US1675889A - Electric wave signaling system - Google Patents

Description

FIPBIOZ OR 196759889 July 3, 1928.

. A. w. KISHPAUGH ELEGT'RIC WAVE SIGNALING SYSTEM 'T3514 Filed April 28, 1925 y wi :Luksic x irivlr-uul Panarea July s, 192s.

PATENT @ENCE ARTHUR W. KISHPAUGH, OF EAST ORANGE, NEW JERSEY, ASSIG-NOR, BY MESNE AS- SIGNMENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

ELECTRIC WAVE SIGNALING SYSTEM.

Application led April 28, 1925. Serial No. 26,334.

This invention relates to electric wave signaling systems and more particularly to means for supervising the operation of a radio transmitter.

An object of the invention is to improve monitoring systems for producing an indication as to the quality of signals in an electric Wave signaling system.

An additional object is to indicate the operative condition of a radio transmitter and to indicate the nature of the trouble if the system is inoperative.

Another object is to localize the trouble in a radio transmitting system.

A further object of the invention is to enable supervision of the operation of a radio transmitter.

A feature of the invention is a rectifier capacitively coupled to a transmitting circuit and arranged to operate a visible signal and a loud speaking receiver to enable monitoring of transmitted signals.

To indicate the presence of signal Waves in a transmitting conductor, such as a radio antenna, a rectier is coupled to a condenser in circuit with the conductor and arranged to operate a plurality of indicating devices for giving diierent indications as to the condition of the circuit. One indicator may, for example, be an electric lamp which is lighted during the time current flows in the rectifier to show that it is operative. Another indicator may be a loud speaking receiver which is operated by the rectified signal modulated waves from the transmitting conductor to reproduce the signals so that a listener may know of their presence in the antenna circuit and may be informed of their quality and of the effectiveness of the modulating system.

The invention is illustrated in the figure of the drawing wherein a monitoring circuit is shown connected to the antenna of a radio transmitter.

The circuit shown in the drawings comprises a source of signals 10, represented as a telephone transmitter, arranged in series with a battery 11 and the primary winding of an audio frequency transformer 12. The secondary winding of this transformer is arranged to supply signal waves to a radio transmitter circuit represented by block 13. This transmitter circuit may be any one of many well known forms such, for example, as that disclosed in Patent No. 1,442,146 to R. A. Heising, January 16, 1923, wherein high frequency waves may be modulated in accordance with signals and supplied to the terminals of adjustable condenser 16. This condenser is arranged to couple the transmitter 13 to an antenna 14 to which it is connected in series with an adjustable inductance 15. By means of the inductance 15 and condenser 16, the antenna circuit may be tuned to the frequency of carrier waves supplied from transmitter 13.

Shunted around condenser 16 is a path including a series of condensers 17 and 18 having capacity such that considerable impedance is offered to high frequency waves. A rectifier including a space discharge tube 19 having ,a heated cathode 20 and an anode 21 has its electrodes connected to the terminals of condensers 18 by a path which includes a blocking condenser 22 of such capacity as to prevent th-e passage of rectified current into a high frequency portion of the rectifier circuit but to readily pass high frequency waves. There is also connected to the anode and cathode of tube 19, a path for rectified currents which includes a high frequency choke coil 23 for blocking high frequency currents, a resistance 24, the primary winding of an audible frequency transformer 25 and the winding of the relay 26. Resistance 24 or impedance is provided to supply the proper impedance in the path of rectified currents. The secondary winding of transformer 25 is connected to the terminals of a loud speaking receiver 27 to which rectified signal waves are supplied and from which audible signals are obtained, corresponding to the waves produced by source 10. Relay 26 has a movable armature 28 arranged to close a contact 29 in a circuit including a battery 30 in series with electric lamp 31.

In the operation of this system, signal waves supplied from source 10 are caused to modulate high frequency waves in transmitter 13, and the resulting modulated waves are supplied to antenna 14 through coupling condenser 16. A small portion of the energy of modulated waves in the antenna circuit is supplied through condensers 17 and 18 to the rectifier 19. These waves readily pass through blocking condenser 22 which is of relatively large capacity. Rectified signal waves are supplied from tube 19 to the path including the transformer 25 and relay 26, high frequency waves from the antenna circuit are prevented from passing directly into this path by virtue of the impedance of choke coil 23. The rectied currents are maintained at a suitable value by means of the impedance 24 and signal Wa ves resulting from the rectification are supplied by transformer 25 to the loud speaker 27.

