Title:
Control circuit for radio receivers
United States Patent 2190546


Abstract:
This invention relates to signaling systems. More particularly, this invention relates to signaling systems employing means for selectively receiving signals impressed upon two or more receiving devices. In radio signaling systems suitable for use at coastal harbor stations, for example,...



Inventors:
Theodore, Laube Otto
Application Number:
US22720138A
Publication Date:
02/13/1940
Filing Date:
08/27/1938
Assignee:
AMERICAN TELEPHONE & TELEGRAPH
Primary Class:
Other Classes:
455/137, 455/140
International Classes:
H04B7/08
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Description:

This invention relates to signaling systems.

More particularly, this invention relates to signaling systems employing means for selectively receiving signals impressed upon two or more receiving devices.

In radio signaling systems suitable for use at coastal harbor stations, for example, it appears desirable to provide two or more radio receivers located at various points so that low power ship transmitters in the service area may always be within reliable signal range of some one of the various receivers. In setting up such an arrangement the output circuits of the various receivers may be wired to a common terminal in such a way that a signal received by any one of the various receivers will be heard by the operator.

In an arrangement of the type just referred to it has been found that the signal-to-noise ratio at the common terminal to which the various receiver circuits are wired will be determined largely by the poorest of the signals of any individual radio receiver. Thus, if but one of the various receivers has a low signal-to-noise ratio, the signals at the common terminal may become practically unintelligible and the operator will be unable to decipher the signals even though the same signals may be received satisfactorily by one or more of the other receivers. According to the present invention, these conditions which ofttimes prevent the reception of signals may be removed by incorporating into the receiving system suitable means for selecting that receiver which delivers the best signals and for excluding the outputs of all other receivers from the system. With such an arrangement all of the various receivers will always be available for monitoring purposes to receive signals from a ship transmitter within the service area, but immediately after a call is received from such a ship transmitter, the receiver delivering the best output may be selected, if desired, or the outputs of two or more receivers may be combined, if preferred, while the remaining receivers are disconnected from the circuit. In that case signals of good quality may be received and the outputs of receivers which are not delivering good signal energy may be eliminated. After a call is completed, however, all of the receivers are returned to the monitoring condition automatically and thus held available- for another call.

It is one of the objects of this invention to employ a plurality of radio or other receivers to 6K simultaneously monitor one- orý more radio or other transmitters and to select the receiver delivering the best signal output and transmit its signals.while disconnecting the remaining receivers from-the circuit.

It is another object of this invention to com-: bine the outputs of two or more radio receivers of a plurality of such receivers and transmit the com ined output of the selected receivers while disconnecting the remaining receivers from the circuit. It is anothr: object of this invention to provide arrangements to re-connect all of the various receivers to the circuit after a call has been completed so that all of the receivers will be available to receive another call. The remaining objects and features of this invention may be better understood from the detailed: description hereinafter following, when read in connection with the accompanying drawing showing two embodiments of this invention merely for the purpose of illustration, Figure 1 illustrating one form of circuit arrangement for controlling the outputs of two or more radio receivers and Fig. 2 illustrating a modified arrangement to accomplish the same end. Referring to Fig. 1 of the drawing, a radio transmitter RT is associated with a plurality of radio receivers RRI and RR2, only two of:which are shown" merely for the purpose' of illustration.

The transmitter and the various receivers may form part of a coastal harbor radio telephone system arranged so that signals may be transmitted by an operator from a common point through the transmitter RT and signals received by theý various receivers RRi, RR2, etc. The radio receiver RR, is connected to one of the input circuits of a hybrid coil network ICi through the armatures and back contacts of a relay Ri. Similarly, the output circuit of the radio receiver RR2 is connected to another input circuit of the same hybrid coil network HCi through the armatures and back contacts of a relay Rz2 The hybrid coil network HC1 is of the type described in Patents Nos. 1,780,962 and 1,780,963, issued November 11, 1930, to A. Bailey et al. Such a hybrid coil network may be employed to combine the outputs of the two radio receivers RRi and RR2 and the combined energy may be transmitted to a receiving orother circuit, as will be described more fully hereinafter. It will be understood that the hybrid coil network referred to is but one form of combining circuit and that other combining circuits may be used instead thereof.

The output circuit of the hybrid coil network HCi is connected to the input circuit of a hy. brid coil network HC2. The radio transmittej RT is connected to the output circuit of the sam hybrid coil network HC2. The tip and ring contacts of the jack J are connected to the third circuit of the hybrid coil network HC2. A telephone circuit (not shown) of well known type is connected by means of a plug to the jack J so that telephone or other signals may be transmitted through the network HC2 to the transmitter RT for transmission through space, while signals received at either or both of the input circuits of the network HC2 may be received over the tip and ring contacts of the jack J by the operator's circuit connected thereto. The hybrid coil network HC2 may be of any well known type, for example, of the familiar three-winding transformer type.

