US1792756A - Modulation system - Google Patents

Description

Feb; 17, 1931. M. OSNOS MODULATION SYSTEM Filed Oct. 22 1925 5 SOURCE INVENTOR MENDEL OSNQS TTORNEY Patented Feb. 17, 1931 UNITED STATES PATENT OFFICE MENDEL OSNOS, F BERLIN, GERMANY, ASSIGNOR TO GESELLSCHAFT FT TR DRAHT- LOSE TELEGRAPHIE M. B. H., OF BERLIN, GERMANY, A CORPORATION OF GER- MANY MODULATION SYSTEM Application filed October 22, 1925, Serial No.

ductor with hooks 1 and 2, while B indicates a ferromagnetic substance surrounding or coating the conductor. As can be seen, the flux lines flow in the way as just stated, that is to say, they only surround this conductor. Of course, such a keying or telephony choker can be adapted also to any other con venient form of construction. For instance as shown by Fig. 2, a plurality of such conductors can be arranged in parallel, and can be passed by current in the same direction.

In this case the common feature may be regarded to reside in that the magnetic flux substantially surrounds but this one conductor, seeing that the main flux passed through the iron. An especially important field of application for such conductors is in connection with the production of and action upon very short electromagnetic waves.

The view heretofore held was that, in order to diminish the losses the thickness of the ferro-magnetic layer should be chosen as small as feasible. This arrangement is based upon the theory that in case where such a conductor is to be used for the purposes of key- 5 'ing or telephony, the aim should be to raise the iron losses as much as possible, while the losses in the non-magnetic conductor should be reduced as far as feasible, for in this manner the modulation of a transmitter will be much more thorough and efficient. By the aid of the keying and telephony choker, a resistance is cut in and out of the antenna or a consuming circuit. This resistance is made up of two parts, i. e., a constant resistance dependent upon the losses in the non-magnetic conductor, and a variable portion residing in the losses occasioned in the ferro-magne-tic material. It can be seen therefrom that for best operation the constant part must be minimized as much as possible, while the va- 64,245, and in Germany November 20, 1924.

riable part is to be raised to the greatest possible degree. By the key work and the action upon a controlling choker, as is well known, a variation in the losses and the self-inductance is brought about.

Now, in accordance with the present invention the key and telephony choker must be so dimensioned that the ratio between the change in loss resistance and the change in the selfinductance is made high. A suitable form of construction of the invention consists in that a good electric conductor, for instance, copper wire is enveloped by individual massive tubelets, the thickness of the iron layer comparatively to the thickness of the conductor being chosen at such a ratio that the thickness of the iron layer amounts to over-1/20th of the diameter of the conductor. In the presence of such proportions the condition of relation between change in the losses and change in the self-inductance is fulfilled. Instead of tubelets, also small iron disks could, if desired, be employed, the thickness of these small disks having to be chosen so as may be convenient. Under certain circumstances it may,for instance, be suitable to choose the thickness of these small disks at about 0.07 mm. In this case the iron losses consist substantially in hysteresis losses, whereas in the case of thicker disks the iron losses consists of both hysteresis and eddy-current losses.

Another form of construction consists in that the non-magnetic conductor is wrapped with a heavy iron Wire.

Other advantages will be apparent in connection with the various figures of the drawing in which:

Fig. 1 is an element of my arrangement.

Fig. 2 is a system in which it is used.

To further explain the applications of the present invention a diagram of connection is shown in Fig. 2 for a frequency-raising arrangement comprising the use of a telephony or keying choker of the kind as hereinbefore described. Referring to the said figure G is the high frequency generator, Al the circuit tuned to the generator frequency, T1 a frequency changer by means of which the wave All is produced. T2 is a frequency changer for short waves by means of which multiplication to wave A33 is produced. Connected with this circuit is the keying choker consisting of two parts D1 and D2 by Way of two condensers C1 and C2. The condensers are bridged by the keying or microphone or other modulator circuit, the latter containing a modulator current source S. The condensers preclude the direct current, while they permit of the passage of high frequency current, as

can be seen from tlie fig urje means of an.

additional transformer T3 multiplication of the frequency to the working wave A99 is obtained. It is with this circuit that the antenna A is united.

It is a recommendable plan to embed the keying or telephony choker into'a' refractory material such as concrete or asbestos, and to further enclose it inside an atmosphere poor in oxygen.

Having thus described my invention, what I claim is v I 1 In a high frequency modulation system, a magnetic modulator, comprising, an elongated non-magnetic inductor core, and a sheath of magnetic material enveloping said inductor core, said magnetic material being of a thickness such that variations in imped ance due to variations in iron loss" substan tially exceed variations 1n= impedancedue to inductance loss.

2. In a high frequency modulation system,-

a non-magnetic conductor having a ferromagnetic layer,said layer being of such thickness that variations in the iron losses substa'ntially exceed the Variations in self-inductance during intervals" of keying, surrounding the said conductor, means for impressing high frequency currents on said conductor, and means for superposing direct currents upon said conductor for modulating said high frequency currents'by causing the losses in the ferro-magnetic material due to hysteresis and eddy currents to substantially exceed thenon-magnetic material losses.

3. In a high frequency modulation system; a non-magnetic conductor, a source of high frequency energy connected with said conductor, a layer of ferro-magnetic material enveloping said non-magnetic conductor, a: source of modulation currentconnected with said conductor for controlling the magnetic saturation of said ferro-magnetie material, means for superposing said modulating currents upon said high frequency currents in said conductor for modulating said high frequency currents passing therethrough, said conductor having the enveloping layer of ferro-magnetic material surrounding" the same of such thickness that variations in" the hysteresis and eddy current losses in the magnetic material, due to modulation currents impressed thereon, substantially exceed the variations in self-inductance during the periods of modulation of said high frequency current energy.

tance'of said non magnetic corei'n accordance with thesaturation thereof so as to modulate said high frequency current.

MENDEL osnos.

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