Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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DESCRIPTI01V
FAST TUNER SY;STEM
FIELD OF THE INVENTION
The present invention relates generally to audiovisual display systems, such
as
televisions, and more particularly to an audiovisual display system having two
or more
tuners and a control system for providing fast tuning during sequential
channel changes,
and rapidly displaying information from sequential channels.
BACKGROUND
Various forms of audiovisual display systems which display information
received
from electromagnetic transmissions are known in thc: art. One common example
is a
television set which is used to display information rc;ceived from
broadcasters and the like
via over-the-air transmissions, from cable systems, or from other sources of
information.
Television sets includes a tuner which receives a signal from the source of
information and
delivers a video signal corresponding to a selected channel to a television
screen or
display.
More recently, some television sets have included two tuners, for example in
2 0 picture-in-picture (pip) systems where one tuner provides information for
the main display
while the other tuner provides information for a reduced sized picture. Such
televisions
include a video selector switch which selectively couples one or both of the
tuners to the
television display. When a channel change instruction is received for one of
the tuners, the
selected tuner is re-tuned and then may be coupled (if not already) to the
display in
2 5 response to the instruction.
However, because each tuner is tuned only when a new change channel
instruction
is received for that particular tuner, the fastest that conventional dual
tuner televisions, can
change channels is the time required for a single tuner to completely re-tune,
similar to
single tuner televisions. This delay may be particul~~rly noticeable and
inconvenient when
3 0 a television user is "channel surfing," i.e. rapidly changing through the
channels in
sequence. When a channel change signal is received by the television, the user
must wait
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until the selected tuner has time to completely re-t~.me to the new channel
before the user
can view it and determine whether to continue along the sequence of channels.
Accordingly, there is a need for an audiovisual display, such as a television,
which
rapidly tunes faster than conventional televisions to speed up the time to
change channels,
SUMMARY OF THE INVENTION
The present invention is directed to an audiovisual display, such as a
television,
with a fast tuner system for reducing the time to change channels,
particularly during
sequential channel changes. The audiovisual display system in accordance with
the
present invention generally includes a display, a plurality of tuners adapted
for connection
to a source of information, and a selector coupled to the plurality of tuners
to selectively
couple one of the plurality of tuners to the display. A control system is
coupled to the
plurality of tuners and the selector for toggling the selector in response to
channel change
instructions to cyclically couple one of the plurality of tuners to the
display. Preferably,
when a first tuner of the plurality of tuners is coupled to the display in
response to a first
sequential channel change instruction, the control system is adapted to
preemptively tune a
second tuner of the plurality of tuners to a sequenti,~l channel, whereby when
a second
sequential channel change instruction is received, the control system toggles
the selector to
couple the second tuner of the plurality of tuners to the display.
2 0 The audiovisual display system may also include a user interface, such as
a remote
control including an input for providing sequential channel change
instructions, adapted to
provide channel change instructions to the control .system. In one preferred
embodiment,
the audiovisual system is a television set having two or more internal tuners
controlled by
the control system. Alternatively, the television may include one or more
internal tuners
2 5 and an external tuner which may be detachably coupled to the selector and
the control
system, such as a VCR.
In accordance with a method of using the fast tuner feature of an audiovisual
display system of the present invention, the process of fast tuning is
triggered when a first
signal indicative of a channel change is received. In response to the first
signal, the
3 0 control system detects a channel change instruction in the first signal,
and a first tuner is
coupled to the display (which may be re-tuned to the indicated channel or may
be
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preemptively tuned to it). If a sequential change instruction, such as channel
up, channel
down or selection from a favorite channels list, is detected in the first
signal, the second
tuner is preemptively tuned to a sequential channel.. If the audiovisual
display includes a
third tuner, the third tuner may also be preemptively tuned to another
sequential channel
when a sequential channel change instruction is detected in the first signal.
When a second signal indicative of a channel change is received, the control
system tries to detect a selection pattern, preferably by comparing the first
and second
signals to detect whether the first and second signals include the same
sequential channel
change instruction. If a selection pattern is detected, i.e. the first and
second signals
include the same sequential channel change instruction, the second tuner is
coupled to the
display without having to wait for it to re-tune. The decoupled tuner, i.e.
the first tuner,
may then be preemptively tuned to another sequential channel in anticipation
of a third
sequential channel change instruction.
Thus, the control system of an audiovisual display system in accordance with
the
present invention cycles through the tuners, preemptively re-tuning one or
more decoupled
tuners in response to sequential channel change instructions in anticipation
of similar
sequential channel change instructions being received. This allows the time
lapse to show
information on the display due to re-tuning to a selected channel to be
substantially
reduced compared to single tuner systems or systems without this method of
control.
2 0 Accordingly, a principal object of the present invention is to provide an
audiovisual display system having multiple tuners that may be cyclically and
preemptively
tuned, for fast tuning the system during sequential channel changes.
Other objects and features of the present invention will become apparent from
consideration of the following description taken in conjunction with the
accompanying
2 5 drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a first preferred embodiment of a fast tuner
television
system in accordance with the present invention.
3 0 FIG. 2 is a schematic representation of time required for channel changes
in the
audiovisual system of FIG. 1.
