TRANSMISSION SYSTEM BASED ON THE PROPAGATION OF ELASTIC WAVES THROUGH ELECTRIC CABLES

Description

OBJECT OF THE INVENTION

[0001] The present memory describes a patent of invention relative to communication systems by means of elastic waves that use electrical cables as transmission medium. These cables are used both for the distribution of the electrical energy and for the communications in all their varieties.

FIELD OF APPLICATION

[0002] The application field is the signal and data transmission, as well as the transmission of voice and video and of any other type of information by power transmission and distribution networks, or, by communication links. In this second case, the networks are diverse and include both the extensive networks of fixed telephony and the local area network within buildings. Also signals of apparatuses, devices, sensors and transducers can be sent, on the basis of elastic waves and through point to point connections. That is to say, the application field includes all those connections made by means of electrical conductors and in which the elastic waves can add another physical communication level well appropriated for Internet access. The field of application also includes communication through the conductive pathways of printed circuit boards and communications inside integrated circuits.

HISTORY

[0003] In these last years, the spectacular growth of communications has required a parallel effort in the increase of the transmission capacity of the networks. In general, two alternatives have been followed. The first consists, simply, of adding new lines, for example with fiber optic or cordless links. The second one is less evident but it shows spectacular results: it is an improvement of the real line capacity by a change of the transmission technology. It is the case, for example, of the ADSL in the telephone lines or the PLC systems in the electrical lines. This last case is specially revealing. Thus, infrastructures designed specifically for electrical power transmission are being used to carry information too. The invention described in this document deepens in this concept even further.

DESCRIPTION OF THE INVENTION

[0004] As we know in the present time, the telecommunications have been based on the propagation of electromagnetic waves. In the last decades, the optical fibers are contributing with a renewed impulse in boosting the transmission capacity of the networks. Although they are electromagnetic waves too, their carrier frequencies are so elevated that they have a radically different behavior in materials and, therefore, they require completely new infrastructures. On the other hand, the elastic waves that so intimately been have bound to the mankind communication (consider the voice) have had a very secondary play in modem transmission infrastructures. The present invention proposes the use of the elastic waves as a transmission system but with a new form: propagating by the electrical conductors. The elastic waves propagate with greater speed and minor attenuation in metals, as the copper, than through the air. In addition, the electrical conductors are excellent high frequency wave-guides for the elastic signals.

[0005] This makes possible the use of infrastructures already constructed and that extend through continents, countries, cities, buildings and houses as additional transmission medium of any type of signal. Thus, cables of the electrical lines, in addition to energy, transmit data modulated on the elastic waves. Within buildings, equipment of any type can communicate by means of their plugs to the mains. No additional cable is required. So, local area networks may be built through the cables that power the computers. Or the mains could serve as a distribution network, to users within the building, of the information coming from an external getaway.

[0006] On the other hand, in telephony cables, with their interesting topology of point to point connection, other additional channels of communications by elastic waves with greater bandwidth could be added. These additional transmission channels, supported by elastic waves, can also be incorporated to data cables in order to increase their capacity. Thus, in its maximum performance, a cable can simultaneously transmit electrical energy along with voice and video and data -by means of electromagnetic waves- and, also, have additional transmission channels by elastic waves. Further more, the electrical cables usually have two wires, which makes possible two complete channels of elastic waves. We use the term electrical cable in a wide sense. With electrical cable we mean every conductor, with or without dielectric cover, and with the function of transmitting electricity. This concept also includes conductive pathways of printed circuit boards and electrical links inside integrated circuits.

[0007] Besides to add communication channels on existing infrastructures, or to equip the new ones with greater capacity of transmission, the communication with elastic waves has an important advantage: there is no electromagnetic emission. As well, they are basically immune to electromagnetic noise.

PREFERRED FORMS OF THE INVENTION

[0008] The proposed system of transmission includes the following components:

1) Electrical signal to elastic waves converters. Although they can be constructed with electrical devices, such as coils or condensers, typically they are structures based on piezoelectric or magnetostrictive materials that when applying voltage or electrical current generate strains and forces that propagate elastically;

2) Dielectric connections. Through them the elastic waves produced by the converters are propagated to the transmission medium, or, the elastic waves propagated by cables are transmitted to the converters. They adapt the mechanical impedance of the converters to the mechanical impedance of the wire within its insulating covering. On the other hand, the dielectric connections are made of insulating material to get galvanic isolation of the converter circuits from the cables voltages. Thus, one obtains independence between the electrical potential of the generating circuits of the elastic signals and the electrical potential of the transmission means. In case of cables for distribution of electrical energy, the voltage is rather elevated (for example, 220V) compared with electronic circuits signals. In addition, the separation by means of a dielectric allows the elimination of the noise due to electric and magnetic fields, as well as, the noise reduction of the other transmission channels based on electromagnetic signals;

3) Elastic waves to electrical signals converters. They are based on piezoelectric materials, or another type of devices like capacitive sensors. When these structures are strained by the small forces produced by the elastic waves they generate electrical signals.

4) Transmission medium constituted by electrical cables basically. They are made up of a conductive material, in most of the occasions, covered by insulating material. The wires of electrical cables usually are metals of low resistivity such as copper, silver or aluminum. There is an enormous variety of electrical cables and by all of them the elastic waves, in different modes of propagation, can be transmitted.

[0009] Optionally, a new class of components is required: the dielectric bridges. They have the mission of transmitting the elastic signals between segments of the same one, or another one, electrical cable in such a way that certain apparatuses are avoided, like relays, switches, metering devices... that could interrupt the transmission means or produce attenuation, reflection or another type of effects on the elastic waves. On the other hand, it is necessary to consider that additional electrical connections to the existing ones should not be established. For that reason, these dielectric bridges must be based on non-conducting electricity materials.

[0010] Finally, as transmission system it requires many other elements, such as filters, clocks, coders, decoders.... These components are not described because they are well known by the experts in this field.

[0011] The terms used in this report are not meant to limit their wider interpretation. The materials, forms and dispositions of the elements can be changed as long as the essence of the invention is not altered.

Claims

1. - Transmission system based on elastic waves propagation through electrical cables characterized by having a number of electrical signals to elastic waves converters, a number of elastic waves to electrical signals converters, a number of dielectric connections of the converters to the transmission medium and a transmission medium that includes a number of electrical cables.

2. - Transmission system based on elastic waves propagation through electrical cables, according to the first claim, characterized by having a number of dielectric bridges in the transmission medium.