Патент USA US2112446код для вставки
March 29, 1938. c. PELMULDER ET Al. 2,112,446 MEANS FOR REMOTE TUNING OF RADIO RECEIVERS Filed Deo. 8, 1936 _ „mm N Eï ONKD.L »m1 è mm,ww +S my@.9 um', Om/ @vub Patented Mar. 29, 1938 2,112,446 UNITED STATES PATENT OFFICE 2,112,446 MEANS FOR REMOTE TUNING 0F RADIO RECEIVERS Chester Pelmulder, San Francisco, and Hans 0. Storm, Palo Alto, Calif., assignors to Globe Wireless Ltd., San Francisco, Calif., a corpo ration of Nevada Application December 8, 1936, Serial No. 114,782 7 Claims. Our invention relates to a means and method for the supervisory tuning of radio receivers from a transcribing station located at a distance from a radio receiver, and more particularly to a sys tem which employs a single telephone pair simul taneously energized for supervisory tuning and for transmission of the radio signals. It is par ticularly adapted for use when a transcribing sta tion is located at such a distance from the re 10 ceiver that the greatest possible economy in the use of connecting wires must be obtained. Among the objects of our invention are: To utilize a single telephone pair between a tran scribing station and a radio receiving station for 1 the simultaneous transmission of the radio sig nals to the transcribing station and tuning control impulses from the transcribing station; to provide a means and method of controlling the tuning of a remote radio receiver over a standard telephone 20 line; to provide a means and method of control ling the tuning of a remote radio receiver by im pulses carried by the same telephone pair that carry the received signals to the transcribing sta tion; to provide a means and method of sending 25 radio signals and tuning control impulses over a single telephone pair wherein only the audio-fre quency rights are available; and to provide a means and method of utilizing an existing com mon power source for the control of a radio re 30 ceiver situated at a distance from a transcribing station. Our invention possesses numerous other ob jects and features of advantage, some of which, together with the foregoing, will be set forth in the 35 following description of specific apparatus em bodying and utilizing our novel method. It is therefore to be understood that our method is ap plicable to other apparatus, and that we do not limit ourselves, in any way, to the apparatus of (Cl. 171-97) a downtown location where messages received may be quickly and efliciently dispatched to their addressees` It is also obvious that in such an ar rangement the greatest possible economy in the use of connecting wires must be obtained, and, for example, it is common practice to utilize a standard telephone connection between the re ceiving station and the transcribing station, the signals passing through the telephone switch~ board system exactly as do telephone conversa tions. Under these circumstances the use of a standard telephone pair on which audio frequency rights only are available would be much cheaper than the use of special circuits. The main difficulty, however, in transcribing signals coming to a transcribing station’ through a telephone pair from a remote receiver lies in the fact that the radio signals to be received may accidentally or purposefully vary somewhat from time to time in frequency, and if an oscillating 20 radio receiver is utilized the local oscillator will also vary somewhat in frequency. It is, therefore, of great advantage that the transcribing operator should have a supervisory control of the tuning of the receiver in order that 25 the signal volume be maintained by retuning as oscillator or signal frequencies change. It is also at times desirable to vary the output frequency of _an oscillating receiver to avoid interfering sig nals or to meet the personal differences in the 30 hearing of various operators. Modern receivers and transmitters do not diverge widely from that frequency to which they are adjusted, and it is obvious, therefore, that a large latitude in tuning supervision is not necessary. Ordinarily, such supervisory tuning would have to be exercised over a separate circuit than that used for the reception of the signals. Such dupli cation of connections, however, is expensive, and 40 the present application, as we may adopt vari our present invention allows both the tuning su ous other apparatus embodiments, utilizing the method, within the scope of the appended claims. The figure is. adiagram showing a preferred cir~ cuit for the practice of our invention, the diagram 45 being reduced to lowest terms and being shown without such accessories as switches, fuses, limit pervision impulses and the signal impulses to pass simultaneously, without interference, through the same telephone pair, thus greatly reducing the expense and allowing the operator at the tran scribing station to control at all times the tuning 45 of the receiver giving forth the signals to which he is listening. inasmuch as ordinary telephone pairs are de signed to carry audio impulses only, We prefer to utilize, for tuning control power, commercial al 50 ing resistors, meters, spark Suppressors, power factor correction condensers, or repeaters which might be required on longer lines. It> often occurs that a radio receiving station is located on the outskirts of a city, or beyond, in order to reduce interference to a minimum and in order to obtain proper directional characteris tics of the receiver antenna system. It is often advantageous to transmit the received signals to 40 ternating current which is taken from the same alternating current power system that supplies the receiving station, and since the