US1394600A - Wireless-telegraph receiver - Google Patents

Description

G. M. WRIGHT.

WIRELESS TELEGRAPH RECEIVER.

APPLICATION HLED JUNE 8,1916.

1,394,600.. I Patented Oct, 25, 1921.

nears m PATENT @FFHQE.

GEORGE MAURITOE 'WRIGHT, OF LONDON,

ENGLAND, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO RADIO CORPORATION OF AMERICA, A CORPORATION OF DELAWARE.

WIRELESS-TELEGRAPH RECEIVER.

noises due to atmospherics shall be so re-" duced that they do not overpower the sounds due to the signals it is desired to read. It has before been proposed to magnify the received signals by the employment of a circuit including a valve or vacuous tube containing an anode, a screen and a hot filament.

According to the present invention such a valve or vacuous tube containing an anode, a screen or grid and a metallic or carbon filament is employed but the filament is only heated to such a degree that there is no magnification. A valve in such a condition is not able to pass more than a certain definite amount of current and the currents due to atmospherics are therefore reduced to the dimensions of those due to the signals, and the noise in the telephone is no greater than the notes produced by the signals. If the sounds are too weak an ordinary magnifying valve circuit may be interposed between the circuit. The natural resistance of the aerial may then be made considerable so as to damp the atmospherics while the effective resistance is reduced by the interaction of the incoming and outgoing circuits of the valve.

The invention is illustrated by the accompanying drawing in which Figure 1 is a diagrammatic view of the preferred form of apparatus for carrying out my invention.

Fig. 2 is a diagrammatic view of a modi fied form of apparatus by which the invention may be practised.

Fig. 3 is a diagrammatic view of a third form of apparatus embodying my invention.

11 Fig. 1, a is a vacuous tube inclosing a filament b heated by a. battery 0, a grid or Specification of Letters Patent.

Application filed June 8,

Patented Oct. 25, rear. 1916. Serial No. 102,509.

screen d completel inclosing the filament and an anode e. A n inductance f shunted by a condenser g is connected to the grid and to, a resistance It across the battery 0 and is coupled to an aerial 2'. A second inductance 7c shunted by a condenser Z is connected to the anode and through a high tension battery m to the filament and is coupled to a receiver a. The two systems f g and is Z should have the maximum inductance possible and the minimum capacity.

A coil 0 in the system 7" g is arranged to react with the system 70 Z so that no signals however strong can get through unless the valve is alight. Without such a coil signals may get through owing to the capacity of the valve, the eads, etc.

The filament is run at such a brilliancy or rather dullness that the strength of the signals in the receiver is less than or at most no greater than that which they would have if the receiver were coupled directly to the aerial.

By this means the strength of atmospherics is limited to that of the signals.

In practice it is found that greater sensitiveness with better limiting is obtained if the stream of electrons be directed along a narrow path by means of a magnet 9.and also if only a small portion of the filament be covered with electron emitting material such as lime instead of the whole of the filament being covered.

Fig. 2 shows a similar arrangement except that, to prevent signals getting through owing to the capacity, shunting condensers p p and a choke coil 9 shunted with a condenser 'r are employed in place of the reaction coil 0. This method, however, is more troublesome and no more effective than the reaction coil.

Fig. 3 shows an arrangement in which the aerial, which is coupled directly to the receiver, includes a resistance 8 and is coupled to the two inductances 7 and is connected to a valve as in Fig. 1.

The valve is used so that there is slight magnification and thus for the narrow limits within which owing to the dullness of the filament it can magnify, the resistance 8 is neutralized. The resistance is thus efi'ective for the large amplitudes of atmospherics but is neutralized for the weaker amplitudes of signals.

In view of the principles disclosed inthe foregoing specification, those skilled in the art can rearrange and add to the apparatus herein shown without difiiculty but without departing from the spirit of my invention.

What I claim is 2- 1. In a wireless telegraph receiver, a vacuous tube, an anode, a grid and a filament all contained in the tube, means for heating the filament, an inductance connected in series with the grid and the filament, and a second inductance connected in series with the anode and the filament, the filament being only heated to such a degree that there is no magnification.

2. In a wireless telegraph receiver, the combination of an aerial, .a vacuous tube, an anode, a grid and a filament all contained in the tube, means for heating the filament, an inductance in series with the grid and filament and coupled to the aerial and a second inductance in series with the anode and the filament, the filament being only heated to such a degree that there is no magnification.

3. In a wireless telegraph receiver, a vacuous tube, an anode, a grid and a filament all contained in the tube, means for heating the filament, an inductance connected in series with the grid and the filament, a second inductance connected in series with the anode and the filament, the filament being only heated to such a degree that there is no magnification, and a capacity across each inductance.

4. In a wireless telegraph receiver, a vacuous tube, an anode, a grid and a filament all contained in the tube, means for heating the filament, an inductance connected in series with'the grid and the filament, a second inductance connected in series with the anode and the filament, and a capacity across each inductance. the filament being only heated to such a degree that there is no magnification, and the two inductance circuits being arranged to interact on one another.

5. The combination of an aerial a resist ance forming part thereof, a vacuous tube, an anode, grid and filament contained there in, means for heating the filament, an inductance coupled to the aerial and connected in series with the grid and the filament, and a second inductance coupled to the aerial and connected in series with the anode and the aaaeoo filament, the filament being-only heated to such a degree that there is not more than very small magnification.

6. The method of reducing the effects of interfering currents in a radio receivin circuit including an evacuated vessel havlng a cathode and two anodes which consists in impressing the signal and interfering potentials on a circuit connected to the cathode and one of said anodes and limiting the maximum electron flow to substantially the value produced by the maximum signal potential and receiving said electron flow through a circuit connected to the cathode and the other of said anodes.

7. The combination with an aerial of an evacuated tube, a plurality of electrodes in said tube including a filament, a grid and an anode, a source of continuous current connected between said filament and anode, an inductance coupled with said aerial and connected to said grid and filament whereby the oscillations received by said aerial-will affeet the electron stream from said filament and means for limiting the normal heating of said filament to such a degree that there is not more than slight magnification.

8. The method of operating a receiving circuit including an evacuated vessel having a plurality of electrodes therein, one of which is heated sufficiently to give off electrons, said method comprising impressing the current to be received on said circuit and maintaining said heated electrode at so low a temperature that there is not more than a slight magnification of the received current in the portion of the receiving circuit throughsaid vessel.

9. The combination with a transmission circuit, of an evacuated tube, a plurality of electrodes in said tube including a filament, a source of continuous current connected between said filament and another electrode, an inductance coupled with said transmission circuit and so connected to certain of the elements associated with said tube that the oscillations received by said transmission circuit will afl'ect the electron stream from said filament, and means for limiting the normal heating of said filament to such a degree that there is not more than a very small magnification.

GEORGE MAURICE WRIGHT.

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