The sleeve contact of the jack J is connected to the winding of a relay R3 in such a way that current may be transmitted through the winding of this relay whenever the plug P is inserted into the jack J. The armature of this relay connects a battery Bo to the windings of two or more relays designated R 1, R12, etc., through corresponding resistors Zn and Z12, respectively. The terminals of the winding of relay Rn are connected to the "on" and "off" contacts of a non-locking key Ki, the armature of which is grounded. Similarly, the terminals of the winding of the relay R12 are connected to the "on" and "off" contacts of a non-locking key K2, the armature of which is also grounded. The upper armatures and back contacts of relays Rn and R2, respectively, control the circuits of lamps Ln and L12, current for illuminating lamp Lu being provided by battery Bel while battery Bi2 supplies the current to illuminate lamp Li2. A single battery may replace batteries Bn and B12 if so desired. The relays Rli and R2 are normally unoperated and, therefore, the lamps Ln and Li2 are normally illuminated.

The upper make contact of relay Rn is connected to one terminal of the winding of relay Ri, the other termnal of which is connected to a battery Bi, as shown. Similarly, the upper make contact of the relay Ru2 is connected in circuit with the winding of relay R2 and a battery B2. Both relays R, and R2 are normally unoperated so that both radio receivers RRi and RR2 are connected to the respective input circuits of the hybrid coil network HCi. When the relay Ri is operated the radio receiver RRi is disconnected from the corresponding input circuit of the network HCi and an impedance Zi is substituted therefor. Similarly, the operation of relay R2 will disconnect the radio receiver RR2 from the corresponding input circuit of the network HCi and substitute the impedance Z2 therefor. The impedances Zi and Z2 are shown in the form of resistors merely for the sake of simplicity but may be devices having inductance, capacitance and resistance which correspond to the inductance, capacitance and resistance components in the output circuits of the receivers RRi and RR2, respectively.

When a signal is received by one or more of the various radio receivers RRi, RR2, etc., the operator may plug the cord circuit into the jack J to receive the call. When this happens the relay R3 will operate to connect the battery Bo to the windings of relays Rn and R12 in parallel through resistors Zn and Zl2, respectively. The outputs of the receivers RRi, RR2, etc., will be combined in the network HCi and the combined Senergy will be transmitted through the network HC2 to the operator's circuit which is plugged into the jack J.

If the operator desires to cut off the radio receiver RRi he will move the armature of the key Ki to its "off" contact momentarily. The relay Rn will then be operated, current flowing from the battery Bo through the armature and Scontact of relay R3, resistor Zn, the winding of Srelay RI, the "off" contact of armature of key Ki, and ground. The operation of relay R1 will open the circuit of the lamp Lu at the upper back contact of this relay, at the same time connecting ground to the lower terminal of the winding of relay Ru for the purpose of locking up the relay Rn. The closure of the upper make contact of relay Rnl will cause the relay Ri to operate, current flowing from battery Bi, through the winding of relay Ri, and over the make contact and armature of relay Rn and ground. The operation of relay Ri will disconnect the radio receiver RRi from the circuit and replace that receiver with the impedance Zi. In that case the signals received by the radio receiver RR2 will be transmitted through the networks HCi and HC2 to the exclusion of the signals that may be impressed upon the radio receiver RRi.

Similarly, by moving the armature of key K2 to its "off" contact momentarily, the radio receiver RR2 may be disconnected from the hybrid coil network HCi and the impedance Z2 substituted therefor. At the same time the lamp Li2 will be extinguished by the opening of the circuit of the upper back contact of the relay R12 and the relay R12 will be locked up by the closure of the lower make contact thereof.

If the operator desires to reconnect the radio receiver RRi to the hybrid coil network HCi he will merely throw the armature of the key Ki in reversed direction to its "on" contact momentarily. When this happens the upper terminal of the winding of relay Rn will be grounded through the "on" contact and armature of key Ki. The relay Rn will, therefore, release. The lamp Lii will then become reilluminated by the closure of the circuit of the upper back contact of the relay. The relay Ri will become released upon the opening of the upper make contact of relay Ru and therefore the impedance Zi will be disconnected from the hybrid coil network HC1 and the receiver RRi substituted therefor. Similarly, by reversing the position of the armature of the key K2 and moving it to its "on" contact momentarily, the lamp Li2 will become illuminated, the relay Ri2 released, the relay R2 released, the impedance Z2 disconnected from the corresponding input circuit of network HCi and the radio receiver RR2 substituted for the impedance Z2.

