US2375547A - Coupling system for loading devices such as aerials - Google Patents

Description

' 1945- v P. F. GAMET 2,375,547

, COUPLING SYSTEM FOR LOADING DEVICES SUCH AS- AERIALS Filed may 9, 1942 EL; WW

TRAA/JM/TTER TRA MSM/ 775/? l2 156215 Paul, ($1917.67;

\ has? Rh E) Patented May 8, 1945 COUPLING SYSTEM FOR LOADING DEV-ICES SUCH AS AERIALS Pierre Paul Garnet, Paris, France; vested in the Alien Property Custodian Application May 9; 1942,- Serial No.442,373 Y In France May 26, 1941. g

2 Claims.

This invention has for its subjectmatter improvements in and relating to coupling systems for radio-frequency output devices such as antennas. I i

The matching over a wide range 'of wave lengths of a transmission line through a coupling box connected between the said transmission line and the output device or through'adjustable inductance coilsconnected in series in one of the conductors of the said transmission line obliges the operator to make an adjustment for the different operating wave lengths. This adjustment is generally obtained by varying the electric'constants of the coupling impedances or the inductance coil connected in series in the transmission line. l

These matching or adjusting circuits are ex-,

pensive and require considerable space.

The present invention has for its object to avoid these disadvantages and to permit of obtaining without diiferent adjustments a convenient matching of the transmission line from the point of view of the supply voltage over a wide range of wave lengths.

On the other hand it is often necessary to vary the voltage which is delivered by'the high-frequency generator by the transmission line to any output device. This variation is generally obtained by a modification of the connection of the high-frequency generator with the transmission line as, for instance, by means of adjustable taps on the inductance coil of the oscillatory circuit. Such adjustable taps are of adifiicult and delicate construction and do not permit an accurateregulation.

Another object of the invention is to remedy this inconvenience and to provide a device permitting to control the coupling values within certain limits.

The same difficulties are encountered in coupling systems for coupling two radio generators connected in parallel when they are not well matched or balanced.

Still another object of the present invention is to remedy these inconveniences and to provide a device which compensates in a certain measure for the differences in the energy produced by one of the radio generators, these differences bein due, for instance, to an accidental variation of the potential of the grid bias.

Improved coupling systems which permit to attain the above mentioned objects present the characteristic features which appear from the following description and more particularly from the appended claims.

-Couplin'g systems according to the present invention are shown in the appended drawing, in

' which:

Figure 1 is a diagram of the coupling of a high frequency generator with a transmission line with stationary waves through a fixed resistance;

Figure 2 is a diagram of the coupling of a highfrequencygenerator with a transmission: line with stationary waves through a variable resistance;

Figure 3 is a diagram of the coupling of a transmission line for stationary waves with two highfrequeney generators connected in parallel.

The diagram shown in Figure -1 comprises a transmitter station I comprising an oscillatory circuit formedof a variable capacity 2 and of an inductor 3; a tap 4 provided on the inductor 3 g is connected with' a resistance 5 ill'SGliBS-jWith the conductor 6 of a co-axial transmission line I;

the other extremity of this transmission 'line is connected-with the output device 8 (an antenna,

for instance) p The operation of this coupling system is as follows:

The oscillating circuit transmits the high-frequency oscillations which it produces to the output device 8 through the medium of the resist ance 5 and of the co-axial transmission line 1. The input impedance of the unit formed of the co-axial transmission line 1 and the output device 8 varies as a function of the wave lengths which are produced by the generator I.

Owing to these variations of the impedance of the transmission line 1 and of the output device 8 as a function of the wave lengths which are transmitted, the high-frequency excitationvoltage varies.

For a small inputimpedance, the high-frequency excitation voltage is moderate and if the tap on the inductor 13 corresponds to an excitation'voltage which is higher than the voltage which had been intended, a voltage drop is pro-Y I duced across the terminals of the-resistance 5.

Thus, the impedance between the tap A and the output device 8' seen from the transmitter side is increased owing to the resistance.

For a high input impedance, the high-frequency excitation voltage is entirely transmitted; indeed, the value of the resistance 5 is negligible with respect to the input impedance ofv the transmission line.

Thus, the resistance 5 tends to bring the con- .nected impedance seen from the transmitter side to such a value that fixed coupling-is possible on the inductor 3.

The transmitter apparatus shown on Figure 2 j s is similar to that shown in Figure 1, but the fixed resistance 5 is replaced by a variable resistance I 9; The latter permits of varying within' certain limits the high frequency voltage transmitted by the generator I to the output device 8 owing to the voltage drop RI caused by the current flowing through the said resistance. When a loose coupling is desired, theres'i'stance is adjusted to the maximum of its value." On the vcontrary,-when a close coupling is desired, the resistance is adhave been shown'at the input of the .co-axial point on the transmission line.

The transmitter apparatus shown in Fig ure 13 comprises two transmitter stations l0 and H" connected with a common transmission line through'zthe medium of resistances i3 and M,

the resistance I 3 connecting the transmitter 1-0 with the transmission line-t2 while the resist-J anoe -I4wconnects the transmitter H with the transmission line l2. v. l I 3, the station--| 0 has-variable capacity 2 2; randifinductor -23, with tap 24, which correspond respectively to capacity 2, inductor 3- with tap 4, at station I inFig. 1;v vAlso in-Fi'g. 3,

the Istation H has variablescapacity 22a, and in duct'or 123a with variable 'tap- 2411, which :cor-respondwrespectively to capacity 2, and inductor r Theoperation of the device i-s asjvfol-lowsz The current delivered; from the transmitters roams .flows through each of the resistances l3 and M; if, for any reason, for instance owing to anaccidental variation of the grid excitation, one of the transmitters produces alarger output, a stronger current flows through the corresponding resistance which dissipates more energy, thus tending to bring to its normal value the energy received-by the output device.

'Ifhe invention is of general applicability and can be appliedto all kinds of output devices; it is transmission line, but they can be located ?atany";

more particularly advantageous for transmitters for working stations with a wide range of wave lengths, or for transmitting devices which use largebands such as the transmission of images in television I claim:

' 1; In a high-radio-frequency circuit system,

apairof radio-frequency oscillator circuits each comprising an inductance. having an adjustable tap, aradio-fr'equency power consumption unit, a co-axial transmission line having its axial conductor zconnectedvto said power consumption unit,

and individual connections each comprising a series resistance extending between the end of said axial conductor remote from said consumpe tion uni-t, and-said adjustable t-a-ps respectively.

2, In a high-radio frequency circuit system, a pair of radimtrequency oscillator circuits each comprising an inductance having an adjustable tap, .a trans-mitting antenna unit, a -co-axial transmission line having its axial conductor connected to said antenna unit, and i-ndividualconnections each comprising a series resistance -ex' tending between the end of said axial aconduct'or remote from said antenna unit, and :said adjust able taps respectively..- 7 I PIERRE PAUL GAMET.

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