Note: Descriptions are shown in the official language in which they were submitted.
~-~Cs~ 2~
1 31 3405
PATENT
MESSAGE DELIV~RY SYSTEM
Field of the Invention
This invention relates to an information
transmission system capable of transmitting in parallel
a plurality of video signals, audio signals, and other
signals between a central unit and a plurality of
terminal units each provided at a different passenger
seat in a passenger vehicle, or at a different seat in a
stadium, theater, or the like. More particularly, the
invention relates to a forced transmission of messages
in an ~verride mode in a system of the type described in
the preceding sentence.
Backqround of the Invention
Aircraft are conventionally provided with an
audio/video system to entertain passengers during
flights of long duration. Conventional aircraft are
further provided with a reading light and an attendant
call light for each passenger seat.
However, in conventional aircraft and other
passenger vehicles, routine announcements such as
explanations regarding the manner in which lif~-~ackets
are to be used and so on, are provided only at
predetermined times, e.g. before a movie is started or
the like.
Further, if an announcement is made ~for example in
the event of an emergency) while a movie is being shown,
some passengers may miss the announcement while
observing the movie.
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U.S. Patent 4,584,603,issued April 22, 1986 to
Harrison discloses provision of a video display
individually on the back of each seat in an alrcraft.
However, U.S. 4,584,603 fails to disclose an override
operation for displaying messages or announcements at
each video display.
SUMMARY OF THE INVENTION
The invention is a message delivery system for
transmitting signals to a plurality of terminal units
which solves the above-mentioned problems. In a
preferred embodiment in which each terminal unit is
located at a different passenger seat in a passenger
vehicle, the invention comprises:
(a) a head end apparatus comprising means for
reproducing video programs, means for reproducing audio
programs, means for reproducing messages, controller
means having key means for generating a command signal
for the messages, modulator means for modulating the
video programs, the messages, the audio programs,
and the command signal, in different fre~uency bands,
respectively, and multiplexer means for multiplexing the
modulated video programs, audio programs, messages and
command signal;
(b~ a plurality of terminal units each comprising
a tuner means for receiving and demodulating the video
programs, the audio programs, the messayes and the
command signal, a decoder means for decoding the command
signal and generating in response to the command signal
an override signal for forcing the tuner means to select
the frequency band of the messages, a display means, an
audio output terminal, a volume control, and a means for
selecting the vid~o proyrams and the audio programs;
and
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(c) means for transmitting the video programs, the
audio programs, the messages and the command signal from
the head end apparatus to the terminal units.
These and other feature and advantages of the
present invention will become apparent from the
following detailed description of the preferred
embodiment taken in conjunction wi-th the accompanying
drawings, throughout which like reference numerals
designate like elements and parts.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a block diagram showing a preferred
embodiment of a message delivery system according to
the present invention;
Fig. 2 is a plan view showing a panel o~ the
selection indicating apparatus appearing in Fig. l;
Fig. 3 is a view of two units of the selection
indicating apparatus of the invention, each attached to
the back of a passenger seat;
Fig. 4 is a block diagram of another preferred
; embodiment of the invention;
Figs. 5A - 5C and 6A - 5D are diagrams showing
signal formats used in the invention;
Figs. 7A - 7C are diagrams showing examples of
messages of the type displayed by the invention; and
Fig. 8 is a perspective view of a preferred
embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
An embodiment of a message delivery system
according to the present invention will hereinafter be
explained with reference to Fig. l. The embodiment of
Fig. l is adapted for the transmission of messages,
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video signals, audio signals, and other signals in an
aircraft.
The "transmitting side" (also referred to as the
"central control portion" or "central control unit") of
invention will first be described w:ith reference to Fig.
1.
In Fig. 1, reference numerals :La to ld designate
video tape recorders provided in the transmitting side
such as in an aircraft crew's room. ~ideo tape recorder
la is used for an override operation and may be loaded
with a cassette tape explaining how to put on a
life-jacket or the like. Each of video tape recorders
lb to ld is loaded with a cassette tape of a video
program such as a movie. Each of video tape recorders
la to ld is respectively provided with a terminal V for
outputting a reproduced video signal and with terminals
L, R and A for outputting reproduced audio signals. In
an embGdiment in which video tape recorders la to ld
store bi-lingual programs, terminals L and R are used
for outputting left-channel and right-channel audio
signals in a first language, respectively, and terminal
A is used for outputting a monaural audio signal in a
second language.
