US1706339A - Cable circuits - Google Patents

Description

March 19, 1929. G, WUCKEL 1,706,339

CABLE cRcUITs Filed June 6, 1927 INVENTOR ATTORNEY by a sheath which may be made of lead, .as is well known. llt will also be understood that any number of layers may be provided and that each layer may have any desired number of quads and that each quad may orA obtainable with the phantom circuits of the A multiple-twin type of cable construction.

ln accordance with the present invention a novel arrangement is provided-for increasing the cut-od frequency of any desired number of quads without affecting the normal cut-ol frequencies of the other quads of the cable, all of which may be accomplished without changing the spacing of the loading coils or of the repeaters and without any change in the general construction of the cable. ln order to more clearly understand the principles underlying this invention, a mathematical analysis will be resorted to. 'lhe attenuation constant of a coil loaded circuit is given approximately, within the transmitting range, by the following expression:

ln this expression, i?, is the resistance of the conductor, R: is the resistance of the loading coil, U and L are the capacity and inductance, respectively, per unit of length, of the circuit and A is a factor dependent upon leakage. The attenuation constant may also be expressed in the following manner:

an ai d w01 L e058 @ewa (2) in which 2 M 3 wo Sq/ 7 U wo representing the cut-od frequency while s represents the distance between loading coils. llt readily follows that the equation may be rewritten in the following form:

s i a, .irl

icroaaae tenuations will be substantially equal when the product of B0, 0 and wo is the same for both circuits.

@ne of the features of this invention is to provide a method of design by which the cutoff frequency of any group of circuits may be increased without requiring any change in the diameter of the quads. ln practicing this method, use is made of an empirical curve (not shown). Using primed symbols for the roup of circuits having the higher cut-oftl frequency, then w o then the first terms on the right of Equations ln cases where the dierence between the second terms of Equations (4c) and are not negligible a correction may be made in the desiRgn of the loading coil in which the ,F M1 facto L, l

is an example, assume the following data relating to a group of circuits of low cut-oh frequency:

R0=57-8 ohms per kilometer 9 ohms per kilometer 0.1 henries per kilometer 0.0335 microfarads per kilometer 0.8 micromhos per kilometer @0:17300 radians (equivalent to 2760 cycles per second) c ,=2 kilometers llt follows, then, that Assuming that the side circuits of a multiple-twin quad have the constants listed above, the phantoms would have a cut-oil frequency of 22,000 radians (3500 cycles). 'llo obtain this frequency in the group of circuits of high cut-oil? frequency in a star quadded cable, we have the relation: Y

'lhe empirically derived curve mentioned hereinbefore in which R0 is plotted against U, shows that in a cable in which the quads are of equal diameter, the requirements of thc circuits of high cut-off frequency will be met by using conductors 1.3 millimeters in diameter (27 ohms per kilometer), which have a capacity of 0.055 microfarads per kilometer.

` Vlhe empirically derived curves mentioned above are obtained by tests of experimental cables. rllhey showL the relation between R0 and 0 for star quads of various diameters.

approximately.

is important.

@ttttttttsftttz @t @tttttttcttmt y Mmm Nt www@ @mmm ttm-t w, mt t@ i Gtmtttt wtmtttt.

tt is ht'by ttttitt that @rmt appear@ itt ttt@ printed spctmttm @t th@ thm@ ttttmtvttt patttttqutttg mtmttttm as tolltwvs: Page 3, time ttt, ctamm t, attt' the Rettet "C" tmf the vt/@tet "im" tread "s"; stmt that tilt@ said lLttts Patent @hamm be mad wttt this confection thettt that th@ sam@ mty tstmttttm t@ the mmm? @t ttt@ tts@ im ttt@ Ptttttt @ttw Signed and matted this; 23M tttty @t Attivit, A. D.. W29.

Ml. JL Motte, (that) Atztittg Ctttttmsmtt @t lpftttntts.,

CERTIFICATE OF CORRECTION.

Patent No. 1,706, 339. Granted March 19, 1929, to

GUNTER WUCKEL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, line 111, claim 1, alter the letter "C" for the word "in" read "is"; and that the said Letters Patent should be read with this correction therein that the same may conform to` the record of the case in the Patent Office.

Signed and sealed this 23rd day of April, A. D. 1929.

M. J. Moore, (Seal) Acting Commissioner of Patents.

Images