WO2013118163A1

WO2013118163A1 - Broadcast receiver and method for searching for broadcast station

Info

Publication number: WO2013118163A1
Application number: PCT/JP2012/000783
Authority: WO
Inventors: 秀樹原
Original assignee: 三菱電機株式会社
Priority date: 2012-02-06
Filing date: 2012-02-06
Publication date: 2013-08-15
Also published as: JP5734467B2; JPWO2013118163A1

Abstract

A broadcast receiver is provided with: a main tuner (3a) which receives radio waves and is sequentially set to tuning frequencies in a range of frequencies for which searching is to be carried out; a sub tuner (3b) which receives radio waves and is sequentially set to tuning frequencies each offset from a respective tuning frequency set for the main tuner (3a) by the frequency difference Δf between a center frequency and either of the frequency bands symmetrically adjacent to the center frequency; a radio wave state determination unit (11) which determines whether the difference in the electric field strength level of the radio waves received by the tuners (3a,3b) is a predetermined value; and a search control unit (15) which determines the frequency of the broadcast station from the frequencies of the radio waves received by the tuners (3a,3b) on the basis of the determination results of the radio wave state determination unit (11).

Description

Broadcast receiver and broadcast station search method

The present invention relates to a broadcast receiver of, for example, HD (High Definition) radio broadcast and a broadcast station search method thereof.

When performing a broadcast station search for a broadcast station whose frequency spectrum is symmetric with respect to the center frequency of the broadcast frequency band, such as HD radio broadcast, the process of determining the digital broadcast station by decoding the broadcast station data received by the tuner Since time is required, the time required for the broadcast station search is longer than that in the case of analog broadcasting.

As a conventional technique for shortening the time required for broadcast station search, there is a broadcast receiver disclosed in Patent Document 1, for example. This broadcast receiver uses the symmetry of the spectrum of an HD radio broadcast wave, and if there is a received signal with an electric field strength equal to or greater than a threshold value within a specific frequency offset range from the tuning frequency, the tuning frequency of the HD radio broadcast station is set. If it can be considered as a frequency and HD radio broadcast can be received at the frequency, it is determined as an HD radio broadcast station, and if HD radio broadcast cannot be received, it is determined as an analog broadcast station.

JP 2009-141468 A

In the conventional technique represented by Patent Document 1, since broadcasting station search is performed with one tuner, it is necessary to always retune to tuning frequency +200 kHz and check the electric field strength and frequency offset. Also, if it is determined from the frequency offset and electric field strength that there is a broadcasting station at the tuning frequency, it is necessary to retune the retuned frequency to the original frequency again. There was a problem of becoming longer.

The present invention has been made to solve the above-described problems, and a broadcast receiver and a broadcast station that can reduce the time required for searching for a broadcast station having a symmetric frequency spectrum with respect to the center frequency of the broadcast frequency band. The purpose is to obtain a search method.

In the broadcast receiver according to the present invention, the frequency spectrum is symmetric with respect to the center frequency of the broadcast frequency band, and the difference between the electric field intensity level of the center frequency and the electric field intensity level of the adjacent frequency band symmetrically with respect to the center frequency is predetermined. In a broadcast receiver that performs a broadcast station search for a broadcast that is a value, a tuning frequency of a frequency band to be searched is sequentially set, and a tuning frequency that is set in the first tuner, and a tuning frequency that is set in the first tuner, A second tuner that receives radio waves by sequentially setting a tuning frequency that is offset by a frequency difference between the center frequency and a frequency band that is symmetrically adjacent to the center frequency, and each radio wave received by the first and second tuners. Radio wave condition determination unit for determining whether or not the electric field strength level difference of the signal is a predetermined value, and radio wave condition determination Based on the determination result by, from the frequency of the electromagnetic wave received by the first and second tuner, and a search control unit that determines the frequency of the broadcast station.

According to the present invention, there is an effect that the time required for searching for a broadcasting station whose frequency spectrum is symmetrical with respect to the center frequency of the broadcast frequency band can be shortened.

It is a block diagram which shows the structure of the radio receiver which concerns on Embodiment 1 of this invention. It is a figure which shows the example of a display of a broadcast station search result. It is a figure which shows the frequency spectrum of FM hybrid broadcasting and AM hybrid broadcasting. 3 is a flowchart showing an operation of the radio receiver according to the first embodiment. It is a figure which shows the frequency spectrum of an electromagnetic wave condition. It is a table | surface which shows the electromagnetic wave condition of each frequency. 6 is a diagram showing a display example of a broadcast station search result by the radio receiver according to Embodiment 1. FIG. It is a table | surface which shows the determination result of each frequency. It is a figure explaining the shortening effect of the time which a broadcast station search requires. It is a figure which shows the frequency spectrum of AM hybrid broadcasting. It is a flowchart which shows operation | movement of the radio receiver which concerns on Embodiment 2 of this invention.

