US1443011A - Atmospheric-disturbance-reducing means - Google Patents

Description

Jam 23, 1923; MMM 1l. H. 1.1. M. DE R. DE BELLESCIZE.

ATMOSPHERIC DISTUHBANCE REDUCNG MEANS. FILED NOV' 3. 1922.-

a@ M5 @www pk MMM llll HENRI JEAN' 'JOSEPH MARIE lun RIEGNAULD me BELLESCTZE, 0F '.lOUlLltl', FRANCE.

.AllllTllSlPHERllIlll-IIDTSTUlltlBANClil-RIEJIINUCTNGlA v 4Apjiilicaution nledl November A, 1922. Serial lto. wte.

To all/whom t may concern:

Be it known that l, HENRI JEAN Josnrrr MARIE DE REGNAULD DE BELLESCIZE, a citizen of the Republic of France, and a resident of 2l Rue Victor Clappier, Toulon, Far, France, have invented new and useful lmprovements in Atmospheric- Disturbance- Reducing Means (for which l have filed an application in France, Uctober 11, 1921), of which the following is a specification accompanied by drawings.

ln Wireless telegraphy sometimes amplitude limiting arrangements are used for preventing the current received by the telephone or the registering apparatus'from exceeding a certain maximum limit, no matter what the intensity of the oscillation generated by the receiver. Arrangements answering this. description may, e. g., b'e composed of a three-electrode tube, or two tubes connected in series. The output circuit of the limiting apparatus can supply only a limited current variation dm (Fig. 1), and the arrangement is so provided that, almost the totality mn of this variation is obtained by the potential dillerence Mn that the signal generates between the incoming terminals of the limiting apparatus.

These arrangements are suiliciently etticient for short Waves and low-speed operation. However, it the wave length or the operating speed is increased, such arrangements ,cannot serve to eliminate trouble caused by strong disturbances. As a matter of fact, such disturbances generate in the resonator tree oscillations of great initial amplitude lthe duration of which may exceed thatof a point or interval between two consecutive signals.

ln accordance with the present invention, this drawback is remedied by controllingr the edective resistance and the individual frequency of the resonator subjected to such disturbances, byl means of an electromoti've force ot reaction derived from the amplitude limiting apparatus. Reactions in receiving` apparatus comprising three-electrode tubes are of common usage, but they have not as yet been derived from an element (e. g., tube or group ot tubes) which has the special function ol limiter. This arrangement is new and so are the manipulating means oil which use is made of this arrangement. The

Fig. 3 is a curve of a current caused by a disturbance at the output side of the limitin'g device. y

Fig. 4 is a curve of the potential of thereaction on the resonator caused by the said current.

Tn Fig. 2 it is assumed that theresonator 1-2--3 is simultaneously actuated by a-signal and an aperiodic disturbance. llt may be, e. g., an antenna comprising a self-induction 1, a tuning condenser 2, and an ohmic resistance 3.' This resonator actuates an amplifier shown at 5 and then an amplitude limiting device illustrated at 'l'.` The current j oit this limiting device has a characteristic ol the form shown in Fig. 1. The receiving arrangement comprises the usual elements, e. g., a resonator 9 tuned to the frequency of the signal, a detector 10, a registering galvanometer 11. Furthermorethe following means are rovided tor controllin the adjustment 0F the apparatus:

djusting to the limitr value MN of the potential did'erence caused by the signal at the terminals of the limiter 7. This result may, for instance, be obtained by means oll the switchl 6 which changes the primary ol the transformer 1A in a manner to vary the amplification.

Adjusting, distinct from the above, ol the electromotve force ol reaction exercised Vby the limiter on-'the resonator 1 2. This adjusting is effected, e. g., 'by adecting in a suitable manner the mutual induction coefficient between a coil 13 forming part of the resonator and a coil 12 traversed by a part z' ot the plate current j, the coils 12 and 13 constituting the primary. and secondary coils ot a variable coupling arrangement 4l.

Adjusting el the phase ot current e". Thia phase may be varied by almost 180o under the control of the condenser 8. Furthermore, the coil 12 may be reversed in a inanner to change the sign of the mutual inductance 4 which is equal to a dephasing of 1:.

Notwithstanding the fact that the invention is independent of the theory by means of which it may be explained, the functioning of the appara-tus may be set forth in the following manner to give the best method of utilization and adjusting. R, L, C are, respectively, the resistance, the selfinduction and the capacity of the resonator 1--2, 8., its logarithmic decrement;

in the coil 13 by coil 12 traversed by current z'.

The oscillation in the resonator 1-2 is governed by the equation the currents i and 7' remain always proportional tothe potential difference o. rl`he electromotive force of reaction has` therefore, the expression fzKgV sin (ost-tip) Ks is a constant coefficient as long as none of the elements of the receiver are modified. il; is a phase which may be adjusted by means of condenser 8.

