BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a method of
transmitting a wide-band broadcasting such as a television
broadcasting and a transmitting and receiving apparatus
therefor, and relates more particularly to a transmission
method and a system structure suitable for transmitting and
receiving limited information to and in a narrower area than
a transmission area.
Description of the Prior Art
In a wide-band broadcasting as represented by a
broadcasting of pictures, conventionally the same program
has been broadcasted by using a carrier such as radio waves,
for example, to all the transmission areas from a
broadcasting station. Further, at a receiver side, a picture
signal of a television program broadcasted by a carrier such
as radio waves is received by a signal receiver and is
demodulated so that the picture is reproduced by a picture
receiver.
A result of a first study made by the applicant within
the company will be explained below with reference to Fig.
7. Referring to Fig. 7, a reference numeral 201 denotes a
broadcasting station, 202a and 202b subscribers and 203 a
broadcasting area. In Fig. 7, the broadcasting station 201
transmits program pictures by using radio waves, for example,
to the broadcasting area 203. On the other hand, the
subscribers 202a and 202b receive the radio waves transmitted
by an antenna respectively, demodulate by a picture receiver
the picture signal of the program transmitted by the carrier
such as radio waves and obtain pictures on the picture
receivers. One example of the structure of transmission
facilities in the broadcasting station 201 is shown in Fig.
8 and its operation will be explained below. In Fig. 8,
reference numerals 211 denotes a server for storing program
pictures to be broadcasted, 212 a transmitter, and 213 a
transmission antenna. In the broadcasting station 201,
program pictures are supplied from the server 211 to the
transmission facilities 212 according to a predetermined TV
program based on a predetermined time schedule, and the
program pictures are modulated into a transmission signal and
this signal is amplified. The transmission signal is
transmitted to the broadcasting area 203 shown in Fig. 7 from
the transmission antenna 213. In this case, a TV program
includes a sports program, a commercial, weather forecast and
a movie, for example, as shown in Fig. 9. Program pictures
for each program are arranged in time series at predetermined
times. Next, one example of the structure of the receiving
facilities at the subscriber 202a side is shown in Fig. 10.
In Fig. 10, reference numerals 231 denotes a receiving
antenna, 232 a receiving apparatus and 233 a picture
receiver. The subscriber 202a receives with the receiving
antenna 231 the radio waves transmitted from the broadcasting
station 201, demodulates the received signal into a picture
signal by the receiving apparatus 232, and displays the
demodulated picture signal of the TV program in pictures by
the picture receiver 233. In the mean time, the subscriber
202b also has a similar structure and displays the picture
of a TV program in the picture receiver in a similar manner.
As explained above, according to the current structure, the
subscribers in the broadcasting area 203 can watch TV
programs transmitted in time series at the same time by the
picture receivers.
The above-described structure has been efficient since
programs can be broadcasted to a wide broadcasting area with
one set of transmission facilities. However, according to
the above-described structure, it is considered that
sufficient considerations have not been given to the
broadcasting of area limited information to the subscribers
who are staying in that area. Taking a weather forecast as
an example, a predetermined time is allocated to the weather
forecast in a TV program. Accordingly, there is a limit to
the amount of information on the weather forecast which can
be broadcasted within this allocated time. For example, only
the weather forecast relating to the whole broadcasting area
can be broadcasted. However, when the broadcasting area is
widely distributed, there is a case where the weather
information is changing depending on the areas where the
subscribers are staying. It has been known that in such a
case, the conventional structure has a problem in that
subscribers can not obtain weather information of the areas
of the subscribers. The above problem similarly arises in
other information such as commercial and traffic
information, for example. In other words, it has been known
that according to the conventional structure, when
subscribers want to know relatively sufficient information
of a narrow area as compared with the information on the whole
area, they can not obtain such information because of the wide
broadcasting area.
SUMMARY OF THE INVENTION
In view of the foregoing, it is a main object of the
present information to achieve a transmission and receiving
of information on a narrow area even in a wide-band
broadcasting to thereby realize more convenient broadcasting
for subscribers.