Hereinafter, in order to describe the present invention in more detail, modes for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of a radio receiver according to Embodiment 1 of the present invention, where the broadcast receiver according to the present invention is applied to a radio receiver mounted on a mobile body (for example, a vehicle). Is shown. The radio receiver 1 shown in FIG. 1 has a symmetrical frequency spectrum with respect to the center frequency of the broadcast frequency band, as in HD radio broadcasting, and the electric field intensity level of the center frequency (the electric field intensity level of the carrier frequency of analog broadcasting) A broadcast station search is performed for a broadcast wave in which the difference between the electric field intensity level of the adjacent frequency band symmetrically with respect to the center frequency (the electric field intensity level of the modulation band of digital broadcasting) is a predetermined value. As shown in FIG. 1, the main antenna 2a, the sub antenna 2b, the main tuner 3a, the sub tuner 3b, the radio wave state detection unit 4, the decoder unit 5, the operation unit 6, the calculation control unit 7, the display unit 8 and An external storage device 9 is provided.

The main tuner 3a is a tuner that receives radio waves of the tuning frequency via the main antenna 2a, and the sub tuner 3b is a tuner unit that receives radio waves of the tuning frequency via the sub antenna 2b. The radio wave condition detector 4 detects a detector value indicating the radio wave condition of each tuning frequency of the main tuner 3a and the sub tuner 3b. The decoder unit 5 decodes the digital data received by the main tuner 3a and the sub tuner 3b.

The operation unit 6 is an operation unit that receives an operation from the user, and may be a software key or button displayed on the screen of the display unit 8 that performs input with a touch panel in addition to hardware such as a keyboard and buttons. For example, the user refers to the broadcast station list displayed on the display unit 8, selects a broadcast station of a program to be listened to, and designates the broadcast station using the operation unit 6.

The calculation control unit 7 is a control unit that performs calculation processing such as channel selection, broadcast station search, and display processing. The display unit 8 is a display device such as a liquid crystal display, a plasma display, or an organic EL display. The external storage device 9 is a storage device that stores each detector value indicating a radio wave condition and a broadcast station list.

The arithmetic control unit 7 includes, as functional blocks, a main tuner reception frequency setting unit 10, a radio wave condition determination unit 11, a sub tuner reception frequency setting unit 12, a data reception control unit 13, a broadcast station list creation unit 14, and a search control unit. 15 and a display control unit 16.
The main tuner reception frequency setting unit 10 is a frequency setting unit that sets a reception frequency in the main tuner 3a.

The radio wave status determination unit 11 determines the radio wave status of each tuning frequency based on each detector value indicating the radio wave status of each tuning frequency of the main tuner 3a and the sub tuner 3b detected by the radio wave status detection unit 4. The sub tuner reception frequency setting unit 12 sets the reception frequency in the sub tuner 3b. The data reception control unit 13 controls the decoding operation by the decoder unit 5 based on the instruction issued from the search control unit 15.

The broadcast station list creation unit 14 creates a broadcast station list of broadcast stations that can be received at the current position based on data input from the decoder unit 5 and the data reception control unit 13. In the broadcast station list, broadcast stations that can be received at the current position are listed. As information about each broadcast station, the broadcast station name, the reception frequency, and the electric field strength (the electric field strength level) of the reception frequency at the time of search. Etc. are registered. Further, the broadcast station list creation unit 14 stores the created broadcast station list in the external storage device 9.

The search control unit 15 controls each operation by the main tuner reception frequency setting unit 10, the sub tuner reception frequency setting unit 12, the data reception control unit 13, and the broadcast station list creation unit 14 according to the instruction command received by the operation unit 6. At the same time, it is a control unit that reads a detector value indicating the radio wave status stored in the external storage device 9.
The display control unit 16 is a display control unit that controls the display operation by the display unit 8. For example, a broadcast station list stored in the external storage device 9 is read and displayed on the display unit 8.

When an FM radio station search is performed in the US where HD radio is broadcast, for example, as shown in FIG. 2, the frequency and the station name are displayed on the display screen, and the user can display the frequency displayed on the screen. By selecting the broadcast station name, the user can listen to the desired broadcast.
When the frequency is displayed as the broadcast station search result, the broadcast station of this frequency is analog broadcast, and when the broadcast station name is displayed, the broadcast station is HD radio broadcast. In the example shown in FIG. 2, broadcast stations with list numbers 1 to 4 are HD radio broadcast stations, and

list numbers

5 and 6 are analog broadcast stations.

The broadcasting station name of HD radio broadcasting is called SIS (Station Information Service), and SIS data is obtained by decoding digital data extracted from broadcast waves. However, there is a problem that it takes a long time to complete the decoding, and the time required for the broadcast station search is prolonged.

3A and 3B are diagrams showing frequency spectra of FM hybrid broadcasting and AM hybrid broadcasting. FIG. 3A is a frequency spectrum of FM hybrid broadcasting, and FIG. 3B is a frequency spectrum of AM hybrid broadcasting. . FM hybrid broadcasting and AM hybrid broadcasting are one of HD radio broadcasting formats that transmit digital signals simultaneously with analog broadcasting.

As shown in FIG. 3A and FIG. 3B, the FM hybrid broadcast and the AM hybrid broadcast have a carrier frequency of analog broadcast located at the center of the frequency band and a digital frequency band adjacent to the frequency axis. It has the feature of symmetry.
In the present invention, for searching for a broadcasting station having a symmetric frequency spectrum as shown in FIG. 3, two tuners are used at the same time, and each tuner is always tuned to a frequency separated by a specific frequency, thereby searching for the broadcasting station. (SIS data acquisition) Time is shortened.

