U.S. patent number 3,701,024 [Application Number 05/102,844] was granted by the patent office on 1972-10-24 for local and national warning alarm system.
Invention is credited to Billie Joe Ball, Donald F. Fitzgerald, James H. Knowles.
United States Patent |
3,701,024 |
Knowles , et al. |
October 24, 1972 |
LOCAL AND NATIONAL WARNING ALARM SYSTEM
Abstract
An alarm and information communication system utilizing existing
radio broadcast facilities to transmit a warning alarm signal and
emergency information to the population in the event of a local or
national emergency; the system consists of a warning alarm signal
generator as an available program source at the broadcast stations
and warning alarm signal and emergency information receivers are
provided for use by the general public. The system provides for
designation of some radio broadcast stations as "local stations"
and some as "regional stations" by Civil Defense or other
appropriate authority; each alarm signal and information receiver
is adapted to continuously monitor one local and one regional
broadcast station whereby, upon reception of a signal of a
specified frequency from the local station or reception of a signal
from the regional station, the receiver will emit an alarm signal
and then broadcast the pertinent information.
Inventors: |
Knowles; James H. (Jackson,
MS), Ball; Billie Joe (State College, MS), Fitzgerald;
Donald F. (State College, MS) |
Family
ID: |
22291967 |
Appl.
No.: |
05/102,844 |
Filed: |
December 30, 1970 |
Current U.S.
Class: |
455/526; 455/140;
455/227; 455/228; 455/229 |
Current CPC
Class: |
H04H
20/59 (20130101); H04H 20/28 (20130101); G08B
27/008 (20130101) |
Current International
Class: |
H04H
1/00 (20060101); G08B 27/00 (20060101); H04b
001/16 () |
Field of
Search: |
;325/364,466,51,302,303
;340/164,181,224 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Murray; Richard
Assistant Examiner: Weinstein; Kenneth W.
Claims
What is claimed is:
1. A local and national alarm and information communication system
comprising:
alarm signal generating means for supplying an alarm signal of a
predetermined frequency to be broadcast by designated local and
regional radio stations,
receiving units for use by individuals in the system, each of said
units including a first receiving means for receiving said alarm
signal and audio signals broadcast by said designated local radio
station and a second receiving means for receiving said alarm
signal and audio signals broadcast by said designated regional
radio station, first switching means connected to said first and
second receiving means, said first switching means including a
signal gate, means for supplying a reference voltage from said
first receiving means to said signal gate,
second switching means movable between a first and second position
in response to reception of said alarm signal by a said receiving
unit, said second switching means being connected to said signal
gate and said signal gate being shiftable between a first position
wherein signals are passed only from said first position wherein
signals are passed only from said first receiving means to said
second switching means when said local radio station is
broadcasting and a second position in response to the absence of a
broadcast signal from said local radio station wherein signals are
passed only from said second receiving means to said second
switching means,
audio broadcasting means connected to said second switching means
and operating to broadcast said alarm signal and information when
said second switching means is in said second position.
2. The system as claimed in claim 1 wherein said second switching
means is a signal gate and said alarm signal passed through said
first switching means is fed through a narrow band pass filter to
an amplifier and to a demodulator connected to the output of said
amplifier, said demodulator being connected to a pulse counter
providing a voltage output for shifting said signal gate from said
first position to said second position upon sensing of a
predetermined number of pulses by said counter.
3. The system as claimed in claim 2 wherein the output of said
counter actuates a visual alarm.
4. The system as claimed in claim 1 wherein said audio broadcasting
means comprises an audio amplifier and speaker connected to said
amplifier.
5. The system as claimed in claim 2 wherein a manual switch is
provided between said second switching means and said audio
broadcasting means, said manual switch being shiftable between one
position wherein said second switching means is connected to said
audio broadcasting means and another position wherein said audio
broadcasting means is connected through a potentiometer to said
first switching means.
6. The system as claimed in claim 5 wherein said manual switch is
mechanically linked with a second switch in a circuit for providing
a resetting voltage to said second switching means so that when
said manual switch is moved to said other position said second
switch will close said circuit and said second switching means will
be reset.