In order to achieve the above-mentioned object, in the
first aspect of the present invention there is provided, in
the transmission of information signals such as picture
signals, a main information signal for transmitting program
pictures and coded signals of a limited information signal
such as commercial information and an area signal for showing
an applied area of the limited information signal are
multiplexed and that a control signal for starting the
display of the above-described limited information signal at
a predetermined time is also included in the information
signal for transmission.
A control signal for ending the display of the
above-described limited information signal at a
predetermined time is also included in the above-described
control signal for transmission.
There are a plurality of combinations of the limited
information signals and the area signals and these are coded
and transmitted in time series.
All the plurality of limited information signals before
they are coded have the same display time when they are
displayed in pictures respectively.
Menu screen information is transmitted to enable the
subscribers to select easily a limited information signal to
be displayed on the picture receiver from the plurality of
limited information signals.
The main information signal, the limited information
signal and the area signal are transmitted by being frequency
multiplexed.
Furthermore, at least the main information signal and
the limited information signal are transmitted by being
time-division multiplexed.
In the second aspect of the present invention there is
provided, in the transmission of information signals such as
picture signals, a plurality of the limited information
signals and the area signals are coded and that at the time
of transmitting the coded signals by time-division
multiplexing with the main information signal, the
transmission time of the coded signals becomes a
predetermined time.
In the third aspect of the present invention there is
provided, in a transmitting apparatus for transmitting
information signals such as picture signals, the
transmitting apparatus is structured to include:
a storage unit for storing a main information signal
such as program pictures, a limited information signal such
as a commercial and an area signal for showing an applied area
of this limited information signal, a coding unit for coding a limited information signal
read from the storage unit and an area signal, a control signal generating unit for generating a
control signal relevant to the display of the limited
information signal, and a multiplexing unit for multiplexing a main information
signal output from the storage unit, a coded signal from the
coding unit and a control signal from the control signal
generating unit and for generating a transmission signal.
In the fourth aspect of the present invention there is
provided, in a receiving apparatus for receiving an
information signal such as a picture signal, the receiving
apparatus is structured to include:
a unit for extracting the main information signal and
the coded signal from a received signal, a unit for decoding a signal for showing an applied area
from an extracted coded signal, a display control signal generating unit for detecting
a control signal relevant to a display of a limited
information signal from the received signal and for
generating a display control signal based on the detected
signal, a control signal generating unit for generating a
control signal for selecting a limited information signal to
be displayed, a limited information storage unit for storing a
limited information signal coded according to the decoded
signal for showing an applied area and for reading a coded
limited information signal corresponding to the control
signal based on a timing of the display control signal, a unit for decoding a limited information signal from
a signal read from the limited information storage unit, and an output change-over unit for selecting a main
information signal from the extracting unit based on a
display control signal from the display control signal
generating unit and an output signal from a limited
information signal from the limited information signal
decoding unit.
The display control signal generating unit includes a
unit for generating a display control signal so that a main
information signal is displayed after a predetermined period
of time since the display control signal generating unit has
started a display of a limited information signal.
The control signal generating unit includes a memory
unit for storing an optional control signal.
A telephone line is connected to the control signal
generating unit and the control signal generating unit
includes a unit for setting a control signal through the
telephone line.
Furthermore, the control signal relating to the display
includes menu screen information, the display control signal
generating unit includes a unit for generating selective
screen information for facilitating a selection from the menu
screen information, and the control signal generating unit
includes a unit for generating a control signal based on the
selective screen information.
According to the structure of the first aspect of the
present invention, in the transmission of information
signals such as picture signals, a main information signal
for transmitting program pictures and a limited information
signal for transmitting the coded limited information signal
such as commercial information are multiplexed, and an area
signal for showing an area to which the limited information
signal is applied is coded, and a control signal for
displaying the limited information signal at a predetermined
time is transmitted. Accordingly, information closely
linked to the areas of subscribers can be transmitted, and
further, the display of this information can be started at
a predetermined time.