Next, the operation will be described.
FIG. 4 is a flowchart showing the operation of the radio receiver according to the first embodiment. Details of the broadcast station search according to the first embodiment will be described with reference to FIG. In the following, the FM hybrid broadcast shown in FIG. 3A is taken as an example.
First, when the operation unit 6 receives an instruction to perform a broadcast station search from the user, the operation unit 6 issues a command to the search control unit 15 to set each tuning frequency of the main tuner 3a and the sub tuner 3b. The search control unit 15 causes the main tuner reception frequency setting unit 10 to set the tuning frequency of the main tuner 3 a in accordance with a command from the operation unit 6, and causes the sub tuner reception frequency setting unit 12 to set the tuning frequency of the sub tuner 3 b. Instructs to set.

The main tuner reception frequency setting unit 10 sets the tuning frequency fm (n) of the main tuner 3a in accordance with an instruction from the search control unit 15. The sub-tuner reception frequency setting unit 12 also sets the tuning frequency fs (n) of the sub-tuner 3b according to the instruction from the search control unit 15 (step ST1). At this time, the tuning operation is performed so that the tuning frequency fm (n) of the main tuner 3a and the tuning frequency fs (n) of the sub-tuner 3b always maintain the relationship represented by the following formula (1).
However, the execution order n of tuning is n = 1, 2, 3,..., Meaning the nth tuning. Δf is a predetermined offset frequency.
fm (n) = fs (n) −Δf (1)

In the above equation (1), the case where the tuning frequency fs (n) of the sub-tuner 3b is larger than the tuning frequency fm (n) of the main tuner 3a is shown. To do. As the offset frequency Δf, an appropriate value is selected according to the broadcast standard to be searched. In this example, Δf = 200 kHz.
Here, description will be made on the assumption that the gain from the radio wave input stage to the detection stage of the main tuner 3a and the sub tuner 3b is the same, but the gain from the radio wave input stage to the detection stage of both

tuners

3a and 3b is assumed. Even if they are different, the present invention can be applied by introducing a coefficient for correcting the gain.

Next, the radio wave condition detection unit 4 is tuned by the main tuner 3a and the sub tuner 3b, respectively, and the electric field intensity and noise value (multipath, USN) in the received radio waves of the frequencies fm (n) and fs (n). (Ultrasonic noise)) is acquired, and each detector value is stored in the external storage device 9 as a detection result of the radio wave condition (step ST2).
The radio wave condition detection unit 4 detects each detector value indicating the radio wave condition at the tuning frequency received by each of the

tuners

3a and 3b each time tuning is performed by the main tuner 3a and the sub-tuner 3b. The data is sequentially stored in the external storage device 9 in association with the execution order n.

Subsequently, the radio wave condition determination unit 11 reads out each detector value indicating the radio wave condition acquired by the radio wave condition detection unit 4 in step ST2 from the external storage device 9, and based on the value of each detector value, the main tuner 3a It is determined whether or not the tuning frequency fm (n) is a receivable broadcasting station (step ST3). In addition, although the case where the radio wave condition determination unit 11 reads the detector value stored in the external storage device 9 has been shown, the determination is performed by sequentially inputting the detector value detected in real time by the radio wave condition detection unit 4. You may make it perform.

When the radio wave condition determining unit 11 determines that the broadcast station is not receivable from the radio wave condition specified by the value of each detector value, such as a low electric field strength or a high noise value (step ST3; NO), that effect Is notified to the search control unit 15.
When the search control unit 15 receives the notification from the radio wave condition determination unit 11, the search control unit 15 determines that the frequency fm (n) is “no broadcast station”, and notifies the broadcast station list creation unit 14 to that effect. When the broadcast station list creation unit 14 receives a notification indicating that the frequency fm (n) is “no broadcast station”, it indicates that the frequency fm (n) does not need to be displayed in the list because there is no broadcast station. The indicated information is stored in the external storage device 9 (step ST4).

On the other hand, when the radio wave condition determining unit 11 determines that the tuning frequency fm (n) is a receivable broadcasting station (step ST3; YES), the sub tuner 3b acquired by the radio wave condition detecting unit 4 in step ST2 Whether the difference between the received electric field strength Fs (fs (n)) of the radio wave having the tuning frequency fs (n) and the received electric field strength Fm (fm (n)) of the main tuner frequency is −10 dB. Determination is made (step ST5).
When the tuning frequency is 200 kHz apart at the frequencies fm (n) and fs (n) and the electric field strength level difference is −10 dB, FM which is one of the HD radio broadcasting formats shown in FIG. It can be judged that there is a possibility of a broadcasting station for hybrid broadcasting.
Note that −10 dB is a difference in electric field strength level between an analog broadcast wave and a digital broadcast wave in FM hybrid broadcasting, and a margin in a range that does not affect the determination result may be set.
This time, FM hybrid broadcasting is taken as an example, and X = −10 in the following formula (2). However, when the present invention is applied to a broadcasting wave other than HD radio broadcasting, it corresponds to the spectrum of the broadcasting standard. Select a value for X.
Fs (fs (n)) − Fm (fm (n)) = X (2)

