Television – Receiver circuitry – Tuning
Reexamination Certificate
1997-11-24
2001-02-13
Harvey, David E. (Department: 2714)
Television
Receiver circuitry
Tuning
C348S734000
Reexamination Certificate
active
06188448
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to audiovisual display systems, such as televisions. More particularly, it relates to audiovisual display systems having two or more tuners for selecting channels or sources of information. Most particularly, it is directed to television systems having two tuners, wherein one tuner is connected to a cable box and is under control of the television and another tuner is connected other than through a cable box.
BACKGROUND OF THE INVENTION
Various forms of audiovisual display systems which receive display information via electromagnetic transmission have been known to the art. One common example is a television, where the information to be displayed is transmitted from a broadcaster, cable head or other source by electromagnetic communication.
The earliest televisions utilized a single tuner connected to an antenna. The antenna would receive the transmitted electromagnetic information at various frequencies, and the tuner would be used to select a desired channel. Such systems were straightforward in that the information transmitted over the various channels was fully available for display on the television.
Over time, television signals were transmitted over cable. The use of cable provided for increased bandwidth compared to the prior systems, and afforded information providers the opportunity to provide more channels to the customer. Cable systems typically included various levels of programming, often offering a basic package which included those channels which were available through non-cable reception, namely, the publicly available or “free” channels. Further, cable systems often provided various “premium” channels, for which a cable subscriber was billed an additional amount beyond the basic services. Typically, a cable box is provided from the cable company to the customer which receives the cable information and serves as a channel selector for provision of the channel to the television. Ordinarily, a channel is selected for communication between the cable box and the television, often channel 3 as that channel is not typically utilized in public, over the air transmissions. The cable box serves as a decoder or descrambler for the various premium channels. Selective accessing of premium channels may be accomplished by the cable company, either locally or through the cable connection, programming the cable box. By doing so, the cable box maintains a list of entitled or accessible channels.
Televisions having two tuners are known in the art.
FIG. 1
shows a simplified diagrammatic view of a dual tuner system. A television
10
includes a display
12
. A first tuner
14
and a second tuner
24
are labeled tuner one and tuner two, respectively (though the designations may be reversed). The first tuner
14
has an input
16
adapted to be coupled to a source of picture information, such as supplied from cable box
30
. A selector
32
(shown diagrammatically in
FIG. 1
) may provide a selective connection between the first tuner output
18
and the display
12
. Similarly, the second tuner
24
receives as input
26
a signal from any number of sources, as shown in
FIG. 1
being adapted to receive the cable input
34
. The selector
32
may be selectively coupled to the tuner two output
28
to display the information from tuner two
24
on the display
12
. While not shown in the simplified diagrammatic view in
FIG. 1
, such dual tuner televisions
10
may be used in picture-in-picture systems wherein a first display
12
further includes a reduced sized picture
36
. Tuner one
14
would then supply the display information for the main display
12
and tuner two would supply the picture information for the reduced sized picture
36
.
In typical operation, tuner one
14
is set to a selected channel, e.g., channel 3, which receives the output of the cable box
30
on that selected channel. The tuning of the system is then performed by tuning the cable box
30
. The combined system of the cable box
30
and tuner one
14
serve to select the channel on the cable box
30
, and to provide it to selector
32
via tuner one
14
. Channel selection is typically made via the cable remote control
40
.
Historically, such a dual tuner television system
10
when operated with a cable box
30
, required multiple remote controls
40
,
42
. A cable remote
40
was used principally for purposes of channel changing. A television remote control
42
was principally used to change between tuner one
14
and tuner two
24
, as well as to adjust the volume, set color levels and cause other television related features to be set or adjusted.
Recently, efforts have been made to reduce the number of remote controls required for operation of the television
10
and cable box
30
. One effort utilizes the television
10
to control the cable box
30
under operation of a single remote control. When a request for a channel change is sent from the remote control
42
to the television
10
, the television
10
in turn communications the channel change request to the cable box
30
. Since no feedback is provided from the cable box
30
to the television
10
in such systems, it has proved necessary to provide control information from the television
10
to the cable box
30
in a relatively slow manner. Often, this control information transfer slows channel changing by a factor of
10
.
FIG. 2
shows a chronologic display of channel entry, with time going from the left to the right. In order to effect a first channel change
50
, the television
10
sends a first digit to the cable box
30
at a time designated by marker
52
. At a later time designated by marker
54
, the television
10
sends a second digit to the cable box
30
. At time indicated by marker
56
, the television
10
sends an enter command to the cable box
30
. Finally, at time indicated by marker
58
, the cable box
30
actually tunes. Thus, the cumulative time from the initiation of a request until actual changing of the cable box
30
can be significant, in current practice taking on the order of 2 seconds. When scrolling through channels, such as through the use of the up channel button or in reviewing favorite channel lists, the time becomes cumulative, and is often viewed as a significant annoyance to the viewer. As shown in
FIG. 2
, from the first change
50
to the fifth change
60
, intervening changes are of substantially equal length.
Despite the desirability of having a two tuner system which may be controlled by a single remote, yet which does not suffer from the disadvantage of slow tuning, no optimal system has been yet presented. The system of this invention seeks to remedy those deficiencies.
SUMMARY OF THE INVENTION
Systems and methods are provided for the fast, effective tuning operation in a multiple tuner audiovisual display system. The system utilizes two or more tuners, which serve to select desired channels. A first tuner is adapted for connection to a source of coded information, such as a cable box. In the preferred embodiment, the combination of the first tuner and the tuner of the cable box together serve to select the desired channel and to supply the information to the display. At least one other tuner, denominated a second tuner, is adapted for connection to a source of information. A selector selectively couples a tuner to a display under action of a control system. The control system includes memory for storing indications of channel maps associated with the first tuner and cable box combination and the second tuner. The control system selects the second tuner when a channel is available as indicated by the channel map for that tuner, but selects the first tuner and cable box combination when the channel map indicates that the selected channel is available on the first tuner and cable box combination, but not on the second tuner. In the preferred embodiment, the first tuner and cable box combination are used for tuning only if the channel is unavailable to the second tuner.
In the preferred embodiment, the first tuner is connected to a cable box,
Hulse Adrian
Pauley Nicholas J.
Harvey David E.
Lyon & Lyon LLP
Mitsubishi Digital Electronics America Inc.
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