Radio device, radio device control method, and program

Abstract

To evaluate the audio quality of radio broadcasts and appropriately switch radio audio in a radio device, such as an in-vehicle radio device.SOLUTION: A radio device includes: a receiving unit that receives digital radio signals which are radio signals of digital radio broadcasts, analog radio signals which are radio signals of analog radio broadcasts, and IP radio signals which are radio signals of IP radio broadcasts, which are simultaneously broadcasted; an evaluation unit that evaluates the sound quality of the analog radio audio using the digital radio audio based on the digital radio signals and the analog radio audio based on the analog radio signals; and a switch unit that switches the audio output of the digital radio audio to either the analog radio audio or the IP radio audio based in the IP radio signals, on the basis of the sound quality evaluation.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a radio device, a control method for a radio device, and a program. [Background technology]

[0002] Conventionally, in a car radio device, the signal reception environment changes as the vehicle in which the radio device is mounted moves, and therefore there is a demand for audio output control that takes such environmental changes into account.

[0003] Furthermore, radio devices receive broadcasts of the same content in different formats, and switch between these formats for output. For example, Patent Document 1 discloses a configuration in which, when the reception quality of a radio broadcast currently being received deteriorates, another radio broadcast that is simultaneously broadcasted is identified and switched to. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-108229 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, there are differences in the characteristics of simulcasts using different formats, so when switching between simulcasts, it is desirable to take into consideration the conditions and characteristics before and after the switch.

[0006] In view of the above-mentioned problems, the present disclosure aims to evaluate the audio quality of radio broadcasts and appropriately switch radio audio in a radio device such as an in-vehicle radio device. [Means for solving the problem]

[0007] The present disclosure provides a radio device having a receiving unit that receives digital radio signals that are radio signals for digital radio broadcasting, analog radio signals that are radio signals for analog radio broadcasting, and IP radio signals that are radio signals for IP radio broadcasting, all of which are in a simulcast relationship; an evaluation unit that performs a sound quality evaluation of the analog radio audio using digital radio audio based on the digital radio signals and analog radio audio based on the analog radio signals; and a switching unit that switches the audio output of the digital radio audio to either the analog radio audio or IP radio audio based on the IP radio signals based on the sound quality evaluation.

[0008] The present disclosure also provides a method for controlling a radio device, comprising: a receiving step of receiving a digital radio signal that is a radio signal for digital radio broadcasting, an analog radio signal that is a radio signal for analog radio broadcasting, and an IP radio signal that is a radio signal for IP radio broadcasting, all of which are simulcast; an evaluation step of evaluating the sound quality of the analog radio audio using digital radio audio based on the digital radio signal and analog radio audio based on the analog radio signal; and a switching step of switching the audio output of the digital radio audio to either the analog radio audio or the IP radio audio based on the IP radio signal, based on the sound quality evaluation.

[0009] The present disclosure also provides a program that causes a computer to execute the following steps: a receiving step of receiving a digital radio signal that is a radio signal for digital radio broadcasting, an analog radio signal that is a radio signal for analog radio broadcasting, and an IP radio signal that is a radio signal for IP radio broadcasting, all of which are simulcast; an evaluation step of evaluating the sound quality of the analog radio audio using digital radio audio based on the digital radio signal and analog radio audio based on the analog radio signal; and a switching step of switching the audio output of the digital radio audio to either the analog radio audio or the IP radio audio based on the IP radio signal, based on the sound quality evaluation.

[0010] Any combination of the above components, and conversion of the present disclosure into a method, device, system, storage medium, computer program, etc., are also valid aspects of the present disclosure. [Effects of the Invention]

[0011] According to the present disclosure, it is possible to evaluate the audio quality of radio broadcasts and appropriately switch radio audio in a radio device such as an in-car radio device. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a block diagram showing a configuration example of a radio device according to a first embodiment; [Figure 2] FIG. 1 is a block diagram showing an example of the configuration of a voice quality evaluation unit according to a first embodiment; [Figure 3] Conceptual diagram for explaining the evaluation of signal waveforms for each broadcast [Figure 4] Flowchart of audio output processing according to the first embodiment [Figure 5] Flowchart of analog radio quality evaluation processing according to the first embodiment [Figure 6] FIG. 1 is a graph illustrating an example of quality evaluation according to the first embodiment. [Figure 7] A block diagram showing an example of the configuration of a voice quality evaluation unit according to Modification 3. [Figure 8] A block diagram showing an example of the configuration of a voice quality evaluation unit according to Modification 4. [Figure 9] A block diagram showing an example of the configuration of a voice quality evaluation unit according to Modification 5. [Figure 10] A block diagram showing an example of the configuration of a voice quality evaluation unit according to Modification 6. [Figure 11] A block diagram showing an example of the configuration of a voice quality evaluation unit according to Modification 7. [Figure 12] FIG. 10 is a block diagram showing a configuration example of a radio device according to a second embodiment. [Figure 13] FIG. 10 is a block diagram showing another example of the configuration of a radio device according to the second embodiment. [Figure 14]FIG. 10 is a block diagram showing another example of the configuration of a radio device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, with appropriate reference to the accompanying drawings, embodiments specifically disclosing a radio device, a radio device control method, and a program according to the present disclosure will be described in detail. However, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters or redundant description of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