7. A receiving unit for use by persons in a local and national
alarm warning system comprising:
first receiving means for receiving an alarm signal of a specified
frequency and audio signals broadcast by a first radio
transmitter,
second receiving means for receiving said alarm signal and audio
signals broadcast by a second radio transmitter,
first switching means including a signal gate and means for
supplying a reference voltage from said first receiving means to
said signal gate, said signal gate being connected to said first
and second receiving means,
second switching means including a signal gate movable between a
first, circuit breaking position and a second, circuit closing
position, a narrow band pass filter connected to said first
switching means, an amplifier and demodulator connected in series
to said filter, a pulse counter connected to said demodulator for
providing a voltage output for moving said signal gate of said
second switching means from said first position to said second
position upon sensing of a predetermined number of pulses by said
counter,
said second switching means being connected to said first switching
means and said first switching means being shiftable between a
first position wherein signals are passed only from said first
receiving means to said second switching means when said first
radio transmitter is operating and a second position in response to
the absence of a broadcast signal from said first radio transmitter
wherein signals are passed only from said second receiving means to
said second switching means, and
audio broadcasting means connected to said second switching means
and operating to broadcast said alarm signal and information when
said second switching means is in said second position.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a system for providing a warning
alarm signal and emergency information to members of the public in
the event of a local or national emergency and also relates to a
receiver which automatically receives the alarm signal and
emergency information. More particularly, the present invention
consists in part of an alarm signal generator which is connected to
the control console of a designated existing AM radio broadcast
station. In the event of a local or national emergency, the
generator is used to generate an alarm signal which is broadcast by
the radio station to be followed by a broadcast of emergency
information. As part of the system, the invention includes a
warning alarm signal and emergency information receiver for use by
members of the public. The receiver is adapted to continuously
monitor a particular signal frequency from a local station as well
as a particular frequency from a regional station. Upon reception
by the receiver of a signal of the specified frequency, the
receiver will respond and sound an alarm and then automatically
function as a conventional radio receiver to transmit emergency
information to individuals within audio range of the receiver.
Prior to the present invention, no practical warning system has
been proposed that is capable of alerting individuals of either a
local or national emergency and at the same time disseminating
useful information in the form of precautionary instructions to
enable individuals to cope with the emergency. Moreover, there has
long been a need for a system that is capable of awakening persons
who are asleep to warn them of an impending danger. Such a system
is of particular importance in localities where tornadoes or
hurricanes occur. Additionally, since many of the present day
building structures are designed to specifically keep out external
noise, thus rendering the use of the common Civil Defense sirens
substantially ineffective, the need for an interior alarm system
has become increasingly important.
The warning systems suggested by the prior art have, in general,
required the installation of costly equipment into the
communication facilities normally found in an individual's
residence. Such systems have also required the installation of
expensive transmitting equipment to provide a suitable source for
an alarm signal.
The system of the present invention overcomes all the foregoing
disadvantages, on the one hand, by making use of presently existing
radio broadcast facilities and, on the other hand, by providing an
inexpensive yet reliable receiving unit which is effective to alert
individuals at any hour whether they are asleep or not and to
apprise them of an emergency which is either local or national in
character.
SUMMARY OF THE INVENTION
The system of the present invention includes an alarm signal
generator which is installed at designated local and regional radio
stations. Such stations would be designated by the Civil Defense
authorities or other appropriate authority and would be selected
such that the entire nation would be divided up into a plurality of
regions and each region would be divided into a plurality of
localities having a local radio station capable of broadcasting to
all the inhabitants of the locality. A regional radio station would
be one that has a higher broadcast power output such that it would
be able to broadcast to all of the inhabitants within a specified
number of contiguous localities as well as having a reasonably
clear channel frequency.