Television tuner 2 is provided with a terminal V
for outputting a video signal and terminals L and R for
outputting the left and right channels of an audio
signal, respectively.
Still picture reproducing apparatus 3 is capable of
reproducing still picture information recorded in a
compact disk (CD) ROM~ such as maps, an airport guiding
drawing, or the like. The still picture reproducing
apparatus 3 is provided with a terminal V for outputting
a video signal representative of a still picture and a
terminal A for outputting an audio signal associated
with the still picture.
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Audio reproducing apparatus 4a and audio
reproducing apparatus 4b each include three sets of
compact disk players (CD players) and tape recorders~
The audio reproducin~ apparatus 4a, 4b are respectively
provided with six pairs of terminals L and R for
outputting left channel and right channel audio signals.
Controller 5 comprises a microphone 5a, a volume
control 5b for adjusting the level of an audio signal
received at the microphone 5a, an announce key 5c, an
override key 5d and pause keys 5e to 5g for setting the
video tape recorders lb to ld into a pause or stop mode.
Video signals from the respective terminals V of the
video tape recorders la, lb and audio signals from the
respective terminals ~, R and A of these recorders are
supplied to controller 5. Controller 5 is provided with
a terminal V for outputting a video signal and terminals
L, R and A for outputtin~ audio signals~ Usually, the
terminals V, L, R and A of the controller 5 output the
video signal supplied from terminal V of the video tape
recorder lb and the audio signals supplied from
terminals L, R and A of video tape recorder lb.
However, when the override key 5d is pressed to trigger
the override operation, the terminals V, L, R and ~ of
the controller 5 output the video signal supplied from
terminal V of video tape recorder la and audio signals
supplied from terminals L, R and A of video tape
recorder la. When the announce key 5c is pressed to
initiate the announce operation, an audio signal from
microphone 5a is delivered to the output terminal A of
controller 5.
CADA encoders 6 and 7 are of the type used in the
conventional cable digital audio/data transmission
system (CADA system) disclosed in U.S. Patent 4,684,981
issued August 4, 1987. The CADA encoders are capable of
time-division-multiplexing a plurality of digital audio
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and data signals and transmitting the multiplexed
signals over a vacant one channel band width (6 MHz) of
a CATV, thus transmitting signals (e.g., music) with
high efficiency without damaging their quality. Each of
CADA encoders 6 and 7 is provided with an A/D
(analog-to-digital) converter and a shift register. The
time-division-multiplexing operatioll is carried out by
converting a plurality of audio signals into digital
signals in the A/D converter, inputting the digital
signals in parallel to the shift register at
predetermined locations, and then outputting the digital
signals from the shift register in series at a high
speed. Not only digital audio signals but also control
data and data comprising computer soPtware can be
multiplexed by the CADA encoders in this manner.
The audio signals delivered to the output terminals
L, R and A of controller 5 are supplied to encoder 6.
The audio signals delivered to the output terminals L, R
and A of the video tape recorders lc and ld are also
supplied to encoder 6. The audio signals delivered to
the output terminals L and R of the tuner 2 and the
output terminal A of the still picture reproducing
apparatus 3 are also supplied to encoder 6. The audio
signals delivered to the six pairs of output terminals L
and ~ of audio reproducing apparatus 4a and the six
pairs of output terminals L and R of audio reproducing
apparatus 4b are supplied to encoders 6 and 7 through
controller 5.
When one of the override key 5d, the announce key
5c, and the pause keys 5e to 5g of the controller 5 is
pressed, the controller 5 generates control data SCl
having contents corresponding to the pressed key. The
control data SC1 is supplied to the encoder 6.
Encoder 6 has output terminals A to E from each of
which a pause or stop control signal is outputted in
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response to the control data SCl. The video tape
recorders lb to ld and the audio reproducing apparatus
4a and 4b are respectively controlled by the pause or
stop signals delivered from the terminals A to ~ of the
encoder 6. More specifically, when the override key 5d
and the announce key 5c are pressed, the pause control
signal is outputted from all of the terminals A to E, so
that the video tape recoxders lb to ld and the audio
reproducing apparatus 4a and 4b all enter a pause or
stop mode. When the pause keys 5e to 5g are pressed,
pau6e or stop control signals are outputted from output
terminals A to C, placing the video tape recorders lb to
ld into a pause or stop mode, respectively.
