A signal cable includes a first connector having at least one signal lead and a ground lead, and being operable to couple to a first mating connector of a first piece of electronic equipment; a second connector having at least one signal lead and a ground lead, and being operable to couple to a second mating connector of a second piece of electronic equipment; at least one signal wire and a ground wire electrically connecting the respective at least one signal leads and the respective ground leads of the first and second connectors; and at least one switch disposed with at least one of the first and second connectors, the at least one switch having selectable make/break contacts coupled between the ground lead and the ground wire of the at least one of the first and second connectors such that an electrical path between the ground leads of the first and second connectors may be selectively opened and closed.
Description
BACKGROUND OF THE INVENTION
The present invention relates to cable interconnection between electronic equipment and, more particularly, to a connector and/or cable capable of selectively opening or closing a ground connection between two pieces of electronic equipment.
Noise problems often occur when undesirable ground loops are produced. Such ground loops are often formed when multiple pieces of electronic equipment are connected to one another through cables. To illustrate this problem, reference is made to FIG. 1
, which shows a first piece of electronic equipment 10
connected to a second piece of electronic equipment 20
by way of a cable 30
. The cable 30
includes a first connector 32
and a second connector 34
that are operable to mate with the first piece of electronic equipment 10
and the second piece of electronic equipment 20
, respectively. The cable 30
also includes signal wires 36
a
, 36
b
and a ground wire 36
c
for electrically connecting respective signal and ground leads 12
, 14
, 16
of the first piece of electronic equipment 10
to signal and ground leads 22
, 24
, 26
of the second piece of electronic equipment 20
. The first piece of electronic equipment 10
includes a connection from earth ground 1
to ground lead 16
(and/or chassis). Similarly, the second piece of electronic equipment 20
includes a connection from earth ground 2
to ground lead 26
(and/or chassis).
An undesirable ground loop may be produced when the cable 30
electrically connects the ground lead 16
of the first piece of electronic equipment 10
to the ground lead 26
of the second piece of electronic equipment 20
. This is so because the respective earth grounds 1
, 2
of the first and second pieces of electronic equipment 10
, 20
, respectively, are not at precisely the same potential as a function of time. Thus, noise currents flow between the earth grounds 1
, 2
by way of the ground wire 36
c
of the cable 30
. The connections to the respective earth grounds 1
, 2
are often made by way of respective AC power cords and chassis connections for the first and second pieces of electronic equipment 10
, 20
. Consequently, the noise currents are often in the audible range, for example, 60 Hz, 120 Hz, 180 Hz, etc. (often referred to as “hum”).
With reference to FIG. 2
, the ground loop problem illustrated in FIG. 1
may be solved by replacing the first piece of electronic equipment 10
with a piece of electronic equipment 40
that includes a switch 42
that is operable to interrupt the electrical path between the earth ground 1
and the ground lead 16
. Unfortunately, very few pieces of electronic equipment include such a switch 42
. When a piece of electronic equipment includes such a switch 42
, it often is a very high-end unit with a correspondingly high purchase price. Consequently, users often opt for the electronic equipment 10
, 20
of FIG. 1
and either live with the undesirable hum or take other, less advantageous, approaches to eliminating the noise currents. For example, users may attempt to disconnect the earth ground 1
from, for example, the first piece of electronic equipment 10
by removing the earth ground terminal from the AC power cord or utilizing a three-prong to two-prong adapter (often called a “cheater”), which performs the same function. In either case, the chassis of the first piece of electronic equipment 10
will float with respect to earth ground 1
and, therefore, present an electrical shock hazard to those handling the first piece of electronic equipment 10
.
With reference to FIG. 3
, it is noted that a cable 50
may include a connector 52
having a switch 58
coupled between signal leads 54
, 56
. In order to achieve a mute condition, a user may connect leads 54
, 56
together by way of the switch 58
(thereby shorting any differential signal from reaching the second piece of electronic equipment 20
). The muting switch 58
, however, does not solve the ground loop problem between earth grounds 1
, 2
.