Rectified current flowing through the the winding of relay 26 maintains its armature against 29 thereby closing the circuit of lamp 31 which remains lighted as long as high frequency waves of sufficient energy are present in the antenna circuit.

A listener hearing the signals reproduced by loud speaker 27 is informed that the Waves present in the antenna are modulated and hence that transmitter 13 is functioning properly, since the presence of signal modulated waves in the antenna circuit is indicated. Should no signals be heard in the receiver 27, two conditions may be present in the circuit, namely, no signal waves may be present in the antenna circuit owing to the inoperativeness of the transmitter 13 or the rectifier 19 may be inoperative. The latter condition is indicated by the signal lamp 31 remaining dark, showing that relay 26 is inoperative and that therefore no rectified current is fiowing. If lamp 31 is lighted, and no signals are heard in the loud speaker 27, the presence of carrier waves in the antenna circuit is indicated and the operator is informed that signals may be impressed from source 10 with the assurance that they will be transmitted unless the modulating apparatus is defective. If the lamp is lighted and no signals are heard then the trouble is localized in the speech input or modulating apparatus.

The present invention is of considerable importance in connection with radio broadcasting systems where a close supervision of the operation of the transmitter is eX- tremely desirable. The coupling condenser arrangement for supplying Waves to the rectifier 19 has important advantages among which are simplicity and ease of connection, economy in construction and the elimination of complex coupling arrangements heretofore used in similar arrangements.

Although the invention is described in connection with a specic embodiment, numerous modifications employing the principles of the invention will occur to persons skilled in the art, consequently the invention is to be limited only as indicated by the scope of the appended claims.

hat is claimed is:

1. A monitoring system for modulated high frequency waves comprising a single pick-up means for the waves, one device supplied by said pick-up device for indicating the presence of the waves and another device for indicating the presence of and the nature and effectiveness of the signaling variations therein.

2. In an electric wave transmission system, an antenna, a source of signal modulated carrier waves coupled to said antenna, a rectifier, a capacity coupling between said rectifier and said antenna, said coupling including a plurality of condensers and a plurality of indicating devices responsive to waves from said rectifier.

3. In a radio transmitting system, means for producing signal modulated carrier waves, an antenna, a capacity coupling for said antenna and said means, and a rectier connected to said coupling and arranged to operate a plurality of signal devices adapted to give different kinds of signals.

4. In combination, a radio transmitter including an antenna, a rectifier, a capacity coupling between said antenna and said rectifier for applying modulated Waves from said transmitter to said rectifier, a path of high impedance to modulated waves, and of low impedance to Waves of modulating frequency connected to said rectifier, and means in said path for operating a visible signal and a sound reproducing device.

5. In combination, a radio transmitter and a radio receiver, an antenna circuit, said transmitter and receiver being capacitively coupled to the same points in said antenna circuit, said receiver including a rectifier and a plurality of devices for produring signals of different kinds coupled thereto.

6. In combination, an antenna, a radio transmitter circuit coupled to said antenna, a radio receiving circuit also coupled to said antenna, a rectifier in said receiving circuit arranged to receive modulated signal waves from said transmitter and to derive signal frequency waves therefrom, a lamp signal normally operated by current from said rectifier, and a sound reproducer arranged to receive signal frequency Waves from said rectier.

l 7. In an electric wave transmission system, an antenna circuit supplied with signal modulated carrier Waves, a rectier capacitively coupled to said circuit, an output circuit connected to two electrodes of said rectifier wherein signal frequency Waves are produced, said output circuit including in series a high frequency choke coil, a resistance, a primary Winding of a transformer to be rectified, a visible signal and an audiand the Winding of a relay, said transformer ble signal, said signals being adapted to having a secondary Winding connected to a. be activated by current from said rectier. 1o signal reproducing device, and Said relay In Witness whereof, I hereunto subscribe 5 being arranged to control a visible signal. my name this 22 day of April, A. D., 1925.

8. In combination, a radio transmitter, a rectifier coupled thereto, a source of Waves ARTHUR W. KISI-IPAUGH.

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