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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a audio-visual system.
Particularly the present invention relates to an audio-visual system
including a bus for interconnection of various components thereof.
2. Description of the Related Art
Recently, audio-visual (AV) systems have been introduced in which control
of various system components may be effected in accordance with operating
instructions sent to an audio-visual center. FIG. 17 shows an example of
such an conventional AV system with connecting bus.
In FIG. 17 an AV center 1 (such as a television monitior, or the like) is
connected to a plurality of image sources 2a, 2b and 2c, which may, for
example, include a video tape deck, a tuner, satellite decoder, etc. The
AV center 1 is connected individually to each of the image sources 2a, 2b,
2c, respectively, via signal cables 3 which generally include an video
signal cable and an audio signal cable (left and right audio cables may be
provided for stereo audio). In addition, the AV center 1 is connected in
series to the image sources 2a-2c via bus cables 5 interconnected via
connectors 4. The bus cables generally include a - balance cable, +
balance cable and ground cable. It will be noted that each of the image
sources are provided with two connectors 4 for allowing series connection
of the components and that a first (i.e. input) side connector 4, as well
as the connector 4 of the AV center 1 are provided with end resistance
means 6. The end resistance means 6 of the image sources 2a-2e are
designed so as to be defeated in the case wherein bus cables are connected
to both input and output sides of the component (2a-2c), and the end
resistance 6 of the AV center 1 is defeated according to the presence of a
bus cable (output) being connected thereto. Thus, according to the system
of FIG. 17, the end resistance means 6 of the AV center 1 as well as of
the image sources 2a and 2b are inactive due to the presence of the bus
cables 5, while the end resistance 6 of the image source 2c is active,
since no bus cable 5 is connected to the output side thereof.
According to the system as described above, sufficient control of the AV
system is possible. However, recently, since such sophisticated bus
systems are becoming increasingly part of ordinary AV products, there is a
desire to simplify interconnection arrangements for AV components in order
to allow the average consumer to utilize such products with a minimum of
confusion.
For example, in the system described above, there is an obvious one to one
correspondence between the signal cables 3, the AV center 1, and each of
the image source components 2a, 2b and 2c. However, with respect to the
series connection of the bus cables 5, such one to one correspondence is
not readily evident and misinstallation may easily occur when such
connections are effected by a non-professional, since the way in which the
signal cables are connected is not analagous to the manner in which the
bus cables 5 are connnected. Thus, there is a tendency, for example, for a
user to connect a bus cable to the output side of the final component in
the system (i.e. 2c) rendering the end resistance means 6 of the system
inoperative, leading to malfunction of the bus system overall.
Thus it is desirable to provide an AV system including bus functions, in
which the connection between each respective component and the AV center 1
is the same for all components. Thus, confusion between signal cable
interconnection and bus system interconnection may be avoided and ease of
use for the consumer is greatly enhanced, while sophisticated functioning
of the AV system overall need not be compromised.
SUMMARY OF THE INVENTION
It is therefore a principal object of the present invention to overcome the
drawbacks of the related art.
It is a further object of the present invention to provide an AV system
including a bus function in which interconnection of system components is
simplified. In addition, a number of cables, connectors etc., necessary
for system operation may be substantially reduced, thus lowering costs.
In order to accomplish the aforementioned and other objects, a AV system is
provided as described below.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a block diagram of a first embodiment of an audio-visual system
utilizing AV bus cables according to the invention;
FIG. 2 is a circuit diagram of the bus connection system within the
audio-visual system of FIG. 1;
FIG. 3 is a schematic representation of bus connection between an AV center
and an image source via a AV bus cable according to the invention;
FIG. 4 is a flow chart of an OSD display processing method of the system of
the invention;
FIG. 5 is a schematic view of a first state of the AV bus of the first
embodiment;
FIG. 6 is a schematic view of the AV bus of FIG. 5 in an alternative second
state thereof;
FIG. 7 is a block diagram of a second embodiment of an audio-visual system
according to the invention;
FIG. 8 is a block diagram of a second embodiment of an AV bus cable
connection according to the invention;
FIG. 9 is an modification of a connection between an AV center and an image
source according to the invention;
FIG. 10 is a block diagram of a third embodiment of an AV bus cable
connection according to the invention;
FIG. 11 is a schematic diagram of a connection between a master component
and slave component in relation to the AV system of the invention;
FIG. 12 is a block diagram of a fourth embodiment of an AV bus cable
connection according to the invention;
FIG. 13 is a perspective view of an AV bus cable of a fifth embodiment;
FIG. 14 is a circuit diagram of connection of the bus system of the fifth
embodiment;
FIG. 15 is a diagram of a fifth embodiment, of an AV bus connection of the
invention;
FIG. 16 is a schematic view of a fifth embodiment of circuit connections of
the AV bus of the invention; and
FIG. 17 shows a block diagram of a conventional AV system including signal
cable and bus cable interconnections.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, particularly to FIGS. 1-7, a first preferred
embodiment of an AV system 1 according to the invention will be described
hereinbelow in detail.
