[0001] 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.
[0002] 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.
[0003] 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.
[0004] 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.
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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.
[0011] Therefore, the present invention has been implemented in view of the foregoing situation,
[0012] 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.
[0013] 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.
[0014] 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.
[0015] 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.
[0016] 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.
[0017] A preferred embodiment according to the present invention will be described hereunder
with reference to the accompanying drawings.
[0018] Fig. 2 is a systematic block diagram showing the construction of a receiver according
to an embodiment of the present invention.
[0019] 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.
[0020] 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.
[0021] 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.
[0022] 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.
[0023] 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.
[0024] 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.
[0025] 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.
[0026] 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.
[0027] 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.
[0028] 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.
[0029] 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.
[0030] 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.
[0031] 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.
[0032] 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]
[0033] 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.
[0034] 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).
[0035] 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.
[0036] 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.
[0037] 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).
[0038] 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.
[0039] 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.
[0040] 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.
[0041] 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).
[0042] 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).
[0043] 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.
[0044] 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.
[0045] 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.
[0046] Thereafter, the processing returns to the step 103 and then waits for the key input
again.
[0047] 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]
[0048] 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.
[0049] 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.
[0050] 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.
[0051] 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.
[0052] 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.
[0053] 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]
[0054] 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.
[0055] 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.
[0056] 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.
[0057] 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.
[0058] 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.
[0059] 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.
[0060] 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.
[0061] 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.
[0062] 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.
[0063] 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.
[0064] 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.
1. 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 element for displaying a list of the character sequences indicating the
broadcast stations on the basis of the data of said past record table; and
said 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 said display element.
2. The receiver for the digital audio broadcast as claimed in claim 1, wherein the character
sequences to be displayed on said display element are displayed in order of the reception
frequency of the broadcast in said past record table.
3. The receiver for the digital audio broadcast as claimed in claim 1, wherein the character
sequences to be displayed on said display element are displayed in order of the character
sequences in said past record table.
4. The receiver for the digital audio broadcast as claimed in claim 1, wherein the character
sequences are displayed on said display element in order of items selected by a user.
5. The receiver for the digital audio broadcast as claimed in claim 1, 2, 3 or 4 wherein
when the character sequences are displayed on said display element, information on
broadcast stations which can be received, information on broadcast stations which
were previously received, and information of other frequencies transmitted through
the broadcast are simultaneously displayed while being divided in accordance with
a display mode.
6. 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 corresponding to the names of the groups in the past record table; and
said 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.
7. The receiver for the digital audio broadcast as claimed in claim 6, wherein the names
of the groups to be displayed on said display element are displayed in order of the
reception frequency of the broadcast in said past record table.
8. The receiver for the digital audio broadcast as claimed in claim 6, wherein the names
of the groups to be displayed on said display element are displayed in order of the
group names in said past record table.
9. The receiver for the digital audio broadcast as claimed in claim 6, wherein the names
of the groups to be displayed on said display element are displayed in accordance
with the type of the program.
10. The receiver for the digital audio broadcast as claimed in claim 6, wherein the names
of the groups to be displayed on said display element are displayed in order of items
selected by a user.