The system of the present invention also includes alarm signal and
emergency information receivers for location in homes, offices,
factories, businesses, schools and the like which is tuned for the
reception of a signal from a local station and from a regional
station. The receivers are designed so that when the local radio
station is in operation and transmitting, the receiver will not
respond to the regional station. If a station selected as a local
station is not transmitting, then the receiver will automatically
receive and respond to the alarm signal and information transmitted
from a regional station.
It is contemplated that in the event of a local emergency, the
proper local authority would notify the local radio station of such
an emergency and provide the station with emergency information for
broadcast. The station operator would turn the alarm signal
generator on as a program source to transmit the alarm signal to
the receiver units within its broadcast range. Reception of the
alarm signal by the receiver units would initiate the emitting of
an alarm as an audio output from the receiver unit and,
subsequently, upon termination of the transmission of the alarm
signal, the receiver unit would broadcast emergency information.
The station operator would allow the alarm signal generator to
operate for a sufficiently long period of time so as to effectively
attract the attention of persons within an audio range of a
receiver unit.
In the event of a national emergency such as an enemy attack,
emergency information can be transmitted to the individual, local
and regional radio transmitting stations by existing Civil Defense
networks. The station operators, both local and regional, would
then actuate their respective alarm signal generators for
designated periods of time as a program source and then broadcast
the pertinent information as it is received from the Civil Defense
network. If the local station is not in operation at the time of
the emergency, the alarm signal and information would be received
automatically from the regional station by the individual
receivers.
It is an object of the present invention to provide a system using
existing radio broadcast facilities to transmit a warning alarm
signal and emergency information to the population in the event of
a local or national emergency.
Another object of the present invention is to provide an
inexpensive and uncomplex alarm signal generator at designated
broadcast stations and inexpensive and reliable warning alarm
signal and emergency information receivers for distribution to
members of the public.
A further object of this invention is to provide a system wherein
an audible alarm would be sounded by the receiver units capable of
arousing a sleeping individual.
A still further object of this invention resides in the provision
in a system of receiver units capable of continuously monitoring
both local and regional broadcast stations, the operation of which
is controlled by reception of an alarm signal from one of said
stations.
Another object of the present invention resides in the provision of
a system having a receiver unit capable of broadcasting emergency
information automatically.
Still another object of the present invention is to provide an
alarm signal generator for use in existing radio stations which can
be inexpensively installed and maintained in operation and which
will not interfere with normal broadcasting operations.
Another object of this invention is to provide a warning alarm
signal and emergency information receiver that will remain in a
quiescent state until a warning alarm signal is transmitted and
received, in which case the receiver will respond and sound an
alarm and serve automatically as a radio to receive and relay
emergency information.
Another object of this invention is to provide a system in which
the alarm signal generator produces the same type of alarm signal
thus rendering the receiver unit usable in any locality of the
nation.
BRIEF DESCRIPTION OF THE DRAWINGS
Further additional objects and advantages will become apparent as
consideration is given to the following detailed description of the
preferred embodiment of the invention as is illustrated in the
accompanying drawings forming part of this specification and
wherein:
FIG. 1 is a diagrammatic illustration showing a simplified version
of the distribution and relationship between local and regional
broadcast stations and alarm receivers comprising the system of the
present invention;
FIG. 2 is a schematic illustration of the warning alarm signal
generator to be used to produce the alarm signal at a radio
broadcast station; and
FIG. 3 is a schematic diagram of the warning alarm signal and
emergency information unit.
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 1 of the drawings, there is graphically
illustrated a simplified example of a regional broadcast area 10
which is made up of three localized broadcast areas 12, 14 and 16.
These areas are chosen so that each will have a local broadcast
station 18, 20 and 22, respectively, each having a radio broadcast
power output capable of reaching all of the inhabitants within its
boundary. The regional broadcast radio station 24 must, of course,
have a broadcast power output capable of reaching all of the
inhabitants within the region made up of areas 12, 14 and 16. In
the diagram illustrated, the regional broadcast station is
indicated as operating on carrier frequency f.sub.0 and the three
local broadcast stations are indicated as operating on carrier
frequencies f.sub.1, f.sub.2 and f.sub.3 respectively. It will be
noted that each warning alarm signal and emergency information
receiver, one of which is indicated at 26, is capable of receiving
signals from one regional as well as from one local station. It is
within the contemplation of the present invention that the
broadcast distribution network illustrated in FIG. 1 will be
repeated throughout the nation so as to include all inhabited
areas.