Accordingly, there is a need in the art for a connector and/or cable that can effectively eliminate ground loop noise problems while still maintaining one or more signal connections between equipment.
SUMMARY OF THE INVENTION
In accordance with at least one aspect of the present invention, a signal cable includes: a first connector having at least one signal lead and a ground lead, and being operable to couple to a first mating connector of a first piece of electronic equipment; a second connector having at least one signal lead and a ground lead, and being operable to couple to a second mating connector of a second piece of electronic equipment; at least one signal wire and a ground wire electrically connecting the respective at least one signal leads and the respective ground leads of the first and second connectors; and at least one switch disposed with at least one of the first and second connectors, the at least one switch having selectable make/break contacts coupled between the ground lead and the ground wire of the at least one of the first and second connectors such that an electrical path between the ground leads of the first and second connectors may be selectively opened and closed.
Preferably, the first and second mating connectors of the first and second pieces of electronic equipment each include at least one mating signal lead and a mating ground lead for connection to the respective at least one signal lead and ground lead of one of the first and second connectors; the mating ground leads are electrically connected to respective chassis grounds of the first and second pieces of electronic equipment; and the at least one switch is operable to selectively open and close an electrical path between the chassis grounds of the first and second pieces of electronic equipment.
In accordance with at least one further aspect of the present invention, a connector operable to couple to a mating connector of a piece of electronic equipment includes: at least one signal lead and a ground lead operable to electrically connect to at least one signal wire and a ground wire, respectively, of a cable; and at least one switch having selectable make/break contacts, one of the make/break contacts being electrically connected to the ground lead and the other make/break contact being operable to electrically connect to the ground wire of the cable such that an electrical path between the ground lead and the ground wire may be selectively opened and closed.
In accordance with at least one further aspect of the present invention, a system includes: a first piece of electronic equipment having a first mating connector that includes at least one mating signal lead and a mating ground lead, the ground lead being electrically connected to a chassis ground of the first piece of electronic equipment; a second piece of electronic equipment having a second mating connector that includes at least one mating signal lead and a mating ground lead, the ground lead being electrically connected to a chassis ground of the second piece of electronic equipment; and a signal cable including: a first connector having at least one signal lead and a ground lead, and being operable to couple to the first mating connector of the first piece of electronic equipment; a second connector having at least one signal lead and a ground lead, and being operable to couple to the second mating connector of the second piece of electronic equipment; at least one signal wire and a ground wire electrically connecting the respective at least one signal leads and the respective ground leads of the first and second connectors; and at least one switch disposed with at least one of the first and second connectors, the at least one switch having selectable make/break contacts coupled between the ground lead and the ground wire of the at least one of the first and second connectors such that an electrical path between the chassis grounds of the first and second pieces of electronic equipment may be selectively opened and closed.
In accordance with at least one further aspect of the invention, a connector operable to couple between a mating connector of a piece of electronic equipment and a mating connector of a cable, includes: a first end having at least one signal lead and a ground lead operable to electrically connect to at least one mating signal lead and a mating ground lead, respectively, of the mating connector of the piece of electronic equipment; a second end having at least one signal lead and a ground lead operable to electrically connect to at least one signal wire and a ground wire, respectively, of the mating connector of the cable; and at least one switch having selectable make/break contacts, one of the make/break contacts being electrically connected to the ground lead of the first end and the other make/break contact being operable to electrically connect to the ground lead of the second end such that an electrical path between the ground leads may be selectively opened and closed.
Other aspects, uses and advantages of the present invention will be apparent to one skilled in the art based on the disclosure herein taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
For the purposes of illustrating the invention, there are shown in the drawings forms that are presently preferred, it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.