When the difference between the electric field intensity levels of the radio waves at the frequencies fm (n) and fs (n) is not −10 dB (step ST5; NO), the radio wave state determination unit 11 notifies the search control unit 15 to that effect.
When the search control unit 15 receives a notification indicating that the electric field strength level difference is not 10 dB, the frequency fm (n) is not the HD radio broadcast station shown in FIG. 3A, but the analog broadcast station frequency. The broadcast station list creation unit 14 is notified of this.
Upon receiving notification that the frequency fm (n) is an analog broadcast station, the broadcast station list creation unit 14 adds the frequency fm (n) to the broadcast station list as an analog broadcast station, and this broadcast station list is externally added. The data is stored in the storage device 9 (step ST6).

Further, when the electric field strength level difference between the radio waves of the frequencies fm (n) and fs (n) is −10 dB (step ST5; YES), the radio wave state determination unit 11 notifies the search control unit 15 to that effect. When the search control unit 15 receives a notification indicating that the difference in electric field strength level is −10 dB, the (n−1) th tuning frequency fm (n−1), fs (n) by the main tuner 3a and the sub-tuner 3b. Each detector value indicating the radio wave status of -1) is read from the external storage device 9 (step ST7), and is output to the radio wave status judging unit 11.

When the radio wave condition determination unit 11 receives each detector value indicating the radio wave condition from the search control unit 15, the radio wave condition determination unit 11 uses the value of the detector value to generate a radio wave having a frequency fs (n−1) according to the following equation (3). Whether or not the difference (−X) between the electric field strength Fs (fs (n−1)) and the electric field strength Fm (fm (n−1)) of the radio wave having the frequency fm (n−1) is 10 dB. Determination is made (step ST8). The 10 dB is a difference in electric field strength level between an analog broadcast wave and a digital broadcast wave in FM hybrid broadcasting, and a margin within a range that does not affect the determination result may be set.
Fs (fs (n−1)) − Fm (fm (n−1)) = − X (3)

When the electric field strength level difference between the radio waves at frequencies fs (n-1) and fm (n-1) is not 10 dB (step ST8; NO), the radio wave state determination unit 11 notifies the search control unit 15 to that effect. . When the search control unit 15 receives a notification indicating that the electric field strength level difference is not 10 dB, the search control unit 15 determines the frequency fm (n) as the frequency of the analog broadcast station and notifies the broadcast station list creation unit 14 to that effect. In accordance with the notification indicating that the frequency fm (n) is an analog broadcasting station, the broadcasting station list creation unit 14 proceeds to the process of step ST6 and adds the frequency fm (n) to the broadcasting station list as an analog broadcasting station. The broadcast station list is stored in the external storage device 9.

In addition, when the electric field strength level difference between the radio waves of the frequencies fs (n-1) and fm (n-1) is 10 dB (step ST8; YES), the radio wave state determination unit 11 informs the search control unit 15 to that effect. Notify them. Since the spectrum is symmetric with respect to the frequency axis according to the notification from the radio wave condition determination unit 11, the search control unit 15 has a frequency fm (n) that is possible for a broadcasting station of HD radio broadcasting shown in FIG. It is determined that the frequency is extremely high.
If it judges as mentioned above, search control part 15 will instruct data reception control part 13 to acquire SIS data of frequency fm (n).

Next, the data reception control unit 13 receives the SIS data of the frequency fm (n) of the main tuner 3a by controlling the operation of the decoder unit 5 in accordance with the above instruction from the search control unit 15 (step ST9a). . The data reception control unit 13 determines whether or not the SIS data having the frequency fm (n) has been acquired, that is, whether or not the SIS data having the frequency fm (n) can be received (step ST10).

If the SIS data of frequency fm (n) cannot be received (step ST10; NO), the data reception control unit 13 determines that the frequency fm (n) is an analog broadcasting station, and creates a broadcast station list to that effect. Notification to the unit 14. In accordance with the notification indicating that the frequency fm (n) is an analog broadcasting station, the broadcasting station list creation unit 14 proceeds to the process of step ST6 and adds the frequency fm (n) to the broadcasting station list as an analog broadcasting station. The broadcast station list is stored in the external storage device 9.

The SIS data of the frequency fm (n) can be received (step ST10; YES), that is, when the SIS data of the frequency fm (n) is acquired, the frequency fm (n) is an HD radio broadcasting station, so the decoder unit 5 However, the broadcast station list creation unit 14 is notified that the frequency fm (n) and the frequency fm (n) are HD radio broadcast stations.
Upon receiving the notification from the decoder unit 5, the broadcast station list creation unit 14 adds the frequency fm (n) as an HD radio broadcast station to the broadcast station list, and stores this broadcast station list in the external storage device 9 (step ST11).

