US 2330241 A
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Description (OCR text may contain errors)
Sept. 28, 1943. G. G. ROBERTS 2,330,241
RADIO RECEIVING DEVICE Filed Oct. 17, 1941 2 Sheets-Sheet l W R R O R Y wh m m. w h mm M m e W Y W B N n m \P h H v u I i 4,/J-\||\ i n w N Q I N .2 [WI N |W| k w m xwiwoum NN QM v? H M? H m F 4 a *4 o i ww H I N w w m I L.
ATTORNEYS Sept. 28, 1943. G. G. ROBERTS RADIO RECEIVING DEVICE 2 Sheets-Sheet 2 Filed Oct. 17, 1941 nlll Ill.
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Patented Sept. 28, 1943 A Gerald Roberts Akron, Ohi QasSig-nor'to WgONeil, Akron, Ohio Application Octoberl'l, 1941, serial-Nailin 7 Claims. (omen- This invention relates to acommunication system and more particularly. toa radio receiving 7 device whichamay be remotely controlled to faciliate, or insure the reception'tof special messages. i
In the present'emergency it is oftentimes desirable, that specialmessages, news broadcasts, newsrofapproaching airraids, etc. be disseminated torentire districts'with the greatest pos siblespeed. to, enable appropriate measures to be taken. Since'air raids;.etc. are usually oflocalized character, it is undesirable that messages be broadcast 'throughzall the various radio stations to. which several members of the populace may be listening. Therefore; it is'desirable that only one-station, hereinafter designated .defense station be commissioned: to carry. such broadcasts; and .thatits announcements be received by all of the" receivers regardless of how they are tuned;
It .isan objectrof the presenttinvention to'provide-treceptive meanswhich will automatically receive any important broadcasts from the defense station. l
Itis a furtherobjectioi the present invention to provide receptive means, controllable by the defense station whichzautomatically substitutes a special'broadcast ioraany broadcast being received,
It is a further object of the, present invention to provide receptivemeans controllablerby'the designated, defense station, to automatically sub-:-
stitute aspecialrbroadcast forthat towhichthe receiver was'originallytuned and after the special 1 broadcast is completedgtox-again'rtune, the. radio? receiver to its original station.
Other objects ,willbe; apparentfrom .the l'fol-t.
lowing descriptionsof;theinvention; as illustrated va-l andpf a given-frequency. -Preferably; the
devicealso, has automatic disconnecting means for disconnecting the speaker from-thev output of; the receiver in response to modulations of a second g-ivenfrequency in-the output ofthe-sta tion to which the receiver-is-tuned. The auxiliary I receiver, maybe used-alone or in-conjunction by the accompanying. drawings, in which like 7 parts are designated by like 1- numeralsv of *reference" throughout the'several views and" in which: Figure-1 shows in diagrammatic form-one. em:-
bodimentof the presentinvention; and
Fig 2 illustrates anotheri embodiment: of :the
The radio receiving device of the" present: in-v vention has an auxiliary receiventunable to the 1 designated station, and preferably, fixedly. tuned thereto, a speaker adapted-tooperatezwhen connected .into the output of 'the receiver; but normally. unconnected thereto,v automatic connecting means for connecting the speaker to the out:
put of the receiver in responseto modulations 1' in :the output-oithe deiense station, which modulations are over a; predetermined minimum; interwith a -main radio receiver, and, if desired, both receivers may; have a common speakerewhich is normally connected-to the outputof saidmain" receiver. a
Referring more particularly to li-ig. ,"1- of the drawings, the receivi-ng means may have a selectively tunable main radio receiverh A and an auxiliary receiver -B. The mainreceiver A may havethe usual input-circuit with an'antenna-and a g-roundi. and theusual audio output circuit comprising wires 3 and 4,- between which a speak er S-is-usuallyconnected. 1
iAccording tothe present invention; automatic connectingmeans is provided for connecting-the speaker S-tothe .output; of the auxiliary "receiver, B; which is preferably: fixedly tuned to the designated controlling ordefense station for -the,area, andafori disconnecting itfrom the audio output of the selectively tunable receiver A." ,The auxiliar'y. receiver- B may have the usualainput. circuit comprising-a groundfi; and awire 5, which iscon-i nected to. the antenna I,- and the usual audio out-:-
putcircuitcomprisingwires land 8.-
The connecting. means of tion' comprises circuit C1;
tothe audio frequency output land f the fixedly tunedlauxiliary receiver B. The circuit Cr; comprises a suitable band-pass filter N1 having. its-input,.c.onnected,to the output of thereceiver B. A rectifier tubevi is connec ted'between the output; of the-filter and the inputof a delay netfrequency towhich the connecting means is responsiveand the'delaynetwork servesas the means forv predeterminingthe minimum interval through whichth'e connecting frequency must be maintained .toi'cause response thereto.