[0014] (Inventor's knowledge) With the recent trend toward more sophisticated and electrified automobiles, noise emitted from vehicles and in-vehicle equipment can interfere with radio signals and degrade radio signal reception. For example, analog radio broadcasts are prone to sound quality degradation due to external factors such as multipath interference, adjacent interference, vehicle noise, and external noise. In contrast, digital radio broadcasts are more noise-resistant and less affected by vehicle noise, but they tend to have a smaller reception area than analog radio broadcasts. When a car radio is outputting digital radio broadcasts, reception conditions can deteriorate rapidly when the car attempts to leave the reception area. In such cases, switching to analog radio broadcasts, which have a wider reception area and are simultaneously broadcast, can be considered as a sound source. However, due to the influence of noise, switching to analog radio broadcasts may not be optimal in terms of sound quality under certain circumstances. More specifically, when digital radio broadcast reception conditions deteriorate, switching to analog radio broadcasts may also result in poor analog radio reception conditions. In such cases, the quality of the audio output remains poor both before and after the switch.

[0015] For example, when switching between digital and analog radio broadcasts, the digital service identifier and the analog identifier can be used to switch between simulcasts. However, if the switching is based solely on the identifier information, the audio quality after the switch cannot be guaranteed, and there may be a large difference in sound quality before and after the switch.

[0016] <First Embodiment> [Device configuration] FIG. 1 is a block diagram showing an example of the configuration of a radio device according to the first embodiment. Radio device 100 according to this embodiment is configured to be able to receive analog radio broadcasts, digital radio broadcasts, and IP radio broadcasts, and to switch between any of them to output audio. Analog radio broadcasts, digital radio broadcasts, and IP radio broadcasts each include radio signals corresponding to multiple services, and a selected service from among these is output as audio. In this embodiment, it is assumed that at least some of the analog radio broadcasts, digital radio broadcasts, and IP radio broadcasts corresponding to multiple services are in a simulcast relationship, in which the same content is broadcast.

[0017] Generally, digital radio broadcasts have high noise resistance and good audio quality within their reception area, but tend to suffer from a deterioration in sound quality, such as sudden sound cutoff, once outside the reception area. Analog radio broadcasts, on the other hand, have a wider reception area than digital radio broadcasts, and may be able to output audio even in locations where digital radio broadcasts cannot be received. However, analog radio broadcasts are more susceptible to environmental influences and tend to have worse audio quality than digital radio broadcasts.

[0018] IP radio broadcasting also offers high audio quality and may be able to output audio outside the coverage area of ​​digital or analog radio broadcasting.However, IP radio broadcasting has longer delays than digital or analog radio broadcasting, and there may be costs associated with using it, such as paying fees.

[0019] Taking into consideration the characteristics of each radio broadcast as described above, the radio device 100 according to this embodiment has a configuration for switching the audio output of each radio broadcast.

[0020] The radio device 100 according to this embodiment is assumed to be, for example, an in-vehicle radio device mounted in a vehicle (not shown) and configured to be operable by a user. The in-vehicle radio device may be configured as a single device that outputs radio signals, or may be configured as one function of a so-called navigation device. The term "vehicle" is not limited to a passenger car, but may refer to any mobile object, such as a motorcycle, bus, or truck. The configuration shown in FIG. 1 is an example, and one component may be divided into multiple components, or multiple components may be integrated into one component. Only components related to the functions of this embodiment are shown here, and the device may be configured to provide other functions.

[0021] Antenna 101 receives radio signals related to analog radio broadcasting and transmits them to analog radio receiving unit 102. Antenna 101 receives analog radio broadcasting radio signals in a predetermined frequency band transmitted from a nearby base station, but the frequency band and standard are not particularly limited. Antenna 104 receives radio signals related to digital radio broadcasting and transmits them to digital radio receiving unit 105. Antenna 107 receives radio signals related to IP radio broadcasting and transmits them to IP radio receiving unit 108.

[0022] The analog radio receiving unit 102 performs filtering and A / D conversion on the received radio signal for analog radio broadcasting, and provides the result to the analog demodulation unit 103. The digital radio receiving unit 105 performs filtering and A / D conversion on the received radio signal for digital radio broadcasting, and provides the result to the digital demodulation unit 106. The IP radio receiving unit 108 performs filtering and A / D conversion on the received radio signal for IP radio broadcasting, and provides the result to the IP demodulation unit 109.

