative condition only after energization of said lock-in relay by received signal energy within said predetermined frequency band.

9. A system as set forth in claim 8 wherein said receiving means includes a filter connected to an output circuit of said receiver, and an aural signal reproducing means for reproducing aural intelligence substantially concurrently with operation of said facsimile recorder, without interference from said facsimile signals.

10. A system as set forth in claim 8 wherein said receiving means includes a second relay circuitously connected to an output circuit of said receiver, said second relay being connected with an aural alarm device for initiating operation of said alarm device by said signal energy substantially concurrently with initiation of operation of said facsimile recorder, said facsimile recorder producing a recorded verification of reception of said signal energy.

11. In a receiving system, a carrier wave receiver, relay means circuitously connected with an output circuit of said receiver, said relay being responsive to signal energy within a predetermined frequency range, an aural alarm device electrically connected with said relay, said aural alarm device being rendered operative upon energization of said relay, a second relay means circuitously connected with an output circuit of said receiver and responsive to signal energy received thereby, and normally-off graphic recording means circuitously connected to an output circuit of said receiver and said relay, said graphic recording means being placed in operation by energization of said second relay.

12. In a receiving system, a carrier wave receiver, a filter connected to the output of said receiver, said filter having circuit means for passing signal energy within a predetermined frequency range, a signal rectifier connected to the output circuit of said filter, a relay connected to the output circuit of said signal rectifier and responsive to rectified signal energy within said predetermined frequency range, graphic recording means connected to said relay and controllable thereby, said graphic recorder being placed in operation only when said relay is energized by said rectified signal energy, a second filter connected to an output circuit of said carrier wave receiver, said second filter having circuit means for passing signal energywithin a second predetermined frequency range, and aural signal reproducing means connected with an output circuit of said second filter for reproducing aural signal intelligence.

WILLIAM S. HALSTEAD.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2531497 *Apr 14, 1947Nov 28, 1950Motoview IncTelevision view finder
US2628274 *Feb 20, 1946Feb 10, 1953Homrighous John HMultiplex television system
US2664461 *May 10, 1950Dec 29, 1953Zenith Radio CorpSubscriber receiver enunciator
US2707207 *Apr 27, 1949Apr 26, 1955De Baun James RTelevision system
US7554439Oct 11, 2006Jun 30, 2009Lookout Portable SecurityRemote monitor system with radio dispatch
US7936263Jun 25, 2009May 3, 2011Lookout Portable SecurityRemote monitor system with radio dispatch
US8144009Apr 13, 2011Mar 27, 2012Lookout Portable SecurityRemote monitor system with radio dispatch
Classifications
U.S. Classification358/425, 381/77, 358/469
International ClassificationH04M11/04
Cooperative ClassificationH04M11/045
European ClassificationH04M11/04B