When the processing of step ST4, step ST6, and step ST11 is completed, the search control unit 15 determines whether or not scanning has been completed for all frequencies in the frequency band to be searched (step ST12). If scanning has not been completed for all frequencies (step ST12; NO), the search control unit 15 adds “+1” to the tuning execution order n of the main tuner 3a and the sub tuner 3b, that is, the tuning frequency. Each setting is advanced by one step (step ST13), and the process returns to step ST1 to continue the search.

If scanning has been completed at all frequencies in the frequency band to be searched (step ST12; YES), the display control unit 16 causes the display unit 8 to display the broadcast station list stored in the external storage device 9 (step ST12). ST14) The broadcast station search is terminated.

Next, a specific aspect of the present invention will be described by taking the radio wave situation shown in FIG. 5 as an example.
In FIG. 5, the HD radio broadcasting station has a frequency of 88.1 MHz, and for convenience, it is assumed that there is no broadcasting station at a frequency of 89.1 MHz or higher. Moreover, each detector value (electric field strength, noise value) indicating the radio wave condition of each frequency shown in FIG. 5 is as shown in FIG.
The broadcast station search is started, for example, from the frequency currently being listened to by the main tuner 3a.
Here, the tuning is started from the main tuner 3a of 87.7 MHz and the sub-tuner 3b of 87.9 MHz.

(A) First Tuning In the first tuning, the main tuner 3a is tuned to 87.7 MHz and the sub-tuner 3b is tuned to 87.9 MHz (step ST1), and the detector value indicating the radio wave status is the radio wave status detector 4. And stored in the external storage device 9 (step ST2). In the example of FIG. 6, at 87.7 MHz, since the electric field strength (15 dB) is low and the noise value (40%) is high, it is determined that the broadcast station is not receivable (step ST3), and the information is stored in the external storage device. 9 (step ST4). Thereafter, since scanning of all frequencies has not been completed, tuning to the next frequency is performed (step ST13).

(B) Second Tuning In the second tuning, the main tuner 3a is tuned to 87.9 MHz and the sub-tuner 3b is tuned to 88.1 MHz (step ST1), and the detector value indicating the radio wave status is the radio wave status detector 4. And stored in the external storage device 9 (step ST2). The frequency of each digital modulation band (87.9 MHz, 88.3 MHz) symmetrically adjacent to the analog broadcast carrier frequency (88.1 MHz) located at the center of the HD radio broadcast frequency band has a high electric field strength. The noise value becomes high. Therefore, it is determined that 87.9 MHz is not a receivable broadcasting station (step ST3), and the information is stored in the external storage device 9 (step ST4). Again, since scanning of all frequencies has not been completed, tuning to the next frequency is performed (step ST13).

(C) Third Tuning In the third tuning, the main tuner 3a is tuned to 88.1 MHz and the sub-tuner 3b is tuned to 88.3 MHz (step ST1), and the detector value indicating the radio wave status is the radio wave status detector 4. And stored in the external storage device 9 (step ST2). At 88.1 MHz, since the electric field strength (60 dB) is high and the noise value (5%) is low, it is determined that the broadcast station is receivable (step ST3).
In the determination of step ST5, as shown in FIG. 6, the difference between the electric field intensities (50 dB (sub) -60 dB (main)) between 88.1 MHz (main) and 88.3 MHz (sub) is −10 dB.
In step ST7, the detector value indicating the radio wave status of the tuning frequency (87.9 MHz, 88.1 MHz) of the main tuner 3a and the sub tuner 3b for the second tuning is called from the external storage device 9.
Thereafter, the electric field intensity level difference (60 dB (sub) -50 dB (main)) of radio waves received by the second tuning of the main tuner 3a and the sub tuner 3b in the determination of step ST8 is as shown in FIG. Since it is 10 dB, it is determined that the third tuning frequency of 88.1 MHz is highly likely to be an HD radio broadcast station, and SIS data reception processing is performed in step ST9. In the example shown in FIG. 5, since 88.1 MHz is used as an HD radio broadcasting station, SIS data can be received. Therefore, 88.1 MHz is added to the broadcast station list as being an HD radio broadcast station, and is stored in the external storage device 9 (step ST11). Thereafter, since scanning of all frequencies has not been completed, tuning to the next frequency is performed (step ST13).

(D) Fourth Tuning In the fourth tuning, the main tuner 3a is tuned to 88.3 MHz and the sub-tuner 3b is tuned to 88.5 MHz (step ST1), and the detector value indicating the radio wave status is the radio wave status detector 4. And stored in the external storage device 9 (step ST2). Similar to 87.9 MHz, 88.3 MHz is a digital modulation band that is symmetrically adjacent to the analog broadcast carrier frequency (88.1 MHz) located at the center of the frequency band of HD radio broadcast, so that the electric field strength (50 dB) Is high, but the noise value (45%) is also high. Therefore, it is determined that the broadcast station is not receivable (step ST3), and the information is stored in the external storage device (step ST4). Since scanning of all frequencies has not been completed, tuning to the next frequency is performed (step ST13).