[0023] The analog demodulation unit 103 acquires and demodulates a radio signal of a frequency specified by a user's station selection, etc., from the analog radio signals received by the analog radio receiving unit 102. Acquiring a radio signal of a specified frequency is sometimes called filtering. The analog demodulation unit 103 then transmits the demodulated analog radio signal as analog radio audio to the audio quality evaluation unit 110 and audio source switching unit 111. The analog demodulation unit 103 may also perform noise identification and noise removal processing.

[0024] The digital demodulation unit 106 acquires and demodulates a radio signal of a frequency specified by a user's station selection, etc., from among the digital radio signals received by the digital radio receiving unit 105. The digital demodulation unit 106 then transmits the demodulated digital radio signal as digital radio audio to the audio quality evaluation unit 110 and the audio source switching unit 111. The digital demodulation unit 106 may further perform noise identification and noise removal processing.

[0025] The IP demodulation unit 109 acquires a radio signal of a frequency specified by a user's station selection, etc., from the IP radio signals received by the IP radio receiving unit 108, and demodulates the received radio signal. Then, the IP demodulation unit 109 transmits the demodulated IP radio signal to the sound source switching unit 111 as IP radio audio.

[0026] The sound quality evaluation unit 110 evaluates the sound quality of the analog radio sound received from the analog demodulation unit 103 based on the digital radio sound received from the digital demodulation unit 106. Then, the sound quality evaluation unit 110 outputs sound quality evaluation information to the sound source switching unit 111 as the evaluation result of the analog radio sound.

[0027] The sound source switching unit 111 controls switching of the sound source to be output from among the acquired analog radio audio, digital radio audio, and IP radio audio, and outputs the audio to the audio output unit 112. Although details will be described later, in this embodiment, when the reception conditions of the digital radio audio deteriorate, the sound source to be switched to is determined based on sound quality evaluation information from the audio quality evaluation unit 110. The audio output unit 112 outputs the acquired radio audio using a speaker or the like.

[0028] Each block shown in FIG. 1 may be realized by, for example, a control unit or a storage unit (not shown). The control unit (not shown) may be configured using, for example, a central processing unit (CPU), a micro processing unit (MPU), a digital signal processor (DSP), a graphical processing unit (GPU), or a field programmable gate array (FPGA). The storage unit (not shown) is a storage area for storing and holding various data, and may be configured, for example, by a non-volatile storage area such as a read only memory (ROM) or a hard disk drive (HDD), or a volatile storage area such as a random access memory (RAM). For example, the control unit may realize some or all of the functions of the blocks shown in FIG. 1 by reading and executing various data and programs stored in the storage unit.

[0029] 1, a storage unit may be provided that stores and manages, for a certain period of time, the radio signal before demodulation by the analog demodulation unit 103, the digital demodulation unit 106, and the IP demodulation unit 109 or the demodulated radio audio. The audio quality evaluation unit 110 may then perform audio quality evaluation using the stored radio audio.

[0030] (Speech Quality Evaluation Section) 2 is a block diagram showing an example of the configuration of the sound quality evaluation unit 110 according to this embodiment. The sound quality evaluation unit 110 receives analog radio audio and digital radio audio corresponding to analog radio broadcasting and digital radio broadcasting, respectively, which are simulcast together, and outputs sound quality evaluation information for the input analog radio audio.

[0031] The audio quality evaluation unit 110 includes a time offset correction unit 201, a correlation derivation unit 202, and a threshold determination unit 203. The time offset correction unit 201 derives the time offset between analog radio audio and digital radio audio and corrects this time offset. Generally, digital radio audio takes longer to demodulate, so it tends to be delayed. Furthermore, because analog radio audio and digital radio audio are the same content, their waveform characteristics are similar. Therefore, by capturing these characteristics, it is possible to identify the time offset. Note that a known method can be used to derive the time offset, and a detailed description thereof will be omitted here.

[0032] The correlation derivation unit 202 calculates the dot product of the analog radio audio and the digital radio audio whose time offset has been corrected by the time offset correction unit 201. FIG. 3 is a diagram showing examples of analog radio audio 300 and digital radio audio 310. The analog radio audio 300 and the digital radio audio 310 are audio signals whose time offset has been corrected, and are assumed to be the same content. The analog radio audio 300 includes an audio signal 301, residual noise 302, and periodic noise 303. The digital radio audio 310 includes an audio signal 311 and residual noise 302. The degree of waveform similarity is calculated by taking the dot product of these. The correlation derivation unit 202 then outputs the calculated degree of similarity to the threshold determination unit 203.

[0033] The threshold determination unit 203 compares the degree of match calculated by the correlation derivation unit 202 with a predetermined threshold to evaluate the sound quality of the analog radio audio. As described above, digital radio broadcasts have high resistance to noise. Therefore, when comparing the digital radio audio and analog radio audio of the same content, if the degree of match is low, it can be assumed that noise is superimposed on the analog radio audio. A threshold is set in advance taking into account the level of that noise, and if the degree of match is below the threshold, the quality of the analog radio audio is deemed to be low. By making this determination, the threshold determination unit 203 obtains sound quality evaluation information for the analog radio audio and outputs it to the sound source switching unit 111.

