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The present invention relates to a receiver for digital audio broadcast.
As digital audio broadcast has been known DAB (Digital Audio
Broadcasting) conforming to Eureka 147 standards). According to DAB, 64
programs of digital audio signals or digital data at maximum are simultaneously
transmitted by using 1.5MHz as a transmission frequency band width, OFDM
(Orthogonal Frequency Division Multiplex) as a modulation system and layer II of
MPEG audio as data compression of audio signals.
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Accordingly, in DAB, programs are set in a hierarchical structure as shown in
Fig. 1 of the accompanying drawings. That is, as described above, DAB uses a
transmission frequency band of 1.5MHz for one channel. This transmission channel
is called as "ensemble", and an ensemble is selected by establishing synchronization
with the central frequency of the ensemble concerned.
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The ensemble is divided into groups each called as "service". In the case of
Fig. 1, the ensemble is divided into four services. Each service is further divided into
some "service components", and each service component is set as a digital audio
signal or digital data constituting one program.
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In this case, each service corresponds to a general
broadcast station. For example, the services are used like a
soccer game at a main site is broadcasted through a first service
component, a soccer game at a second site is broadcasted through
a second service component, a soccer game at a third site is
broadcasted through a third service component, etc.
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The ensemble and the service are provided with respective
names which are called as "ensemble label" and "service label",
and the data of character sequences representing these names
are transmitted at the same time. With respect to the service
component, there are two cases where the label is transmitted
and where no label is transmitted.
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A service ID for identification is further allocated to
each service, and the service ID is transmitted at the same time.
The service component is provided with a serial number every
each service, and the serial number thus provided is
transmitted.
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Accordingly, when a user wishes to listen to a program
of DAB, it is necessary for the user to carry out a process of
selecting an ensemble (frequency), selecting one of plural
services in the ensemble thus selected on the basis of a service
ID and then selecting a desired service component (program) from
the selected service on the basis of a serial number.
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However, it is cumbersome and inconvenient for the user
to carry out the above operation in order to listen to a broadcast
program. Further, when the user listens to DAB while driving a car, it is
cumbersome to carry out such an operation, and in some cases it may induce a traffic
accident.
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In view of the foregoing situation, there has been proposed a DAB receiver in
which upon pushing a scan key, a broadcast frequency band is scanned to select
ensembles in turn. Further, there has been also proposed another type DAB receiver
in which upon pushing one of plural preset keys, an ensemble which is beforehand
registered in association with the pushed key is selected and received.
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However, in the case of the scan-selection type DAB receiver in which an
ensemble is selected by a scan key, a user waits until his/her desired ensemble is
selected. In the case of the preset type receiver in which an ensemble is selected by a
preset key, it is necessary for the user to register ensembles in association with the
respective preset keys in advance, and it needs an extra work.
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Therefore, the present invention has been implemented in view of the
foregoing situation,
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An object of the present invention is to provide a digital audio broadcast
receiver which can select a program immediately and facilitate the selection
operation of the program.
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Another object of the present invention is to provide a
digital audio broadcast receiver which can omit an extra work
of beforehand registering ensembles in association with preset
keys as in the case of a preset type receiver.
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In order to attain the above objects, according to an
aspect of the present invention, there is provided a receiver
for digital audio broadcast in which plural programs and data
of character sequences indicating broadcast stations are
broadcasted through one transmission frequency band,
characterized by comprising: a past record table provided to
a controller with which when the digital audio broadcast is
received, the data of the reception frequency thereof and the
data of the character sequence thereof are paired and
registered; a display device for displaying a list of the
character sequences indicating the broadcast stations on the
basis of the data of the past record table; and the controller
for controlling selection of the broadcast on the basis of the
reception frequency data corresponding to a character sequence
which is selected from the list displayed on the display device.
