Device for the remote transmission of signals and in particular video signals

• US 5,089,886 A
• Filed: 05/24/1990
• Issued: 02/18/1992
• Est. Priority Date: 02/04/1987
• Status: Expired due to Fees

• Current Assignee: Compagnie Generale De Videotechnique
• Original Assignee: Visicable+
• Inventors: Grandmougin, Gerard
• Primary Examiner(s): Dwyer, James L.
• Assistant Examiner(s): Chan, Wing F.
• Application Number:
  US07/527,720
• Time in Patent Office: 635 Days
• Field of Search: 358/86, 455/3, 455/5, 375/36
• US Class Current: 725/143
• CPC Class Codes: H04B 3/00 Line transmission systems combined with near-field transmission systems H04B5/00
• CPC Class Codes: H04N 7/108 the cable being constituted by a pair of wires

Abstract

A device for the transmission of signals, including video signals, between at least one transmitting assembly and at least receiving assembly by means of a twin-wire connection line provided at each end with a symmetric transformer and supplied by at least one current generator, wherein the generator supplies symmetrically on the wires of the line and is controlled by the signals to be transmitted, of which the frequency is between 50 Hz and 30 MHz, the line being balanced at each end by an impedance equal to its characteristic impedance.

Claims

1. A transmission device for signals, comprising:

at least one transmitter assembly including first and second current generators mounted in series with a matching impedance;

at least one receiver assembly including a diode bridge;

a twin-wire line;

a symmetrical transformer having a magnetic core mounted on each end of said line connecting said line to said receiver assembly and to said transmitter assembly, the windings of said transformer made from twin-wire cable;

said first generator being driven by one of said signals to be transmitted and delivering a current symmetrically into one wire of said line;

said second generator being driven by the inverse of said one of said signals to be transmitted and delivering a current symmetrically into the other wire of said line;

wherein said line is balanced at each end by an impedance of a value equal to the characteristic impedance of said line, and said matching impedance is of a value equal to the characteristic impedance of said line, and said signals are in a frequency range of 50 Hz to 30 MHz.

2. A device according to claim 1, wherein the two wires (6-7) are identical and have a diameter which is less than or at most equal to 1 mm.

3. A device according to claim 1, wherein the transmitter assembly (4) includes a limiter (26) for the feeding current of generators (23-24).

4. A device according to claim 3, wherein the current limiter (26) is connected to a positive power feed terminal of one of generators (23), a detector (27) being connected to its negative power feed terminal.

5. A device according to claim 1, wherein the twin-wire cable forming the windings of the symmetrical transformers (56-102) is made from the wires (6-7) of the line.

6. A device according to claim 5, wherein the transmitter assembly (4) and the receiver assembly (5) are respectively a receiver and a transmitter.

7. A device according to claim 1, wherein the line wires can be cylindrical, and are kept parallel by means of a common covering made of an insulating material.

8. A device according to claim 1, wherein the matching impedance (25), in series with the generators, includes resistors and a capacitor adapted for separating the continuous component of the signals to be transmitted.

9. A device according to claim 1, wherein the matching impedance (25) of the line is made of two equal impedance units (95-96) mounted in series, a node where said impedance units are joined being connected to ground through a capacitor (97).

10. A device according to claim 1, wherein in each receiver assembly (5), the line matching impedance is mounted in parallel on said line and is made of two equal impedance units mounted in series, a node where said impedance units are joined connected to ground through a capacitor.

11. A device according to claim 1, wherein the receiver assembly (5) includes two current generators (35-36) supplying a feeding current for said receiver assembly.

12. A device according to claim 11, wherein the receiver assembly (5) includes a complementary current generator (170) operating symmetrically having its voltage controlled by modulated signals distinct from those controlling generators (23-24) of the transmitter assembly (4).

13. A device according to claim 12, wherein the modulated signals which control the complementary generator (170) are remote control signals.

14. A device according to claim 11, wherein a voltage limiter (39) is mounted between the two current generators (35-36) of the receiver assembly (4).

15. A device according to claim 14, wherein the voltage limiter (39) is a Zener diode.

16. A device according to claim 11, wherein the current generators (23-24, 35-26) are equivalent to a resistor with respect to the current continuous component.

17. A device according to claim 1, wherein the signals to be transmitted which control the current generators (23-24) of transmitter (4) result from the superimposition of first signals and of second signals, previously modulated and possibly amplified.

18. A device according to claim 1, wherein the signals transmitted to the receiver assembly (4) via line (6-7) pass through a differential amplifier (42) and are separated by filtering (43-46).