[0034] [Processing flow] Fig. 4 illustrates a flowchart of the switching process according to this embodiment. This process flow is realized by the cooperation of the blocks of radio device 100 shown in Fig. 1, but for simplicity, the process will be described collectively as being performed by radio device 100.

[0035] In this example, we will assume that analog radio broadcasting, digital radio broadcasting, and IP radio broadcasting, which are simulcasts, are receivable and that a switch is being made from a digital radio broadcast that is currently outputting audio. Whether or not a corresponding simulcast is available for each radio broadcast may be determined, for example, based on identification information assigned to each radio signal. This processing flow is also executed repeatedly at predetermined time intervals.

[0036] The radio device 100 receives radio signals of radio broadcasts for a certain service content (step S401). The service content here may be specified by a user using a user interface provided in the radio device 100, or the radio device 100 may select any service according to the user's preferences.

[0037] The radio device 100 determines whether the reception status of the digital radio broadcasting among the radio signals received in step S401 is good (step S402). If the reception status of the digital radio broadcasting is good (step S402: YES), the processing of the radio device 100 proceeds to step S409. On the other hand, if the reception status of the digital radio broadcasting is not good (step S402: NO), the processing of the radio device 100 proceeds to step S403.

[0038] The radio device 100 determines whether the reception status of the analog radio broadcasting among the radio signals received in step S401 is good or not (step S403). If the reception status of the analog radio broadcasting is good (step S403: YES), the processing of the radio device 100 proceeds to step S404. On the other hand, if the reception status of the analog radio broadcasting is not good (step S403: NO), the processing of the radio device 100 proceeds to step S406.

[0039] The radio device 100 executes a sound quality evaluation process for the analog radio sound (step S404). Details of this process will be described later with reference to Fig. 5. After that, the process of the radio device 100 proceeds to step S405.

[0040] The radio device 100 determines whether the sound quality of the analog radio audio is good or not based on the sound quality evaluation information obtained in the sound quality evaluation process of step S404 (step S405). If the sound quality of the analog radio audio is good (step S405: YES), the process of the radio device 100 proceeds to step S408. On the other hand, if the sound quality of the analog radio audio is not good (step S405: NO), the process of the radio device 100 proceeds to step S406.

[0041] The radio device 100 determines whether the reception status of IP radio broadcasting, among the radio signals received in step S401, is good (step S406). Note that the user of the radio device 100 may set whether or not IP radio broadcasting is available, taking into account factors such as the need to pay fees. In such cases, it may also be determined whether or not IP radio broadcasting is available. If the reception status of IP radio broadcasting is good (step S406: YES), the processing of the radio device 100 proceeds to step S407. On the other hand, if the reception status of IP radio broadcasting is not good (step S406: NO), the processing of the radio device 100 proceeds to step S408. In this embodiment, if the reception status of analog radio broadcasting is not good and the reception status of IP radio broadcasting is also not good, the sound source is switched to analog radio audio to prevent the audio output from becoming silent.

[0042] The radio device 100 switches the sound source to output IP radio sound (step S407), and then ends this processing flow.

[0043] The radio device 100 switches the sound source to output analog radio sound (step S408), and then ends this processing flow.

[0044] The radio device 100 switches the sound source to output digital radio audio (step S409). If digital radio audio is already being output, the audio output is continued. Then, this processing flow ends.

[0045] (Analog radio audio quality evaluation processing) 5 is a flowchart of the analog radio sound quality evaluation process according to this embodiment. This process corresponds to step S404 in FIG.

[0046] The radio device 100 determines whether or not it can receive digital radio broadcast radio signals (step S501). The determination of whether or not it can receive digital radio broadcast radio signals may be made based on whether or not it can receive digital radio broadcast radio signals at a signal level that is to be used as a reference for deriving a degree of match, which will be described later. The digital radio broadcast radio signals received here may be radio signals within a predetermined range going back a certain period from the present time. In this case, the radio signals within this range may be stored and managed in a storage unit (not shown). If it can receive digital radio broadcast radio signals (step S501: YES), the processing of the radio device 100 proceeds to step S502. On the other hand, if it cannot receive digital radio broadcast radio signals (step S501: NO), the processing of the radio device 100 proceeds to step S510.

[0047] The radio device 100 demodulates the received radio signal of the digital radio broadcast and acquires the digital radio sound (step S502).

