US1501726A - Signaling system - Google Patents

Description

July 15 1924.

1,501,726 C. W. RICE SIGNALING SYSTEM Filed June 5, 1919 Inventor: Chester W.Rice,

' His .i'" Lt,TT1@S Patented July 15, 1924.

H UNITED STATES 1,501,726 PATENT OFFICE.

CHESTER W. RICE, F SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

} SIGNAIJNG SYSTEM.

Application filed June 5,

To all whom it may concern:

Be it known that I, CHEs'rER W. RICE, a citizen of the United States, residing at Schenectad in the county of Schenectady,

State of ew York, have invented certain new and useful Improvements in Signaling Systems, of which thefollowing is a specifioation.

. My present invention relates to signaling systems and more particularly to a system for receiving signals and producing an audible indication of the signals received.

The object of my invention is to provide a system for producing an audible indication by means of signaling currents of inaudible frequency, and especially si naling currents of a frequency below audibi 'ty.

The novel features which-I believe to be characteristic of my invention are set forth with particularity in the appended claims, the invention itself however both as to its organization and method of operation will best be understood by reference to the following description taken in connection with the accompanying drawing in which I have indicated diagrammatically in Figs. 1, 2 and 3 three different ways in which my invention may be carried into eifect.

My improved system as indicated in the drawing makes use of a Wheatstone bridge having the usual four arms 1, 2, 3 and 4. Arm 1 includes the plate circuit. of an electron discharge relay 5 having a cathode 6, an anode 7 and a grid 8 enclosed in an evacuated envelope. Arm 2, as indicated in Figs. 1 and 3, is made up of a resistance 9 and a condenser 10, and arms 3 and {l are made up of resistances 11 and 12 respective ly. A source of current 13 ofaudible fre quency is connected to the opposite terminals .14 and 15 of the bridge and a signal indicating device, which in the present case is the usual telephone receiver 16, is connected to the othertwo opposite terminals 17 and 18. Condensers 19 and 20 are preferably inserted in series with the receiver. A source of direct current 21 is included in series with the source of audible frequency current 13 for the purpose of supplying the normal constant current for the operation of the electron discharge relay 5. The electron discharge relay is provided with a grid circuit which includes the grid 8, a resistance 22 and the cathode 6 of the device. The arms of the bridge are so adjusted that under normal 1919. Serial no. 301,987.

conditions a balance is obtained and no current will flow through the receiver 16. The

signaling-current supplied from the conductors 23 and 24: is then caused to flow throughresistanoe 22 and thus produce a variation in potential of the grid 8. As a result the resistance of the electron discharge relay 5 is varied and the balance of the bridge is u set. Current from the source Fig. 2, the arm 2 of the bridgeis also made up of an electron discharge relay 25, the grid 26 of which may if desired be permanently connected to the cathode 27. In some cases the use of a second electron discharge relay will enable the desired balance of the bridge to be obtained more readily. By varying the potential of the grid by means of a source of potential 30 the resistance of relay 25 may be varied and the desired balancing of the bridge obtained. In some cases where the signaling current is of extremely small intensity the resultant variation in the balance of the bridge may be too small to produce a" suflicient flow of current thro'ughthe receiver 16 to produce the de sired indication. In such case the audible frequency current may be caused to flowthrough. a resistance 28 which is included in the grid circuit of an electron discharge amplifier 29, the receiver 16 in this case being included in the plate circuit of this amplifier. The final balancing of the bridge may be effected conveniently by variation of resistances 30 which are included in the filament heating circuits.

The system which I have described is adapted to a great variety of uses among which is the reception of continuous wave radio telegraphic signals which, as is well known, will' produce no audible indication in the ordinary receiving devices unless they are combined with locally produced waves according to the well known heterodyne method or broken up into groups by the so called ticker method. My invention permits of the reception of such signals without recourse to the expedients mentioned.

While I have indicated three modificaemployed without departing from the scope of my invention as set forth in the appended claims.

What I claim as new and desire to secure it by Letters Patent of the United States, is

l. The combination in a signaling system of a source of signalingtcurrent of-inaudible frequency, a lVheatstone bridge, a source of current of audible frequenc connected to two opposite terminals of sai bridge, a rec'eiving device connected to the other two opposite terminals of said bridge, said bridge being normally so adjusted. that no audible frequency current will flow through said receiving device, an electron discharge relay in one arm of said bridge and means actuated by the signaling current for vary-- ing the resistance of said relay and there-- by causing an audible frequency current to flow in said receiving device.

2. The combination in a signaling system of a source of signaling current of inaudible frequency, a l Vheatstone bridge, a source 015 current of audible frequency connected to two opposite terminals of said bridge, a receiving device connected to the other two opposite terminals of said bridge, said bridge being normally so adjusted that no audible frequency current will flow through said receiving device, an electron discharge relay havin a plate circuit included in one arm of sai bridge, a grid circuit for said relay and means for impressing the signaling current u on said grid circuit.

3. The com ination in a signaling system of a source of signaling current of inaudible frequency, a Wheatstone bridge, a source of current of audible frequenc connected to two opposite terminals of said bridge, a

receiving device connected to the other two opposite terminals of said bridge, said brid e being normally so adjusted that no audi le frequency current will flow through said receiving device, two electron discharge relays in two of the arms of said bridge, and means actuated by the signaling current for varying the resistance of one of said relays and thereby causing an audible frequency current to flow in said receiving device.

a, The combination in a signaling system of a source of signaling current or" inaudible frequency, a Wheatstone bridge, a source of current of audible frequency connected to two opposite terminals of said bridge, a receiving device connected to the other two opposite terminals of said bridge, said bridge being normally so adjusted that no audible frequency current will flow through said receiving device, two electron discharge relays having plate circuits included in two of the arms of said bridge, a grid circuit for one of said. relays and means for impressing the signaling current upon said grid circuit.

5. Apparatus for amplifying electrical currents comprising a Wh'eatstone bridge having a tri-electrode device connected by its plate and filament electrode in one of the branches of the bridge, with the circuit carrying the current to be amplified connected between the grid and filament, and an indicator connected across said bridge.

6. Apparatus for. am lifying electrical currents comprising a eatIstone bridge having two t-ri-electrode devices connected by their plate and filament electrodes in two of the branches of the bridge with the circuit carrying the current to be amplified connected between the rid and filament of one of said devices an an indicator connected across said bridge.

in witness whereof, I have hereunto set my hand this 23rd da of May, 1919.

CH ESTER W. RICE.

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