FIG. 1
is a schematic diagram illustrating the interconnection of two pieces of electronic equipment in accordance with a technique of the prior art;
FIG. 2
is a schematic diagram showing the interconnection of two pieces of electronic equipment in accordance with another technique of the prior art;
FIG. 3
is a schematic diagram illustrating the interconnection of two pieces of electronic equipment in accordance with still another technique of the prior art;
FIG. 4
is a schematic diagram of the interconnection of two pieces of electronic equipment in accordance with at least one aspect of the present invention;
FIG. 5
is a schematic diagram of the interconnection of two pieces of electronic equipment in accordance with at least one further aspect of the present invention;
FIG. 6
is a schematic diagram of the interconnection of two pieces of electronic equipment in accordance with at least one still further aspect of the present invention;
FIG. 7
is a perspective view of a connector suitable for use in accordance with at least one aspect of the present invention; and
FIG. 8
is a schematic diagram of the interconnection of two pieces of electronic equipment in accordance with at least one still further aspect of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings wherein like numerals indicate like elements, there is shown in FIG. 4
a schematic diagram illustrating the interconnection of a first piece of electronic equipment 10
and a second piece of electronic equipment 20
utilizing a cable 100
in accordance with at least one aspect of the present invention. The cable 100
includes a first connector 110
and a second connector 120
at respective ends of signal wires 130
, 132
, and ground wire 134
. The first connector 110
preferably includes a first signal lead 112
, a second signal lead 114
, and a ground lead 116
as would be used, for example, in a balanced connector (such as an XLR connector) The first connector 110
is preferably operable to couple to a mating connector 18
of the first piece of electronic equipment 10
such that the first signal lead 112
of the first connector 110
engages a first signal lead 12
of the mating connector 18
. Similarly, the second signal lead 114
of the first connector 110
preferably engages a second signal lead 14
of the mating connector 18
. Finally, the ground lead 116
of the first connector 110
preferably engages a ground lead 16
of the mating connector 18
. The second connector 120
preferably includes a similar configuration as the first connector 110
inasmuch as a balanced arrangement is contemplated, where the second connector 120
is preferably operable to couple to a mating connector 28
of the second piece of electronic equipment.
Preferably, a signal wire 130
electrically connects the first signal lead 112
of the first connector 110
to the signal lead 122
of the second connector 120
. It is preferred a second signal wire 132
electrically connects the second signal lead 114
of the first connector 110
to the second signal lead 124
of the second connector 120
. It is also preferred that a ground wire 134
electrically connects the ground lead 116
of the first connector 110
to the ground lead 126
of the second connector 120
. The ground wire 134
may be a shield for one or more of the signal wires 130
, 132
. Further, the ground wire 134
may be electrically connected to respective shells of the first and second connectors 110
, 120
.
The first connector 110
preferably includes at least one switch 118
having selectable make/break contacts 117
, 119
coupled between the ground lead 116
and the ground wire 134
. The switch 118
is preferably activated by a user when he or she wishes to interrupt the electrical path between the ground leads 116
, 126
of the first and second connectors 110
, 120
. When the ground leads 16
, 26
of the first and second pieces of electronic equipment 10
, 20
are connected to the earth grounds 1
, 2
, respectively, the user may selectively open and close the electrical path therebetween. Advantageously, a ground connection (e.g., chassis ground) between the first and second pieces of electronic equipment 10
, 20
may be opened without severing the connection between the chassis of the first piece of electronic equipment 10
and earth ground 1
or the connection between the chassis of the second piece of electronic equipment 20
and the earth ground 2
. Thus, a ground loop may be interrupted without creating a shock hazard to users of the equipment.
The one or more aspects of the present invention as illustrated in FIG. 4
may be implemented using any suitable connector 110
, including but not limited to, XLR connectors, RCA connectors, BNC connectors, TNC connectors, ⅛ inch connectors, and ¼ inch connectors.