(E) Fifth Tuning In the fifth tuning, the main tuner 3a is tuned to 88.5 MHz and the sub-tuner 3b is tuned to 88.7 MHz (step ST1), and the detector value indicating the radio wave status is the radio wave status detector 4. And stored in the external storage device 9 (step ST2). At 88.5 MHz, since the electric field strength (40 dB) is high and the noise value (10%) is also low, it is determined that the broadcast station can be received (step ST3), and the determination in step ST5 is performed. Here, the difference in electric field strength level (40 dB (sub) -10 dB (main)) from the frequency 88.7 MHz of the sub tuner 3b is not 10 dB. Therefore, 88.5 MHz is determined as an analog broadcasting station and stored in the external storage device 9 (step ST6). Since scanning of all frequencies has not been completed, tuning to the next frequency is performed (step ST13).

(F) Sixth Tuning In the sixth tuning, the main tuner 3a is tuned to 88.7 MHz and the sub-tuner 3b is tuned to 88.9 MHz (step ST1), and the detector value indicating the radio wave status is the radio wave status detector 4. And stored in the external storage device 9 (step ST2). Here, since the electric field strength (10 dB) at 88.7 MHz is low and the noise value (52%) is high, the processing is the same as the result of the first tuning.

(G) Seventh Tuning In the seventh tuning, the main tuner 3a is tuned to 88.9 MHz and the sub-tuner 3b is tuned to 89.1 MHz (step ST1), and the detector value indicating the radio wave status is the radio wave status detector 4. And stored in the external storage device 9 (step ST2). Here, since the electric field strength (30 dB) at 88.9 MHz is high and the noise value (15%) is low, the same processing as the result of the fifth tuning is performed, and 88.9 MHz is used as an analog broadcasting station as an external storage device. 9 (step ST6).

Thereafter, the same processing is performed, and the broadcast station list stored in the external storage device 9 is displayed on the display unit 8 when the scanning of all frequencies is completed. In this example, it is assumed that there is no broadcasting station at a frequency of 89.1 MHz or higher, so three broadcasting stations (one for HD radio broadcasting and two for analog broadcasting) are displayed on the display unit 8 as shown in FIG. Is displayed. The determination result for each frequency in each step by the broadcast station search method described above is as shown in FIG.

By using the broadcast station search method according to Embodiment 1 described above, it is expected that the time of at least one tuning is shortened for each HD radio broadcast station as compared with the search method of Patent Document 1. That is, in the search method of Patent Document 1, as shown in FIG. 9A, (a) tuning to 88.1 MHz, (b) seek up to 200 kHz, frequency offset measurement, (c) original frequency (88. 3 steps of (a), (b), and (c) are required to retune to 1 MHz) and to determine the HD radio broadcasting station if SIS data can be acquired by decoding received data.

On the other hand, in the first embodiment, as shown in FIG. 9B, (A) frequency tuning to 87.9 MHz with the main tuner 3a and 88.1 MHz with the sub-tuner 3b, (B) If the main tuner 3a, which is the frequency, is tuned to 88.1 MHz, the sub-tuner 3b is tuned to 88.3 MHz, and the 88.1 MHz SIS data of the main tuner 3a can be acquired, then it is determined to be an HD radio broadcasting station 2 Steps are fine. For example, assuming that there are 30 HD radio broadcast stations, and that one tuning operation (including acquisition of the detector value) takes 50 milliseconds, the search time for the broadcast station search method according to the first embodiment is as follows. Can be shortened by about 1.5 seconds.

In the above description, the FM hybrid broadcast is taken as an example, but the present invention is also applicable to the AM hybrid broadcast shown in FIG. That is, as shown in FIG. 10, by setting the offset frequency Δf of the tuning frequency of the two

tuners

3a and 3b and the electric field intensity level difference X between the analog broadcast and the digital broadcast to appropriate values, the same as in the FM hybrid broadcast The search method can be applied. In the case of AM hybrid broadcasting, for example, Δf may be 10 kHz and X = 10 dB.

As described above, according to the first embodiment, the tuning frequency of the frequency band to be searched is sequentially set and the main tuner 3a that receives the radio wave, and the tuning frequency set in the main tuner 3a is set as the center frequency. A sub-tuner 3b that receives a radio wave by sequentially setting a tuning frequency offset by a frequency difference Δf between adjacent frequency bands symmetrically with respect to the center frequency, and a difference in electric field strength level between the radio waves received by the

tuners

3a and 3b. Based on the radio wave condition determination unit 11 that determines whether or not the value is a predetermined value, and the determination result by the radio wave condition determination unit 11, the frequency of the broadcasting station is determined from the frequency of the radio wave received by the

tuners

3a and 3b. And a search control unit 15. With this configuration, it is possible to shorten the time required for the broadcast station search of a broadcast station whose frequency spectrum is symmetric with respect to the center frequency of the broadcast frequency band.

Embodiment 2. FIG.
In the second embodiment, when a frequency that may be an HD radio broadcast station is specified by the search method shown in the first embodiment, the frequency is stored in the external storage device 9 as a candidate for the HD radio broadcast station. save. Thereafter, when one more candidate frequency is specified, the frequency stored in the external storage device 9 and the broadcast station data of the newly specified frequency are received by the two

tuners

3a and 3b. Receive each one.

