JP3453470B2 - DAB receiver - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DAB receiver for receiving DAB signals.

[0002]

2. Description of the Related Art Conventionally, in order to detect a DAB signal, DA is used.
When the tuning frequency is sequentially increased from the lower limit frequency of the frequency band in which the B signal is considered to exist, the level of the received signal is detected, the detected level exceeds a predetermined threshold value, and a Null symbol is received, It is determined that the signal received at the reception frequency at that time is a DAB signal.

[0003]

By the way, at present,
The frequency of the DAB signal is assigned to the empty channel of the TV broadcast, and the signal of the TV broadcast is detected in the process of seeking the frequency of the received signal to detect the DAB signal, and the detected signal at this time exceeds the above threshold value. And depending on the timing (eg fading)
Since a signal similar to the Null symbol is detected, the frequency of the television broadcast may be erroneously determined to be the frequency of the DAB signal.

Therefore, the conventional apparatus has a problem that it takes a long time to receive the actual DAB signal, that is, the seek time of the DAB signal is long.

An object of the present invention is to provide a DAB receiver capable of shortening the seek time of DAB signals.

Further, in the conventional TV tuner, T
Since the frequency band from the lower limit to the upper limit of the V signal is sequentially sought, if within the frequency band,
Since it is necessary to seek the band in which the TV signal does not exist, there is a problem that the seek time of the TV signal is long.

An object of the present invention is to provide a DAB receiver capable of shortening the seek time of non-DAB signals such as TV signals.

[0008]

SUMMARY OF THE INVENTION The present invention is a DA during reception.
The TII detection means for detecting the TII (transmitter identification signal) of the B signal, the DAB signal frequency detection means for detecting the receivable DAB signal frequency by sweeping the frequency of the DAB frequency band, and the predetermined TII have been detected . At this time, the frequency list of receivable DAB signals detected by performing the frequency sweep by the DAB signal frequency detecting means is used as the predetermined TI.
Possess a TII pair DAB signal frequency list storage means corresponding to memory and I, the DAB signal having a predetermined TII
A DAB signal seek instruction was issued during reception.
In case of DAB stored in correspondence with the above predetermined TII,
The seek operation is performed based on the signal frequency list .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a circuit diagram showing a DAB receiver R1 which is an embodiment of the present invention.

The DAB receiver R1 includes a DAB tuner unit 1
0, DAB signal processing unit 20, and MPEG decoder 30
, D / A converter 40, synchronization unit 50, and control unit 6
0, the memory 70, the background detection unit 80, and C
It has a CD drive unit 81 for driving D, a recording tape drive unit 82 for driving a recording tape, and an AM / FM radio 83.

The DAB tuner section 10 receives a signal of a predetermined frequency based on the frequency setting signal from the control section 60, outputs an S meter output signal which is a received signal strength signal, and outputs a Null symbol. Is. The DAB signal processing unit 20 inputs the tuning signal, outputs the phase reference symbol to the synchronizing unit 50, outputs the processed signal to the MPEG decoder 30, and outputs the TII (transmission identification signal) to the control unit 60. Is.

The "Null symbol" is a non-signal portion inserted at the beginning of the frame of the DAB signal, and the "phase reference symbol" is inserted next to the Null symbol in the frame of the DAB signal. Symbol, which is a known fixed pattern.

The D / A converter 40 converts the digital signal output from the MPEG decoder 30 into an analog signal and outputs it as an audio output signal.

The synchronization unit 50 receives the Null symbol from the DAB tuner unit 10 and the phase reference symbol from the DAB signal processing unit 20, and outputs a synchronization detection signal to the control unit 60.

The control unit 60 detects the received signal strength based on the S meter output signal (received signal strength signal) from the DAB tuner unit 20, and the DAB signal processing unit 20 causes the TII.
(Transmission identification signal) is received, the synchronization detection signal from the synchronization unit 50 is input, and the frequency setting signal is sent to the DAB tuner unit 10.
Is to be supplied to.

The memory 70 stores a frequency list of receivable DAB signals in association with a predetermined TII.

That is, the control unit 60 is an example of TII detecting means for detecting TII (transmitter identification signal), and is an example of DAB signal detecting means for detecting receivable DAB signals. Further, the memory 70 stores the frequency list of the receivable DAB signals detected by the DAB detection means in correspondence with the predetermined TII when the predetermined TII is detected, in association with the predetermined TII. Is an example of.

Further, the background detecting section 80 has a D
It is an example of a background operation detecting unit that detects that a device other than the AB receiver is operating in the background. Note that the TII detection means detects TII and the DAB detection means detects a receivable DAB signal during the background operation.

FIG. 2 is an explanatory diagram of TII in the above embodiment.

