Title:
Radio receiving device
United States Patent 2330241


Abstract:
This invention relates to a communication system and more particularly. to a radio receiving device which may be remotely controlled to faciliate or insure the reception of special messages. In the present emergency it is oftentimes desirable that special messages, news broadcasts, news of...



Inventors:
Roberts, Gerald G.
Application Number:
US41539841A
Publication Date:
09/28/1943
Filing Date:
10/17/1941
Assignee:
Neil W. O.
Primary Class:
Other Classes:
381/396, 455/68, 455/136, 455/140, 455/149, 455/355
International Classes:
G08B27/00
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Description:

This invention relates to a communication system and more particularly. to a radio receiving device which may be remotely controlled to faciliate or insure the reception of special messages.

In the present emergency it is oftentimes desirable that special messages, news broadcasts, news of approaching air raids, etc. be disseminated to entire districts with the greatest possible speed to enable appropriate measures to be taken. Since air raids, etc. are usually of localized character, it is undesirable that messages be broadcast through: all 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 that its announcements be received by all of the receivers regardless of how they are tuned It is an object of the present; invention to provide receptive means which will automatically receive any important broadcasts from the defense station.

It is a further object of the present invention to provide receptive means, controllable by the defense station, which automatically substitutes a special broadcast .for:any broadcast being received.

It is a further object of the present .invention to provide receptive_ means controllable by the designated defense station, to automatically substitute a special broadcast for that to which the receiver was originally. tuned and after the special broadcast is completed to again tune the radio receiver to its original station.

Other objects will be apparent from the fol-lowing description of the invention; as illustrated by the accompanying drawings, in which like parts are designated by like numerals of reference throughout the-several views and in which: Figure 1 shows in diagrammatic form one embodiment of the present invention; andFig. 2 illustrates another, embodiment of the present invention.

The radio receiving device of: the present invention has an auxiliary receiver tunable to the designated station, and preferably fixedly tuned thereto, a speaker adapted -to operate when connected into the output of the: receiver, but normally unconnected thereto, automatic connecting.means for connecting the speaker to the output of the receiver in response to modulations in:the output of the defense station, which modulations are over a predetermined minimum interval and-of a given frequency. Preferably, the device also has automatic disconnecting means for. disconnecting the speaker from-the output ofl the receiver in response to modulations of a second given frequency in the output of the station to which the receiver is tuned. The auxiliary receiver- may be used alone or in conjunction with a-main radio receiver, and, if desired, both receivers may have a common speaker which is normally connected to the output of said main receiver.

Referring more particularly to Fig.: 1 of the drawings, the receiving means may have a selectively tunable, main radio receiver A and an 15. auxiliary receiver B. The main receiver A may have the usual input circuit with an-antenna and a ground 2, and the usual audio output circuit comprising wires 3 and 4, between which a speaker S isusually-connected.

According-to,the present invention; automatic connecting means is provided for connecting the speaker S to.the output of the auxiliary receiver B, which is. preferably: fixedly tuned to the designated controlling or defense station for the area; and for disconnecting it from the audio output of the selectively tunable receiver A. The auxiliary. receiver B may have the usual input circuit comprising- a ground-6 and a wire 5, which is connected to the antenna I, and the usual audio output circuit, comprising wires 7 and 8.

The connecting means of the present invention comprises circuit Ci; the disconnecting means comprises circuit C2. Both are connected to the audio frequency- output 7 and 8 of the fixedly tuned auxiliary receiver B. The circuit Ci comprisesa. suitable band-pass filter Ni having its input.connected to the output of the-receiver B. A rectifier tube Vi is connected between the output.: of the filter and the input of a delay net40, work.Di.: ..The grid of the vacuum-tube Ti, whichcontrols relay, means Ri which is adapted to energize a coil 28 of a relay R3. and connect the. control coil of the speaker S between the outputs 7 and 8 of the receiver B, is connected to the 45- output of the delay network Di. The band-pass filter Ni serves as the means for selecting the frequency to which the connecting means is responsive and the delay' network serves as the means for predetermining the minimum interval 50, through which the connecting frequency must be maintained to cause response thereto.

The band-pass filter Ni is tuned to a control' frequency Fi, which is the frequency chosen to effect connection with the special broadcast and . ; which corresponds ;to the control modulations in: 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, 10 and II, usual capacitors 12, 13 and 14, and a resistance 15 suitably arranged and having the desired values to permit passage therethrough only of frequencies within the desired narrow range. The input side 18 of the band-pass filter Ni is connected to the wire 7, which is the positive side of the output of the receiver B. The output side 19 of the band-pass filter N1 is connected to the plate 16 of the rectifier tube Vi. The cathode 17 of the rectifier tube Vi is connected to the input side of the delay network Di, which comprises the high resistance 20, the resistance 21 and the capacitors 22 and 23, respectively. The output side 24 of the delay network Di is connected to the grid of the vacuum tube Ti. The cathode of the vacuum tube Ti is suitably biased in the usual manner by selecting appropriate values for the resistances and 28, which are disposed between the ground 27 and the wire 29. which is connected to a suitable source of positive voltage. The actuating coil 30 of the relay Ri is connected in series with the wire 29 and the plate of the vacuum tube Ti.

The disconnecting means includes the circuit C2 and is adapted to respond to a second given frequency PF, 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 Fs but not Fi. 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 Ci. The valves of the inductances and capacitances in the band-pass filter N2 are, 4 however, so chosen that they respond to a frequency F2, which differs from the frequency Fi.