Since the basic configuration of the broadcast receiver according to the second embodiment is the same as that of the first embodiment, the broadcast receiver according to the second embodiment is replaced with a radio receiver for vehicles, that is, FIG. As an example, the configuration of the receiver will be described with reference to FIG.

Next, the operation will be described.
FIG. 11 is a flowchart showing the operation of the radio receiver according to Embodiment 2 of the present invention. FIG. 11 specifically shows the processing contents of steps ST1 to ST3, step ST5, step ST7, and step ST8 in the flowchart shown in FIG. 4 as an HD radio broadcast station search sequence. It is.

The search control unit 15 initializes the value of the counter k (k = 0) when a frequency that can be an HD radio broadcast station is specified in the broadcast station search sequence (step ST1a).
Next, when the search control unit 15 performs an HD radio broadcast station search sequence and identifies a frequency that is likely to be an HD radio broadcast station, the search control unit 15 obtains information indicating that the frequency and the frequency is an HD radio broadcast station. Save in the external storage device 9. At this time, the value of the counter k is incremented by 1 (k = k + 1) (step ST2a).

Thereafter, the search control unit 15 determines whether or not the counter k is “2” in the broadcast station search sequence, that is, whether or not two frequencies that may be HD radio broadcast stations are specified ( Step ST3a).
At this time, if the counter k is “2”, that is, two frequencies that are likely to be HD radio broadcast stations are specified (step ST3a; YES), the search control unit 15 includes the main tuner reception frequency setting unit 10 and The sub-tuner reception frequency setting unit 12 is controlled to tune the main tuner 3a and the sub-tuner 3b to receive the broadcast waves by tuning two frequencies that may be HD radio broadcast stations, The reception control unit 13 is instructed to acquire SIS data of the main tuner 3a and the sub tuner 3b.

The main tuner reception frequency setting unit 10 sets one of two frequencies that may be an HD radio broadcast station in the main tuner 3a in accordance with the instruction from the search control unit 15. In addition, the sub-tuner reception frequency setting unit 12 also sets the other of the two frequencies that may be an HD radio broadcast station in the sub-tuner 3b in accordance with the above instruction from the search control unit 15.
As a result, the main tuner 3a and the sub tuner 3b receive radio waves of frequencies that may include SIS data.

Next, the data reception control unit 13 controls the operation of the decoder unit 5 according to the instruction from the search control unit 15 to determine whether or not the SIS data of the frequencies of the main tuner 3a and the sub tuner 3b can be acquired. That is, it is determined whether or not SIS data can be received.

When the SIS data of the two frequencies cannot be received, the data reception control unit 13 determines that the two frequencies are analog broadcasting stations, and notifies the broadcasting station list creation unit 14 to that effect. In accordance with the notification indicating that the two frequencies are analog broadcast stations, the broadcast station list creation unit 14 adds the two frequencies to the broadcast station list as analog broadcast stations, and stores the broadcast station list in the external storage device 9. Save to.

In addition, when the SIS data of the two frequencies is acquired, since the two frequencies are HD radio broadcast stations, the decoder unit 5 creates a broadcast station list indicating that the two frequencies are HD radio broadcast stations. Notification to the unit 14. Upon receiving the above notification from the decoder unit 5, the broadcast station list creation unit 14 adds the two frequencies as HD radio broadcast stations to the broadcast station list, and stores the broadcast station list in the external storage device 9. At this time, the search control unit 15 initializes the value of the counter k (k = 0) (step ST4a).

When the value of the counter k is not “2”, that is, when two frequencies that can be HD radio broadcast stations are not specified (step ST3a; NO), or when the processing of step ST4a is completed, the search control unit 15 determines whether or not scanning has been completed for all frequencies in the frequency band to be searched (step ST5a).
At this time, if scanning has not been completed for all frequencies (step ST5a; NO), the search control unit 15 adds “+1” to the tuning execution order n of the main tuner 3a and the sub tuner 3b, that is, the tuning frequency. The setting is advanced by one step (step ST6a), and the process returns to step ST2a to continue the HD radio broadcast station search sequence.

On the other hand, if the scan is completed at all frequencies in the frequency band to be searched (step ST5a; YES), the search control unit 15 determines that the main value is equal to or greater than “0” (k> 0). The tuner receiving frequency setting unit 10 tunes the main tuner 3a to frequencies that may be HD radio broadcast stations that have been specified only once when scanning has been completed for all frequencies. While controlling to receive, it instructs the data reception control unit 13 to acquire the SIS data of the main tuner 3a.
The main tuner reception frequency setting unit 10 sets a frequency that may be an HD radio broadcast station in the main tuner 3a in accordance with the instruction from the search control unit 15. As a result, the main tuner 3a receives a radio wave having the above frequency that may include SIS data.

Next, the data reception control unit 13 controls whether the SIS data of the main tuner 3a has been acquired by controlling the operation of the decoder unit 5 according to the instruction from the search control unit 15, that is, the SIS data can be received. It is determined whether or not. When SIS data cannot be acquired at the above frequency, the data reception control unit 13 determines that the frequency is an analog broadcast station and notifies the broadcast station list creation unit 14 to that effect. Upon receiving notification that the frequency is an analog broadcast station, the broadcast station list creation unit 14 adds the frequency to the broadcast station list as an analog broadcast station, and stores the broadcast station list in the external storage device 9. save.