According to the first embodiment, an AV control center 10, which may be a
television set, video monitor, or the like, is connected to a plurality of
image source components 11a, 11b, 11c via a first AV signal connector 12
and a second AV bus connector 13.
The image source components 11a, 11b and 11c respectively include
corresponding connectors, that is, an AV signal connector 14 for output of
an image signal input to the AV signal connector 13 of the AV control
center 10 via an AV signal cable 16, and an AV bus connector 15 for
connection to the AV bus connector 13 of the AV control center 10 via an
AV bus cable. Thus, according to this arrangement a 1:1 correspondence is
established in cable connections between the AV control center 10 and any
of the image source components 11a, 11b and 11c. That is, each image
source component 11 requires an AV bus cable 18 and an AV signal cable 16
between itself and the AV control center 10.
Referring now to FIGS. 2 and 3, a circuit diagram of bus connection within
the AV control center 10 is shown. As may be seen, the AV bus comprises a
positive (+) balance line L1, a negative (-) balance line L2 and a ground
line L3, the lines L1 and L2 are connected at first and second ends of the
bus circuit by first and second resistors R1 and R2.
In addition, the AV bus of the AV control center 10 includes a plurality of
switch groups t extracted from the AV bus lines L1, L2, L3 at each of the
AV bus connectors 13 thereof, Each switch group includes an output
terminal group t1 (t1, t1, t1) and an input terminal group t2 (t2, t2, t2)
which comprise the terminal portions of each of the connectors 13.
The input terminal group t2 and the output terminal group t1 as well as the
AV bus lines L1, L2 and L3 are interconnected via a switch group SW1. The
switch group SW1 is operable to adopt a closed, or ON, state according to
connection of a first plug 17a (FIG. 3) of the AV bus cable 18 to the
connector 13 of the AV control center 10 and to adopt an open, or OFF,
state according to disconnection of a first plug 17a from one of the
connectors 13.
FIG. 3 shows a detailed circuit diagram of the interconnection between a
connector 13 of the AV control center 10, a first plug 17a, its AV bus
cable 18 and a corresponding second plug 17b and the connector 15 of an
image source component 11 to be connected to the AV system 1.
The AV bus cable 18 comprises an output side bus line B0 and an input side
bus line B1 each including a + balance line L1, a - balance line L2 and a
ground line L3, similarly to the internal AV bus of the AV control center
10. In addition, first ends of each of the bus lines B0 and B1 are
connected to a switch group t3 of the first plug 17a, while second ends of
the bus lines B0 and B1 are connected to a switch group t4 of the second
plug 17b of the AV bus cable 18.
The second plug 17b further includes a switch group SW2 operable between
the AV bus lines L1, L2, L3 of the output side bus line B0 and the AV bus
lines (L1-L3) of the input side bus line B1 in a manner analagous to the
switch group SW1 of the internal AV bus of the AV control center 10. That
is, the switch group SW2 is opened (switches assume an OFF, or open state)
according to attachment of the second plug 17b to a connector 15 of an
image source component 11 and closed (switches assume an ON, or closed
state) according to disconnection of the second plug 17b from the
connector 15.
The connector 15 includes an input terminal group t5, an output terminal
group t6, a detecting switch SW3, and a projecting member 21. Upon
connection of the second plug 17b to the connector 15 of the image source
component 11, the following occurs.
When the second plug 17b is connected to the connector 15, the projecting
member 21 is active to turn OFF the switch group SW2. Further, according
to such connection, the detecting switch SW3 is closed (ON). When the
detecting switch SW3 becomes ON a microcomputer (not shown) of the image
source component 11 becomes active to output an on-screen display (OSD)
image to the CRT (not shown) of the AV control center 10 for displaying a
present connective state of the AV system 1, as shown in the flowchart of
FIG. 4.
Thus, following connection of all image source components 11a, 11b and 11c,
the state of the switch group SW1 becomes OFF, while the state of the
switch group SW2 the AV bus cable 18 also becomes of OFF to produce the
connective state of the AV system 1 as shown in FIG. 5.
FIG. 6 shows a connective state of the AV system 1 if the third image
source component 11c is disconnected from the system. As may be seen, when
only two image source components 11 are utilized, the state of the switch
group SW1 of the third connector 13 remains closed (ON) while the switch
groups SW1 of the first and second connectors 13 are open (OFF) since they
are connected to the image source components 11a and 11b. Thus the
resistor R2 of the internal AV bus of the AV control center 10 is active
to provide the end resistance for the overall AV bus of the AV system 1.