The radio receivers RRi and RR2 are the only two receivers shown in the drawing but, as already explained, other receivers may be added to the system. If two other receivers are employed they may be connected to a hybrid coil network similar to the one designated HCi and the output of the additional hybrid coil network combined with that of the ouput of the network HCu in still. another hybrid coil network which may be connected to the three-winding coil network HCu, as illustrated and explained in the patents to A. Bailey et al., above designated. Of course, as many more radio receivers may be connected to the system as may be found desirable.

The arrangement in Fig. 1 of the drawing permits the output of one of the radio receivers w such as RRi to be transmitted through the hybrid E coil networks HCi and HC2 to the operator's set ci to the exclusion of the outputs of all other radio receivers. It will be understood, also., that the output of. the radio receiver RRz may be thus ti selectively transmitted to the operator's set to E the exclusion of the outputs of the other radio c receivers. Similarly, if three or more radio re- r ceivers are employed, the outputs of any two or b more, of these various receivers may be combined r and transmitted through the hybrid coil net- b work HC2 to the operator's set while the outputs c of the remaining receivers are suppressed or elim- i: inated from the operator's circuit. When a call t has been completed the operator's plug P will c be removed from the jack J and all of the var- a ious radio receivers will be returned to their monitoring condition to receive signals simultaneously from any radio transmitter within the service area. t Fig. 2 illustrates a modification of the arrangement shown in Fig. 1. As in Fig. 1 relays Rii and R12 control relays Ri and R2, respectively, which in turn connect the receivers IRR and RR2 to the hybrid coil network HCi or substitute the corresponding impedances Zi and Z2 respectively, for the receivers RRi and RR2.

When the operator's plug P is inserted in the jack J, relay R3 operates so that battery Bo may be connected through the armature and contact of the relay R4 to the windings of relays Ru and Ra2 (and to, other relays which may be connected to the circuit) through the corresponding resistors Zi and Zi2, respectively. The key Ko controls the operation of the relay R4. Keys Kii and Ki2 control the operation of relays R21 and R22, respectively, the latter relays being associated with the corresponding relays Rni and Rlz. As the relays Rui and R12, are normally unoperated, the lamps Lii and Lit2 are normally illuminated, as already described with respect to Fig. 1.

Before the operator's plug P is inserted into the jack J, relay R3 is unoperated and therefore the relays Rit and Ru2 will be unoperated and will remain unoperated. But after the operator's plug P is inserted into the jack J and relay R3 is operated, the relays Rii and R12 may only then be operated, and this will be described more fully hereinafter.

While the operator's plug is inserted into the jack J the key Kui may be closed momentarily.

The relay R21 will then operate, current flowing from battery B2i through the winding of relay R2, over the contacts of key Kii and ground.

The operation of relay R21 opens the circuit of relay Ral at the back contact of relay R21, thereby preventing the operation of relay Rat. The release of relay Rut will cause the lamp Lii to be illuminated or to remain illuminated if pre6 viously in this condition. At the same time the armature of relay R21 becomes grounded at its "make" contact and causes the operation of relay R12, current for the relay R12 being provided by the battery Bo connected to the contact of relay R3 the current flowing over the armature and contact of relay R4 through resistor Z12, over the winding of relay Ra2, the armature and back contact of relay R12, the armature and back contact of relay R22, the armature and make contact of relay Rii and ground. Hence relay R1z will operate and its operation will cause the relay R2 to operate, which in turn will disconnect the receiver RR2 from the input circuit of the hybrid coil network HC1 and replace the receiver RR2 ith the impedance Z2. Thus the operation of key n will remove the radio receiver RR2 from the ircuit as well as all other receivers except the adio receiver RR. , The operation of key K12 will cause the opera- n ion of relay R22, current flowing from battery 22, through thr h e winding of relay R22, over the ontacts of key K12 and ground. The operation of elay R22n will open the circuit of relay Ri2 at the ack contact of relay R22 , so that relay R12 will emain unoperated. The lamp Li2 will therefore ie illuminated. The release of relay R12 will ause the receiver RR2 to be connected to the nput circuit of the network HCP . The operaion of relay lR2 will place ground on the "make", ;ontact:of the relay and cause relay Rn to operete. The current for relay R11 is supplied by )attery Bo through the contact and armature cf relay R3, over the armature and contact of relay R4, resistor Zil, the winding of relay Rui, ;he armature and back contact of relay Rsu, the armature and back contact of relay R2i, the armature and make contact of relay R22 and ground. The closure of the make contact of relay R11 will connect ground to the lower terminal of the winding of this relay and lock up the relay. The operation of relay R11 will cause the operation of relay R1, as in the case of Fig. 1, and disconnect the radio receiver RR1 from the hybrid coil network HC1 and substitute the impedance Z: for the radio receiver RRi. Thus. the operation of key Ki2 will disconnect the, receiver RRi from the circuit as well as all other receivers except the radio receiver RR2.