Also, when SIS data is acquired at the above frequency, since the frequency is an HD radio broadcast station, the decoder unit 5 notifies the broadcast station list creation unit 14 that the frequency is an HD radio broadcast station. Upon receiving the notification from the decoder unit 5, the broadcast station list creation unit 14 adds the frequency as an HD radio broadcast station to the broadcast station list and stores the broadcast station list in the external storage device 9. The process so far corresponds to step ST7a.

Thereafter, the display control unit 16 displays the broadcast station list stored in the external storage device 9 on the display unit 8 (step ST8a), and ends the broadcast station search.

As described above, according to the second embodiment, after the search control unit 15 determines the frequency of the search target broadcast station and then determines a new frequency as the frequency of the search target broadcast station, Is set in the main tuner 3a as a tuning frequency, and the other frequency is set in the sub-tuner 3b as a tuning frequency, and the

tuners

3a and 3b receive broadcast station data of both frequencies. In this way, when two possible frequencies of the HD radio broadcasting station are identified, the

tuners

3a and 3b receive the SIS data of the two frequencies, so that the method of the first embodiment is compared. Thus, the SIS data acquisition time can be reduced by half.

In the first and second embodiments, the case where the tuner performing the broadcast station search has one set of the main tuner 3a and the sub tuner 3b is shown, but two sets of the main tuner 3a and the sub tuner 3b are provided. You may use above. Even in this case, if a specific frequency is offset by a set of tuners for a broadcast station search, a broadcast station search similar to the above can be performed.

Further, in the first and second embodiments, the case where the broadcast station search method according to the present invention is applied to the search of the HD radio broadcast station is shown. However, in the broadcast station whose frequency spectrum is symmetrical with respect to the center frequency of the broadcast frequency band. If there is, it can be applied not only to the radio broadcast but also to the television broadcast. In the first and second embodiments, the case where the broadcast receiver according to the present invention is applied to an in-vehicle radio receiver is shown. However, the present invention can also be applied to a portable terminal having a broadcast reception function.

In the present invention, within the scope of the invention, any combination of each embodiment, any component of each embodiment can be modified, or any component can be omitted in each embodiment. .

The broadcast receiver according to the present invention can reduce the time required for searching for a broadcasting station such as an HD radio broadcast, and is therefore suitable for an in-vehicle radio receiver whose surrounding radio wave condition is likely to change due to vehicle travel.

1 radio receiver, 2a main antenna, 2b sub antenna, 3a main tuner, 3b sub tuner, 4 radio wave status detection unit, 5 decoder unit, 6 operation unit, 7 arithmetic control unit, 8 display unit, 9 external storage device, 10 Main tuner reception frequency setting unit, 11 radio wave condition determination unit, 12 sub tuner reception frequency setting unit, 13 data reception control unit, 14 broadcast station list creation unit, 15 search control unit, 16 display control unit.

Claims

Broadcast station search for broadcasting in which the frequency spectrum is symmetric with respect to the center frequency of the broadcast frequency band, and the difference between the electric field intensity level of the center frequency and the electric field intensity level of the adjacent frequency band symmetrically with respect to the center frequency is a predetermined value In a broadcast receiver that performs
A first tuner that receives radio waves by sequentially setting tuning frequencies of frequency bands to be searched;
A second tuner that receives radio waves by sequentially setting a tuning frequency obtained by offsetting the tuning frequency set in the first tuner by a frequency difference between the center frequency and the frequency band adjacent symmetrically with respect to the center frequency. When,
A radio wave condition determination unit that determines whether or not the difference in electric field strength level between the radio waves received by the first and second tuners is the predetermined value;
And a search control unit for determining the frequency of the broadcasting station from the frequency of the radio wave received by the first and second tuners based on the determination result by the radio wave state determination unit. Receiving machine.
After determining the frequency of the search target broadcast station, the search control unit determines a new frequency as the frequency of the search target broadcast station, and sets one frequency as a tuning frequency in the first tuner. 2. The second tuner as a tuning frequency is set in the second tuner, and broadcast station data of both frequencies is received by the first and second tuners. Broadcast receiver.
2. The broadcast receiver according to claim 1, wherein the broadcast is an HD (High Definition) radio broadcast.
A broadcast station of a broadcast wave in which the frequency spectrum is symmetric with respect to the center frequency of the broadcast frequency band, and the difference between the electric field intensity level of the center frequency and the electric field intensity level of the adjacent frequency band symmetrically with respect to the center frequency is a predetermined value In the search method,
Sequentially setting the tuning frequency of the frequency band to be searched to the first tuner and receiving radio waves;
The tuning frequency set for the first tuner is offset by the frequency difference between the center frequency and the adjacent frequency band symmetrically with respect to the center frequency, and the tuning frequency is sequentially set for the second tuner to receive radio waves. And steps to
Determining whether or not the difference in electric field strength level between the radio waves received by the first and second tuners is the predetermined value;
And a step of determining the frequency of the broadcast station from the frequency of the radio wave received by the first and second tuners based on the determination result.