In DAB, a single frequency network (SFN) is implemented. That is, the single-frequency network is a method of covering a wide reception area Er by transmitting broadcast radio waves of the same frequency (for example, transmission frequency f = 223.36 MHz) from a plurality of transmitters T1, T2, T3. In this case, the transmitter sends a TII specific to that transmitter. For example, the TI of transmitter T1
I = 01, TII = 02 for transmitter T2, and TII = 03 for transmitter T3. Then, by receiving this TII and analyzing the received TII, the position where the receiver exists can be roughly known.

Next, the operation of the above embodiment will be described.

FIG. 3 shows the DAB receiver R of the above embodiment.
3 is a flowchart showing the operation of the control unit 60 in FIG.

First, equipment other than the DAB receiver R1 such as a CD drive unit 81, a recording tape drive unit 82, AM /
When the detection unit 80 detects that the FM radio 83 is operating, that is, the background operation is being performed (S
1) Receive an arbitrary DAB signal, read the TII (transmitter identification signal) being received at this time (S2), and if this read TII is different from the TII read immediately before (S3), DAB In order to seek all the frequencies from the lower limit to the upper limit of the frequency band, the signal is received at the lower limit frequency of the DAB frequency band (S4).

At this time, if the received signal strength is greater than or equal to the predetermined threshold value (S11), the Null symbol is detected (S12), and the phase reference symbol is detected (S1).
3) The current reception frequency is registered in the DAB frequency list stored in the memory 70 together with the TII at that time (S14). Then, the reception frequency is increased by one step (for example, 16 KHz) (S15), and step S11 is performed.
Then, the above operation is repeated.

When the Null symbol can be detected,
If it is determined that the DAB signal is likely to be received (it is determined that the Null symbol can be detected even with fading) and the phase reference symbol can be detected, the DAB signal is detected.
It can be judged that the signal has been received without fail.

On the other hand, when the received signal strength exceeds the predetermined threshold value (S11) but the Null symbol is not detected (S12), the signal currently being received is the TV frequency, and therefore is stored in the memory 70. Register the current reception frequency together with TII in the TV frequency list that is stored (S
16), the reception frequency is increased by one step (S15), the process returns to step S11, and the above operation is repeated.

If the received signal strength does not exceed the predetermined threshold value (S11), it can be recognized that there is no broadcast at the current reception frequency, and the current reception frequency is below the upper limit of the DAB frequency. After checking (S17), the reception frequency is increased by one step (S15), and step S11
Then, the above operation is repeated. When the received signal strength exceeds the predetermined threshold (S11) and the current received frequency reaches the upper limit of the DAB frequency (S17), the process returns to step S1.

FIG. 4 shows a memory 70 in the above embodiment.
Example of DAB frequency list stored in
It is a figure which shows the specific example of a frequency list with TII. In the memory 70, TII = 02 and TII = 0.
Also for 3, the same DAB frequency list and TV as in FIG.
A frequency list is stored.

According to the above embodiment, once the TV frequency list is created, when the user is receiving the DAB signal from the transmitter having the identification signal of the predetermined TII (for example, TII = 01), When the seek operation of the DAB signal is performed, the frequencies registered in the TV frequency list can be excluded from the seek target, and by doing so, the seek operation of the DAB signal can be speeded up.

Also, once the DAB frequency list has been created, the user may use the DA from the transmitter having a predetermined TII.
When the seek operation of the DAB signal is performed while receiving the B signal, only the frequencies registered in the DAB frequency list can be targeted for the seek, and by doing so, the DAB signal The seek operation can be further speeded up.

FIG. 5 shows a DAB which is another embodiment of the present invention.
It is a block diagram which shows receiver R2.

The DAB receiver R2 is the DAB receiver R1.
A TV tuner 90, a TV tuner control unit 91,
A memory 92 is added, and instead of the control unit 60, the control unit 6
1 is provided. The control unit 61 has the same function as the control unit 60, and has the same function as the TV tuner control unit 91.
V frequency list (TV frequency list corresponding to TII)
And the function of sending The memory 92 is
The TV frequency list is stored corresponding to TII. The TV tuner control unit 91 is a means for storing the TV frequency list in the memory 92, and at the time of seeking the TV frequency, seeks only the TV frequency in the TV frequency list stored in the memory 92 as a seek target. is there.

Next, the operation of the DAB receiver R2 will be described.

FIG. 6 is a flow chart showing the operation of the DAB receiver R2.

The flowchart shown in FIG. 6 is basically the same as the flowchart shown in FIG. 3, except that when the reception frequency reaches the upper limit of the DAB frequency band (S1
7) The difference is that the detected TV frequency list is sent to the TV tuner control unit 91 in correspondence with TII (S21).