With reference to FIG. 5
, at least one other aspect of the present invention provides for utilizing at least one switch 118
in the first connector 110
and at least one second switch 128
disposed in a second connector 140
. Selectable make/break contacts 127
, 129
of the second switch 128
are preferably coupled between the ground lead 126
and the ground wire 134
, thereby providing an additional place at which the electrical path between earth grounds 1
, 2
may be interrupted.
With reference to FIG. 6
, in accordance with one or more further aspects of the present invention, undesirable ground loops may be compensated for when unbalanced interconnections are utilized (such as by way of RCA connectors). In particular, a cable 200
preferably includes a first connector 210
, a second connector 220
and first and second signal wires 230
, 232
. For the purposes of the unbalanced interconnection, the signal on the second signal wire 232
may be considered a return or ground with respect to the signal on the first signal wire 230
. The first signal wire 230
preferably electrically connects a first signal lead 212
of the first connector 210
and a first signal lead 222
of the second connector 220
. The second signal (or ground) wire 232
preferably electrically connects a second signal lead 214
of the first connector 210
and a second signal lead 224
of the second connector 220
. The first connector 210
preferably includes at least one switch 218
coupled between the second signal lead 214
and the second signal wire 232
such that the electrical path therebetween may be opened and closed in accordance with the desires of the user. It has been found that opening this electrical path does not mute the signal on the first signal wire 130
and, thus, the primary function of the cable 200
(e.g., delivering a signal from the first piece of electronic equipment 10
to the second piece of electronic equipment 20
) is not disturbed. Opening this electrical path, however, has been found to yield desirable reductions in noise propagation, reduced hum, etc. It is noted that at least one other switch (not shown) may be disposed with the second connector 220
without departing from the spirit or scope of the invention.
Advantageously, certain ground, return and/or signal connections between the first and second pieces of electronic equipment 10
, 20
may be opened without severing the connection between the chassis of the first piece of electronic equipment 10
and earth ground 1
or the connection between the chassis of the second piece of electronic equipment 20
and the earth ground 2
. Thus, a ground loop may be interrupted without creating a shock hazard to users of the equipment. Further, expensive and/or high-end equipment (which may be difficult to obtain) that includes internal ground interruption switches need not be employed.
By way of example, FIG. 7
illustrates a suitable XLR connector 110
having a switch 118
that the user can selectively activate to open and/or close the electrical path between lead 116
and a corresponding wire (not shown).
Referring now to FIG. 8
, a schematic diagram illustrating the interconnection of a first piece of electronic equipment 10
and a second piece of electronic equipment 20
utilizing a conventional cable 30
and a connector 300
in accordance with at least one aspect of the present invention is shown. The connector 300
includes a first end preferably having a first signal lead 302
, a second signal lead 304
, and a ground lead 306
, it being understood that any number of signal and/or ground leads are contemplated without departing from the scope of the present invention. The connector 300
also preferably includes a second end having a first signal lead 308
, a second signal lead 310
, and a ground lead 312
corresponding to the respective leads of the first end. The connector 300
is preferably operable to couple to a mating connector of the first piece of electronic equipment 10
such that the first signal lead 302
of the connector 300
engages a first signal lead 12
of the mating connector of the first piece of electronic equipment 10
. Similarly, the second signal lead 304
of the connector 300
preferably engages a second signal lead 14
of the mating connector. Finally, the ground lead 306
of the connector 300
preferably engages a ground lead 16
of the mating connector. The second end of the connector 300
is preferably operable to engage a connector 32
of the cable 30
such that the first signal lead 308
, second signal lead 310
, and ground lead 312
engage corresponding first signal lead 32
A, second signal lead 32
B, and ground lead 32
C of the cable 30
. The interconnection of the cable 30
to the second piece of electronic equipment 20
is in keeping with the disclosure hereinabove.