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According to another aspect of the present invention,
there is provided a receiver for digital audio broadcast in
which plural programs are grouped, and the plural programs, the
data representing the names of the groups and the data of the
character sequences indicating broadcast stations are
broadcasted through one transmission frequency band,
characterized by comprising: a past record table provided to
a controller with which when the digital audio broadcast is received, the data of the
reception frequency thereof, the data of the character sequence thereof and the data
corresponding to the name of the group thereof are assembled as a set and registered;
a display device for displaying a list of the names of the groups on the basis of the
data of the data corresponding to the names of the groups in the past record table; and
the controller for controlling selection of the broadcast on the basis of the reception
frequency data corresponding to a name which is selected from the list displayed on
the display device.
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The invention will be further described by way of example with reference to
the accompanying drawings, in which:-
- Fig. 1 is a diagram showing a hierarchical structure according to the present
invention;
- Fig. 2 is a systematic diagram showing an embodiment of the present
invention;
- Fig. 3 is a flowchart showing the process flow according to the embodiment
of the present invention;
- Figs. 4(A) and 4(B) are tables in the present invention; and
- Figs. 5(A), 5(B) and 5(C) are displays on a screen in the present invention.
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A preferred embodiment according to the present
invention will be described hereunder with reference to the
accompanying drawings.
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Fig. 2 is a systematic block diagram showing the
construction of a receiver according to an embodiment of the
present invention.
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In Fig. 2, a broadcast wave signal of DAB is received by
an antenna 11, and the signal thus received is supplied to a
tuner circuit 12 which is designed in a superheterodyne
structure to convert the signal to an intermediate frequency
signal. Thereafter, the intermediate frequency signal is
supplied to an A/D converter circuit 13 to be subjected to A/D
(Analog-to-Digital) conversion, thereby obtaining a digital
signal.
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The digital signal thus obtained is supplied to an
orthogonal demodulation circuit 14 to be decoded into data of
an in-phase component (real-axis component) and an orthogonal
component (imaginary-axis component), and these data are
subjected to complex Fourier Transform in an FFT circuit 15 to
output frequency components every symbol. The output of the FFT
circuit 15 is supplied to a viterbi decoder circuit 16 to be
subjected to deinterleave and error correction, and also
digital audio data of a desired program (service component) are
selected.
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Subsequently, the data thus selected are supplied to an
audio decoder circuit 17 to be subjected to decode processing
such as MPEG data expansion, and the digital audio data of the
desired program are picked up from the decoder circuit 17.
Thereafter, the digital audio data thus picked up are supplied
to a D/A converter circuit 18 to be D/A-converted to analog audio
signals L, R, and then the signals L, Rare supplied to amplifiers
19L, 19R to be amplified, and then supplied to speakers 21L,
21R to reproduce the original broadcast signal.
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A microcomputer 31 is provided as a system controller.
Since the tuner circuit 12 is generally designed so that an
ensemble (reception frequency) is selected by PLL, the data of
a frequency division ratio N of a variable frequency dividing
circuit in the PLL are supplied as frequency data for ensemble
selection from the microcomputer 31 to the tuner circuit 12.
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Further, selection signals SSV, SNO are supplied from the
microcomputer 31 to the viterbi decoder circuit 16, a service
is selected on the basis of the signal SSV, and digital audio
data of a desired service component (program) are selected from
the selected service on the basis of the signal SNO.
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Data necessary to identify or specify a program, that is,
the data of an ensemble label (representing the name of an
ensemble), a service label (representing the name of a service),
etc. are picked up from the viterbi decoder circuit 16, and then
these data are supplied to the microcomputer 31.
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The microcomputer 31 is provided with a selection routine
100 as shown in Fig. 3 as a part of the program which is to be
executed in the microcomputer 31, through which a desired
program (service component) is selected in the manner as
described later.
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The microcomputer 31 is further provided with a memory
32 comprising, for example, a flash memory or a RAM which is
backed up by a battery (not shown). That is, the memory 32
comprises a non-volatile memory, and it can keep written data
even when it is powered off.
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For example, as shown in Fig. 4(A), the memory 32 is
provided with a past record table HTBL having past records of
programs which were previously received. That is, the table HTBL
holds a plurality of sets each comprising the frequency division
ratio N of the variable frequency dividing circuit in PLL of
the tuner circuit 12, an ensemble label, a service ID, the serial
number of a service component and a reception time as data when
the program (service component) is received.