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FIG. 3 is a schematic view of a second prei:erred embodiment of a fast tuner
television system in accordance with the present invention.
FIG. 4 is a schematic view of a third preferred embodiment of a fast tuner
television system in accordance with the present invention.
FIG. SA through SC are schematic representations of time, comparing the time
required for channel changes in a one, two and three tuner system
respectively.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning now to the drawings, FIG. 1 shows, a first preferred embodiment of a
fast
tuner television 10 in accordance with the present invention. The television
10 includes a
conventional display 12 and a pair of internal tuners 14, 16 (identified as
Tuner 1 and
Tuner 2 respectively), the tuners 14, 16 each being connected to a source of
information
18, such as a conventional source of cable television signals. The tuners 14,
16 are also
coupled to a video selector switch 20 which is adapted to selectively couple
one of the
tuners 14, 16 or a video input 22 to the display 12.
The television 10 includes a control system 24, preferably a micro-computer,
coupled to the tuners 14, 16 and the video selector ;>witch 20. Alternatively,
the control
system 24 may include a sequencer, one or more analog or digital devices
and/or discrete
or integrated components, as will be appreciated by those skilled in the art.
Preferably, the
2 0 control system 24 is responsive to a user interface, such as a remote
control device (not
shown). The television 10 may include a receiver (,not shown) coupled to the
control
system 24 to receive output from the remote control device, such as infrared
radiation
bearing information regarding television control, as is known in the art.
The control system 24 is adapted to alternatc;ly tune the tuners 14, 16 and/or
toggle
2 5 the video selector switch 20, thereby alternately coupling one of the
tuner 14, 16 to the
display 12, to display a selected channel received from the source of
information 18 on the
display 12. Most preferably, when one of the tuners, for example Tuner 1, is
coupled to
the display 12 in response to a first sequential channel change instruction,
the control
system 24 directs the other decoupled tuner, i.e. Tuner 2, to preemptively
tune to a
3 0 sequential channel in anticipation of receiving a second sequential
channel change
instruction, whereupon the control system 24 may toggle the video selector
switch 20 to
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couple the decoupled tuner, Tuner 2, to the display 12, as explained more
particularly
below. In addition, the control system 24 may include memory (not shown) for
storing a
previous channel change instruction and/or a comp~~rator (not shown) for
comparing
channel change instructions to detect selection pattf;rns.
During use, the operation of the television 10 generally proceeds as follows.
A
first signal is received indicative of a channel change, for example, from a
remote control
device controlled by the television user. The control system 24 couples a
first tuner (e.g.
Tuner 1 ) to the display 12 in response to the first signal. The first tuner
may already be
"preemptively" tuned to the selected channel as explained below, or may be re-
tuned when
it is coupled to the display 12. The control system :Z4 detects whether the
first signal is a
sequential channel change instruction, such as channel up, channel down, or a
favorite
channel selector, e.g. super quick view (SQV). If a sequential channel change
instruction
is detected, the control system 24 re-tunes the second or decoupled tuner
(Tuner 2) to the
next channel in the sequence, i.e. "preemptively" tuning the second tuner in
anticipation of
receiving another similar sequential channel change instruction.
When a second signal indicative of a channel change is received, the control
system 24 compares the first and second signals to detect a selection pattern,
i.e. whether
the second signal is the same sequential channel ch~mge instruction as the
first signal. If a
selection pattern is detected, the second tuner (Tuner 2) is coupled to the
display 12 and
2 0 the first tuner (Tuner 1 ) is decoupled, thereby displaying the
information from the second
tuner without having to wait the time required to re-tune to the desired
channel. In
addition, the control system 24 preemptively tunes the first or then-decoupled
tuner (Tuner
1 ) to the next channel in the sequence. When a third signal indicative of a
channel change
is then received, the control system 24 repeats the sl:eps described above,
comparing the
2 5 third signal to the second signal, coupling the decoupled tuner (Tuner 1 )
if a selection
pattern is detected, and then preemptively tuning the then-decoupled tuner
(Tuner 2).
With reference to FIG. 2, a diagrammatic view of the time for channel changing
is
shown when employing the present invention, generally showing time proceeding
from
left to right. Time block 30 depicts the minimum time required for a single
tuner to
3 0 completely re-tune when a channel change instruction is received. Time
blocks 32a-32j
depict a series of channel changes using the television 10 of FIG. 1 when
sequential
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channel instructions, e.g. a series of "channel up" signals, are received. In
block 32a,
Tuner 1 is tuned (or preemptively tuned) and coupled to the display 12 in
response to
signal 1. While Tuner 1 is tuning, Tuner 2 is preemptively tuned to the next
channel in the
sequence in anticipation of signal 2, as indicated in block 32b.
When signal 2 is received, Tuner 2 is coupled to the display 12, and as
indicated in
block 32c, Tuner 1, now decoupled from the display 12, is preemptively tuned
in
anticipation of signal 3, and so on until signal 10 is received, whereupon
Tuner 2 is re-
tuned in block 32j, (partially shown in dots to indicate the time for Tuner 2
to completely
re-tune in response to signal 10. Thus, if a television user is "channel
surfing," i.e. rapidly
sequencing through the channels on the television set, the control system 24
cycles or
"ping pongs" between Tuner l and 2, thereby reducing the time to change
channels by as
much as fifty percent, as explained further below.