The connector 300
preferably includes at least one switch 314
having selectable make/break contacts coupled between the ground leads 306
, 312
of the first and second ends of the connector, respectively. The switch 314
is preferably activated by a user when he or she wishes to interrupt the electrical path between the ground lead 16
of the first piece of electronic equipment 10
and the ground lead 32
C of the cable 30
. The user may selectively open and close the electrical path between ground leads 16
, 26
of the first and second pieces of electronic equipment 10
, 20
and, therefore, selectively open and close the electrical path between the earth grounds 1
, 2
, respectively. Advantageously, a ground connection between the first and second pieces of electronic equipment 10
, 20
may be opened by way of connector 300
even when a conventional cable 30
is employed. Although not shown in figures, the connector 300
may be interposed between cable connector 34
and the second piece of electronic equipment 20
. Alternatively, the connector 300
may be disposed as shown in FIG. 8 and a
second connector (similar to that of connector 300
) may be interposed between cable connector 34
and the second piece of electronic equipment 20
such that two switches are available for interrupting the ground interconnection between the first and second pieces of electronic equipment 10
, 20
.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.
Claims
1. A signal cable, comprising:a first connector having at least one signal lead and a ground lead, and being operable to couple to a first mating connector of a first piece of electronic equipment; a second connector having at least one signal lead and a ground lead, and being operable to couple to a second mating connector of a second piece of electronic equipment; at least one signal wire and a ground wire electrically connecting the respective at least one signal leads and the respective ground leads of the first and second connectors; and at least one switch disposed with at least one of the first and second connectors, the at least one switch having selectable make/break contacts coupled between the ground lead and the ground wire of the at least one of the first and second connectors such that an electrical path between the ground leads of the first and second connectors may be selectively opened and closed.
2. The signal cable of claim 1, wherein:the first and second mating connectors of the first and second pieces of electronic equipment each include at least one mating signal lead and a mating ground lead for connection to the respective at least one signal lead and ground lead of one of the first and second connectors; the mating ground leads are electrically connected to respective earth grounds of the first and second pieces of electronic equipment; and the at least one switch is operable to selectively open and close an electrical path between the earth grounds of the first and second pieces of electronic equipment.
3. The signal cable of claim 1, wherein one such switch is disposed with one of the first and second connectors such that the electrical path between the ground leads of the first and second connectors may be selectively opened and closed.
4. The signal cable of claim 1, wherein the ground wire is a shield for the at least one signal wire.
5. The signal cable of claim 1, wherein the first connector includes first and second signal leads; the second connector includes first and second signal leads; and first and second signal wires electrically connect the respective first and second signal leads.
6. The signal cable of claim 1, wherein the first and second connectors each include a shell and the ground leads are electrically connected to the respective shells.
7. The signal cable of claim 1, wherein the first and second connectors are taken from the group consisting of XLR connectors, RCA connectors, BNC connectors, TNC connectors, ⅛ inch connectors, and ¼ inch connectors.
8. A connector operable to couple to a mating connector of a piece of electronic equipment, comprising:at least one signal lead and a ground lead operable to electrically connect to at least one signal wire and a ground wire, respectively, of a cable; and at least one switch having selectable make/break contacts, one of the make/break contacts being electrically connected to the ground lead and the other make/break contact being operable to electrically connect to the ground wire of the cable such that an electrical path between the ground lead and the ground wire may be selectively opened and closed.
9. The connector of claim 8, wherein:the mating connector of the piece of electronic equipment includes at least one mating signal lead and a mating ground lead for connection to the respective at least one signal lead and ground lead; the mating ground lead is electrically connected to an earth ground of the piece of electronic equipment; and the at least one switch is operable to selectively open and close an electrical path between the earth ground of the piece of electronic equipment and the ground wire of the cable.
10. The connector of claim 8, wherein the ground wire is a shield for the first and second signal wires.
11. The connector of claim 8, wherein the connector includes a shell and the ground lead is electrically connected to the shell.
12. The connector of claim 8, wherein the connector includes first and second signal leads operable to electrically connect to first and second signal wires of the cable.