The band pass filter'Nri's tuned to 'a-control frequency Fir which is the frequency chosen toefiectz'connection' with-the special broadcast and which. corresponds Lto ithe, control modulations :in 1- thepresent invene; the disconnecting. means-comprises circuit C2. Both are connected the radio frequency transmitted by the control station when it is desired to transmit a special broadcast, The band-pass filter may comprise usual inductances 9, .IB and II, usual capacitors I2, i3 and I4, and a resistance suitably arranged and having the desired values to permit passage therethrough only of frequencies within the desired narrow range. The input side l8 of the band-pass filter N1 is connected to the wire 7, which is the positive side of the output of the receiver B. The output side l9 of the band-pass filter N1 is connected to the plate l6 of the rectifier tube V1. The cathode I! of the rectifier tube V1 is connected to the input side of the delay network D1, which comprises the high resistance 20, the resistance 2| and the capacitors 22 and 23, respectively. The output side 24 of the delay network D1 is connected to the grid of the vacuum tube T1. T1 is suitably biased in the usual manner by selecting appropriate values for the resistances 25 and 25, which are disposed between the ground 2'! and the wire 29. which is connec ed to a suitable source of positive voltage. The actuating coil of the relay R1 is connected in series with the wire 29 and the plate of the vacuum tube T1. The disconnecting means includes the circuit 02 and is adapted to respond to a'second given frequency F2. with which the output of the transmitter to which the receiver B is fixedly tuned is modulated when it is desired to disconnect the speaker S from the auxiliary receiver and to reconnect it to the main receiver. The circuit C2 comprises a band-pass filter N2, which passes frequency F2 but not F1. a rectifier tube V2. a delay network D2 and a relay R2. which is actuated by the vacuum tube T2. The elements of the circuit C2 are connected similarly to the elements of the circuit 01. The valves of the inductances and capacitances in the band-pass filter N2 are, however, so chosen that they respond to a frequency F2, which differs from the frequency F1.
One contact 32 of the relay R1 is connected to one side 33 of the power supply P, which may be the usual 110-volt light supply; the other terminal or armature 34 of the normally open relay R1 is connected through a wire 35 to a pole 36 of the relay R3 and to a terminal of the actuating coil 28. The other terminal of the actuating coil 28 is connected throu h the armature 31 of the normally closed relay R2 to the other side 38 of the power supply P. A contact 40 of the relay R3 is connected throu h the wire to the wire 33, so that when the coil R3 is once energized by operation of the relay R1. energization of the coil R3 will be maintained after connection is broken between contacts 32 and the armature 34. Means such as an armature 42 connected to one side of the power line P and actuated by the relay'Rs may he provided in conjunction with the contact 45 to operate the signal device or buzzer 43 when the relay R3 is first energized. In such a case. a manually operated switch 46 may be provided to disconnect the signal or buzzer during the special broadcast. The third pole or armature of the relay R3 is connected to the actuating coil of the speaker S. The contact 48 with which the armature or pole 41 makes electrical connection when the relay coil 28 is not energized is connected-to the positive side 3 of.
the audio output of the selectively tunable main receiver A. The contact is adapted to make electrical connection with the armature 41 when the coil 28 is energized. It is connected to the The cathode of the vacuum tube 1 positive side of the output of the auxiliary, and preferably fixedly tunable, receiver B.