~ master controller 8 is provided. Master
controller 8 comprises a computer which controls the
overall system, and is preferably located in the cabin
of the aircraft. Master controller 8 is connected with
a display 81 and a keyboard 82. Master controller 8
generates control data SC2 (fox controlling one or more
terminal apparatus units located in the receiving side
of the system) in response to a command from keyboard 82
and supplies control data SC2 to encoder 6. The control
data SC2 may be, for example, data for controlling the
luminance of a display in the terminal apparatus, data
for polling the conditions of each passenger seat at
which a terminal apparatus is located, or other data.
The data can be monitored by the display 81 connected to
the master controller 8.
Menu data is written in ROM 9a, and a different set
of game data is written in each of ROMs 9b to 9h. Each
data signal SD read out from the ROMs 9a to gh (for
example, for use with computer software) is supplied to
a signal processing circuit lO in which, for example, an
error correcting code may be added thereto, and is
supplied to encoder 7 thereafter.
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Control data signals SCl and SC2 are supplied also
to the encoder 7 from the encoder 6.
A time-division-multiplexed signal SCAl emerges
from output terminal 0 of encoder 6. Signal SCAl
includes the plurality of digitally converted audio
signals generated in encoder 6, and the control data
SC1 and SC2 supplied to encoder 6~ The signal SCAl is
supplied to a modulator llf to be amplitude-modulated,
preferably by a VSB (vestigial sideband~ system.
A time-division-multiplexed signal SCA2 emerges
from an output terminal 0 of the encoder 7u Signal SCA2
includes the plurality of digitally converted audio
signals generated in encoder 7, and the control data
(SC1 and SC2) and the signal SD supplied to encoder 7.
The signal S~2 is supplied to modulator llg to be
amplitude-modulated, preferably by a VSB system.
The video signal delivered to the output terminal V
of controller 5 is supplied to modulator lla. The audio
signal delivered to the terminal A of controller 5 is
supplied both to modulator lla and to encodér 6. In
modulator lla, an ordinary television signal is
generated by frequency modulating the audio signal and
frequency~multiplexing the frequency modulated audio
signal with the video signal. This television signal is
thereafter amplitude-modulated, preferably by a VSB
system.
The video signals delivered to the respective
output terminals V of the video tape recorders lc, ld,
the tuner 2, and the still picture reproducing apparatus
3 are respectively supplied to modulators llb to lle to
be amplitude-modulated, preferably by a VSB system.
The modulators lla to llg modulate the signals
supplied thereto in frequency bands chosen so as to
prevent cross modulation, such as in every other channel
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_g_
above the ~0 channels of the television broadcasting
band.
Output signals from the modulakors lla to l~g are
supplied to an adder 12 in which they are
frequency-multiplexed. The frequency--multiplexed signal
SMF from the adder 12 is supplied through a signal
distributor 13 to one end of a leaky cable 21. Cable
21 sexves as a bi-directional signal transmission means.
The other end of leaky cable 21 terminates at terminal
resistor 22. A coaxial cable whose periphery is
spirally indented so as to leak a large amount of
signals i5 suitable for use as cable 21.
The receiving side o~ the system of the invention
will next be described.
Fig. 1 shows terminal apparatus unit 30, of the
type that preferably will be mounted on the back of a
plurality of passenger seats in an aircraft. Although
only one terminal apparatus unit 30 is illustrated in
Fig. 1, preferably there will be the same number of
terminal units ~O as there are passenger seats in the
aircraft. Each terminal apparatus 30 is provided with
an antenna 31 which receives the frequency multiplexed
signal S~F leaking from the leaky cable 21. The
frequency-multiplexed signal SMF recei~ed at the
antenna 31 is supplied through a signal distributor 32
to a television tuner 33 and a CADA tuner 34. Tuner 33
is capable of seleotively receiving channels in the
output frequ~ncy bands of the modulators lla to lle,
while the tuner 34 is capable of selectively receiving
channels in the output frequency bands of the
modulators llf and llg. Tuners 33 and 34 are controlled
in their channel seleotions by a ~election and display
apparatus 35.