[0048] The radio device 100 determines whether or not it can receive analog radio broadcast signals (step S503). The determination of whether or not it can receive analog radio broadcast signals may be based on whether or not it can receive analog radio broadcast signals at a signal level that can be used as a target for evaluation and determination in order to derive a degree of match, which will be described later. Furthermore, the analog radio broadcast signals received here may be radio signals within a predetermined range going back a certain period from the present time, similar to the digital radio broadcast signals in step S501. In this case, the radio signals within this range may be stored and managed in a storage unit (not shown). If it can receive analog radio broadcast signals (step S503: YES), the process of the radio device 100 proceeds to step S504. On the other hand, if it cannot receive analog radio broadcast signals (step S503: NO), the process of the radio device 100 proceeds to step S510.

[0049] The radio device 100 demodulates the received analog radio broadcast radio signal to obtain analog radio audio (step S504).

[0050] The radio device 100 corrects the time difference between the digital radio audio acquired in step S502 and the analog radio audio acquired in step S504 (step S505). As described above, since the digital radio audio and the analog radio audio have the same content, it can be assumed that the waveform characteristics are the same. Therefore, by comparing the respective waveform characteristics, the time difference can be identified and corrected.

[0051] The radio device 100 derives the degree of match between the digital radio audio and analog radio audio whose time offset has been corrected in step S505 (step S506). The degree of match can be derived by taking the dot product of the waveform signals of the digital radio audio and analog radio audio.

[0052] The radio device 100 determines whether the degree of match calculated in step S506 is equal to or greater than a predetermined threshold (step S507). If the degree of match is equal to or greater than the threshold (step S507: YES), the process of the radio device 100 proceeds to step S508. On the other hand, if the degree of match is smaller than the threshold (step S507: NO), the process of the radio device 100 proceeds to step S509.

[0053] The radio device 100 determines that the sound quality of the analog radio sound as the switching destination candidate is "good" (step S508), and then ends this processing flow, and proceeds to step S405 in FIG.

[0054] The radio device 100 determines that the sound quality of the analog radio sound as the switching destination candidate is "poor" (step S509), and then ends this processing flow, and proceeds to step S405 in FIG.

[0055] The radio device 100 determines that the audio quality of the analog radio audio as a candidate for switching is "unknown" (step S510). In other words, if either the digital radio or the analog radio for evaluating audio quality cannot be received, the evaluation result is "unknown." In this embodiment, if the evaluation result is "unknown," it is treated as a "YES" determination in the subsequent step S405 in FIG. 4. However, this is not a limitation, and for example, the determination in step S405 in FIG. 4 may be "NO" based on user settings, etc. Then, this processing flow ends, and the process proceeds to step S405 in FIG. 4.

[0056] (Variation 1) In the above configuration, an example is shown in which sound quality is evaluated based on the degree of match between analog radio audio and digital radio audio, but this is not limiting.Furthermore, sound quality may also be evaluated by combining the signal strength of the analog radio audio.

[0057] FIG. 6 is a graph illustrating changes in the strength of a radio signal in an analog radio broadcast. In FIG. 6, the vertical axis represents the signal strength of the radio signal, and the horizontal axis represents the passage of time. There is a certain correlation between the signal strength of a radio signal and audio quality; the higher the signal strength, the higher the audio quality. Therefore, a threshold value Th may be used to determine the likelihood of a sound quality evaluation result for analog radio audio. For example, if the signal strength of the analog radio audio used in the sound quality evaluation exceeds the threshold, the likelihood of the sound quality evaluation result may be considered high. On the other hand, if the signal strength of the analog radio audio used in the sound quality evaluation is below the threshold, the likelihood of the sound quality evaluation result may be considered low.

[0058] The sound source to be switched to may then be adjusted based on the likelihood of the sound quality evaluation result. Note that multiple thresholds may be used to determine the likelihood in stages according to the thresholds. The thresholds in this case may be the same as the thresholds used to determine whether analog radio audio can be received in step S503 of FIG. 5.

[0059] The rate of change in signal strength may also be combined to evaluate sound quality. For example, as shown in graph 610 of FIG. 6, the signal strength of the analog radio audio temporarily falls below threshold Th after time tb. However, since the signal strength of the analog radio audio subsequently exceeds threshold Th and returns to a good state, the quality of the analog radio audio is good and switching to IP radio audio may not be necessary. In this way, combining changes in the signal strength of the analog radio audio over a certain period of time enables more appropriate switching.

[0060] (Variation 2) In the above processing, the quality evaluation is performed using the degree of match based on the dot product of the analog radio audio and the digital radio audio in the audio quality evaluation unit 110. Alternatively, the quality evaluation may be performed based on the difference between the analog radio audio and the digital radio audio, i.e., the error signal.

[0061] 3, subtraction of analog radio audio 300 from digital radio audio 310 results in error signal 320. Error signal 320 contains residual noise 321 and periodic noise 322. The quality of the analog radio audio is evaluated depending on the extent to which such noise is contained in the signal.

