US1645542A - Circuit arrangement for high-frequency sending stations - Google Patents

Description

. 1645 542 Oct, M. OSNOS CIRCUIT ARRANGEMENT FOR HIGH FREQUENCY SENDING STATIONS Filed Dec. 27. 1922 2 Sheets-$heet '1 Q MENDEL mos 351 his Gum,

allllllllfll! K 1645,542 Oct. 1 ,1927. MOSNOS v CIRCUIT ARRANGEMENT FOR HIGH FREQUENCYSENDING STATIONS Filed De c. 27. 1922 2 Sheets-Sheet 2 Patented Oct. 18, 1927.

UNITED STATES 1,645,542 PATENT- OFFICE;

MENDEL OSNOS, OF BERLIN, GERMANY, ASSIGNOR TO GESELLSCHAFT DRAHT- VLOSE TELEGRAPHIE M. B. H. HALLESCHES, OF BERLIN, GERMANY, A CORPORATION OF GERMANY.

CIRCUIT ARRANGEMENT FOR HIGH-FREQUENCY SENDING STAT IONS Application filed December 27, 1922, Serial No. 609,215,and in Germany February 11, 1922; 7

As is well known, the frequency of the zurre-nt supplied by the source of energy in a sending station may be amplified by means of one or a plurality of saturated iron core choke. coils. The harmonics produced by the choke coils are conducted to an intermediate circuittuned to the desired operating wave, and the operating energy is trans- 'mitted from this circuit to the oscillating circuit of the antenna which is galvanically or inductively coupled with the intermediate circuit and which is also tuned to the operatin wave. i

Fig. l is a diagrammatic representation of a well known form of circuit arrangement for use in effecting frequency amplification by means of a saturated iron core choke coil, and

Figs. representations of circuit arrangements of various forms in which the invention may be embodied.

In Fig. 1 g is the generator, and ,L is an air core choke coilconn'ected in parallel with the generator for the purpose of correcting the power factor in the generator, L O is a tuning group composed of a self-induction and a capacity, and L is aniron core choke coil which is saturated during the major part of the basic period. This iron core choke coil is connected with the secondary oscillating circuit II, that is, the intermediate circuit, composed of a capacity C, and

an inductance I which (or a part of which) is directly or inductively (the drawings illustrate the inductive coupling) coupled with' the operating circuit, in the present case the antenna A and its tuning coil L A The tuning elements L C must be so selected that the current traversing them is as far as possible of a sine wave form. In that case the harmonics produced by the iron core choke coil will not be able to balance each other in the primary circuit I and will be forced into the intermediate circuit II from which they are inductively transmitted to the antenna.

However, the above-described well-known sending station has a very material defect: In order to present a very high resistance to the operating or useful wave, the self-induc tion 1, must be very large. For this reason,

with a given primary current its volt am sumption' of the condenser C must be greater than that of the inductance, L for insuring the proper functioning of the station, the volt ampere consumption vof the condensers is also very large. It will be seen, therefore, that the dimensions of both devices L and G are necessarily verylarge because the dimensions must be determined by their volt-ampere loading. Thisv increases the cost of the station and leads also to difliculties in arranging it, e. g. on ships where the space at the disposal of sending apparatus is very small.

Furthermore, the large volt-ampere consumption causes great energy losses which 1 reduce the operating radius of. the station. 2 to 8 inclusive are diagrammatic.

The present invention eliminates this drawback in a manner such thatthe operating wave instead of being blockedout of the primary circuit is conducted to thec'ir- -cu1t. The separate secondary intermediate sistances in series tuned to the desired, operating harmonic).

In the circuit arrangement shown in Fig. 2, the primary and secondary circuits are combined in a single circuit, and the antenna circuit is directly or indirectly coupled with the self-induction L,, a direct coupling being illustrated in the drawing. The circuit is so tuned that two, waves will be particularly pronounced therein: The fundamental and the desired harmonic. k

. The capacity C,, which is connected in parallel with the. generator adds to the capacitive loading of the generator for the basic wave. However, to the desired harmonic electromotive force which is generated in the iron, core choke coil L this capacity will present a much lower imped t me than the generator and will therefore divert the harmonic from the latter.

Fig, 3 represents a further improvement on the above described circuit arrangement. In the circuit shown in this figure, in addition" to the capacity O an inductance L, is connected in parallel with the generator. This inductance and the capacity C are so proportionedthat for the fundamental frequency the lagging current flowing through L is larger than the leading current flowing through C Furthermore, the whole circuit may be tuned to the basic frequency or, in stead ofthis, the lagging wattless current of the inductance L may be caused to be surficient notonly'for coveringthe leading current of the branch C but also for entirely or partially or overlappingly covering the preferably leading component 01 the fun'da mental wave current through L L 0,, whereby the generator 9 is required to supply substantially only the watt component ofthe current necessary for covering the losses and the operating output. By suitably tuningthe circuit C L the terminal potentialof the generator may also'be made equal to the unloaded running potential which occurswhen the generator current as i a vector halves the angle between the vectors of the inside potential and the terminal potential, lagging behind the former and advancin'gahead of the latter. In this case the wattless current through L must be slightly smaller than the; sum of the wattle es basic wave'currents through G and through L Furthermore, an additional condition must 'be satisfied in" that the oscillating circuit must be tuned to the desired high frequency vwhich is supplied "by the iron core choke coil. The establishment of the above-mentioned conditions is in theoryalways possible, becausewith a given inductance of the generator gand the iron chokecoil L}, we have at our disposal four independent constants L C L C in the circuit I.