Video and audio si~nals emerging from tuner 33 are
supplied to the selection and display apparatus 35, and
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the time-division-multiplexed signal SCAl or SCA2
emerging from tuner 34 is supplied to a CADA decoder
36. The CADA decoder 36 is constructed so as to effect
substantially the inverse operations to those performed
in CADA encoders 6 and 7. More specifically, CADA
decoder 36 decodes the time-division-multiplexed signal
SCAl (or SCA2) or CADA data, produces a desired
demultiplexed signal, and supplies the same to selection
and display apparatus 35 or personal computer 37.
Decoder 36 is provided with a shift register and a D/A
con~erter. The time-division-multiplexed signals SCAl
and SCA2 are serially input to the shift register. The
control data SC1 or SC2 is extracted in parallel form
at a predetermined location in the shi~t register. The
desired audio signal and computer software data signal
SD are also extracted in parallel form at predetermined
locations in the shift register, in response to control
signals from selection and display apparatus 35. The
audio signal is converted into an analog signal by the
D/A converter. Decoder 36 requires a pair of D/A
converters for the left channel and right channel of a
stereo audio signal. The audio signals emerging from
decoder 36 are supplied to selection and display
apparatus 35. The computer software data SD is supplied
to personal computer 37 and written into a random access
memory (RAM) therein. An embodiment of decoder 36 is
described in above-referenced U.S. Patent 4,684,981.
Fig. 2 is an example of a preferred arrangement of
the panel of selection and display apparatus 35. The
panel of selection and display apparatus 35 may be
mounted on the back of a passenger seat, as shown in
Fig. 3.
Fig. 2 shows a display 35a, which may comprise a
flat cathode ray tube or an LCD (liquid crystal display)
or the like, an audio output tPrminal 35b for connecting
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a pair of head phones 35c thereto, and a game terminal
35d for connecting a joy stick 35e (shown in Fig. 1), a
keyboard 43 (indicated by dashed lines in Fig. l), or
the like for playing games.
Further, the selection and display apparatus 35 is
provided with a television selectinq key 35f, a music
selecting key 35g, a channel display 35h, a channel-down
key 35i and a channel-up key 35j.
The television channel can be sequentially changed
by first pressing the television selecting key 35f and
then pressing the channel-down key 35i or the channel-up
key 35j. Thus, when the channel received by the
television tuner 33 is changed se~uentiallyl the display
35a sequentially displays images reproduced ~rom the
video signals derived from the video tape recorders lb
to ld, the tuner 2 and the still picture reproducing
apparatus 3, and corresponding audio signals from C~DA
decoder 36 are outputted to the audio output terminal
35b. When the audio signal is bi-lingual, two audio
channels are assigned for one video display. A first
language is outputted from the first channel; and a
second language from the second channel.
The music channel can be sequentially changed by
first pressing the music selecting key 35g and then
pressing the channel-down key 35i or the channel-up key
35j. In this manner, the audio signal outputted from
the CADA decoder 36 is changed, and the audio signals
outputted from the audio reproducinq apparatus 4a and 4b
are sequentially outputted to the audio signal output
terminal 35bo
The selection and display apparatus 35 is also
provided with a menu display key 35k, a cursor-down key
35e, a cursor-up key 35m and an enter key 35n. By
pressing the menu key 35k, a video signal based on data
from the menu ROM 9a is supplied to the selection and
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display apparatus 35 from the personal computer 37 and a
menu is displayed on thP display 35a.
By p.essing the enter key 35n after selecting a
game by moving the cursor on the display with the
cursox-down key 35~ and the cursor-up key 35m, a video
signal and an audio signal based on data of the selected
game from the game ROMs 9b to 9h are supplied from the
personal computer 37 to the selection and display
apparatus 35. Then, the game is displayed on the
display 3~a and the game sound signal is outputted to
the audio output terminal 35b.
Selection and display apparatus 35 also includes an
attendant call key 35p, a reading light key 35q and a
volume control 35r.