[0062] First, the audio quality evaluation unit 110 calculates the signal strength at a predetermined interval for the error signal obtained by subtraction. Similarly, the audio quality evaluation unit 110 calculates the signal strength at the above-mentioned predetermined interval for the radio signal of the digital radio audio. The signal strength power for the signal can be calculated, for example, using the following equation (1):

[0063]

number

[0064] Furthermore, the audio quality evaluation unit 110 calculates the S / N (signal-to-noise ratio) from the signal strength power_N of the error signal and the signal strength power_S of the digital radio signal, and compares this S / N with a predetermined threshold to evaluate the quality of the analog radio audio. Specifically, if power_S / power_N is greater than a predetermined threshold, the audio quality of the analog radio signal may be determined to be high. The audio quality evaluation unit 110 then outputs the sound quality evaluation information of the analog radio audio determined in this way to the audio source switching unit 111, thereby enabling appropriate audio source switching.

[0065] (Variation 3) In the second modification, an example of sound quality evaluation based on an error signal between analog radio audio and digital radio audio was shown. As shown in Fig. 3, the error signal 320 may contain periodic noise 322 that can adversely affect sound quality. When the periodic noise appears as a relatively small value, there is a possibility that the influence of the periodic noise cannot be properly considered when evaluating quality using only the S / N ratio. Therefore, the third modification is configured to further capture periodic noise and evaluate sound quality.

[0066] 7 is a block diagram showing an example configuration of a sound quality evaluation unit 700 according to Modification 3. The sound quality evaluation unit 700 includes a time offset correction unit 701, a subtraction unit 702, a threshold determination unit 703, an autocorrelation unit 704, and a threshold determination unit 705. The time offset correction unit 701 derives the time offset between the analog radio audio and the digital radio audio and corrects this time offset. The subtraction unit 702 subtracts the analog radio audio from the digital radio audio and outputs an error signal as the difference between these two audio signals.

[0067] Threshold value determination unit 703 derives the signal strength and S / N based on the error signal obtained by subtraction unit 702, and performs sound quality evaluation. The processing here is the same as in Modification 2. Threshold value determination unit 703 then outputs the evaluation result of the quality of the analog radio audio based on the signal strength.

[0068] The autocorrelation unit 704 detects the periodicity of the waveform by performing autocorrelation on the error signal obtained by the subtraction unit 702. The period for determining whether or not periodic noise is present is not particularly limited, and may be a predetermined time width. For example, a waveform such as periodic noise 322 shown in FIG. 3 may be detected. A known method may be used for the autocorrelation of the waveform, and a detailed description thereof will be omitted here.

[0069] The threshold determination unit 705 compares the periodic noise obtained by the autocorrelation unit 704 with a preset threshold to determine the quality of the analog radio audio. If the level of the periodic noise exceeds the threshold, the quality of the analog radio audio is considered to be low. The threshold determination unit 705 then outputs an evaluation result of the quality of the analog radio audio based on the autocorrelation.

[0070] (Variation 4) In the third modification, an example was shown in which an error signal between analog radio audio and digital radio audio obtained by subtraction unit 702 is used. Furthermore, in the fourth modification, an example in which an adaptive filter is used will be described. It is assumed that the frequency characteristics of analog radio audio and digital radio audio differ. Therefore, a modification will be described in which the error signal is obtained after frequency characteristic correction is performed so that these frequency characteristics match.

[0071] Fig. 8 is a block diagram showing an example of the configuration of a sound quality evaluation section 800 according to this modification 4. The difference between the sound quality evaluation section 700 of Fig. 7 shown in modification 3 and the sound quality evaluation section 800 according to this modification 4 is that an adaptive filter 802 is provided instead of the subtraction section 702. The configurations of the time lag correction section 801, threshold determination section 803, autocorrelation section 804, and threshold determination section 805 of the sound quality evaluation section 800 are the same as in modification 3.

[0072] Adaptive filter 802 performs frequency characteristic correction on the digital radio audio so that the frequency characteristics approach those of the analog radio audio. A known technique may be used for this correction method, and although detailed description will be omitted here, the correction is performed based on the relationship between the frequency characteristics of the analog radio audio and the digital radio audio. After performing frequency characteristic correction, adaptive filter 802 then performs subtraction processing on the analog radio audio and the digital radio audio to derive an error signal. The subsequent processing is the same as in Modification 3.

[0073] (Variation 5) A radio signal may be configured as a stereo signal with a right channel R and a left channel L. In such a configuration, there is a concern that processing each channel would increase the processing load. Therefore, a fifth modification will be described, in which the signals of these two channels are converted into a monaural signal, i.e., a sum signal, and then processed.

[0074] Fig. 9 is a block diagram showing an example of the configuration of a sound quality evaluation unit 900 according to Modification 5. The difference between the sound quality evaluation unit 800 of Fig. 8 shown in Modification 4 and the sound quality evaluation unit 900 according to Modification 5 is that a monaural conversion unit 901 has been newly added. The configurations of the time lag correction unit 902, adaptive filter 903, threshold determination unit 904, autocorrelation unit 905, and threshold determination unit 906 of the sound quality evaluation unit 900 are the same as those of Modification 4.