By transmitting a control signal for ending the display
of the limited information at a predetermined time, the
display of main information can be started compulsively even
if the display of the limited information signal is not
finished within a predetermined time period due to an error
of a storage medium or the like, for example, at the
subscriber side. Therefore, it becomes possible to avoid an
occurrence of time loss in program pictures.
By transmitting the limited information and the area
signal by a plurality of number in time-series, the areas to
which the limited information are applied can be narrowed so
that further detailed information can be provided.
By setting the time for displaying a plurality of
pre-coded limited information signals in pictures to be all
the same, all the selective displays of the limited
information signals received in different areas or by
different subscribers can be finished at the same time.
Accordingly, it is possible to avoid an occurrence of a
disturbance of program pictures structured by a main
information signal depending on areas and subscribers.
By transmitting menu screen information for selecting
a limited information signal to be displayed by a picture
receiver from a plurality of limited information signals, a
subscriber can easily select a limited information signal of
an area different from the limited information signal of a
pre-set area. This helps to further increase the convenience
of the subscribers.
By transmitting the main information signal and limited
information signals by multiplexing the frequencies of these
signals, the limited information signals corresponding to
many areas can be transmitted during the period while program
pictures are being transmitted in the main information
signal. This enables a provision of further detailed
information.
By time-axis compressing program pictures in the
picture information signal, the main information signal and
the limited information signals can be transmitted by
time-axis muliplexing, so that the limited information
signals corresponding to many areas can be transmitted during
the period while the program pictures are being transmitted
in the main information signal. This enables a provision of
further detailed information.
Next, according to the second aspect of the present
invention, by coding a plurality of the limited information
signals and the signals for showing the applied areas of the
limited information signals and further by setting the time
of transmitting the coded signals at a predetermined time
when transmitting the coded signals by time-division
multiplexing with the main information signal, the plurality
of limited information signals can be transmitted within a
time for displaying the limited information signals, so that
information closely linked to the areas of the subscribers
can be transmitted.
According to the third aspect of the present invention,
in a transmitting apparatus for transmitting information
signals such as picture signals, a main information signal
for transmitting program pictures, a limited information
signal such as a commercial and an area signal are coded and
multiplexed, and a control signal for displaying the limited
information signal is also multiplexed for transmission.
Therefore, information closely linked to the areas of the
subscribers can be transmitted and, at the same time, the
display of these information can be started at a
predetermined time so that this increases the convenience of
the subscribers.
According to the fourth aspect of the present
invention, the picture signal receiving apparatus extracts
the main information signal and the coded signal from a
received signal, decodes a signal for showing an applied area
of the limited information from the extracted coded signal,
stores the coded limited information signal in a limited
information storing unit according to the decoded area
signal, reads from the limited information storing unit a
display control signal from a display control signal
generating unit for detecting a control signal relevant to
the display of the limited information signal and for
controlling the display and a limited information signal
selected from a plurality of limited information signals
based on a control signal for selecting a limited information
to be displayed, and decodes and outputs these information.
Therefore, information closely linked to the areas of the
subscribers can be displayed during a period of time for
displaying the limited information signals, which can help
to increase the convenience of the subscribers.
Since a display control signal is generated so that the
main information signal is displayed after a predetermined
period of time since the display control signal generating
unit started the display of a limited information signal,
information closely linked to the areas of the subscribers
can be displayed during the period while the limited
information signal is being displayed. Further, even if an
error has occurred in the limited information storing unit,
the main information signal can be displayed without
displaying the limited information signal again, so that time
loss is not generated in the program pictures.
Since the control signal generating unit is structured
to include a memory unit for storing a desired control signal,
a control signal can be automatically set at the time of
displaying the limited information signal, so that the
subscribers need not set the selection each time.
Since a telephone line is connected to the control
signal generating unit and a control signal of the control
signal generating unit can be set through the telephone line,
the control signal of the limited information signal can be
automatically set, so that the subscribers need not set the
selection each time.