Selection and display apparatus 35 (also re:~erred
to herein as "selection indicating apparatus 3511) is
controlled by a CPU (not shown~ in CP.DA decoder 36 on
the basis of the control data SCl, SC2 extracted by CADA
decoder 36O
If override key 5d of controller 5 is pressed to
initiate an override operation while passengers are
watching a movie on the display 35a or listening to
music, tuner 33 is forced to recei~e the frequency
channel having the output frequency band of modulator
ll~, display 35a of selection indicating apparatus 35 is
forced to display an imaye reproduced from the video
signal outputted to terminal V of video tape recorder
la, and audio output terminal 35b is forced to output
the audio signal supplied to output terminal A of video
tape recorder la.
When announce key 5c of controller 5 is pressed to
initiate an announce operation, tuner 33 is forced to
receive the frequency channel having the output
frequency band of modulator lla, and audio output
terminal 35b is forced to output the audio signal from
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microphone 5a. In this event, the video signal is
muted so that display 35a does not display any image.
Further, any one of the television selecting key 35f,
the music selecting key 35g, the channel-down key 35i,
the channel-up key 35j and the ~olume adjuster 35r, or
all of them are disabled (prohibited from operatin~.
Additionally, the volume to all terminal units may be
caused to be uniform.
When CADA encoder 6 or 7 ceases to function, due to
a malfunction for example, the control data SCl supplied
to selection indicating apparatus 35 is the same as
that indication initiation of an override operation, so
that the selection indicating apparatus 35 is forced
into the same mode of operation as in the override
mode.
When an override operation is effected while a
passenger is playing a game on terminal display 35a,
perso~al computer 37 is temporarily prohibited from
executing the game. Also in this case, all or some of
the functions of unit 35 may be disabled, such as
channel selection and volume adjustment by television
selecting key 35f, music selecting key 35g and so on.
When the override key 5d or the announce key 5c is
pressed again to terminate the override operation or the
announce operation, selection and display apparatus 35
is released from the override condition and
automatically returned to its condition as of
initiation of the override or announce operation. More
specifically, video tape recorders lb - ld and audio
reproducers 4a and 4b are automatically released from
the pause or stop state and set into the reproducing
mode. The terminal units 30 are also returned to their
selected conditions as of the initiation of the override
or announce operation, so that reproduction of the video
signal and the audio signal resumes from the respective
1 3 1 3405
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interrupted points. Thus, the passengers can view a
complete mo~ie or listen to musical program without
missing any scene of the movie or any part of the music.
if the ovsrride or announcement operation had
S interrupted a game, personal computer 37 resumes its
execution, so that play of the game may resume.
When the selection state is overriden (forced into
a condition) as described above, channel display 35h
displays a signal indicative of the forced condition.
Selection and display apparatus 35 may optionally
include an additional display may for this indication.
The luminance of display 35a is automatically
controlled in accordance with the luminance of the
passenger's cabin in response to control data SC2.
When the control data SC2 re~uests transmission of data
from one or more units 35, the CPU within the CADA
decoder 36 of each relevant unit 35 generates data
indicative of a condition of the associated one of units
35 or data detected by sensor 39 (such as data
indicating whether the seat belt is fastened and whether
the seat is reclined, or the like). The requested data
is supplied to transmitter 38 to be modulated to a
frequency outside the frequency bands of modulators lla
through llg. Then, the modulated data is supplied
through signal distributor 32 and antenna 3~ to leaky
cable 21. The data is next supplied from leaky cable 21
through signal distributor 13 to CADA encoder 6 from
which the data is supplied to master controller 8 to be
utilized.
When attendant call key 35p on selection
indicating apparatus 35 is pressed, control data is
generated from the CPU in the asscciated CADA decoder
36. This control data is supplied to transmitter 38 to
be modulated and is thereafter supplied through signal
distributor 32 and antenna 31 to leaky cable 21. Then,
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the data is supplied from leaky cable 21 through signal
distributor 13 to CADA encoder 6. A CPU (not shown)
within CADA encoder 6 controls a switching box ~0 on
the basis of the data received from cable 21 so as to
light the corresponding attendant call lamp 41.