frequency of this alternating current in the power system is usually 6G’ cycles per second, and the received 55 2 2,112,446 signals are usually on the order of 1000 cycles per second, it is obvious that they may be passed over an ordinary telephone pair without interference with central station equipment or change of cen tral station design. on the same pair. Output leads 46 from the re ceiver I lead to the hybrid coil assembly, one of them being connected directly to the line and the other to an intermediate point in the hybrid coil Referring directly to the drawing for a more de tailed description, a radio receiver I, having a use in this service. split symmetrical main tuning condenser 2, bal anced with respect to ground, is further provided 10 with a split remote control band spread condenser 2' of relatively smaller capacitance, in parallel with the main tuning condenser, and with a split remote control condenser 3 of relatively larger capacitance, connected in series between the two 15 sections of condenser 2' by lead wires 2”, which on account of their proximity to ground potential in the balanced condenser system, may be of rela tively great length without affecting the tuning range. The remote control condenser 3 is pref 20 erably rotated through the- medium of friction discs 4 by a tuning motor 5. 'I'he tuning motor is preferably a synchronous motor with a built-in reduction gear, not shown, but obviously may be » any suitable type of motor which can be reversed. 26 'I'he motor 5 is controlled by a contactor assembly which comprises a forward contacter 6, a back ward contactor 1, and a running contactor 8, all supplied from A. C. mains Il through contactor leads III and receiving station leads Il. .The for v30 ward contactor 6 and backward contactor 1 `are controlled by coils I2 and I4 through contacts I5 and movable arms I6, of a diñerential polar relay having coils I1 and I6. Arm I6 is attached to one of the contactor leads I0 through wire It and the 35 return side of contact coils I2 and I4 connected by wire 26 to the other of the A. C. leads I0. 'I‘he common point of relay coils I1 and I6 is con nected to the midpoint of an A. C. transformer 2I by a/ relay lead 22, and the ends of relay coils I1 40 and I6 lead to cathodes 26 and 24 of a pair of double thermionic tubes 21 and 26. While it will be obvious to those skilled in the art that the double cathode tubes herein to be described are the full equivalent of four separate tubes,- sim 45 piicityfof wiring makes the double tube more ad vantageous. . . , Considering the tube assembly for operating the differential relay, the primary 26 of the trans former 2| is attached to station A. C. leads II , and 50 one end of the secondary is connected directly to anode26 of the tube 21 and to anode 20 of tube 26. The other end of the secondary of trans _former 2I goes to another anode II in the tube 21 placed on the opposite side of cathode 2l, and 55 similarly to a second anode 32 in tube 26. Thus> the anodes similarly positioned in both tubes are in parallel, and opposite anodes are connected to` opposite ends of the secondary of transformer 2I primary. Simplex channel 48 is not available for When the telephone pair 44 reaches the tran scribing station it enters a hybrid coil and bal ancing impedance network 46’ similar in all re« spects to the one at the receiving station. Sec ondary 41 of assembly 46’ leads to a pair of receiv ing telephones 48 or a loud speaker, as _the case may be. Alternating current is supplied to the hybrid coil of assembly 46’ through control leads 49 attached to the primary of the hybrid coil and directly to the line, and leads 49 emerge from a reversing switch 50 which is supplied by the sec ondary 5I of a control power transformer 52, the primary 53 of which is attached to the A. C. power lines 9, these being supplied by the same power system that supplies the. receiver. Having described the circuital arrangement of our invention in its lowest terms, we will now de scribe the operation: , The receiver I is tuned roughly by hand, b the operator in charge of the receiving station, to the center of the general frequency band from which signals are to be transcribed, and the re mote control tuning condenser 3 is rotated so that it is in the midpoint of the tuning range desired. 30 If coarse tuning with a large range is desired, the band 4spread condenser 2’ is set to a high ca pacitance, while if fine tuning with a smaller range is desired, it is set to a low capacitance. Signals thereupon emerge from the receiver I, pass along line 46 to hybrid coil 43, and thence over the telephone pair 44, through the. hybrid coil of assembly 46', and are heard at the tran scrlbing station through receiver 46. The oper ator listens to the signals, and if he finds that he 40 wishes to change the tuning of the receiver he operates reversing switch 60. The circuit dia gram gives, by means of'plus and minus signs, the phase conditions that> will exist at one particular point in the A. C. cycle, when the arm of the re 45 versing switch is h_eld to the left. Y For example, let us suppose that reversing switch 66 is in the midpoint so that no A. C. en ergy is passing into the telephone pair. Under these conditions all grids of the two tubes are maintained at a uniform bias by means of bias batteries 6I and 62, and the anode current through both tubes is equal and oppositely directed with respect to the magnetic field in coils I1 and Il, thus balancing the arm I6 of the diiferentiai 55 polar relay midway between contacts Iland the motor does not turn. When, however, it is de sired to run the tuning motor. reversing switch 60 and will thus be always out of phase in the same , may be operated either to the left or right, and a small amount of A. C. power passes into the Two grids are provided for each tube between the cathode and each anode. In tube 21 grids I3 and 34 are connected to the ends of secondary 25 of grid transformer 3l. Similarly, in tube 26. 