If, due to misconnection or malfunction a AV bus cable 18 is connected to
the third connector 13 of the AV control center 10 while in fact the
second plug 17b of the AV bus cable 18 is not connected to the third image
source component 11c, as shown in FIG. 7, the switch group SW1 of the
third connector 13 of the AV control center 10 will be caused to remain
open. However, as a result, the switch group SW2 of the AV bus cable 18
will remain closed due to non-connection to the image source component
11c, thus forming a loop back to the AV control center 10, again allowing
the resistor R2 of the internal AV bus of the AV control center 10 to
provide the end resistance for the overall AV bus of the AV system 1.
Therefore, normal operation may be carried out and no malfunction will
result.
It will be noted that, according to the above-described construction, it is
not necessary to provide end resistance means at each image source
component, thus reducing the cost and complexity of such components.
While the above-described embodiment provides a AV control center 10 with
three connectors 13 for utilizing three image source components 11a, 11b
and 11c, it will be noted that, according to the invention, any number of
connectors 13 may be provided.
A second embodiment of an AV system 1 according to the invention will be
described in detail with reference to FIG. 8. It will be noted that where
the arrangement of subsequently described embodiments disclosed herein
correspond to that of the above described embodiment, redundant
description will be omitted for brevity.
Basically, the second embodiment provides for the AV bus cable 18 and the
AV signal cable 16 to be combined in a single unitary cable C. Connectors
22, 22, . . . of the AV control center 10 are suitable adapted to include
terminals for the AV signal as are the connectors 23, 23, . . . of the
image source components 11a, 11b 11c, etc. Of course, the first and second
plugs 24a and 24b of the unitary cable C are also adapted for transmission
of the additional AV signal. In other respects, the second embodiment is
identical to the above-described embodiment.
However, according to the second embodiment, wiring is further simplified
and overall neatness of the system when fully connected is enhanced.
FIG. 9 shows a third embodiment of the AV system 1 of the invention. This
embodiment basically comprises a modification of the connection between
the image source components 11a, 11b, 11c and the AV bus cable 18.
According to this modification, the AV bus cable 18 is permanently and
non-releasably attached to the image source component 11. Thus, no switch
group SW2 need be provided for loop back, since the AV bus cable 18 is
integral to the image source component 11. As a result, cost and
complexity may be further reduced with no compromise of functionality.
FIGS. 10, 11, and 12 show a fourth embodiment of the AV system 1 according
to the invention; the same reference numerals used in describing the first
embodiment will again be utilized for simplicity of explanation.
As may be seen, the third image source component 11c is utilized as a
master component connected via an additional AV bus cable 18 to a slave
component, that is, a fourth image source component 11d. According to this
embodiment, as seen in FIG. 11, the image source component 11 is provided
with a connector 15 to be connected to the AV control center 10 and a
slave connector 15b for allowing connection of an additional image source
component 11d. The use of the third image source component 11c as a master
component for the fourth image source component 11d is also shown in FIG.
12.
For facilitating such a system, bus lines B2 and B3 are provided between
the connectors 15 and 15a of the image source component. These bus lines
B2 and B3 are interconnected by a switch group SW4 which is switched
according to a projecting portion 19 of the first plug 17a of the AV bus
cable 18, the AV signal may be connected via standard video in/out
connectors and cables (i.e. AV cable 16) or may be integrated similar to
the second embodiment.
FIGS. 13, 14, 15 and 16 show a fifth embodiment of the AV system of the
invention. According to this embodiment, as seen in FIG. 13, a raised
portion 27 is provided on a first plug 26a which connects to the AV
control center 10. A recessed portion 28 corresponds reciprocally to the
arrangement of the raised portion, which has terminals t3, t3 . . .
arranged on side surfaces thereof, as shown in FIG. 14. The projecting
portion is provided on the raised portion 27 for enabling/disabling the
switch group SW1, the AV bus cable 18 has a second plug 26b for connection
to an image source component 11 as described above and sown in FIG. 15.
According to this, the first plugs of a plurality of AV bus cables 18 may
be stacked to obtain a plurality of AV bus connections via a single
connector, as shown in FIG. 16. Thus the number of parts for the AV
control center 10 may be reduced and a plurality of connections may
utilize a common ground line. Also, a user may decide how many bus
connections are required according to individual requirements and may add
more as necessary. Thus convenience and simplicity are enhanced and basic
costs may be reduced.
It will be noted that although, according to the above descriptions, the AV
control center 10 is connected to image source components 11a, 11b and
11c, the components 11 are not restricted only to image or video
components but may also apply to cable or satellite audio signals, or
other types of input.
While the present invention has been disclosed in terms of preferred
embodiments in order to facilitate better understanding thereof, it should
be appreciated that the invention can be embodied in various ways without
departing from the principle of the invention. Therefore, the invention
should be understood to include all possible embodiments and modifications
to the shown embodiments which can be embodied without departing from the
principle of the invention as set forth in the appended claims.
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