When reading light key 35q on selection indicating
apparatus 35 is pressed, cvntrol data is generated from
the CPU in the associated CADA decoder 36. This control
data is supplied to transmitter 38 to be modulated and
lo thereafter supplied through signal distributor 32 and
antenna 31 to leaXy cable 21. Then, the data is
supplied from leaky cable 21 through signal distributor
13 to CADA encoder 6. The CPU within CADA encoder 6
controls switching box 40 on the basis of the data
received from cable 21 so as to turn on or off a
corresponding reading lamp 42.
When keyboard 43 is connected to game terminal
35d, as shown by dashed lines in Fig. 1, the CP~ in the
CADA decoder 36 generates control data. This control
data is supplied to transmitter 38 to be modulated and
thereafter supplied through signal distributor 32 and
antenna 31 to leaky cable 21. The data is next
supplied from leaky cable 21 through signal distributor
13 to CADA encoder 6 from which the data is supplied to
master controller 8. In response thereto, master
controller 8 supplies encoders 6 and 7 with a computer
program such as a word processor program. The program
(which will hereinafter be re~erred to as a word
processor program ~or specificity) is supplied through
leaky cable 21 to terminal apparatus 30 as a
frequency-multiplexed signal and is received by personal
computer 37. When a passenger inputs sentences or the
like from the keyboard ~3, the sentences or the like are
stored in a random access memory (P~M~ in personal
computer 37. Display 35a displays the inputted
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16-
sentences or the like so that the passenger using the
word processor can correct the sentences or the like
while viewing them on display 35a. When an instruction
indicating the termination of a word processing
operation is entered using keyboard 43, data
representing the sentences or the like (converted into
ASCII code) st~red in the RAM of personal computer 37
are supplied through CADA decoder 36 to transmitter 38
to be mod~llated and thereafter are supplied to leaky
cable 21 through signal distributor 32 and antenna 31.
Then, the data is supplied from leaky cable 21 through
signal distributor 13 to CADA encoder 6 from which the
data is supplied to master controller 8. The data
representing the sentences or the like may be supplied
from master controller 8 to disk drive 44 to be
recorded e.g. in a floppy disk. Otherwise, the data is
supplied to printer 45 which prints the sentences or
the like, or to transmitter 46 to be transmitted to a
remote lvcation. The destination of the word processing
data is selected by the user by entry of appropriate
commands on keyboard 43~ Data indicative of the
selected destination is supplied to master controller 8
together with the word processing data itself. The word
processor program may be previously written in the ROM
provided in the personal computer 37 and then utilized.
Any record generated at memory unit 44 and any printed
record generated at printer 45 may be delivered to the
passenger, such as when the passenger exits the
aircraft.
Next, another preferred embodiment of a message
~elivery system according to the present invention will
be described with reference to Figure 4. The Figure 4
system is constructed so as to be able to individually
control the reception of each of the plurality of
terminal units 30. The components in Fig. 4
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corresponding to those in FigO l are designated by the
same reference numerals and the explanation thersof will
ba omitted.
I~ the Fig, 4 embodiment, CADA encoder 6 generates
an address ~ignal corresponding to the termi~al unit 30
which is to be controlled. The address i5 previously set
by the master controller 8 by operatin~ the key board 8z
be~ore th2 operation of the override key 5d or the
announce key ~c. ~his addre~s signal is multiplexed with
the control data SC1, Sc2 and supplied to the leaky cable
21 to be transmitted to the receiving side o~ the system.
The CADA decoder 3~ in each terminal unit o extracts
the address signal from the signals SCA1, SCA~ which are
~upplied from CADA tuner 34. The address signal extracted
by each CA~A decoder 36 is supplied to a comparator 52
wherein th~ extracted address signal is compared with an
hddress ~ignal, generated from an addres~ ge~eratDr 53
including a read-only memory (R0~) or the lik~ provided in
sach terminal unit 30. The selectio~ indicatin~ apparatus
3~ is controlled by an output signal ~rom comparator 52.
~ore specifically, only when the address signal extracted
by the C~DA decoder 36 coincides with the address signal
~rom th~ address generator 53, is reception of ~he
terminal unit 30 controlled by the control data SCl and
2~ SC2 in the manner described above.
~ he rest of the Figure 4 embodiment is constructed
and arranged in the same manner as is the Figure 1
embodiment.
