US2142218A - Radio signaling - Google Patents

Description

Jan. 3, 1939. J. A. SPENCER ET Al.

RADIO S IGNALING Filed Aug. l5, 1936 III.' i

A'AAAAA nAAA A AAAAAA INVENTORS JAMES A. SPENCER AND RICHARD E. MATHES BY Wg ATTORNEY Patented Jan. 3, 1939 t n UNITED STATES PATENT OFFiCE RADIO SIGNALING James A. Spencer, Teaneck, and Richard E.

Mathes, Westfield, N. J., assignors to Radio Corporation of America, a corporation of Delaware Application August 15, 1936, Serial No. 96,162

4 Claims. (Cl. 250-8) This invention relates to radia relaying and The plate current of tube 26 flowing through coil receiving systems. 40 opens the contacts 42 of polar-relay 46, 42, 44,

One object of this invention is toy provide a in turn breaking the circuit through the comradio relaying system employing printen-transbined printer-transmitter apparatus 46, which is mitter apparatus in which received radio Waves normally supplied with operating current from 5 are utilized to actuate the printer apparatus withthe lead 48. out affecting closely associated transmitter ap- In the presence of a signal upon antenna A, paratus. A further object is to provide a'circuit the resulting tone passed on to the rectifier tube arrangement having impedance balanced 6 cuts off current to the anode I6 of the rectifierbranches associated with a demodulating system amplifier tube6. The blocking of tube 6 cuts off 10 for ultra short waves, which balanced circuit arcurrent flow through the resistors i2, I4 whereby rangement is effective to actuate printer mechathe' 'grid 20 of tube 24 is at ground potential. nism, but during such actuation is ineffective to However, since current is flowing through reoperate a closely associated transmitting device. sistance 32, the cathode V50 of tube 24 is at such It is a further object, however, to arrange this a positive potential with respect to ground that transmitting device so that it may be utilized at tube 24 blocks. This action raises the potential times for transmitting an independent signal to of grid 34 with respect to its cathode 38 of tube 'another receiver in the relay system. 36, causing current ow through tube 36 and Further objects, advantages and features 0f the hence through coil 44. Simultaneously, while this 12o present invention will be apparent from a Conaction is going on, tube 2S blocks for the reason 20 sideration of the accompanying drawing, taken that current flow through the resistors 3a, 32 has together with the following more detailed specifisimultaneously held the potential of cathode 52 cation. at positive potential with respect to ground, cut- The accompanying drawing illustrates in wirting off tube 26.

a5 ing diagram form a preferred modification of our Cessation of current flow through coil 40 and 25 radio receiving and retransmitting system. actuating current flow through coil 44 thereupon Turning to the drawing, modulated short Wave closes contacts4 42 and permits current to flo-W signals received upon antenna A are fed into a through the printer mechanism 48. In this way, radio receiver RR whose detected output is fed the printer 46 is actuated by the incoming signals 3o into a tone filter TF. The received tones are fed received upon antenna A without affecting in any 30 through a transformer T into a vacuum tube way the transmitting contact TC. The reason amplifier VA. The output of the amplier is fed for this is that the contacts TC are the contacts to a Second transformer T2 aCTOSS the plates 2, 4 of a polar-relay having impedance-balanced coil of a combined amplier-detector tube 6. T0 sections 54, 56 through which current changes smooth out the rectified tone, a lter F, consisting equally when contacts 42 are opened and closed. 35 of a resistance and condenser in-parallel, is pro- Equal changes through the coil sections 54, 56 vided. The Output 0f the I'eCtieI iS then imdo not affect the transmitting contacts TC. pressed upon the grid 8. as indicated. Causing However, when the transmitting contacts TC amplied, rectified current to flow to the plate l0 are opened and closed, and the transmitter sec- 0f the Combined detector, direct current amplifier tion of the apparatus 46 is actuated, the cathodes 40 tube 6. This amplied Current flows through the 5s, 6o of tubes 62, 64 are combined in potential resistors l2, I4 which form a series connection With respect to the grids of tubes 62, 34 which, as between the Cathode I6 0f tube 6 and groundindicated, are maintained at ground potential In the absence 0f Slgnal Current passes t0 plate and supplied with tone from a tone transformer m of tube E Since the grid 3 is at the potential of 66. With the contacts TC closed the cathodes 45 cathode I6. Consequently, current flows to the assume such potential with respct to ground plate 'o and through resistors l2 m' AS a conse' that tone fed into transformer 66 reappears in queme the Control grlds 2e 22 of tubes 24 25 amplied form in the output transformer 68.

