US1542546A - Device for repeating alternating-current telegraph signals by means of vacuum tubes - Google Patents

Description

. June 16, 1925. 1,542,546

J. P. FERRITER ET AL, DEVICE FOR REFEATING ALTERNATING CURRENT TELEGRAPH SIGNALS BY MEANS OF VACUUM TUBES Filed Aug. 29, 1923 '2 Sheets-Sheet l gwwnto'as Wi @W V m June 16, 1925. 1,542,546

DEVICE FOR REPEATING ALTERNATING CURRENT TELEGRAPH SIGNALS J. P. FERRITER ET AL BY MEANS OF VACUUM TUBES Filed g. 29. 19215 2 Sheets-Sheet 2 Patented June 16, 1925.

UNITED STATES PATENT or cs.

JOHN P. FERBI'IER, OF OCEANPORT, AND WRIGHT JOHNSON, OI REID BANK,

NEW JERSEY.

DEVICE FOB-BEPEATING AIiTERNATTNG-CURRENTTELEGRAPH SIGNALS BY MEANS OF VACUUM TUBES.

Application filed August 29, 1928. Serial No. 660,023.

To. all whom it may 00mm:

Be it known that we, JOHN P. FERRITER and WRIGHT H. JOHNSON, citizens of the United States, residing, respectively, at Oceanport and Red Bank, in the county of Monmouth and State of New Jersey, have invented certain new and useful Improvements in Devices for Repeating Alternating- Gurrent Telegraph Signals y Means of Vacuum Tubes, of which the following is a specification.

This invention relates to vacuum tube repeaters and more especially such as are employed in line telegraphcircuits.

The present types of telegraph repeaters in use are not satisfactory due to mechanical reasons and to repeater lag which causes attenuation of signals. If several setsof repeaters are used, false signals result. Up to the present time vacuum tube repeaters have been impracticable due to the fact that direct current has largely been used for line current. By using alternating line current, the use of tube repeaters is possible and profitable. False signals and other repeater troubles are thereby eliminated.

In order to more clearly disclose the nature of our invention the following figures'of the drawing are attached and in which:

Figure 1 represents an arrangement for two-tube two-wayrepeaters. V

Figure 2 represents a two-way four-tube re eater system.

eferring more particularly to the drawings, Figure 1 shows an ironcore transformer Mhaving the primary windings O and O and the secondary windings, P, and P. A similar transformer m is also provided. N and n are iron] core transformers provided with suitable windings. Tubes 1 and 2 are three-electrode vacuum tubes lighted by a battery-A. The plate potential for the tubes is furnished by batteries B and b. The grids of the tubes are properly biased for correct operation by means of batteries C and 0. AL and dare artificial line rheostats and condensers for the purpose of balancing the repeaters.

The artificial line rheostats and condensers AL are adjusted until a current introduced into the middle point of windings O and O of the transformer.M by means of the transformer N divides equally through 0 to line and O to artificial line. This is similar to balancing an ordinary duplex. A similar balance must be obtained for all so that current supplied by the transformer 71. divides equally through p and p to the artificial line. Thus P, and P are balanced against outgoing current furnished by transformer N and a similar condition obtains for p and p and n.

Suppose that an alternating current, the half-waves of which have their amplitudes modified according to any predetermined signalling flow, comes in over the line alternating current through 0 and through 0 and AL in parallel with the secondary of N to the ground. There is then an unbalance of current in 0 and 0 An alternating electro-motive force will then be induced across the windings P and P in series and impressed on the grid of the tube 1. A large alternating vibration takes place in the plate ing go is similar to that described above.

gure 2 shows a repeater using four tubes. The objectof this system is to divide the voltage across windings P and P (7) and p between two grids so that approximately one-half the voltage is placed upon the grid as is the case when single tubes are used. This allows the tubes to be worked to better advanta e and prevents distortion. The system of balancing is the. same as described above.

Suppose that a signal impressed on M at a given instant makes the grid of tube 1 positive and the grid of tube 2 negative. The plate current of tube 1 will increase through S and the plate current of tube 2 will decrease through S A voltage will be induced in 1 and p in series. At the next half cycle t e grid of tube 1 becomes negative and the grid of tube 2. becomes positive so that the plate current of tube 1- of tube 2 increases through S The action of tubes 3 and 4 is similar to that above described.

Having thus described our invention, we claim:

In combination with a vacuum "tube du-' plex amplifier, an alternating current telegraph line, a plurality of pairs of threeelectrode' vacuum tube detectors, each tube of said pairs having its filament in series with that of another, each pair having an iron core transformer of primary and secondary windings, said primary being connected to said line and to the grid of one tube, said secondary being connected to an artificial lineand to the grid of the other tube, an-

other transformer having its primary and secondary windings connected to the plates said second mentioned transformer, for the.

purpose of providing means for impressing a substantially sustained signalling alternat.

ing current the half-waves of which have their amplitudes modified according to any predetermined signalling fiow.-

In testimony whereof we aflix our signatures.

JOHN P. FERRITER.

WRIGHT H. JOHNSON.

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