~ n t}l~ Fiyur~ 4 em~o~ment, eaGh te~min~l ~ppar~tu
30 corresponding to th2 address signal transmitted from
tha transmitting side iæ solely control l ed in reception
by tha control d~ta SC~ and SC2 . Therefore, the
override, announceme~t, and sther operations described
above with reference to Fig. 1~ may be directed to
individual ones o~ the plurality of terminal units 30.
. ~ ............. . .
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Next, signal fQrmats of the signals SCAl and ScA2
will be explained with reference to Figs. 5A - 5C. The
signal format is improved from that disclosed in
aforementioned U.S. Patent 4,684,981.
Multiplexed signal St shown in Fig. 5A, is a
serial binary signal formed of a number of
super-frames. One super-frame thereof is formed of 256
frames El through ~256. As shown in Fig. 5B, each frame
includes 168 bits and the cyclic period of one frame is
(32 kHz)-l. Each frame has an 8-bit synchronizing code
SYNC, followed by a 4-bit service bit SB, followed by
four 32 bit data packets PCTA - PCTD, followed by four
7-bit error correcting codes (ECCs).
There are two kinds of synchronizing code SYNC as
shown in Fig. 5A: a super-frame-sync SS for the frame
Fl at the head of the super-~frame and a frame-sync FS
~`or the subsequent 255 frames F2 - F256. The bit
patterns of super-frame-sync SS and frame-sync FS are
selected to differ from each other.
The service bits SB, the details of which will be
provided below, are grouped into four groups each
including 77 bits. Each service bit contains data such
as a command, a seat number, and so on.
Each of data packets PCTA - PCTD is formed of 32
bits and is independent of the others. As shown in Fig.
5C, each of the packets PCTA - PCTD is divided into
four channels M1 - M4, each being formed of 8 bits.
Each of the channels Ml - M4 contains a PCM signal
obtained by sampling the audio signals L, R and A at a
frequency of 32 kHz.
Since one frame contains four packets PCTA - PCTD
and each packet has fGur channels Ml - M4, 16-channel
audio signals can be simultaneously transmitted in
time-division multiplexed form by the use of one signal
St. Each channel is sampled at a sampling fre~uency of
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--19--
32 kHz and encoded in 8 bits, so that it complies with
the PCM audio standard of an 8 mm video tape recorder
(VTR).
Data signals from the ROMs 9a - 9h are converted
into a time-division multiplexed bit sequence signal by
signal processing circuit 10 (shown in Fig. 4). The
time-division multiplexed signal emerging from circuit
10 is u~ed as one channel of the 16-channel signals.
The signal emerging from circuit 10 is cyclic, so that
when the last bit of data from ROMs 9a- 9h is
transmitted, the first bit of the data from these ROM's
is retransmitted.
Each channel of the Fig. 5C signal is formed of
eight bits, and eight ROMs 9a - 9h are provided.
Accordingly, in the channel for transmitting data from
the ROMs 9a -9h, each of the first bit through the
eighth bit of the channel corresponds to data from a
different one of ROMs 9a through ROM 9h. Therefore, the
transmission rate of data from each ROM is 32 kbps.
ZO The four error correcting codes ECCs respectively
correct errors which may occur in the packets
PCTA - PCTD.
Since the signal St has format determined as
described above, the bit transmission rate thereof is
calculated as follows:
168 bits x 32 kHz ~ 5.4 Mbps.
One half of the calculated value is the Ny~uist
frequency, so that the signal St can be transmitted in a
video signal bandwidth.
As described above, each of the encoders 6 and 7
can time-division-multiplex sixteen channels of audio
signals, and the time division-multiplexed signal can be
frequency-multiplexed with other video signals.
The service bits SB are preferably used in groups
having a format as shown in Figs. 6A - 6D. To be
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-20
specific, four service bits SB are provided for every
frame, and may be designated Bl - B4. Assuming that
continuous 77 frames are vertically aligned as one
yroup, as schematically shown in Fig. 6A, the service
bits SB for this group have a dimension of vertical 77
bits x h~rizontal 4 bits.
As shown in Fig. 6B, the service bits SB may be
vertically grouped so that each set of 77 bits is
- designated as one channel. A first such channel CHNA
includes 77 bits B1 and second - fourth such channels
CHNB - CHND include bits B2s - B4s, respectively.
