FIELD OF THE INVENTION
This invention concerns the field of radio/VCR/television receiver
input signal switching controls.
BACKGROUND OF THE INVENTION
It is standard practice in the United States for broadcasters to
insert into program material, at various points, a number of commercial messages
of the program's sponsors. Many viewers find these messages to be an irritating
interruption of their viewing pleasure.
Accordingly, many techniques have been devised in an effort to avoid
being subjected to these commercial messages. One such technique is to merely mute
the sound via, for example, a mute pushbutton on a remote control handunit. A
remote control having such a mute function is known from the RCA CRK33 remote control
transmitter handunit manufactured by Thomson Consumer Electronics, Inc., Indianapolis,
Indiana. Unfortunately, muting the sound does not remove the video of the unwanted
commercial message, and the viewer must watch the commercial in order to know
when it has ended, and therefore, when the viewer can "unmute" the sound.
An improved sound muting technique is known from US-A- 3,870,956
(Wolff) issued 11 March 1975. Wolff discloses a circuit to mute the sound of a
television receiver for a predetermined time, at the end of which time the receiver
sound circuitry is automatically unmuted. The circuitry of Wolff, however, does
not affect the video, and thus a viewer is subjected to a series of silent commercial
Of course, a viewer may simply tune to a second channel when a commercial
message is displayed on the first tuned channel. A problem with this technique
is that the viewer has no way of knowing when the commercial message on the first
channel is finished. Consequently, the viewer may be late in returning to the first
channel, and may miss a portion of the program he was watching.
SUMMARY OF THE INVENTION
In order to overcome the above-stated problems, it is desirable that
a tuning system include a timer circuit which can be enabled by a user, before
changing channels to avoid a commercial message, and a memory circuit which, in
response to the enabling of the timer, stores data indicative of the currently
tuned channel. The timer circuit would, upon expiration of a predetermined time
period, return the tuning system to the original channel by use of the stored channel
An apparatus according to the invention comprises the features defined
in claim 1.
In an embodiment of the invention, a television system having picture-in-picture
(PIX-IN-PIX) capability, that is, the capability to produce signals which when
displayed include a first program in a main viewing area of a display screen and
a second program in a secondary (inset) viewing area of same display screen, switches
a first program currently selected to occupy the main viewing area to the secondary
viewing area in response to the sequence of the enabling of a timer, and a selection
of a different program. Upon expiration of the timer period, the first program
is redisplayed in the main viewing area.
In another embodiment of the invention, the controller allows selection
of signals from different signal sources such as a VCR, compact disc player, AM/FM
stereo tuner or the like, to be substituted for the signal from any other of these
sources, during the timed period. Upon expiration of the timed period, the originally
selected signal source will be reselected.
BRIEF DESCRIPTION OF THE DRAWING
FIGURE 1 shows in block diagram form a system suitable for use with
FIGURE 2 illustrates a remote control handunit suitable for use with
FIGURES 3 and 4 are flowcharts of a program used by the controller
of FIGURE 1, and are useful in understanding the invention.
FIGURE 5 illustrates a display screen suitable for use with an aspect
of the invention.
FIGURE 6 illustrates, in block diagram form, apparatus suitable for
use with another aspect of the invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
The invention will now be described with respect to an embodiment
in a television receiver environment, however, it should be understood that the
invention is equally applicable to radio receivers and videocassette recorders
Referring to FIGURE 1, an antenna 100 receives radio frequency (RF)
signals and applies them to a tuner assembly 102. Tuner assembly 102 selects and
amplifies a particular RF signal under control of a tuner controller 104 which
provides bandswitching signals and tuning voltage signals to tuner assembly 102
via a band switch 106.
Tuner assembly 102 converts the received RF signal to an intermediate
frequency (IF) signal and provides IF output signal to IF amplifier and detector
108. IF amplifier and detector 108 amplifies the IF signal applied to its input
terminal and detects the video information contained therein. This detected video
information is then applied as one input to a video multiplexer switch unit 110,
the other input of which is connected to a video input terminal 112.
Tuner controller 104 generates the before-mentioned tuning voltage
signals and bandswitching signals in response to control signals applied from a
system control microcomputer MC 114. Microcomputer 114 receives user-initiated
commands from an infrared (IR) receiver 116 and from a keyboard 118. Microcomputer
114 includes program memory (ROM) (not shown) and stores channel-related data
in a random access memory (RAM) 120. RAM 120 may be of either the volatile or non-volatile
type. One skilled in the art will recognize that if volatile memory is utilized
that it may be desirable to use a suitable form of standby power to preserve its
contents when the receiver is tuned off.