13. The connector of claim 8, wherein the connector is taken from the group consisting of an XLR connector, an RCA connector, a BNC connector, a TNC connector, an ⅛ inch connector, and a ¼ inch connector.
14. A system, comprising:a first piece of electronic equipment having a first mating connector that includes at least one mating signal lead and a mating ground lead, the ground lead being electrically connected to an earth ground of the first piece of electronic equipment; a second piece of electronic equipment having a second mating connector that includes at least one mating signal lead and a mating ground lead, the ground lead being electrically connected to an earth ground of the second piece of electronic equipment; and a signal cable including: a first connector having at least one signal lead and a ground lead, and being operable to couple to the first mating connector of the first piece of electronic equipment; a second connector having at least one signal lead and a ground lead, and being operable to couple to the second mating connector of the second piece of electronic equipment; at least one signal wire and a ground wire electrically connecting the respective at least one signal leads and the respective ground leads of the first and second connectors; and at least one switch disposed with at least one of the first and second connectors, the at least one switch having selectable make/break contacts coupled between the ground lead and the ground wire of the at least one of the first and second connectors such that an electrical path between the earth grounds of the first and second pieces of electronic equipment may be selectively opened and closed.
15. The system of claim 14, wherein one such switch is disposed with one of the first and second connectors such that the electrical path between the ground leads of the first and second connectors may be selectively opened and closed.
16. The system of claim 14, wherein the ground wire is a shield for the at least one signal wire.
17. The system of claim 14, wherein the first connector includes first and second signal leads; the second connector includes first and second signal leads; and first and second signal wires electrically connect the respective first and second signal leads.
18. The system of claim 14, wherein the first and second connectors each include a shell and the ground leads are electrically connected to the respective shells.
19. The system of claim 14, wherein the first and second connectors are taken from the group consisting of XLR connectors, RCA connectors, BNC connectors, TNC connectors, ⅛ inch connectors, and ¼ inch connectors.
20. A connector operable to couple between a mating connector of a piece of electronic equipment and a mating connector of a cable, comprising:a first end having at least one signal lead and a ground lead operable to electrically connect to at least one mating signal lead and a mating ground lead, respectively, of the mating connector of the piece of electronic equipment; a second end having at least one signal lead and a ground lead operable to electrically connect to at least one signal wire and a ground wire, respectively, of the mating connector of the cable; and at least one switch having selectable make/break contacts, one of the make/break contacts being electrically connected to the ground lead of the first end and the other make/break contact being operable to electrically connect to the ground lead of the second end such that an electrical path between the ground leads may be selectively opened and closed.
21. The connector of claim 20, wherein:the mating ground lead of the piece of electronic equipment is electrically connected to an earth ground of the piece of electronic equipment; and the at least one switch is operable to selectively open and close an electrical path between the earth ground of the piece of electronic equipment and the ground wire of the cable.
22. The connector of claim 20, wherein the first end of the connector includes first and second signal leads operable to electrically connect to mating first and second signal leads of the piece of electronic equipment and the second end of the connector includes first and second signal leads operable to electrically connect to first and second signal wires of the mating connector of the cable.
23. The connector of claim 20, wherein the connector is taken from the group consisting of an XLR connector, an RCA connector, a BNC connector, a TNC connector, an ⅛ inch connector, and a ¼ inch connector.
24. A connector operable to couple to a mating connector of a piece of electronic equipment, comprising:at least one signal lead and a ground lead operable to electrically connect to at least one signal wire and a ground wire, respectively, of a cable; and at least one switch having selectable make/break contacts, one of the make/break contacts being electrically connected to the ground lead and the other make/break contact being operable to electrically connect to the ground wire of the cable such that an electrical path between the ground lead and the ground wire may be selectively opened and closed, without affecting any connections between the at least one signal wire and the respective at least one signal lead.
Patent Grant
6566767