The circuit shown in Fig. l differs from the above described circuits in that an additional inductance- L is provided for properly protecting the'generator 9 against harmonics.

It is not absolutely necessary that the branch'C be composed exclusively of condensers; As shown in Fig. 5 an air core choke coil L may be connected in series with th'econ'denser O in which case only the resuiting resistance of this branch will retain its character of a trap for the desired auxiliary frequency. L and C may, for instance, be'so proportioned that their operations will balance each other for the respective harmonics. In this case the branch inquestion will forma short circuit for the respective 'harmonics'and the generator as well as the choke coil L are completely protected from these harmonics.

In view of the fact'that the inductance L provided inthe branch 0,, is traversed by waves ofthepperating frequency, this 111* of the elements 0,, and L,

ofthe branch L,,. However, in that case a for which the susceptances cog-C and ductance may be used also for transmitting energy of the operating frequencyto the antenna circuit in the manner shown in Fig. 5; In this case the inductance L is eliminated. e

An inductance L (see Fi 6) may be provided in series withthe whole branch L,,, C instead of being in series only with C and in this case-also the resulting branch thus obtained will retain its character of a trap for the operating frequency. In this circuit also the antenna may be coupled by means of the inductance L or as shown in Fig. 6 by means ofthe inductance L,. If it is desired that the wholebranch composed connected in parallel and both in series with L be tuned to form a shortcircuit for a certain harmonic, e. g. for the operating wave, then the i'i'ollowing should be noted. In order to make possible that the resulting reactance composed of L and C,,, balances the inductance of the'choke coil L for the corresponding harmonic a it must have a capacitive character for this harmonic. Therefore, the'susceptance 'w C, of the branch' C i or this frequency 103, must have anabsolute value whichis greater than the susceptance l 'w L I we will have a frequency co which is lower than ca or a wavelength i longer than 'w L of both branches are equal to each other. Thismeans that closed circuit L (3,, isin resonance with the frequency w or has an individual wave i Now if in the whole stationamon g others there is a wave the length of which isequal to a, or near a then, no matter how small their amplitude, these waves will generate in the circuit L,,, C, individual oscillations of suitable ampli tude causingundesirable losses. In order to avoid this the ClI'ClllllIJ C must be so pro- .portioned that it have an individual wave a. V which is greater than a and which cannot be found among the harmonics obtained in the station and does not evenapproach too near to these. It may, for instance, be so selected that as nearly as possible it will be midway between two hari'n'onics existing in the station- The inductance L shown in Fig. 6 maybe combinedwith the choke coil L, whereby a circuitnsuch as is shown in- Fi g. 7 is obtained." The variable connection 7: will preferably be so arranged that in thiscase also the branch O Li with the portion ofthe choke coil L connected in'series'therewith' act as trapfor the harmonics, particularly for the operating harmonics; If, for instance, it isdesired'to tune the trap for short circuiting the operating wave, the contact k isso adjusted that the drop of potential caused in the combined reactance L C by the operating wave of the current is substantially compensated bythe opposing potential drop in that part of the choke coil L in series with the trap L C so that for the'operating frequency, the difference in potential between the points Z and 70 will be practically zero. The generator 9 will, therefore, be protected against the corresponding current harmonics.

Instead of combining the whole inductance L with the choke coil L a portion of the inductance may be left separate. An embodiment of such an arrangement is shown in Fig. 8.

In the arrangements shown in Figs. 7 and 8, the contact is may be so adjusted that the inductive effects of generator currents of fundamental frequency passing throughthis contact will balance each other in the two portions of the choke coil L so that the antenna circuit is not influenced by the basic wave. On the other hand, care should be taken that the branch C L in series with the corresponding inductance still performs the service of a trap for the harmonics.

a first inductance connected in series with said generator, a closed circuit comprising a second inductance and :a condenser, a third inductance connected in series with said closed circuit to form a trap circuit, said trap circuit being connected in parallel With said generator, and an antenna coupled with said first inductance.

2. A circuit arrangement for high frequency sending stations comprising a generator, a saturated iron core choke coil, a condenser and a first inductance in series with said generator, a closed circuit compr lsing a second inductance and capacity, a third inductance connected in series with said closed circuit to form a trap circuit, said trap circuit being in parallel with said generator, said third inductance being inductively related to said first inductance, and an antenna circuit coupled to said first and third inductances.

- MENDEL OSNOS.

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