Video multiplexer switch unit 110, under control of system control
microcomputer 114, selects either a video signal derived from a received RF signal,
or a video signal input at terminal 112, for connection to a video signal processor
IR receiver 116 receives IR signals transmitted by, for example,
a remote control handunit such as the one shown in FIGURE 2 and designated 200.
Remote control handunit 200 may include keys 202 for entering the digits 0-9,
for entering channel up and channel down commands and for turning the receiver
on and off. Remote control handunit 200 may also include a key 204 (labelled ANT)
for selecting, as a signal source, either the antenna, or a video input terminal,
via control of multiplexer switch unit 110. Remote control handunit 200 may also
include a key 206 (labelled TIMER), a key 208 (labelled CLEAR), and a key 320
(labelled SWAP), the operation of which will be described below. Remote control
handunit 200 includes therein electronic circuitry (not shown) for encoding a
signal to be transmitted by an IR diode 212 in accordance with the particular keys
Operation of the apparatus illustrated in FIGURES 1 and 2 will now
be described with reference to FIGURES 3 and 4.
If a viewer is watching a television program on, for example, channel
3, and the television program is interrupted for a commercial message, the viewer
may avoid receiving the commercial message by pressing timer key 206 of remote
control handunit 200, and then tuning other channels in the usual way.
When system control microcomputer 114 receives IR or keyboard data,
it enters a keycode decoding routine, the relevant portion of which is shown in
the flowchart of FIGURE 3. The illustrated portion of the decoding program first
checks (step 300) to see if the received code is the CLEAR keycode. If the CLEAR
key has been pressed, then the timing function will be terminated, and the receiver
will not automatically return to the stored channel. If the received keycode is
not the CLEAR keycode, the routine next checks (step 310) for the "commercial timer"
or TIMER keycode. If the TIMER keycode is not received, the program is exited
(step 315). However, if the TIMER keycode is received, the program determines if
the commercial timer is active (step 320). If not, the current status of the antenna
switch is stored (step 325) (if the receiver is so equipped), data indicative of
the currently tuned station is stored in memory 120, the commercial timer active
flag is set (step 330), and the timer count is set to an initial time period of
30 seconds (commercial messages, often simply referred to as "commercials" are
usually presented in multiples of 30 seconds in the United States). The time remaining
in the count is displayed on the display screen via an on-screen display (OSD)
integrated circuit 335. Displaying the remaining time on the receiver screen reminds
the viewer that he has selected the timer function, and that at the end of the
timer period, the receiver will automatically return the tuner to the channel watched
when the timer function was initiated, unless the viewer cancels the timer function
by pressing the "clear" key. This feature prevents a viewer (who may have forgotten
that he engaged the timer) from being surprised when the stored channel is automatically
returned upon the expiration of the timer period.
If during the decoding of the received keycode it is determined that
the keycode is the TIMER keycode and the timer is already active, then the time
period is incremented by 30 seconds (step 340). Because the timer is already active,
and channel data is already stored, it is assumed that the viewer merely wants
to extend the time for viewing the currently tuned channel. Therefore, upon second
and subsequent TIMER keypresses, data relating to the currently tuned channel is
not stored. The maximum time period may be set to any value by the system designer
and programmed into system ROM. In the illustrated embodiment the maximum time
period is 1 hour (step 350). If the timer period is incremented by a viewer beyond
59 minutes, the preferred operation is that the timer "wraps around" to 0 minutes
without clearing the seconds (step 360). This operation is preferred because the
viewer has selected the timer function, and therefore the timer function should
be performed. In this case, the timer function is executed by timing the remaining
seconds until 0:00. Alternatively, incrementing beyond 59 minutes could be treated
in the same way as a CLEAR command. This is not preferred because the viewer, in
this case, has selected the timer function, and has not issued a CLEAR command,
but nonetheless, the timer function is terminated.
Of course, the timer period need not be incremented in discrete units
of 30 seconds as described above. Alternatively, the timer period may be entered
digit by digit via the numbered keys of remote control handunit 200, after a initial
activation of the TIMER key.