With reference now to FIG. 2 there is illustrated in schematic form
an arrangement for generating an alarm signal consisting of a sine
wave oscillator 28, a square wave oscillator 30 and a modulator 32.
The sine wave oscillator 28 preferably operates at a frequency
f.sub.4 to be selected in the range of 500-2,000 Hz and the square
wave oscillator operates at a frequency f.sub.5 chosen within the
range of 2-20 Hz. The sinusoidal signal from oscillator 28 is
passed through line 34 to modulator 32. The square wave signal from
oscillator 30 is passed through line 36 to modulator 32. The
sinusoidal signal is modulated by the square wave signal to produce
a modulated signal that is passed through line 38 to the broadcast
facilities of the radio station. Direct current power to operate
the alarm signal generator would be derived from the standard 60
Hertz station power system using a conventional rectifier and
filter contained within the generator. Provision would be made to
prevent the alarm signal generator from being turned on
accidentally so as to preclude the inadvertent broadcast of the
alarm signal.
Referring now to FIG. 3 of the drawings there is illustrated in
schematic form a warning alarm signal and emergency information
unit for use in the system of the present invention. Generally, the
unit comprises two radio signal receivers of conventional design
which operate in the standard radio broadcast band (540 to 1,600
KHz) and switching means such as gating devices which are actuated
in response to an electrical potential to activate a loudspeaker
when the warning alarm signal is broadcast from the appropriate
radio station. More particularly, there is provided a local
receiver 40 which is tuned to a previously designated local
broadcast station and a regional receiver 42 which is tuned to
receive broadcasts from a previously designated regional radio
station normally operating on a 24 hour basis. Both receivers 40
and 42 would be pretuned by a local distributor or any competent
service technician to the proper stations. Tuning controls would
not be provided in order to prevent unintentional detuning of the
receivers. Direct current power to operate the warning alarm signal
and emergency information receiver unit would be derived from the
commercial 60 Hertz power system using a conventional rectifier and
filter contained within the unit, or a suitable battery source for
use when commercial power is not available.
The circuitry of the unit is arranged so that when the unit is
connected to a power source (not shown) both receivers 40 and 42
are on and functioning to monitor their respective predetermined
frequencies. In the event that the local receiver 40 is receiving
signals generated by a previously selected local radio station, a
reference voltage such as the automatic gain control voltage (the
direct voltage obtained from rectification and filtering of the
amplified station signal) from the receiver will be established
across line 44 to operate a signal gate 46 so that the output of
receiver 40 will be passed through line 48, signal gate 46 to lines
50, 52 and 54 and cut off the output of the regional receiver 42
which would ordinarily be present on line 56. When the local
receiver 40 is not receiving a signal, there will be no reference
voltage across line 44 and the circuitry of the signal gate 46 will
function to pass the output of the regional receiver 42 from line
56 through the signal gate 46 to lines 50, 52 and 54. It will be
understood that the output of the signal gate 46 to lines 50, 52
and 54 is normally the program signal from the local broadcast
transmitter when that station is operating or the normal program
signal from the regional broadcast transmitter when the local
station is not operating.
The output from signal gate 46 which is the normal broadcasting
program of the local station is passed through line 52 to a signal
gate 56, the output of which is connected by line 58 and through
switch 60 and by line 64 to an audio power amplifier 62. Under
normal conditions, signal gate 56 operates to block passage of the
output from signal gate 46 to amplifier 62 with the switch 60 in
the alarm position illustrated in solid lines in FIG. 3. With
switch 60 in the alarm position, that is connecting line 58 to line
64, the unit is in a squelched mode and loudspeaker 78 does not
emit any sound.
