Solutions have been proposed which utilize suitably sized inductors placed at the cable ends. Such prior suggestions, while improving the situation, have proved less than conclusive, however, and they do involve complicated constructions.

The underlying problem of this invention is

to provide a cable as specified in the preamble, which has such constructional and functional features as to obviate the aforementioned shortcomings.

This problem is solved by an electric cable as indicated being characterized in that its flexible shielding carries ferrite inclusions.

Further features and the advantages of a cable according to the invention will become apparent from the following description of an embodiment thereof, given by way of example and not of limitation with reference to the accompanying drawing, in which:

Figure 1 is a perspective view of a cable according to the invention;

Figure 2 is a part-sectional view, drawn to a much enlarged scale, of the cable in Figure 1;

Figure 3 is a perspective view of a cable according to the invention, illustrating a modified

"An electric cable particularly, but not exclusively,

for high-fidelity stereo systems"

DESCRIPTION

This invention relates to an electric cable particularly, but not exclusively, useful with high-fidelity stereo systems and being of the type which comprises at least one conductor and a flexible shielding for protecting the conductor(s) against noise from electromagnetic waves.

There exists a pressing need for electric cables which can transfer electric quantities in true form, i.e. unaffected by noise brought about by electromagnetic waves, magnetic fields, and the like sources of disturbance.

Currently available on the market are cables supplied in a very wide range of per-meter prices which vary between a few thousands Italian lire to about six millions Italian lire, the highest prices being for those cables which are designed to provide top standards in listening quality.

Despite the very high prices carried by such cables, the music enthusiast's demands have been left unsatisfied from the standpoint of quality.

The conventional use of shieldings comprised of copper wire braids has resulted in cable conductors

embodiment thereof; and

Figure 4 is a sectional view, drawn to a much enlarged scale, of the cable in Figure 3.

Referring to the drawing views, generally shown at 1 is an electric cable for a high-fidelity stereo system, e.g. a power supply cable for connecting the system to the mains.

The cable 1 comprises two conductors, 2 and 3, laid side-by-side into a so-called ribbon cable configuration, the conductors 2 and 3 being insulated from each other and the outside world by an insulation 4 formed from a suitable resin, e.g. from PVC.

The cable 1 further comprises a flexible shielding 5, to be described in greater detail hereinafter, for protecting the conductors against noise from electromagnetic waves, and an outer sheath 6 to guard the flexible shielding 5, which sheath is formed from a suitable resin, e.g. from PVC.

In this example, the cable 1 has an outside diameter of about 10 mm.

In the cable 1 of this invention, the flexible shielding 5 is in the form of a tubular resinous jacket 7, e.g. made of a vinyl resin.

Dispersed through the jacket 7 thickness substantial being of 1 mm, for example -- is ferrite 8

which is finely divided in particles or, in other words, powered. The ferrite particle size is selected to lie within the range of 0.01 to 1 mm, preferably to be of 0.5 mm.

The ferrite is provided within the jacket 7 in a by-volume amount ranging from 10% to 90%, preferably of 60%.

The ferrite may be dispersed through the resin as by mixing.

Referring to Figures 3 and 4, an electric cable 10, e.g. a transmission cable, is shown therein which is intended for interconnecting elements of the system, such as the system amplifier and an acoustic box.

The cable 10 comprises two conductors 11 and 12 — of which one is wire-like and the other tubular -- laid coaxially with each other into a so-called coaxial cable configuration. The conductors 11 and 12 are insulated from each other and the outside world by means of tubular insulations 13 and 14.

The cable 10 also comprises a flexible shielding 15, to be described, and an outer sheath 16 guarding the flexible shielding 15.

The flexible shielding 15 is here in the form of two tubular layers, being coaxial with each other

and both indicated at 17, the thickness of each layer 17 ranging from 0.1 to 1 mm, and being preferably of 0.5 mm. Each layer is formed from an adhesive resin which incorporates finely divided ferrite 18 by adhesion thereto. The adhesive resin is a silicone resin, in this example. The particle size of the ferrite 18 is selected to lie between 0.01 and 0.5 mm,

preferably of 0.1 mm.

The layers 17 can be obtained by successively dipping the cable into a pool of adhesive resin and then in a bed of powdered ferrite, or alternatively, by a continuous process of adhesive resin and powdered ferrite spray application.

The cable of this invention has shown to be advantageous in that it can transfer electric quantities with unique fidelity, to provide listening of faultless quality.

Another advantage of the inventive cable is its simple construction, not a trivial advantage with an article which is to be mass produced.

In addition, the cable of this invention can be manufactured in a wide range of sizes and for different quality levels from the standpoint of noise protection for its conductors, according to necessity.

It should be understood that a skilled person

in the art may, in order to meet contingent and specific demands, apply to the cables described several modifications within the protection scope of the invention as defined in the following claims.