One contact 32 of the relay Ri is connected to one side 33 of the power supply P, which may be the usual 110-volt light supply; the other ter- 4 minal or armature 34 of the normally open relay Ri is connected through a wire 35 to a pole 36 of the relay R. and to a terminal of the actuating coil 28. The other terminal of the actuating coil 28 is connected throurh the armature 37 of 5 the normally closed relay R2 to the other side 38 of the power supply P. A contact 40 of the relay R3 is connected through the wire 41 to the wire 33, so that when the coil R3 is once energized by operation of the relay Ri. energization of the 5 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 R3 may be provided in conjunction with 6( 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 6 buzzer during the special broadcast. The third pole or armature 47 of the relay R3 is connected to the actuating coil of the speaker S. The contact 48 with which the armature or pole 47 makes electrical connection when the relay coil 28 is not 70 energized is connected to the positive side 3 of the audio output of the selectively tunable main receiver A. The contact 49 is adapted to make electrical connection with the armature 47 when the coil 28 is energized. It is connected to the 75 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, the control broadcasting station modulates its usual frequency to which the auxiliary receiver B is fixedly tuned with the connecting frequency Fi. This frequency is amplified and applied between the wires 7 and 8 in amplified form. The band-pass filter Ni, being tuned to this frequency, permits it to pass, so that it is applied to the plate 16 of the tube Vi, and if the frequency Fi is continued for the minimum interval, it thereby causes a current of sufficient magnitude to flow through the delay network Di to provide the capacitor 23 and the grid of the tube Ti with sufficient potential to cause the current to flow between the plate and the cathode of the tube Ti. This current flowing through the actuating coil of the relay Ri 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 causes the 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 7 of the receiver B. The connecting frequency FP o0 is transmitted by the control station for only a very short period and when it is discontinued the coil 30 of the relay Ri is de-energized, allowing the armature 34 to return to its original position.

The relay R3, however, is energized by current L5 flowing between the armature 36 and the contact 40.

After the special broadcast has been received, the designated control station will modulate its usual frequency with a suitable disconnect fre0 quency Fi. This frequency will pass through the band-pass filter N2 but will not pass through band-pass:filter Ni. This frequency causes current to flow between the cathode and plate of the tube T2, causing the energizing coil of the relay 5 R2 to be energized and causing the armature 37 of this normally closed relay to be operated so as to disconnect the relay R3 from the wire 38 of the power supply, thus causing de-energization of the actuating coil 28 and causing the speaker S 0 in the armature 47 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 actuSating coil 28 and the wire 38. Since, however, the contact between armature 36 and contact 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 control station. The automatic connecting means. comprises- the same elements: shown: in; the modification- of Fig. 1; and is responsive to a predetermined minimum interval of given modulations of the: outputs of the- station to which, said receiver. B is fixedly tuned. The.broadcast.receiver.'A may comprise the.usual radio frequency and:detector portion, 50 with:an. output between the wires 5.1 andi52, and an, audio frequency portion: 53 with.its input:connected to the:.wires 5I and;54. A power or, recti- I fler. unit (not shown); may be within, either or both.portions of the:receiver A.. Current is supplied to the receiver A from the plug or power source:P through the wires 55. and 5. when.the on-and-off switch- 57 is closed or short circuited.

In accordance with; this modification, shortcircuiting means is also: provided for short-circuiting on-and-off-switch 5T: to connect, the audio frequency amplifier 53 :to its power' supply in response to the predetermined signal of the control station. The- output: wire 5UZ of the radio frequency portion of the receiver A is connected to the contact 4A of: the relay R3i. The armature 47 instead of being connected to. the speaker S. as in Fig. 1, is connected to the input of the audio frequency portion of the receiver A. The short circuiting means comprises an- additional switch or armature 59 added to the relay R- and operated-by the coil 25. The armature 59 is connected through the wire 55 to one terminal of the: onand-off switch 57.;: The. contact. G- is connected to the other terminal: of the switch 57- so. that when the coil 28 of the relay R1 is enereized; current flows between the armature 59 and the contact: 60 to short-circuit the switch 57, so that power is supplied to the receiver A. In the operation of the modification' shownjn. 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 57 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 are substantially amplified.

When disconnect frequency is received by the receiver B. it passes through the circuit C2. causing the coil 28 to be de-energized and the detector output 52 to be again connected to the input 54. If the switch 57 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-in-part 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: 1. A radio receiving device comprising an auxiliary receiver turnable to signal energy from a transmitting station; a speaker:adapted* tooperate when connected into the output of said receiver; but normally un'connected- thereto; connecting means; including a band-pass- filter, a delay network and a relay which are connected in series to the output of said receiver, said filter being- capable offtransmitting only a limited frequency range and being adapted to operate said relay by current passed therethrough, for con.0 necting said speaker to saidireceiver in response to a predetermined minimuni interval of modtulations of the output of the station to which said receiver is tuned, which modulations are within said limited frequency range; a. signal' device; a power supply for said signal device; and-means also operable by a frequency within said limited range for operatively connecting said signal device to said power supply, 2; 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 connecting means including a relay, which is connected to receive current-from 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 maintaiinig operative- connection between said speaker and said output regardless of whether or iot said modulations are continued, and automatic disconnecting means for disconnecting said speaker from the output of said: receiver in response to a predetermined minimum interval of modulations of said station having a second given frequency.

3. 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 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 0 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 frequency 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 connecting means including a relay connected through a band-pass filter to the output of said auxiliary receiver and controllable by given modulations of the output of the transmitting station to which said receiver is tuned, for operatively 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 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; 1( 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 2(1 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 re- r.o sponse 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 in- :i terval 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 :.S 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 0 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.