It has thus been shown that the closure of key " Kir causes the operation of relays R2i and RP2. and allows the relay RaP to remain unoperated, this condition being indicated by the illumination of lamp Lil. It has also. been shown that the operation of key Ki2 causes the operation of relay R22t and relay Rn, causing the relay RI2 to remain unoperated, this condition.being indicated by the illumination of lamp Li2.

If the operator's plug P should remain locked: in the jack J and if it is desired to have all of the radio receivers connected to the operator's set, it is only necessary to operate the key Ko.

The operation of key Ko will cause the operation of relay R4, current flowing from battery B4 through the winding of relay R4 over the contacts ofI key Ko and. ground. The operation of relay R4 will disconnect the battery B4 connected over the contact and armature of relay B3 from the windings of relays Rul, Rn, etc. The relays Ru1 and R12 will therefore be unable to operate and therefore the receivers RRi and RR2 will be connected to the hybrid coil network HCi. After the operator's plug P has been removed from the jack J, relay R3 is released and the operation of key Ko will, of course, serve no useful purpose because no current may then be supplied to the windings of relays Rat and Ri2.

The circuit arrangements illustrated in Figs. 1 and 2 of the drawing have been applied to the selection of the radio receiving circuits whereby one of the radio receivers will be selected and connected to the circuit and all other radio receivers disconnected from the circuit. It will be clear, of course, that the arrangements may be employed for the selection of devices other than radio receivers, for example, detectors or other devices or circuits.

While this invention has been shown and described in certain particular arrangements merely for the purpose of illustration, it will be understoo6d tha the general Principles of this invention may be applied to other and widely varied organizations without departing from the spirit of the invention and the scope of the appended claims.

What is claimed is: 1. In a signaling system, the combination of a plurality of radio receivers located at different points and wired to a common receiving circuit where said receivers simultaneously monitor a distant station, each receiver being adjusted for receiving the same signals from said distant station, means for selecting one of said receivers and for observing its output and for disconnecting all of the other receivers from the receiving circuit, means for indicating which of the various receivers has been selected by the selecting means, and means for subsequently reconnecting all of said radio receivers to the common receiving circult so that the outputs of all of said receivers may again be received by said common circuit.

2. The combination of a plurality of radio receivers all adapted to receive and monitor the same signals, an operator's set with which all of the radio receivers may be connected for simultaneously receiving the outputs of all of said receivers, means for selecting the receiver delivering the best output and for connecting the selected receiver to the operator's set, said means also including means for simultaneously disconnecting all of the remaining radio receivers from the operator's set, and means for subsequently reconnecting all of said radio receivers to the operator's set.

3. The combination of a plurality of radio receiving circuits all of which are simultaneously monitoring a distant station, an operator's set to which all of the receivers may be simultaneously connected so that the outputs of all of said receivers may be simultaneously received, means for selecting the radio receiver delivering the best signals and for disconnecting all other radio receivers from the operator's set, and a plurality of indicating devices each corresponding to one of the radio receivers for indicating which one of the various receivers is connected to the operator's set.

4. The combination of a plurality of radio receivers all of which may be tuned to simultaneously receive signals from a distant station, a telephone circuit to which all of the radio receivers may be connected so that the outputs of all of said receivers may be simultaneously received, means for combining the outputs of certain of said receivers for transmission to said telephone circuit and for disconnecting all of the remaining receivers from the telephone circuit, and indicating means for indicating which of the various radio receivers are connected to the telephone circuit.

5. In a signaling system, the combination of a plurality of receiving circuits all employed for simultaneously monitoring a distant mobile station, a telephone circuit, a combining network interconnecting all of the receiving circuits with the telephone circuit so that the outputs of all of the receiving circuits may be translated into audible signals, means for disconnecting from the combining network certain of said receiving circuits so that the outputs of the remaining receiving circuits will be additively combined in the combining network, and means for subsequently reconnecting all of the receiving circuits to the combining network for further monitoring the distant mobile station.

6. The combination of a plurality of receiving circuits, a plurality of impedance elements, each impedance element corresponding to one of the receiving circuits, a combining network, means for connecting all of the receiving circuits to the combining network, means for disconnecting all of the receiving circuits from the combining network except one and for replacing each disconnected receiving circuit with the corresponding impedance element, and means for subsequently disconnecting all of the various impedance elements and for reconnecting all of the various receiving circuits to the combining network.

7. In a signaling system, the combination of a plurality of interconnected radio receivers for simultaneously monitoring one or more mobile stations that may be transmitting signals, means for selecting that one of said receivers delivering the best output and observing its output and for disconnecting all other of said receivers from the interconnecting circuit, means for transmitting signals to the mobile station from which signals are being received, and means for subsequently reconnecting all of said receivers for again monitoring said mobile stations.

OTTO T. LAUBE.

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