The portion of the program of microcomputer 114 illustrated by the
flowchart of FIGURE 4 is entered once each second in response to an interrupt (which
may be derived by a counter (not shown) counting cycles of the AC line). Upon
entering this portion of the program, microcomputer 114 checks to see if the commercial
timer is active (step 400). If not, the routine is exited. If so, a check of time
remaining is made (step 405), and if the timer count is not equal to 0 minutes,
0 seconds, the count is decremented by 1 second (step 410), the remaining time
is sent to the OSD circuit for display (step 415), and the routine is exited (step
420). If the time in the counter is equal to 0 minutes, 0 seconds, then the channel
memory 120 is addressed, and a comparison made (step 425) to determine if the
receiver is currently tuned to the channel which was tuned when the timer key was
pressed. (If the receiver is equipped with a video multiplexer switch unit 110
for switching between an antenna derived signal and a baseband video signal, then
a check of video multiplexer switch unit status would also be made.) If the receiver
is tuned to the same channel, then no action need be taken other than to clear
the commercial timer active flag (step 430), and remove the "time remaining" display
from the screen (step 435). If the current channel (or video multiplexer switch
unit status) is different from the stored channel (or video multiplexer switch
unit status) then the commercial tuner active flag is cleared (step 440), the
stored channel selected and the video multiplexer switch unit status, if applicable,
is restored (step 445), and the program exited (step 450).
In another embodiment of the invention, a television system (i.e.
television receiver, VCR, or videodisc player) includes PIX-IN-PIX (picture-in-picture)
capability wherein a secondary television picture, derived from a different source
than the main picture, is displayed in smaller form and is usually located in an
inset in a corner of the television screen.
FIGURE 5 illustrates such a PIX-IN-PIX display on a television screen
500. The main picture 510 is displayed over the majority of the display screen,
while the secondary picture is displayed in an inset 520 in smaller form. The
positions of the programs displayed as the main picture and secondary picture may
be interchanged by the use of a SWAP key 210 on remote control handunit 200.
When a commercial message appears in a first program (displayed as
the main picture), a viewer, in accordance with another aspect of this invention,
may start the timer and, by changing channels move the first program to the inset
position, and the newly selected channels to the main position. In this way, the
first program is displayed in the inset position, and the viewer is free to change
the channel displayed in the main screen during the timer period. The first program
will return automatically to the main display area when the timer period expires.
The time remaining 530 is displayed on the screen as a reminder to the viewer
that the timer is engaged, and that the original program will be redisplayed in
the main screen at the end of the timer period. Note that the first program is
transferred to the inset position only if a different channel had been selected.
If no different channel is selected, then only a timer function is enabled, with
no video signal switching required. Note that upon expiration of the timed period,
the original program can alternatively be redisplayed over the entirety of the
screen, thus cancelling the PIX-IN-PIX function.
Although the diagram of FIGURE 1 shows a single tuner and a separate
video input, the scope of the invention is intended to encompass signals derived
from multiple tuners, or multiple baseband sources (audio or video) or any combination
thereof, so long as signal selection data relating to a first signal is stored,
a timer is engaged and the stored signal selection data is used to automatically
reselect the first signal when the time period expires.
In this regard, and in accordance with another aspect of the invention,
the system controller may control more than one kind of signals. For example, the
RCA Dimensia System manufactured by Thomson Consumer Electronics, Inc., Indianapolis,
Indiana, controls, via a common control bus, various audio and video sources, such
as an audio amplifier, an AM/FM stereo tuner, a compact disc player, and a VCR,
in addition to controlling a video monitor.
If the present invention were incorporated into such a system, then
it would be possible to engage the timer when a television or radio commercial
begins, and via commands on the common control bus, switch to another signal source
such as a CD player to listen to music during the timer period. The controller
would, as described above, return to the original signal source upon the expiration
of time period. Such a system is illustrated in simplified form in FIGURE 6. Similarly
numbered elements in FIGURES 1 and 6 perform similar functions. The elements numbered
600&min;-612&min;, and 604&sec; provide for alternate selection of audio sources
in similar fashion to alternate selection of images. For example, CD player 612&min;provides
a baseband audio signal, and is thus similar to terminal 612 at which is developed
a baseband video signal. Note that in this case, the "tuning" information stored
also includes which device was active when the timer was engaged.
As shown in FIGURE 6 an audio multiplexer switch unit 610&min; is
capable of selecting television audio signals, radio audio signals, or CD player
audio signals, for further processing by an audio signal processor (not shown).
Thus, during a television commercial message, system control microcomputer 614
may condition audio multiplexer switch unit 610&min;to disconnect the television
audio signal and allow the user to substitute, during the timer period, an audio
signal from either the radio or a CD player. For simplicity, the controller for
a VCR is not shown, but it is to be understood that the video signals developed
at terminal 612 may be provided by a VCR.