[0075] The monaural conversion unit 901 combines the right channel R and left channel L of the analog radio audio, which is a stereo signal, and outputs the combined signal as a monaural signal to the time lag correction unit 902. Similarly, the monaural conversion unit 901 combines the right channel R and left channel L of the digital radio audio, which is a stereo signal, and outputs the combined signal as a monaural signal to the time lag correction unit 902. The subsequent processing is the same as in the fourth modification.

[0076] (Variation 6) In Modifications 4 and 5, configuration examples were shown in which frequency characteristics are corrected using an adaptive filter. Such adaptive filters require a certain amount of time for correction. In particular, the greater the difference in frequency characteristics, the greater the correction load. Therefore, in Modification 6, a configuration is described in which the high frequency portion of the digital radio signal is removed to bring the frequency characteristics closer to those of analog radio audio in order to reduce the load of the correction process using the adaptive filter.

[0077] Fig. 10 is a block diagram showing an example of the configuration of a sound quality evaluation unit 1000 according to Modification 6. The difference between the sound quality evaluation unit 900 of Fig. 9 shown in Modification 5 and the sound quality evaluation unit 1000 according to Modification 6 is that a low-pass filter 1003 is newly added. The configurations of the monaural conversion unit 1001, time offset correction unit 1002, adaptive filter 1004, threshold determination unit 1005, autocorrelation unit 1006, and threshold determination unit 1007 of the sound quality evaluation unit 1000 are the same as those of Modification 5.

[0078] Low-pass filter 1003 cuts off a predetermined high-frequency band of the digital radio audio. The frequency band to be cut here is determined based on the frequency characteristics of the analog radio audio and the digital radio audio. Low-pass filter 1003 then outputs the processed digital radio audio to adaptive filter 1004. In this configuration, the digital radio audio passes through low-pass filter 1003, causing a delay relative to the analog radio audio. Therefore, a delay process equivalent to the delay of the digital radio audio by low-pass filter 1003 is applied to the analog radio audio, thereby synchronizing the two. In this case, the delay process for the analog radio audio may be performed by a delay circuit (not shown). The subsequent processing is the same as in Modification 5.

[0079] (Variation 7) 2, the configuration for evaluating the quality of analog radio audio using the degree of coincidence obtained by the dot product of analog radio audio and digital radio audio has been described. However, it is also possible to combine this with the configuration of Modification 6.

[0080] Fig. 11 is a block diagram showing an example of the configuration of a sound quality evaluation unit 1100 according to Modification 7. The sound quality evaluation unit 110 explained using Fig. 2 and the sound quality evaluation unit 1000 of Fig. 10 shown in Modification 6 are configured in parallel. The processing of each component is the same as in the above configuration. Therefore, the sound quality of analog radio sound is evaluated from three viewpoints.

[0081] If the cross-correlation between the analog radio signal and the digital radio signal is used when deriving the time offset in time offset correction section 1102, the correlation between these signals is known from the result of time offset correction section 1102, and therefore correlation derivation section 1108 may be omitted. In this case, the correlation information obtained in time offset correction section 1102 is directly input to threshold value determination section 1109 and used.

[0082] When sound quality evaluation is performed from multiple perspectives, as in each of the modified examples, a comprehensive evaluation of the analog radio sound may be performed by, for example, weighting the respective results. Alternatively, a priority may be defined for each sound quality evaluation item, and a comprehensive evaluation may be performed based on that priority.

[0083] [Examples of system configurations according to region] The broadcast configuration of each radio broadcast may differ depending on the region. Below, we will show example configurations of radio devices that assume combinations of radio broadcasts from various regions. Here, we will show an example using the sound quality evaluation unit 1000 in Figure 10 shown in Modification 6.

[0084] 12 shows an example configuration of a radio device 1200 that can be used in areas where hybrid radio broadcasting is used, which transmits and receives both analog and digital radio broadcast signals as a set. An example of a hybrid radio broadcasting system is the In-Band On-Channel (IBOC) system, typified by Hybrid Digital (HD) radio. This system transmits both analog and digital radio broadcasts using the frequencies of existing AM / FM analog broadcasts.

[0085] Radio device 1200, which is designed for such an environment, receives a hybrid radio signal via antenna 1201 and transmits it to hybrid radio receiver 1202. Hybrid radio receiver 1202 extracts the analog radio broadcast radio signal and the digital radio broadcast radio signal from the received radio signal, and outputs them to analog demodulator 1203 and digital demodulator 1204.

[0086] Antenna 1205 receives radio signals related to IP radio broadcasting and transmits them to IP radio receiving unit 1206. IP radio receiving unit 1206 performs filtering, A / D conversion, etc. on the received radio signals and provides them to IP demodulation unit 1207. The subsequent configurations and processes are assumed to be the same as those described in Figures 1 and 10, and therefore will not be described here.

