US1540387A - Telegraph receiving apparatus - Google Patents

Description

A. CLAUSING TELEGRAPH RECEIVING APPARATUS Filed Jan. 25, 1924 Patented June 2, 1925.

UNITED STATES PATENT OFFICE.

AE'rHuaoLAusINe, or BERLIN-CHARLOTTENBURG, GER-MANr, nssreNon To SIEMENS & HALSKE, AKTIENGESELLSCHAFT, or SIEMENSSTADT, NEAR BERLIN, GERMANY,

' ACORPORATION OF GERMANY.

TELEGRAPH RECEIVING PIARATUS. V

Application filed January 25, 1 924. Serial No. 688,503.

To all whom it may concem: Be it known that I, ARTHUR CLAUSING, residing at Berlin-Charlottenburg, Germany, have invented certain new and useful mpro'veme'ntjsin Telegraph Receiving Apparatus, of which the following is a specification.

My invention relates toreceiving apparatus for alternating and direct current telegraphy and kindred transmission of intelligence.

It is well known, that every system of telegraphy, irrespective of whether alternating or direct current be used at the transmitting station, works at the receiving apparatus with pulsating direct current or, in the case of high-Speedtelegraphy with direct currents of positive and negative direction. 1 I

- My invention is based upon the consideratlon that all these signalling currents possess an alternating current character and that in some respectsit is not necessary to make a clear distinction between direct and alternating current te-legraphy, Thus, for

example, in telegraphy by means of positive and negative signal impulses of equal length, the so-called alternation, the alternating character of the current is at once obvious from the analytical expression therefore, which is:

If, for example, 'n be the number of signals per minute, it"follows' that From the equation 1 it will be seen, that the first harmonic (e participates in the rectangular curve form of the impulses with the whole, the third harmonic with one third and the fifth harmonic with one fifth of the amplitude.

In view of the fact that the first harmonic participates to the greatest extent in the formation of the rectangular curve forms and at the same time pomesses the greatest amount of energy, I propose accordingto my invention to adapt the receiving apparatus, for example the telegraph relay for the first harmonic of the telegraph current, to the charmteristic impedance of the line or to the impedance of the amplifier or rectifier tube to which the relay is connected.

In the above example the first harmonic is taken to be the value of (a com .uted from equation 2, as already stated. of signal impulses and intervals of unequal, lengths or durations the adaptation is offected to thesignal impulse of the shortest duration. This holds good for alternating.

n the case current telegraphy, in which the signal impulse of the shortest duration is also chosen as the first harmonic.

If, for instance, a receiving relay be connected directly to a line of the'characteristic impedance Z, the self-inductance f'the relay" must be made of such value that ZzoL The same equation also holds good for the rectifier in alternating current telegraphy. If the tube resistance be equal to Z, then the self-inductance L of the relay must be equal to 1 long positive a'nd negative'signal impulses and 600 telegraph'signals per minute I r a) n- 125 If a receiving relay is connected in series with a rectifier of say 30000 ohms internal resistance, then a rough calculation to ascertain the necessary self-inductance of the rep ceiving relay will give the result Z L 0 henry.

It is practically impossible to mount such an inductance upon an ordinary telegraph relay. Even when em loying the thinnest wire only a small fraction of the calculated 10 henry value can be obtained in a relay of practical size.

According to my invention auxilia means are in such cases employed to effect a suitable adaptation. In this connection the 5 application of translators primarily suggests itself as the'simplest' means of attainmg the end in view. The translator is connected between the tube and the relay and for the first harmonic frequency 0) adapted 9 on the one hand as closely as possible to. the tube, and on the other hand to the relay.

My invention is illustrated in the accom panying drawing'i'n which- Figs. 1 and 2 represent diagrams of the improved receiver circuits according to my invention. 1 Similar letters of reference indicate similar parts. in the various figures of the drawmg. a

The relay is according to my invention coupled with the anode circuit of a three electrode thermionic tube a b means ofv a translatonU, as shown in Figs. 1 and 2, the translator being adapted as previously described.

Experiments have roven .that with receiver circuits accordlng to my invention such large amountsof energy may be supplied to the relay, that at very great contact distances with small pole distance, up to about 2000 telegra-phy letters per minute can be transmitted. The anode current need only be a fraction of that which was required in the hitherto employed receiver circuits. With a single small amplifier and rectifier tube a more treliable operation of the telegraph relay is attained, than with two amplifiers connected in parallel. in the 5 known receiver circuits, in which, furthermore, the relay is capable of operating only when the distance between the contacts is as small as possible.

The preceding specification refers in par ticular to direct and alternating current telegraphy over ordinary wire lines. It will, however, readily be understood that receiver circuits according to this invention may equally well be employed in connection with oscillatory circuits, receiving equipments for radio telcgraphyand the like.

My invention is furthermore, by no means confined to the use of translators as ada ters but any suitable method of adaptation may be used with equal advantage. If, for instance, filter chains are connected in the indefinite receiver circuit their electrical values may be'so chosen that they may likewise be employed fort-he adaptation of the. receiving relay to the tube or theline. What I claim as my invention and desire 7 to secure by Letters Patent is 2- 1. A receiving system for alternating and direct current telegraphy having an impulse current of indefinitefrequency, .in which system the impedance of the receiving apparatus is made substantially equal to the 1m-. pedance'of-the circuit element from which the receiving apparatus receives the current,-the value of said impedances being determined by a frequency constituting the 50 succession of impulses of shortest duration in said impulse current of indefinite frequency for the purpose of transmitting the maximum amount of energy.

2. A receiving system carrying. an impulse current of indefinite frequency and containing a thermionic tube in its circuit said tube being connected to the receiving apparatus, the impedance of said receiving apparatus being equal to the out ut impedance of said tube, the value 0? said impedance being determined by a frequency constituting the succession of impulses of shortest duration in said im ulse current of freqnency, for t e purpose of transmitting t e maximum amount" of en ergy. 4 g

3. A receiving system carrying an impulse current of indefinite frequency and containing a thermionic rectifier tube in its circuit, said tube being connected to the receiving apparatus, the impedance of said receiving apparatus being equal to the output impedance of said tube, the value of said impedance being determined by a he quency constituting the succession of impulses of shortest duration in said impulse current of indefinite frequency, for the purpose of transmitting the maximum amount of energy. v

4. A receiving system carrying ,an impulse current of indefinite frequency and being connected to a line, in combination with an intermediate element connected to said line and to the receiving apparatus, the

input impedance of said intermediate ele ment being equal to the surge impedance of saidline and the-output impedance of said intermediate element being equal to the impedance of said receiving apparatus, the value of said impedances being determined by a frequency constituting the succession of impulses of shortest duration insaid impulse current of indefinite frequency, for the purpose of transmitting the maximum amount of energy. i

5. A receiving system carrying an impulse current of indefinite frequency and containing a thermionic tube in its c1rc'u1t in combination with an intermediate elememes? ment, connected to said tube and to the re ceivi'ng apparatus, the input impedance of said intermediate element being equal to the output impedance of said tube and the output impedance of said intermediate element being equal to the impedance of said receiving apparatus, the value of said imped ances being determined by a frequency corresponding to the frequency given by the succession of impulses of shortest duration in said impulse current of indefinite frequency, "for the purpose of transmitting the maximum amount of energy.

In testimony whereof I afix my signature.

ARTHUR CLAUSING.

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