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In addition, in the memory 32 are stored the frequency
division ratio N of the variable frequency dividing circuit in
PLL of the tuner circuit 12, the service ID and the serial number
of the service component as the data of the last channel, that
is, the data of a program to which a user was just previously
listening when power was switched off.
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The microcomputer 31 is connected to a time counting
circuit 33 for counting the current time, various operation keys
34 serving as input means and LCD 35 for displaying various
information, for example.
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With the above construction, when the receiver is powered
on, the processing of the microcomputer 31 is started from a
step 101 of a routine 100 as shown in Fig. 3. Subsequently,
in a step 102, the data of the last channel are read out from
the memory 32 to select a program to which a user was listening
at the time when the receiver was just previously powered off.
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That is, out of the data thus read out, an ensemble for
which the frequency division ration N is set in the variable
frequency dividing circuit in PLL of the tuner circuit 12 and
which was selected at the time when the power was just previously
switched off is selected, a selection signal SSV indicating a
service ID is supplied to the viterbi decoder circuit 16 to
select a service, and then a selection signal SNO indicating
the serial number of the service component is supplied to the
viterbi decoder circuit 16 to select the service component.
Through the above operation, the user can listen to the program
to which the user was listening when the power was switched off.
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Subsequently, the processing goes from the step 102 to
a step 103 and waits in the step 103 until any key is input.
Upon pushing any key under the standby state in which the
processing waits for the key input, the following processing
is executed in accordance with the type of the pushed (operated)
key.
[When a desired program is selected by using the present
invention]
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In this case, the user pushes a list key out of the keys
34 under the standby state in which the processing waits for
the key input in the step 103. The processing goes from the step
103 to a step 111 and it is judged in the step 111 where the
type of the pushed key in the step 103 is the list key or not.
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In the above case, since the pushed key is the list key,
the processing goes from the step 111 to a step 121, and in the
step 121 the data of the table HTBL are sorted so that ensemble
labels (i.e., ensemble names) are arranged in forward order (for
example, in alphabetical order or the like) while each set of
respective data is packed as a unit as shown in Fig. 4(B).
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Subsequently, the processing goes to a step 122 to supply
the ensemble labels of the table HTBL to LCD 35, and the ensemble
labels (names) of every eight stations are displayed in forward
order on LCD 35 as shown in Fig. 5(A), for example. At this time,
for example, a first ensemble label is displayed in such a manner
as to be surrounded by a rectangular frame, which means a cursor
35C.
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As described above, the names of the ensembles (ensemble
labels) which were previously received are displayed in a list
style in name order (e.g., alphabetical order) on LCD 35.
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Subsequently, the processing goes to a step 123. In the
step 123, the user is allowed to select any one of the ensembles
whose names are displayed on LCD 35. That is, upon pushing a
down cursor key out of the keys 34 in the display state shown
in Fig. 5(A), the cursor 35C is shifted to a second ensemble
label (name) as shown in Fig. 5(B). Upon further pushing the
down cursor key, the cursor 35C is shifted to a third ensemble
label as shown in Fig. 5(C).
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As described above, the cursor 35C is shifted one by one
every time the down cursor key is pushed once. If some ensemble
labels are displayed beyond one frame of LCD 35(that is, all
the ensemble labels cannot be perfectly displayed within one
display frame), when the cursor 35C arrives at the lowermost
line of the display frame, the remaining ensemble labels (which
overflow from the display frame) are subsequently displayed by
scrolling them. When an up cursor key out of the keys 34 is pushed,
the cursor 35C is shifted in the opposite direction to the
direction when the down cursor key is pushed.
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For example, as shown in Fig. 5(B), when the cursor 35C
is located at the second ensemble label "Ensemble B", upon
pushing an enter key out of the keys 34, the ensemble of "Ensemble
B" is selected and then the processing goes to a step 124.