Furthermore, the display control signal generating
unit generates selective screen information from the
transmitted menu screen information, and a subscriber
selects a limited information based on the selective screen
information when necessary so that a control signal is
generated from the control signal generating unit
accordingly. Therefore, a subscriber can easily select a
limited information signal of an area different from the
limited information signal of a pre-set area. This helps to
further increase the convenience of the subscribers.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a block diagram for showing a mode of one
embodiment of the transmitting apparatus according to the
present invention.
Fig. 2 is a diagram for showing a mode for implementing
signals in the transmitting apparatus of the present
invention.
Fig. 3 is a diagram for showing another mode for
implementing signals in the transmitting apparatus of the
present invention.
Fig. 4 is a diagram for showing another mode for
implementing signals in the transmitting apparatus of the
present invention.
Fig. 5 is a block diagram for showing a mode of one
embodiment of the receiving apparatus according to the
present invention.
Fig. 6 is a block diagram for showing one embodiment
of the control signal generating unit according to the
present invention.
Fig. 7 is a block diagram for showing the structure of
a conventional picture broadcasting.
Fig. 8 is a block diagram for showing a mode of one
embodiment of a conventional transmitting apparatus.
Fig. 9 is a diagram for showing a mode for implementing
signals in the conventional transmitting apparatus.
Fig. 10 is a block diagram for showing a mode of one
embodiment of the conventional receiving apparatus.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Modes of embodiments of the present invention will be
explained below with reference to the drawings.
Fig. 1 is a block diagram for showing one example of
the transmitting apparatus according to the present
invention. In Fig. 1, reference numerals 1 denotes a main
server for storing main information signals such as program
pictures and 2 denotes a sub-server for storing limited
information signals such as weather forecast and
commercials, for example, in each area and area signals for
showing applied areas. The main server 1 and the sub-server
2 which are the information signal storing units are
structured by a tape storage unit such as a VTR or a disc
storage unit such as a hard disc or an optical disc, or a
memory, which are not limited. Reference numerals 3 denotes
a coding unit for coding limited information signals and area
signals, 4 a control signal generating unit for generating
control signals relevant to the display of limited
information signals, 5 a multiplexer for multiplexing main
information signals and limited information signals, and 6
a transmitter. The operation of Fig. 1 will be explained
below.
Referring to Fig. 1, according to a predetermined time
schedule, program pictures are supplied as a main information
signal from the main server 1 to the multiplexer 5. In the
mean time, limited information signals and area signals
output from the sub-server 2 are supplied to the coding unit
3 and these signals are converted to limited information
codes and applied area codes and are then supplied to the
multiplexer 5. The control signal generating unit 4
generates a start control signal for starting the display of
limited information signals at a predetermined time at the
subscribers side, for example, and supplies the start control
signal to the multiplexer 5. The multiplexer multiplexes the
main information signals from the main server 1, the limited
information codes and the applied area codes from the coding
unit 3 and the start control signal from the control signal
generating unit 4, modulates these signals to generate a
transmission signal and outputs this signal to the
transmitter 6. The transmitter 6 amplifies the transmission
signal from the multiplexer 5 and transmits the applied
signal to the subscribers. One example of multiplexing
signals by the multiplexer 5 will be explained below with
reference to Fig. 2.
Referring to Fig. 2, reference symbols a denotes a main
information signal, b denotes a signal for showing a limited
information code and an applied area code output from the
coding unit 3, and c denotes a multiplexed signal. The main
information signal includes program pictures read from the
main server 1 according to a predetermined time schedule, and
covers in time-series a normal program such as a drama, a
nation-wide commercial, a nation-wide weather forecast and
a normal program, for example, as shown in Fig. 2a. Next,
the coding unit 3 codes the limited information signals and
area signals read from the sub-server 2, and outputs a
plurality of area codes and limited information codes in
time-series as coded signals as shown in Fig. 2b, for example.
In this case, the same time is set for displaying in pictures
the plurality of limited information signals read from the
sub-server 2. Next, the multiplexer 5 multiplexes the main
information signal and the coded signals by using a frequency
multiplexing, for example, and also multiplexes the start
control signal from control signal generating unit 4, and
generates a transmission signal. In this case, the control
signal is multiplexed by the multiplexer 5 by outputting a
start control signal from the control signal generating unit
4 to the transmitter 6 as a transmission signal at a
predetermined time for starting the display of the limited
information signal, as an example. As a result, a signal as
shown in Fig. 2c is obtained.