In the event a warning alarm signal is transmitted by the local
broadcast station (or by the regional broadcast station when the
local broadcast station is not operating), the output of signal
gate 46 is passed through line 50 to filter 66 where the signal is
passed through a narrow band pass filter with center frequency
f.sub.4 and then to amplifier 68 and then to demodulator 70, the
output of which is the low frequency square wave which was used to
modulate the signal from the sine wave oscillator 28 at the
broadcast station. The square wave signal is passed to a counter 72
where when a desired specific number of pulses of the square wave
have occurred, the voltage output of the counter is passed over
line 74 to signal gate 56 to open the gate and allow the output of
signal gate 46 to pass through line 52, gate 56 line 58 switch 60
and line 64 to the input of the audio power amplifier 62. If a
visual alarm is desired in addition to or instead of the audible
alarm, the output of counter 72 may be passed over a line to a
visual alarm 76. The output of the audio amplifier 62 is passed to
loudspeaker 78. The sound emitted from the loud speaker 78 is a
tone of frequency f.sub.4 which is square wave modulated at a lower
frequency f.sub.5. The full output from the receiver 40 (or
receiver 42) will be present at the input of the audio amplifier 62
as long as switch 60 is in the alarm position as illustrated in
FIG. 3 in solid lines. If the user chooses to reduce the
loudspeaker to a lower level, he may shift switch 60 to the
position shown in dotted lines in FIG. 3 which is the monitor
position and then set the audio level by means of the potentiometer
80. In order to preclude the possibility of making the unit
ineffective as an alarm by inadvertently leaving switch 60 in the
monitor position with the audio gain reduced to zero, an additional
resistor 82 is placed in series with the potentiometer 80 to ground
so that the gain cannot be reduced to zero. With switch 60 in the
monitor position, the normal broadcasting program material would be
heard issuing from speaker 78 which would also indicate to the user
that the switch 60 was not in the alarm position. Of course, in the
event the alarm signal is broadcast while the switch is in the
monitor position, the same will be received and emitted from the
speaker. With switch 60 in the alarm position and when an alarm
signal is received, signal gate 56 will continue to pass the signal
from line 52 to line 58 and produce an audio output until switch 84
which is mechanically ganged with switch 60 is placed in the
monitor position, at which time a D.C. voltage supplied over line
86 will be passed over line 88 to signal gate 56 causing the gate
to shift and block off signals from line 52. Thus signal gate 56 is
reset so that when switches 60 and 84 are returned to the alarm
position, the unit will be placed in its squelched mode ready for
the reception of a subsequent alarm signal.
With the switches 60 and 84 in the alarm position upon termination
of the transmission of the alarm signal by the radio station,
emergency information will be received and passed to the amplifier
and speaker without any adjustment being required of the unit.
It is possible that occasional noise pulses or tone bursts near the
center frequency f.sub.4 of the filter 66 might, over a
considerable period of time, produce enough pulses to the counter
72 to cause shifting of signal gate 56 and resultant audio output.
To prevent such an occurrence, counter 72 may be equipped with a
very low frequency square wave oscillator having a period somewhat
greater than the time required for the counter 72 to operate signal
gate 56 when an alarm signal is detected. This oscillator will
reset the counter 72 on each cycle and prevent accumulation of a
count on extraneous signals and possible resultant false
operation.
From the foregoing it will be understood that the system of the
present invention provides a broadcasting network using a plurality
of local stations and a smaller number of regional stations which
in effect function as a back up network in the event that one or
more local stations are not operating. By using presently existing
telecommunication systems, the system of the present invention can
be utilized to alert the populations of various localities of
emergencies which are only of local concern. In addition, the
regional broadcast network may be resorted to in order to alert
citizens of a regional or even national emergency. In the latter
situations, of course, the local broadcast stations would also
broadcast the alarm signal and information if operating.
The foregoing embodiment illustrates the principles of the present
invention which is capable of modifications without departing from
such principles. The invention accordingly includes all variations
encompassed within the scope of the appended claims.
* * * * *