In the operation of the device of the present invention, the auxiliary fixedly tuned receiver B is operated continuously and is continuously tuned to the designated control station. Normally, however, its audio output is not connected to the speaker S. When a special broadcast is to be heard, thecontrol broadcasting station modulates its usual frequency towhich the auxiliary receiver B is fixedly tuned with the connecting frequency F1. This frequency is amplified and applied between the wires 1 and 8 in amplified form. The band-pass filter N1, being tuned to this frequency, permits it to pass, so that it is applied to the plate H) of the tube V1, and if the frequency F1 is continued for the minimum interval, it thereby causes a current of sufiicient magnitude to flow through the delay network D1 to provide the capacitor 23 and the grid of the tube Tr-with sufficient potential to cause the current to flow between the plate and the cathode of the tube T1. This current flowing through the actuating coil of the relay R1 causes a circuit to be established between the one side 33 of the power supply P successively between contacts 34, along the wire 35, through the actuating coil 28 of the relay R3 and through the armature 37 of the relay R2 to the other side 38 of the power supply. The relay R3 is thereby actuated, thus causing contact to be made between points 36 and 40, and thereby sustaining the current through the actuating coil 28. The actuation of relay R3 also causesthe signal device 43 to be connected across the power line P, and the speaker S to be disconnected from the contact 48 and the output of the receiver A and to be connected to the contact 49. in the output I of the receiver 13. The connecting frequency F1 is transmitted by the control station for only a very short period and when it is discontinued the coil 30 of the relay R1 is de-energized, allowing the armature 34 to return to its original position. The relay R3, however, is energized by current flowing between the armature 36 and the contact 40. 1
After-the special broadcast has been received, the designated control station will modulate its usual frequency with a suitable disconnect frequency This frequency will pass through the band-pass filter N2 but will not pass through band-pass filter N1. This frequency causes current to now between the cathode and plate of the tube T2, causing the energizing coil of the relay R2 to be energized and causing the armature 31 of this normally closed relay to be operated so as to' disconnect the relay R: from the wire 38 of the power supply, thus causing de-energization of the actuating coil 28 and causing the speaker S in the armature 41 to be again connected to the output of the receiver A. Cessation of the' transmission of the frequency F2 automatically deenergizes the actuating coil of the relay R2 so that the connection is again made between the actuating coil 28 and the wire 38. Since, however, the contact between armature 36 and contact 40 has been broken, the relay R3 is not actuated.
In the modification of Fig. 2, the audio outputs 3 and 4 of the receiver A are permanently connected to the speaker S and automatic connecting and disconnecting means are provided for suitably connecting the audio frequency amplifier together with the speaker to the outputs of the auxiliary receiver B in response to a predetermined signal of the controlstation. The
aaso aazr automatic connecting :means. comprises the same elements shown in: the modification: of i Fig: 1', and is responsive to a predetermined: minimum interval. of; given modulations of the: outputsof the station to which. said receiver: B- is fixedly tuned. Tliehroadcast. receiven'A'. may: comprise the-usual .radiozirequ'ency and'i'det'ectorportion: 5
. trol' station. Theoutput wire' 2 of the radio frequency portion offthetreceiverAis connected tothe. contact: 48 0f the relay =Ri.'- The armature 41 instead of -being connected to the speaker. 53;.
as in Fig, l, is'connectedto the': input of: the audio frequency portion of=the receiver A. The short circuiting means comprises an additional switch orarmature 59 added tothe relay Re and operated-by the coi128. The armature Ellis connected through the wire 55 to one teimin'al-of the on and-cit switch 51.: The. contact tilt is connected to the other terminal" of -the switch 51 so. that when-the coil ZB of 'the relay F'nis energized, current flows between thearmat-ure 59- and the contact fiil to short-cii cuit the switch 51, so that power is supplied to the receiver Ax Inthe operation of the modification showndn Fig. 2, the predetermined connecting signal-received'by-the auxiliary-receiver B passes through the circuit C1, as above set forth, and causes the relay R3 to close, which disconnects the input 54 of the audio frequency portion from the detector output 52 and connects it to the output 8 of the auxiliary receiver B. Simultaneously, the switch 51 is short-circuited by connection made between the armature 59 and the contact 60 of the relay R3, so that power is supplied to the audio frequency portion of the receiver A. This portion, together with the speaker S, is thus automatically connected to the output 8 so that signals from the auxiliary receiver B aresubstantially amplifiod.
When disconnect frequency is received by the receiver B. it passes through the circuit C2. causingithe coil 28 to be de-energized and the detector output 52 to be again connected to the input 54. If .the switch 5! is open, the receiver A is disconnected from the source of power.
The modification shown in Fig. 2 is especially desirable in that the weak signals from the auxiliary receiver B are considerably amplified.
The control portion and connecting means of the invention'disclosed herein is claimed in my application Serial No. 456.630, filed August 29, 1942, which is a continuation-impart of this application.
It is to be understood that the particular form of apparatus shown and described are presented for purposes of explanation and illustration and that various modifications of said apparatus can be made without departing from my invention as defined in the appended claims.