65 grids 21 and Il are placed between cathode 24 and local hybrid network. Due to the balance of the local hybrid network this power does not reach the local receivers, but a portion of its goes out over the telephone pair to the hybrid network at the receiving station, where balancing network anodes 20 and 22, and are connected to the ends "of a second grid transformer 4I. 'I‘he primaries 4I andk 42 of transformers I6 and 4l are connected together in parallel. but in reverse phase. and are supplied with energy from secondary 42' of hybrid coil 43, which is connected to standard telephone 4l is preventing-the receiver signals from oper -ating the motor.' The A. C. power, however, will pass through hybrid coil 42 directly to grid trans formers I6 and 40 and all four grids will be ener gized. However, as the primaries 4I and 42 of line 44 leading to the transcri ing station through the medium of the hybrid coil 43 and balancing nected in parallel in opposite phases, not only will impedance 4I, asy iseustomary in the art when 76 energy flowing in opposite directions 1S handle@ grid transformers 36 and 40 respectively are con the potential on each grid of the same tube be opposite, but the phase of each grid will be re versed in ac. )rdance with thc phase of the in 75 aliases 3 Seen that if the reversing switch be held to the multiplication of frequencies, such as are well known to the art. It will also be apparent that the tuning motor left, then tracing through the polarities, the upper CFI right grid is also positive, permitting current flow to the upper filament, while in each of the three remaining combinations of anodes and grids either plate or grid is negative, preventing in system, which need not be in synchronism with coming alternating current, whereas the phase on the anodes will not be changed. Thus it will be crease of current flow. One half-cycle later the left upper grid and left upper plate will be posi tive, so that current will still ñow to the upper filament. Thus, as long as the reversing switch is held to the left a pulsating double frequency cur rent is passed through the upper filaments to 15 the upper coil I8 of the differential polar relay, deflecting the arm I6 of the relay upward, thus energizing forward contactor 6 and running con tactor 8. If the reversing switch be held to the right the two sides of the lower tube become alter 20 nately active, de?lecting the arm I6 of the relay downward and energizing the backward contactor 1, which supplies current to the motor in reverse phase, and the motor reverses. When the revers ing switch is again left open and no A. C. power 25 passed into theA line the tube system immediately balances again, the relay de-energizes, and the motor stops. Inasmuch as the running contactor 8 is energized by the closing of either the forward or backward contactor of the tuning motor, the motor will always run, irrespective of whether a forward or backward connection is used. Thus the operator is able to listen to the signals, and with one hand manipulate reversing switch 50 to change the tuning of the receiver slightly, as he 35 desires. When using heterodyne equipment, the operator will be able to tell by the tone heard in his receiver whether he is approaching the signal need. not be driven, as we have shown from the common A. C. power system. The motor arrange Gl ment shown is desirable, but we deem as full equivalents thereof the use of a separate power the common system, or a direct current motor, or the use of mechanical reversing means actuable 10 by the polar relay system shown. We claim: l. Apparatus for remote control comprising a two-wire line to apparatus to be controlled, comprising four cathode-anode current paths in each of which is disposed a control electrode, means for so energizing said anodes from an al ternating current supply system that two of said anodes shall be in phase opposition to the re maining two of said anodes, means for passing 20 current from said A. C. supply system over said two-wire line, means for impressing said A. C. supply system current upon two of said control electrodes in similar phase relationship, and upon the remaining two of said control electrodes in phase opposition thereto. 2. Apparatus for remote control comprising a two-wire line to apparatus to be controlled, two full-wave grid-controlled rectifying units, hav ing four cathode-anode current paths, with a 30 grid disposed in each of said paths, having two anodes of said rectifying units energized in paral lel from a commercial alternating current power source, and the remaining two anodes thereof energized in parallel from said source in phase 35 opposition to said first mentioned anodes; means for directing current from said commercial A. C. power source onto said two-wire line at a control or receding from it, since the pitch of the beat station, means associated with said rectiñer units note heard will vary in accord with the relation -for applying current from said control station 40 of the signal frequency to the local oscillator fre over said two-wire line to two of said grids in quency. If the direction‘of tuning is incorrect, the operator may reverse it by throwing the switch 50 to the other side. To maintain the proper phasal relations at the double