Turning to FIG. 3, a second preferred embodiment of a television system 110 in
accordance with the present invention is shown. Similar to the first preferred
embodiment,
the television system 110 includes a display 12, a video selector switch 20
and a control
system 24. However, instead of dual internal tuners, the television system 110
has a first
internal tuner 14, and a second external tuner, such as VCR 116, which is
coupled to the
television set 110 via line 122. For example, the video output of the VCR 116
may be
detachably connected to an input port 124, such as the video input of the
television system
2 0 110. The control system 24 is coupled to the VCR 116, for example via a
control port 126
or a remote control (not shown), in addition to the internal tuner 14 and the
video selector
switch 20, whereby the control system 24 may control the VCR 116 and/or its
tuner (not
shown).
During use, the television system 110 operates similarly to the first
preferred
embodiment, except that the VCR 116 replaces the second internal tuner 16 (see
FIG. 1),
thereby eliminating the need for the second internal tuner. Thus, the control
system 24
may cycle between the internal tuner 14 and the V C'.R 116 to preemptively
tune the
decoupled tuner and shorten sequential channel changing times.
Turning to FIG. 4, a third preferred embodiment of a television system 210 in
3 0 accordance with the present invention is shown. The television 210 has a
display 12, first
and second internal tuners 14, 16, a video selector switch 20, and a control
system 24,
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similar to those previously described. In addition, an external tuner, such as
a VCR 116, is
also provided which is coupled to the video selector switch 20, similar to the
arrangement
described above. The control system 24 is coupled to the VCR 116, in addition
to the pair
of internal tuners 14, 16, thus further speeding up sequential channel
changing.
FIG. SC illustrates the operation of the television 2l0 of FIG. 4 or a similar
three
tuner system, which may include other alternative combinations of internal
and/or external
tuners (not shown). During use, for example, when a first signal indicating a
sequential
channel change is received, the first internal tuner :l4 (represented by Tuner
1 in FIG. SC)
is tuned to a first channel or may already be preemptively tuned to the first
channel
(Channel 1 in FIG. SC), and coupled to the display 12. The second internal
tuner 16
(Tuner 2) is preemptively tuned to a second channel in the sequence (Channel
2), and the
external tuner 116 (Tuner 3) is preemptively tuned to a third channel in the
sequence
(Channel 3). When a second signal indicating a sequential channel change is
received, the
second internal tuner 16 (Tuner 2) is coupled to the: display 12 to display
the second
channel (Channel 2). The external tuner 116 (Tune;r 3) is held at the third
channel
(Channel 3), and the first internal tuner 14 (Tuner 1 ), now decoupled from
the display 12,
is preemptively re-tuned to a fourth channel in the sequence (Channel 4).
Although a
particular sequence has been described, it is merely illustrative of the
manner in which the
control system 24 cycles or rotates through the tuners to more quickly provide
information
2 0 on the display 12 in response to sequential channel change instructions.
Thus, as illustrated in FIGS. SA-SC, the present invention contemplates a
television or other audiovisual device having a plurality of tuners, and a
control system for
cycling through the tuners, each tuner after the first reducing the time
required to
sequentially change channels. As indicated, the horizontal width of each block
represents
2 5 the time required to completely re-tune a single tuner. FIG. SA shows the
time required to
change channels using conventional single tuner tuning, i.e. the single tuner
is re-tuned in
response to each signal to change channel, thereby requiring six full re-tune
time periods
to change channels through Channels 1-6.
In contrast, FIG. SB represents the passage of time to sequentially change
channels
3 0 using a dual tuner audiovisual display in accordance with the present
invention, such as the
television 10 of FIG. 1 or the television system 110 of FIG. 3. Each tuner
only tunes every
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other channel, thus Tuner 1 only re-tunes to Channels 1, 3 and 5, while Tuner
2 re-tunes to
Channels 2, 4 and 6. Thus, a dual tuner system may reduce the time to change
channels by
at least about forty percent, and possibly by as much as about fifty percent
As shown in FIG. SC, with three tuner tuning, the individual tuners re-tune
only to
every third channel. Accordingly, the time to sequentially change channels may
be
reduced to as little as about thirty three percent of the time required using
single tuner
tuning, as will be appreciated by those skilled in the art. Additional tuners
may be added,
if desired, each providing a proportional reduction in channel changing time.
Although
previously television tuners were expensive devices, with the development of
integrated
internal tuners, a bank of tuners of any desired number may be provided
without
substantially increasing the cast of the televisions, ;yet providing improved
fast tuning for
television systems.
While the invention is susceptible to various modifications, and alternative
forms,
specific examples thereof have been shown in the drawings and are herein
described in
detail. It should be understood, however, that the invention is not to be
limited to the
particular forms or methods disclosed, but to the contrary, the invention is
to cover all
modifications, equivalents and alternatives falling within the spirit and
scope of the
appended claims.