FIG. 7 is a flowchart showing the seek operation of the TV tuner 90 in the DAB receiver R2.

First, if the TV frequency list is transmitted from the control section 61 (S31), the first frequency of the TV frequency list is read (S32), and the read frequency is already set in the TV tuner 90. If the frequency is not present (S33), the read frequency is preset in the TV tuner 90 (S34), the next frequency in the TV frequency list is read (S35), and the above operation (S33,
When S34 and S35) are repeated and the last frequency in the TV frequency list is preset (S36), the seek operation is ended.

According to the DAB receiver R2, when the TV tuner 90 seeks the TV frequency, only the frequencies in the TV frequency list stored in the memory 92 are sought as the seek target. The operation is speeded up.

That is, the embodiment shown in FIGS.
TII detection means for detecting I, non-DAB signal detection means for detecting receivable non-DAB signals, and the predetermined TI
And a non-DAB signal frequency list storage unit for storing the frequency list of the receivable non-DAB signals detected by the non-DAB detection unit in correspondence with the predetermined TII. It is a DAB receiver. In this case, it has a background operation detecting means for detecting that it is operating a device other than the DAB receiver in the background operation, and the TII detecting means detects TII when the background operation is in progress. , Also non-DAB
The detection means detects a non-DAB signal that can be received.

[0040]

According to the inventions of claims 1 and 2, DA
There is an effect that the seek time of the B signal can be shortened.

According to the third and fourth aspects of the invention, non-DA
There is an effect that the seek time of the B signal can be shortened.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a DAB receiver R1 which is an embodiment of the present invention.

FIG. 2 is a TII (transmitter identification signal) in the above embodiment.
FIG.

FIG. 3 is a flowchart showing an operation of a control unit 60 in the DAB receiver R1 according to the above embodiment.

FIG. 4 is a diagram showing a specific example of a DAB frequency list and a specific example of a TV frequency list stored in a memory 70 together with TII in the above embodiment.

FIG. 5 is a block diagram showing a DAB receiver R2 which is another embodiment of the present invention.

FIG. 6 is a flowchart showing an operation of the DAB receiver R2.

FIG. 7 is a flowchart showing a seek operation of the TV tuner 90 in the DAB receiver R2.

[Explanation of symbols]

R1, R2 ... DAB receiver, 10 ... DAB tuner section, 20 ... DAB signal processing unit, 50 ... same base, 60, 61 ... Control unit, 70, 92 ... memory, 80 ... Background detection 91 ... TV tuner control unit.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04B 1/06 H04B 1/16 H03J 7/18 H04H 1/00

Claims (4)

(57) [Claims] 1. A TII detecting means for detecting TII of a DAB signal being received ; a DAB signal which is swept in the DAB frequency band and can be received.
DAB signal frequency detecting means and for detecting the frequency; upon detection of a predetermined the TII, the DAB signal circumferential
A frequency list of receivable DAB signal detected by performing a frequency sweep by the wave number detecting means, a TII pair DAB signal frequency list storage means for storing in correspondence with the predetermined TII; have a have a predetermined TII When receiving a DAB signal
If the seek instruction of the DAB signal is given to the
DAB signal frequency list stored corresponding to TII of
A DAB receiver characterized by performing a seek operation based on . 2. The method according to claim 1, further comprising background operation detecting means for detecting that a device other than the DAB receiver is operating in the background, and when the background is operating. , The TII detecting means detects the TII, and the DAB signal frequency
Wavenumber detecting means detects a DAB signal frequency that can be received
In the TII vs. DAB signal frequency list storage means.
A DAB receiver, characterized in that it stores a list of DAB signal frequencies corresponding to TII . 3. TII detection means for detecting TII of a DAB signal being received ; TV signal frequency receivable by sweeping a TV frequency band
TV signal frequency detecting means and for detecting the number; when detecting a predetermined TII, receivable T detected by performing a frequency sweep by the TV signal frequency detection <br/> detecting means
The frequency list of the V signal, in correspondence with the predetermined TII and TII pairs TV signal frequency list storage means for storing; have a, when receiving a DAB signal having a predetermined TII
If the seek instruction of the TV signal is given to the
Based on the TV signal frequency list stored corresponding to TII
DAB receiver characterized by performing a seek operation based on the following . 4. The method according to claim 3, further comprising background operation detecting means for detecting that a device other than the DAB receiver is operating in the background, and when the background is operating. The TII detecting means detects the TII, and the TV signal frequency
Detects the receivable TV signal frequency of several detection means, the upper
The TII-to-TV signal frequency list storage means stores the TII.
A DAB receiver characterized by storing a list of TV signal frequencies corresponding to .