anode tubes, 45 it is obvious that suitable phase shifting equip ment may be used, such phase shifting means being well known in the art. g The amount of A. C. power passed through the telephone pair need only be small because of the amplification of the tube system utilized at the receiving station, and as it is straight alternating current no interference with standard telephone equipment is encountered, and both signals and tuning power can thus be passed over telephone pairs where only audio frequency rights are avail able. ' With some telephone lines the repeating equip ment available does not have a low frequency range adequate to care for the transmission of 60-cycle signals; with others, there may be in terference between the ringing currents and the tuning equipment.' In such cases it is obvious that we may use frequencies higher than 60 cycles, which would, however, be tied together as between the transcribing station and the receiving station through the medium of the common alternating power system as described. For this purpose, it is obvious that frequency multipliers may be used at both ends of the two-wire line, involving syn chronous motors and generators, saturated-core transformers which generate harmonics of the power supply frequency, the use of a series of passive full-wave rectiñers serving as frequency doublers, or any other Similar equipment for the phase similarity, and to the remaining two grids in phase opposition thereto, and means for changing the phasal relation of the current ap plied to said grids relative to that on said anodes; a motor actuated by said A. C. power source, and means for controlling the direction of actuation of said motor responsive to the output of said rectiíier unit. 3. Apparatus for remote control, including a two-wire line over which audio-frequency rights only are available, which comprises a motor oper able by direct current in direction responsive to the direction of flow of said current, means for producing a pulsating direct current from a com mercial A. C. source, means for controlling the direction of said current in accord with the phase relations between said A. C. supply and an alter nating current received over said two-wire lines, and means at a control station for directing an alternating current over said line and changing the phase relation thereof to said A. C. supply. 4. Apparatus for remote control from a sta tion connected to controllable apparatus by a two wire line over which audio-frequency rights only are available, comprising means for impressing current uponY said line at said station from a commercial ALC. power supply system, means at said receiving station energized lfrom said com mercial A. C. power supply system for produc 70 ing a pulsating direct current at said apparatus to be controlled, means actuated by current re ceived over said two-wire line for controlling the direction of flow of said pulsating direct current, and means responsive to the direction of flow of 75 4 2,112,446 said pulsating direct current for directly con trolling said apparatus. 5. Apparatus for remote control from a control station connected by a two-wire line over which audio-frequency rights only are available to rotationally controllable apparatus, comprising means for impressing current from an A. C. power supply system upon said two-wire line at said control station, means energized from said A. C. 10 power supply for producing a pulsating direct current at said controllable apparatus, means for controlling the direction of Ilow of said direct current in accord with the phasal relations be tween the current from said A, C. power supply applied to said D. C. producing means and that received from said two-wire line, and directly controlling means energized by said pulsating direct current and responsive to the direction of said current ilow. 6. A device for remote control of rotationally controllable apparatus from a station connected by a two-wire line over which audio-frequency rights only are available to said apparatus which comprises a reversible tuning motor, a diiïerential 25 polar relay through operation of which the direc tion of rotation of said motor may be changed, two full-wave rectifier units having anodes, grids, and cathodes, two of said anodes being energized in phase, and two in phase opposition from a com mercial A. C. power supply, means for connecting said differential relay to said rectiñer units where by the direction of actuation o1' said relay is dependent; upon the grid energization of said rectifier unit, and means for directing a current 5 from said A. C. source at said control station to said rectiiier unit and for controlling the phase relation of said current to said anode energization. 7. Means for remotely controlling the rota tional position of apparatus connected to a control station by two wires on which only audio-fre quency rights are available, comprising a rever sible motor, a polar relay arranged to control the direction of rotation of said motor, two full-Wave rectifier units having anodes, cathodes, and con trol grids disposed within an evacuated envelope. two of said anodes being energized in phase and two in phase opposition from a commercial A. C. power supply, said relay being so connected and arranged with said rectifier units that the direc »tion of relay actuation is dependent upon the grid energization of said units, means for direct~ ing a current from said A. C. source at said control station to said rectiñer unit, and means for con trolling the phase relation of said current to said anode energization. ~ CHESTER PELMULDER. HANS O. STORM.