Each of the channels CHNA - CHND is divided into
seven words WR~A - WRDG, ea~h being formed of ll bits as
shown in Fig . 6B . Each word has its first bit set to
~'0" level and used as a start bit STRT, the subsequent
eight bits are used as data bits DTBT, the next one bit
used as a parity bit PRTY, and the last one bit
determined to be "0" level and used as a stop bit STOP,
as shown in Fig. 6C.
There is one data bit DTBT for each word in each of
the channels CHNA-CHND, and there are seven words for
each 77 frames. Therefore, there are seven data bits
(seven bytes) for the 77 frames. Accordingly, there are
7 bytes x 4 channels of the data bits DTBTs in all.
The second channel CHNB has its first byte set in a
predetermined bit pattern ("AA" in hexadecimal) and is
used as a header HDER, its second byte is used as a
command CMD for identifying a maximum of 256 kinds of
commands, the third and fourth bytes are used as an
address ADRS indicative o~ a seat number (or a number of
identi~ying a particular terminal unit), the fifth and
sixth bytes are used as status information STTS
indicative of data or parameters incident to the command
CMD, and the last byte used as a check sum CS.
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-21-
The command CMD of Fig. 6D represents control data
SCl ~r SC2 ~rom controll r 5 and mas~er controller 8.
For example, when a terminal unit is forced into the
message receiving state, the control data SC2 for this
5 operation is generated from master cont:roller 8 by
operating center keyboard 82 and is tran~mitted as a
command CMD of a signal having Fig. 6D format.
The address ADRS is arbitrarily changed by the
operation of center keyboard 82, so that any of or all
of the terminal units may be specified.
Figs. 7A - 7C are examples of messages which are
supplied during an override operation from video tape
recorder la shown in Figs. 1 and 4. Alternatively, an
override message may be a moving picture showing how to
put on a life-jacket and so on.
Fig. 8 shows a preferred embodiment o~ the
invention which is installed in a cabin of an aircraft.
The components in Fig. B corresponding to those in Figs.
1 and 4 are designated by the same reference numerals.
Disk drive 44, printer 45 and external communication
apparatus 46 are omitted in Fig. 8 for simplicity.
~OMs 9a - 9h and signal processing circuit 10 in Figs. 1
and 4 are accommodated in box 100, and CADA encoders 6
and 7, modulators lla - llg, adder 12 and signal
distributor 3 are accommodated in box 200.
The above embodiments have been described for the
case where the invention is embodied in an aircraft.
The invention may also be implemented in a vehicle
such as a train, a bus or the like, or may be
implemented to provide co~munication between a central
unit and a terminal unit at each of a plurality of seats
in a stadium, a theater, or the like.
In the above-described embodiments, each selection
and display apparatus 35 is arranged on the back of a
passenger seat. Alternatively, each unit 35 can be
.
1313405
mounted at the vicinity of the seat, for example, on
the arm portion of the seat, on a table attached to the
seat or the like. Further, in one variation, only the
display 35a is arranged on the back of a seat, while
other components o~ unit 35 are arranged on the arm
portion of the seat.
According to the present invention, when the
announce or override operation is effected, one or more
terminal units 30 are interrupted by the command siynal
SC1 indicative of this operation and forced to receive
and reproduce the announce or override signal.
Therefore, the passengers will never miss the audio and
visual signals transmitted during the announce or
override operation.
The components lb - ld, ~a, and 4b are ~`orced into
a pause or stop state during the announce or override
operation, and when the announce or override operation
is terminated, the pause or stop mode of operation of
each of components lb - ld, 4a and 4b, is ter~inated and
- 20 the reproducing mode is resumed. At this time, each
ter~inal unit 30 also is returned to its reproducing
mode and may resume reproduction of the video signal V
and the audio siynals L, R, A from the point in time
that the reproduction was interrupted by the announce or
override operation so that the signals are not skipped
and the passengers can view a complete video program or
listen to a complete audio program without missing any
part thereof.
Since each terminal apparatus 30 is partially or
totally prohibited from sele~tion and operation during
the announce and override operations, the passengers
never miss the message.
Although several preferred embodiments of the
invention have been described, it will be apparent that
many modifications and variations on the described
1313405
-23-
embodiments could be effected by one skilled in the art
without departing Erom the spirit or scope o:E the
invention, as claimed below.