Let us transpose. this expression of f in the equation 1. lVe'will [ind that the amplitude V of the oscillation developed by the signal in the resonator is:

E Tt In order that the signal attain its greatest possible intensity, We must annu] the expression wa 2 1- -Ks cqs@ reaction Ks by tightening or loosening the coupling between the coils 13 and 12. The result obtained is the better, the sharper the tuning of the condenser 2. As a result of this, if the amplitude MM of the oscillation at the terminals of the limiting apparatus 7 is insuficient,-this will be noticed for instance by the deviation of the galvanometer ll-the amplification is increased by means of the switch 6 and the tuning of o0, and Ks is again attempted in the above described manner. Summing up, when the `signal is to be received the resonator 1 2 possesses an individual pulsation mo different from that of the signal and given by the over-tension V/E is equal to l *Y 50 rw-o K, sin gl/ or practically it is stronger than if there were no reaction. Finally, the limiting apparatus is sub]ect to an oscillation having an amplitude Which is'slig'htly inferior toithat corresponding to the saturation.

- The free oscillation created in the resonator 1 2 by a strong disturbance is damped under the conditions illustrated in Figs. 3 and 4. Instead of attaining the amplitudes Aa, Bb, which would be the case it the saturation effect did not exist` the variation of the output current of the limiting apparatus does not exceed the amplitude Jfmf permissible by the characteristics. As a result ot' this. instead of affecting the damped sine form indicated on the dot-ted line. the electro-motive force of reaction proportional to line (Fig. 4). This will be the case until time 6 for which the amplitude of the oscilllO tude

rta-aou lating train does not exceed that of the signal. l

rlFhe phenomena. following the instant 0 may be neglected, because a freely damped oscillation having initial amplitude. equal to that of the si nal is rapidly extinguished. lWc have left t erefore the time from 0 to 0. The reaction is no more of sine form, and can therefore not be represented by an` expression of the form KV sin (mt-Hp). However, an examination of Fig. l will show that the reaction is reduced in. proportion tothe intensity of the train, whereby the components llts cos d; and Ks sin :la are replaced byl others X and Y of lower amplirll`he pulsation WZ of the free oscillation must also at alltimes satisfy the equation' filial M ust in the instant t it will have a variable value, which is -diderent from ms of the signal, and nearer to that of o, `individual to the resonator. i

Furthermore, the damping proportional to 1r wo is increased. Y i

ln other Words, the dangerous part of the oscillating train is rapidly damped, and this happens on a frequency diderent from that of the signal. 'llhe disturbance can not,

therefore, disturb .the following circuits, which are tuned eithe'r to the frequency ofthe signal (for instance, the resonator as of llig.l 2) or to the frequency of the modulation resulting from the interference between the signal and a local sending.

rl`he operating condition is the bet-ter the higher the resistance (3L-Fig. 2)' individual to the resonator, and the more the advance. t of the electro-motive force of reaction differs from 90 with respect to the potential difference.4 lf the angle q1 were equal to 90 (this would be obtained ifcondenser 8 were eliminated from Fig. 2) the improvement relative 4,to the damping would subsist, but' not those .relative to the frequency difference between the free oscillation and the signal.

Circuit arrangements like the one shown for impressing upon said resonant circuit anv equal to tors in series either ahead of the amplifier or inside of this apparatus. Obviously, the result would not be modified if the reaction were obtained from a circuit subsequent to the limiting apparatus.

llt should be understood that the invention is not limited to the exemplifcation herein disclosed, but may be -varied in numerous ways in which the essential constituting ele ments are combined. The apparatus, such as the amplifiers, limiters, detectors, etc. may be a suitable type,the purpose of these being merely to. fulfill the above described functions. .f v

Having described my invention l declare that what l claim isv v i l. lln. radio receiving apparatus, the' com'- bination of a resonant circuit, an amplifier operatively associated with said circuit, a

current limiting device, associated with said amplifier, detecting and indicatingr appa'- a ratus, and means for impressing, on said resonant circuit an E lli/ll F derived from said current limiting device. y 2. lln radio receiving apparatus for. discriminatin' y ances, the combination of a resonant circuit. having a natural frequency did'erent from that of the signal desired, an amplifier connected to said circuit, a current-limiting relay connected to said amplifier and means electromotive force derived from said limiting relay. l

3. ln radio receiving' apparatus for, dis` criminating against atmospheric disturb` ances, the'combination of a resonant circuit' 1D0 n having a natural frequency diderent from that ofthe signal desired, an amplifier connected to said circuit, a current-limiting relay connected to said amplifier, means 'for v impressing upon said resonant circuit an electromotwe 4force derived from said current-limiting relay, and means for controlling the phase-relation of the electromotive force supplied to said resonant circuit.v

t. ln radio receiving apparatus for discriminating against atmospheric disturbances, the combination of a resonant circuit yhaving a natural frequency different from that of the signal desired, an amplifier connected to said circuit, a current-limiting tilt` relay connected to Isaid amplifier, means for 4v,impressing upon said resonant circuit an 'electromotive force `derived from said current-limiting relay and meaias for causing f .l

iat

the electromoftive force so impressed to op pose the flow of 'currents having a frequency the naturalI frequency of said circuit. i

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