What I claim is:
l. A radio receiving device comprising an auxiliary receiver turnable to signal energy from a transmitting 'statiomiraispeaker:adapted to oper at'e'when connecteddnto' the output of. said receiver; but normally unconnected: thereto; con; necting? means; including. a: rand-pass filter, a delay network and-a relay which are connected in series to the output of said-receiver, said filter beingl'capable of transmitting only a lirnit'ed fre quency rangeand beingadapted-tooperatesaid relay by current passed therethro'ugh, for connecting said speaker t'o said-receiver in response to a predetermined minimum interval of mo'dulationsof the output of the station to which said receiveris tuned, which-modulationsare within said: limited frequency range; a signal device;- a -power supply for "saidsi'gnaldevice; and me'ans also operable by 'afrequency within said 'limited range m operatively connecting said signal device-to s'aid power supply;
2. A radio receiving device comprising an'auxiliary"receiver-tunable to a signal transmitted fronra transmitting station; a speaker adapted to operatewhen connected into the output' of said receiver, but normally unconnected thereto; and connecting means including arelay, which is connected to receivecurrent from a bandpass filter connected I to the output-' of said receiver; for operatively connecting said speaker to the output of said'receiver inresponse to a predeter mined minimuminterval of" given frequency modulations 'in the output of the transmitting station to which said receiver may be tuned; means for maintaining operative" connection be- I tween said speaker and said output regardless ofwhether or not said modulations are continned;- and automatic disconnecting means 'for disconnecting said; speaker from theoutput or saidreceiver in A. response to a predetermined minimum interval 'ofm'o'dulationsof said station having-a second? given frequency. it
3; Hradio receiving device comprising anaux iliary receiver tunable to a signal transmitted from a transmitting station; a speaker adapted to operate when connected into the output of said receiver, but normally unconnected thereto; and connecting means including a relay which is connected to receive current passed through a band-pass filter connected to the, output of said receiver, for operatively connecting said speaker to the output of said receiver in response to a predetermined minimum interval of given frequency modulations in the output of the transmitting station to which said receiver may be tuned, means for maintaining operative connection between said speaker and said output regardless of whether or not said modulations are continued, and automatic disconnecting means including a relay and a band-pass filter connected to the output of said receiver for disconnecting said speaker from the output of said receiver in response to a predetermined minimum interval of modulations of a second given fre-' quency in the output of said station.
4. A radio receiving device comprising an auxiliary receiver tunable to a signal transmitted from a transmitting station; a speaker adapted to operate when connected into the output of said. receiver but normally unconnected thereto; and
tion to which said receiver is tuned, for oper- Y atively connecting said speaker into the output of said receiver; means for maintaining operative connection between said speaker and said output regardless of whether or not said modulations are continued, and disconnecting means controllable by separate given modulations in the output of the transmitting station to which said receiver is tuned.
5. A radio receiving device comprising anauxiliary receiver tunable to a signal transmitted froma transmitting station; a speaker adapted to operate when connected into the output of said receiver but normally unconnected thereto; and connecting means including a relay which is connected through a band-pass filter connected to the output of said receiver for operatively connecting said speaker to the output of said receiver in response to a predetermined minimum interval of given modulations in the output of the transmitting station to which said receiver may be tuned, said connecting means including a, delay network for predetermining the minimum interval of modulations to which said relay is responsive; and automatic disconnecting means including another relay which is connected through another band-pass filter to the output of said receiver, for disconnecting said speaker from the output of said receiver in response to a predetermined minimum interval of modulations of a second given frequency in the output of said station, said disconnecting means also having in series with its relay and its filter a delay network for determining the minimum interval for response to said second frequency.
6. A radio receiving device comprising a selectively tunable receiver; an auxiliary fixedly tuned receiver; a speaker normally connected in the output of said selectively tunable receiver, but adapted to operate in the output of each receiver; connecting means, including a band-pass filter, a delay network and a relay connected in series to the output of said fixedly tuned receiver, which band-pass filter is capable of passing a given limited frequency range, for connecting said speaker into the output of'said fixedly tuned receiver when modulations within said given frequency range are transmitted by the station to which said auxiliary receiver is fixedly tuned; and disconnecting means, also including a relay, a delay network and a band-pass filter which is adapted to pass a second given frequency, for disconnecting said speaker from the output of said selectively tunable receiver in response to modulations corresponding to said second given frequency transmitted by the station to which said auxiliary receiver is tuned.
7. A radio receiving device comprising a selectively tunable receiver; an auxiliary fixedly tuned receiver; a speaker normally connected in the output of said selectively tunable receiver, but adapted to operate in the output of each receiver; connecting means, including a band-pass filter, a delay network and a relay connected in series to the output of said fixedly tuned receiver, which band-pass filter is capable of passing a given limited frequency range, for connecting said speaker into the output of said fixedly tuned receiver when modulations within said given frequency range are transmitted by the station to which said auxiliary receiver is fixedly tuned; a signal device; a power supply for said signal device and disconnecting means, also including a band-pass filter which is adapted to pass a second given frequency, for. disconnecting said speaker from the output of said selectively tunable receiver in response to modulations corresponding to said second given frequency transmitted by the station to which said auxiliary receiver is tuned, said connecting means also including means for connecting said signal device to said power supply therefor.
GERALD G. ROBERTS.