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By referring to the data table HTBL in the step 124, the
frequency division ratio N which is paired with the ensemble
label selected in the step 123 is picked up, and the frequency
division ratio N thus picked up is set in the variable frequency
dividing circuit in PLL of the tuner circuit 12. Accordingly,
subsequently, the ensemble of the ensemble label selected in
the step 123 is received. For example, if the "Ensemble B" is
selected in the step 123, the frequency division ratio N paired
with the "Ensemble B" is equal to a value N1, so that the value
N1 is set in the variable frequency dividing circuit and the
ensemble B thereof is received.
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Subsequently, the processing goes to a step 125. In the
step 125, by referring to the data table HTBL, the service ID
paired with the ensemble label selected in the step 123 is picked
up, and the selection signal SSV indicating the service ID is
supplied to the viterbi decoder circuit 16 to select the
corresponding service. For example, if "Ensemble B" is selected
in the step 123, the service ID paired with the "Ensemble B"
is equal to a value ID7 and thus the selection signal SSV
indicating the service ID (ID7) is supplied to the viterbi
decoder circuit 16 to select the service of the service ID (ID7).
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Further, the processing goes to a step 126. In the step
126, by referring to the data table HTBL, the serial number
paired with the ensemble label selected in the step 123 is picked
up, and the selection signal SNO indicating the serial number
is supplied to the viterbi decoder circuit 16 to select the
service component of the corresponding serial number. For
example, if the "Ensemble B" is selected in the step 123, the
serial number paired with the "Ensemble B" is equal to a value
2, and thus the selection signal SNO indicating the serial
number 2 is supplied to the viterbi decoder circuit 16 to select
the second service component in the service of the service ID
(ID7).
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In the step 126, if the broadcast of the corresponding
program is finished (the service component is not broadcasted),
the program having the first serial number in the same service
is selected.
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Accordingly, at the time when this step 126 is executed,
the service component (program) of the service in the ensemble
selected in the step 123 out of the reception past records
preserved in the data table HTBL is selected, and then the user
can listen to the program.
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Subsequently, the processing goes to a step 127. In the
step 127, the reception time paired with the ensemble label
selected in the step 123 out of the data of the table HTBL is
renewed on the basis of the current time indicated by the time
counting circuit 33. Thereafter, in a step 128, the frequency
division ratio N of the variable frequency dividing circuit in
PLL of the tuner circuit 12 which is currently carrying out the
reception operation, the service ID and the serial number of
the service component are stored as the data of the last channel
into the memory 32. The data thus stored are read out and used
in the step 102 when the power is afterwards switched off and
then switched on.
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Thereafter, the processing returns to the step 103 and
then waits for the key input again.
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Accordingly, when the list key is pushed under the key
input standby state in the step 103, the list of the ensembles
which were previously received is displayed on LCD 35. By
selecting any ensemble from the list of the ensembles thus
displayed, the user can listen to the program of the ensemble.
[When program selection is carried out by a general
method]
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In this case, in the step 103 the key corresponding to
a desired selection method out of the keys 34 is pushed when
the processing waits for the key input.
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Thereafter, the processing goes from the step 103 to a
step 111. In this case, since the key is not the list key, the
processing goes from the step 111 to a step 112, and it is judged
in the step 112 whether the pushed key is a key relevant to the
program selection. In this case, the key is the relevant key,
and thus the processing goes from the step 112 to a step 131.
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In the step 131, the program selection is carried out by
the same method as a general DAB receiver in accordance with
the selection method of the program for which the key input is
carried out in the step 103. For example, a scan operation is
carried out or a different program (service component) of the
same ensemble is selected. Thereafter, the processing goes to
a step 132 and the table HTBL is renewed in the step 132.
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That is, if a set of the frequency division ratio N of
the variable frequency dividing circuit in PLL of the tuner
circuit 12 under reception operation, the service ID and the
serial number of the service component exists in the data of
the table HTBL, the reception time thereof is renewed on the
basis of the current time indicated by the time counting circuit
33. Further, if any set of the frequency division ratio N of
the variable frequency dividing circuit in PLL of the tuner
circuit 12 under reception operation, the service ID and the
serial number of the service component does not exist in the
data of the table HTBL, it is paired with the current time
indicated by the time counting circuit 33 and newly registered
in the table HTBL. At this time, if the empty capacity of the
memory 32 is lack, a set of data having the oldest reception
time is deleted.