According to the above-described structure, a main
information signal for transmitting program pictures, coded
information of a limited information signal for transmitting
the limited information signal such as commercial
information and the area signal for showing the area to which
the limited information are applied and a start control
signal for starting the display of the limited signal for
displaying the limited information signal at a predetermined
time can be multiplexed and transmitted. Accordingly,
information closely linked to the areas of subscribers can
be transmitted, and further, the display of this information
can be started at a predetermined time. Further, since a
signal for showing an applied area of the limited information
and a limited information signal corresponding to this signal
can be transmitted by a plurality of number in time-series
by coding these signals, the areas to which the limited
information signal is applied can be narrowed, so that
further detailed information can be provided. Further, since
the time for showing the pre-coded limited information
signals in pictures is set all the same, the display of these
limited information signals can be finished at the same time
even if limited information signals of different areas or
different subscribers are selectively displayed.
Accordingly, it is possible to avoid an occurrence of a
disturbance of program pictures structured by a main
information signal depending on areas and subscribers.
Further, since the main information signal and the coded
limited information signals are transmitted by frequency-multiplexing
these signals, limited information signals
corresponding to many areas can be transmitted during the
period while program pictures are being transmitted in the
main information signal, so that further detailed
information can be provided.
In the above-described embodiment, frequency
multiplexing is applied for the multiplexer 5 to multiplex
the main information signal and the coded limited information
signals. However, the present invention is not limited to
this, and these signals can also be multiplexed by time-division
as shown below, for example. Signals which have been
multiplexed by time-division are shown in Fig. 3. In Fig.
3, reference symbols a denotes a main information signal, c
denotes a coded signal in which limited information signals
and area signals are coded, and b denotes a transmission
signal. The main information signal in Fig. 3a shows program
pictures read from the main server 1 according to a
predetermined time schedule, and covers in time-series a
normal program such as a drama, a nation-wide commercial, a
nation-wide weather forecast and a normal program, for
example, as shown in Fig. 2a. The coded signal in Fig. 3c
also covers in time-series a plurality of applied area codes
and limited information codes which are the limited
information signals and the area signals read from the
sub-server 2 and then coded, similar to those in Fig. 2b. In
this case, the plurality of limited information signals read
from the sub-server 2 are set such that their display time
in pictures is all the same. The multiplexer 5 at first
time-axis compresses the main information signal at a
predetermined time interval. Then, the multiplexer 5 also
time-axis compresses the coded signal at a predetermined time
interval. The multiplexer 5 then multiplexes in time-division
the time-axis compressed main information signal
and coded signal respectively, and further multiplexes in
time-division the start control signal, for example, from the
control signal generating unit 4, so that a time-division
multiplexed transmission signal shown in Fig. 3b is
generated. In the above-described structure, limited
information signals corresponding to many areas can also be
transmitted during the period while a program is being
transmitted in the main information signal, so that further
detailed information can be provided.
In the above-described embodiment, the limited
information signals and the area signals are transmitted in
codes during the transmission of a normal program in the main
information signal. However, the present invention is not
limited to this. For example, a plurality of limited
information signals and applied areas may also be coded and
transmitted during a period while the limited information
signals are being displayed. One example of the structure
of signals in this case is shown in Fig. 4. Referring to Fig.
4, reference symbols a denotes a main information signal, c
denotes a coded signal in which limited information signals
and area signals are coded, and b denotes a transmission
signal. The main information signal in Fig. 4a shows program
pictures read from the main server 1 according to a
predetermined time schedule, and covers a normal program such
as a drama, for example, as shown. In this case, a non-signal
period of a predetermined time period is set for the period
when limited information signals are multiplexed. The coded
signal in Fig. 4c also covers in time-series a plurality of
applied area codes and limited information codes which are
the limited information signals and the area signals read
from the sub-server 2 and then coded, similar to those in Fig.