become positive and both tubes 24, 26 pass plate 5o Current Plate Current flow through tube 24 Th1s tone is then fed through a iilter 'lll to moduows through resistors 28, 30 and 32, thereby im late waves generated in a radio transmitter 12, pressing a negative potential on the grid 34 of Whlch modulated waves are then radiated over tube sa with respect to the Cathode 3s of that the transmitting antenna TA to any Suitable tube. As a result of this action, plate current TeCeVng StatiOIl. 55 flows through tube 26, whereas tube 36 is cut 01T. When the contacts TC' are open, cathodes 58, 55

60 of tubes 62, 64 assume a relatively high positive potential with respect to ground, as a consequence of which tubes 62, 64 block and no tone is impressed upon the radio transmitter 12.

The printer-transmitter 4B is preferably of the type known to the art as the Teletype model I4.

It is to be noted that the printer-transmitter apparatus 46 may be connected at some distant point through the intermediary of a suitable landline (not shown) in which case separate positive supply voltages may be supplied at the points marked Y, Y. It is to be understood that this system may be used as part of a radio repeating system or as a link between a radio receiving station and a landline system, it being noted that the printer-transmitter apparatus 46 may be replaced by several printer transmitters connected in series.

Power supply for the various tubes involved may be derived from the power supply circuits PS which are believed to be self-explanatory, it being noted that the heaters of the various tubes are connected to the points marked X, X.

For transmitting purposes, the tone filtered through lter 'l0 may be rectified and used to key the transmitter 'l2 or it may be used to tone modulate radio waves generated at the transmitter 12.

What is claimed is:

1. In combination, means for receiving a keyed and tone-modulated code signal, means for demodulating the signal so as to obtain the keyed marking and spacing components thereof, a pushpull circuit operable under control of the keyed components of said signals, a polarized relay symmetrically disposed in said push-pull circuit, a circuit having impedance-balanced branches and including the coils of a second polarized relay and contacts operativebythe rst said relay,transmitting contacts operable by the second said relay, a telegraph printer andkeyer inone of said branches, radio transmitting apparatus connected to said transmitting contacts, and means including further circuit arrangements such that said telegraph printer is caused to respond to code signals as received, demodulated, and impressed upon both of said relays, while said transmitting contacts remain undisturbed, and said radio transmitting apparatus is caused to respond only to keying operations initiated by said telegraph keyer for sending code signals through said second relay and the transmitting contacts thereof.

2. Radio telegraph apparatus comprising separate transmitting and receiving channels and a. telegraph instrument having a receiving and keying circuit common to both channels, in combination with means including a. push-pull electron tube circuit responsive to received code signals for causing said instrument to record the intelligence Aof said code signals while maintaining said transmitting channel idle, and means including a polarized relay in a circuit having impedance-balanced branches, one of which contains said instrument for causing code signals to be sent out over said transmitting channel under control of said instrument.

3. Apparatus in accordance with claim 2 and including means for demodulating the received code signals when they consist of tone-modulated signaling elements, and means for applying tone modulation to the transmitted signals when they are keyed by said telegraph instrument.

4. Radio telegraph apparatus comprising separate transmitting and receiving channels and a typewriting telegraph unit having a receiving and keying circuit common to both channels, in combination with a tone frequency potential source, a push-pull amplifier the bias of which is adapted to be varied by keying from full cut-off to a normal amplifying condition thereby to transmit code signals modulated by said tone source, an electro-magnetic relay operable by said typewriting telegraph unit to control the bias on said amplifier, and means including a polarized relay under control of received code signals for rendering said typewriting telegraph unit responsive without influencing said amplier and its associated transmitting channel.

RICHARD E. MATHES. JAMES A. SPENCER.

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