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Subsequently, the processing goes to a step 128 to renew
the data of the last channel of the memory 32, and then the
processing returns to the step 103 to wait for the key input
again.
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Accordingly, upon operating (pushing) a key for the
program selection other than the list key in the state where
the key input is set in the step 103, the program corresponding
to the key operation is selected, and the user can listen to
the program.
[Other processing]
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Upon pushing the key corresponding to desired processing
out of the keys 34 when the key input standby state is set in
the step 103, the processing of the microcomputer 31 goes from
the step 103 through the step 111 and the step 112 to a step
141 to execute target processing, for example, processing of
controlling the signal level of the amplifiers 19L, 19R to alter
the volume, and then the processing returns to the step 103 to
wait for the key input again.
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According to the receiver shown in Fig. 2, a list of
ensembles which were previously received is displayed on LCD
35, and any ensemble is selected from the ensembles thus
displayed, whereby the user can listen to the program.
Accordingly, the ensemble can be just immediately selected, and
the selection of the ensemble is easy. Further, it is
unnecessary that ensembles are registered in advance as in the
case of a preset type receiver, and thus no extra time is needed.
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In the foregoing description, the data of the table HTBL
are sorted and displayed in order of ensemble labels in the steps
121, 122. However, the data may be sorted in order of N-value
or reception time so as to be displayed in increasing order of
frequency or in order of reception time from newest to oldest.
Further, a selection frequency for each ensemble may be counted
to sort and display the ensembles in decreasing order of the
count result.
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In the foregoing description, when the list of the
ensembles is displayed, the data of the table HTBL are sorted
in the step 121. However, the data may be sorted when the data
of the table HTBL are altered. Further, the user may be allowed
to beforehand select items when the data of the table HTBL are
sorted.
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In DAB, the frequency information of other ensembles
broadcasted is simultaneously transmitted, so that the
frequency information or the corresponding ensemble labels can
be also displayed in the step 122. In this case, the ensembles
indicated by the frequency information may not be actually
received because of a geographical condition or reception
antenna state. Therefore, the display of the ensembles is
carried out with varying the display mode from the display based
on the data of the table HTBL, for example by attaching an
identification mark to the ensembles, changing the display
color, or grouping and displaying these ensemble labels so as
to discriminate these ensemble labels from the group of the
ensemble labels of the table HTBL.
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Further, the processing may be executed in accordance
with a user's instruction or automatically so as to gain the
frequency information of all the broadcasts receivable at a
current reception place and contain the frequency information
or the ensemble labels thereof in the display of the step 122.
In this case, the display mode for the ensemble labels of
ensembles which are not actually received may be made different
from that of the display based on the data of the table HTBL.
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When the ensemble label of an ensemble which is not
actually received is contained in the display of the step 122,
if the ensemble can be received, the display mode of the ensemble
label may be set to that of the display based on the data of
the table HTBL.
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Further, if the service labels are preserved together in
the table HTBL, the service labels could be displayed in the
same manner as the display of the ensemble labels as described
above.
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In the case of DAB, a service is provided with an
identifier which is called as a program type and indicates a
music genre, and thus the display may be grouped on the basis
of the identifier. Further, when the language is different every
service, an identifier indicating the language is added every
service, and thus the display can be grouped every language.
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Further, when the table HTBL is renewed, the service label
can be renewed. In this case, only a music piece and a language
of desired genre can be selectively displayed in a list of
service labels by performing filter processing on the basis of
the identifier. In this case, plural identifiers may be
subjected to the filter processing. Further, not only the user
can set the filter for the filter processing, but also the
microcomputer 31 may set it on the basis of past reception
records.
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According to the present invention, the program can be
immediately selected, and the selection is easily performed.
Further, it is unnecessary that the ensembles are beforehand
registered as in the case of the preset type receiver, and thus
no extra time is needed.