2a. In this case, the plurality of limited information
signals read from the sub-server 2 are set such that their
display time in pictures is all the same. The multiplexer
5 multiplexes the plurality of area codes in the coded signal
and codes of the limited information signals and inserts the
multiplexed codes into the non-signal period of the
predetermined period of time of the main information signal.
Further, the multiplexer 5 multiplexes the start control
sinal from the control signal generating unit 4 and thereby
generates a transmission signal which is a time-division
multiplexed signal of the main information signal and the
coded signal. In this case, for multiplexing the codes of
the plurality of limited information signals and the area
codes, a time-division multiplexing or a frequency
multiplexing is used, for example. In the above-described
structure, limited information signals corresponding to many
areas can also be transmitted during the period while a
program is being transmitted in the main information signal,
so that further detailed information can be provided.
In the above-described embodiment, the control signal
for multiplexing by the multiplexer 5 is explained by only
the start control signal from the control signal generating
unit 4. However, the present invention is not limited to
this. For example, it is possible to arrange such that not
only the start control signal but also menu information for
facilitating the selection of a limited information signal
at the subscribers side is transmitted. In this case, when
subscribers want to display a limited information signal of
an area different from a limited information signal of a
pre-set area, the subscribers can easily select the limited
information signal, which further increases the convenience
of the subscribers.
In the above-described embodiment, the start control
signal from the control signal generating unit 4 or not only
the start control signal but also the menu screen information
for selecting a limited information signal are multiplexed
by the multiplexer 5 and transmitted. However, in addition
to these control signals, it is also good to transmit and
display end control signal for ending a display of a limited
information signal at a predetermined time. In this case,
when the end control signal is transmitted, the display of
main information can be started compulsively even if the
display of a limited information signal does not end within
a predetermined time period from the display starting time
due to an error of a storage medium at a subscriber side, for
example. Thus, an occurrence of time loss in the program
pictures in the main information can be avoided. Further,
in the above-described embodiment, a control signal is
multiplexed with the time for starting the display of limited
information and then the signal is transmitted. However, the
present invention is not limited to this, but the control
signal may also be transmitted by the time when the limited
information is started by multiplexing the control signal
with a coded signal, for example. In this case, limited
information can also be displayed at a predetermined time by
receiving the control signal at a subscriber side. Thus, an
effect similar to that obtained by the above-described
embodiment can be obtained.
Next, an embodiment of the structure of the receiving
apparatus for receiving picture signals transmitted from the
transmitting apparatus of the above-described embodiment is
shown in Fig. 5. In Fig. 5, reference numerals 11 denotes
an extracting unit, 12 a decoding unit for decoding an applied
area code, 13 a storage unit for storing limited information,
14 a control signal generating unit for generating a control
signal of display information, 15 a decoding unit for
decoding a limited information code, 16 a display control
signal generating unit for displaying limited information,
and 17 a change-over unit for changing over an output signal.
The operation will be explained below. The extracting
unit 11 extracts a main information and a coded signal from
a signal received by a receiving antenna or the like not
shown. The extracted main information signal is supplied to
the output change-over unit 17, and is output to the receiver
not shown from the output change-over unit 17 during a
transmission of a normal program. In the mean time, a coded
signal extracted from the received signal is output to the
applied area decoding unit 12 and the limited information
storage unit 13. The applied area decoding unit 12 extracts
an applied area code from a coded signal, decodes this code
to generate an area signal and then outputs this area signal
to the limited information storage unit 13. The limited
information storage unit 13 stores a limited information code
in a storage medium based on an area signal supplied. The
display control signal generating unit 16 detects a control
signal for starting the display and a control signal for
ending the display, for example, from a received signal,
generates a display starting signal and a display ending
signal based on these signals and supplies the generated
signals to the limited information storage unit 13 and the
output change-over unit 17. The control signal generating
unit 14 generates a control signal for selecting a limited
information signal to be displayed and supplies the signal
to the limited information storage unit 13. The control
signal generating unit 14 is structured to include a memory,
for example, for storing an optional control signal set by
a remote controller or the like in this memory, and generates
each time a control signal for selecting a limited
information signal corresponding to the code for showing an
area of subscribers.
Next, the operation for displaying a limited
information signal will be explained. For displaying a
limited information, upon receiving a display starting
signal from the display control signal generating unit 16,
the limited information storage unit 13 reads a corresponding
limited information code from a storage medium based on a
control signal from the control signal generating unit 14,
and outputs the limited information code to the limited
information signal decoding unit 15. The limited information
signal decoding unit 15 decodes the limited information code
and supplies a limited information to the output change-over
unit 17. The output change-over unit 17 changes over the
output signal from the main information signal to the limited
information signal based on the display starting signal from
the display control signal generating unit 16. Next, for
ending the display, the limited information storage unit 13
ends the reading of the limited information code from the
storage medium based on the display ending signal from the
display control signal generating unit 16, and the output
change-over unit 17 changes over the signal to be output from
the limited information signal to the main information
signal. With the above-described structure, information
closely linked to the areas of subscribers can be selectively
displayed during a period for displaying the limited
information signal, which increases the convenience of the
subscribers. Further, even if an error has occurred in the
limited information storage unit or the like, the main
information can be displayed without displaying the limited
information signal again by the display ending signal.
Therefore, an occurrence of time loss in the program pictures
can be avoided. Further, since the setting of a control
signal in the control signal generating unit 14 can be stored
in the memory, the control signal of the limited information
signal can be set automatically, so that the subscribers need
not set the control signal each time, which can increase the
convenience of the subscribers.
In the above-described embodiment, the display control
signal generating unit 16 detects a control signal for
starting a display and a control signal for ending the display
from a received signal and then generates a display starting
signal and a display ending signal. However, the present
invention is not limited to this, but only the control signal
for starting the display may be detected, for example. In
this case, the object of the present invention can also be
met when the display control signal generating unit 16
generates a display starting signal based on the control
signal for starting the display and a display ending signal
after a predetermined time period since the display starting
signal was generated, for example. Thus, information closely
linked to the areas of subscribers can be displayed during
a period for displaying the limited information signal.
Further, even if an error has occurred in the limited
information storage unit or the like, the main information
can be displayed without displaying the limited information
signal again. Therefore, an occurrence of time loss in the
program pictures can be avoided.
In the above-described embodiment of the receiving
apparatus, description has been made that a control signal
for selecting a limited information signal to be generated
by the control signal generating unit 14 is set by a remote
controller or the like. However, the present invention is
not limited to this, but the control signal can also be set
through a telephone line as shown by a block diagram in Fig.
6, for example. In Fig. 6, reference numerals 20 denotes a
telephone set, 21 a memory, 22 an initialization detecting
unit, and 23 a telephone line. Referring to Fig. 6, for
initializing a control signal, information for setting is
sent from a transmitter side such as a broadcasting station
not shown, for example, through the telephone line 23. Next,
the initialization detecting unit 22 decides an applied area
of a limited information for a subscriber based on the
information for setting, and initializes the memory for the
control signal for selecting a limited information signal.
With this operation, the initialization of the control signal
for a limited information signal can be automated so that the
subscribers can save the setting work.
Further, in the above-described embodiment,
description has been made that the control signal generating
unit 14 generates a control signal for a limited information
signal so as to select a limited information signal
corresponding to the area of a subscriber each time. However,
the present invention is not limited to this, but the control
signal may also be generated by a subscriber's selection from
the menu screen information transmitted when necessary, for
example. The operation of the display control signal
generating unit 16 and the control signal generating unit 14
in this case will be explained by using Fig. 5. The display
control signal generating unit 16 detects menu screen
information from a received signal, generates selective
screen information and outputs this information to the
control signal generating unit 14. The control signal
generating unit 14 generates a control signal for the area
which the subscriber has selected from the selective screen
information and supplies this control signal to the limited
information storage unit 13. With the above-described
operation, a subscriber can easily select a limited
information signal of an area different from a limited
information signal of a pre-set area, which further increases
the convenience of the subscribers.