[0087] With this configuration, it is possible to appropriately switch, for example, from an AM digital radio broadcast to an AM analog radio broadcast of the same content, and similarly, it is possible to appropriately switch from an FM digital radio broadcast to an FM analog radio broadcast of the same content.

[0088] 13 shows an example of the configuration of a radio device 1300 that can be used in areas where FM analog radio broadcasting and the corresponding digital radio broadcasting (DAB: Digital Audio Broadcast) are used. Apart from the configuration of an FM radio receiving unit 1302 and a DAB receiving unit 1305 that receive radio signals, the configuration may be the same as that shown in FIG.

[0089] With this configuration, it is possible to appropriately switch, for example, from a DAB digital radio broadcast to an FM analog radio broadcast of the same content.

[0090] The above configuration example has been described using an example of switching from digital radio broadcasting to radio broadcasting of another format. However, the configuration according to the present disclosure can also be applied to switching control when, for example, between two analog radio broadcasts with the same service content, one analog radio broadcast has higher noise resistance and higher sound quality.

[0091] For example, there are cases where both AM analog radio broadcasting and FM analog radio broadcasting are used, with FM analog radio broadcasting having higher noise resistance and sound quality. On the other hand, there are cases where AM analog radio broadcasting has a wider reception area. Fig. 14 shows an example configuration of a radio device 1400 that can be used in such areas. Apart from the configuration of AM radio receiving unit 1402 and FM radio receiving unit 1405 that receive radio signals, the configuration may be the same as that shown in Fig. 12. In this case, the FM analog radio broadcasting is treated as the digital radio broadcasting in the above example, and switching processing is performed.

[0092] As described above, a radio device (e.g., 100) according to this embodiment includes receiving units (e.g., 101, 102, 104, 105, 107, 108) that receive digital radio signals that are radio signals for digital radio broadcasting, analog radio signals that are radio signals for analog radio broadcasting, and IP radio signals that are radio signals for IP radio broadcasting, all of which are simulcast; an evaluation unit (e.g., 110) that evaluates the sound quality of the analog radio audio using digital radio audio based on the digital radio signals and analog radio audio based on the analog radio signals; and a switching unit (e.g., 111) that switches the audio output of the digital radio audio to either analog radio audio or IP radio audio based on the IP radio signals based on the sound quality evaluation. This configuration enables a radio device, such as one mounted in a vehicle, to evaluate the audio quality of radio broadcasting and appropriately switch the radio audio.

[0093] In addition, in the radio device, the switching unit may switch to analog radio audio if the sound quality evaluation determines that the sound quality of the analog radio audio is good, and switch to IP radio audio if the sound quality evaluation determines that the sound quality of the analog radio audio is poor. With this configuration, if the quality of the analog radio audio has deteriorated, it is possible to omit switching the audio output to analog radio audio and switch directly to IP radio audio.

[0094] In addition, in the radio device, the evaluation unit may derive a degree of match between the analog radio audio and the digital radio audio, and if the degree of match is equal to or greater than a predetermined threshold, evaluate the sound quality of the analog radio audio as good. With this configuration, by using the degree of match between the analog radio audio and the digital radio audio, which are more likely to contain noise, it is possible to appropriately evaluate the sound quality of the analog radio audio.

[0095] Furthermore, in the radio device, the evaluation unit may evaluate the sound quality of the analog radio audio as good if the signal strength of noise contained in the error signal between the analog radio audio and the digital radio audio is smaller than a predetermined threshold. With this configuration, by using the error signal between the analog radio audio and the digital radio audio, which is more likely to contain noise, it is possible to appropriately evaluate the sound quality of the analog radio audio. In particular, it is possible to appropriately capture residual noise contained in the analog radio audio and evaluate the sound quality.

[0096] In addition, in the radio device, the evaluation unit may derive periodic noise contained in an error signal between the analog radio audio and the digital radio audio, and if the periodic noise is smaller than a predetermined threshold, evaluate the sound quality of the analog radio audio as good. With this configuration, it is possible to appropriately capture the periodic noise contained in the analog radio audio and evaluate the sound quality.

[0097] In addition, in the radio device, the evaluation unit may calculate the error signal after correcting the frequency characteristics of the analog radio audio and the digital radio audio so that they match. With this configuration, it is possible to improve the evaluation accuracy by correcting the difference between the frequency characteristics of the analog radio audio and the frequency characteristics of the digital radio audio before performing the quality evaluation.

[0098] In addition, in the radio device, the evaluation unit may apply a low-pass filter corresponding to analog radio audio to the digital radio audio and then correct the frequency characteristics. This configuration makes it possible to reduce the processing load and processing time required to correct the difference between the frequency characteristics of the analog radio audio and the frequency characteristics of the digital radio audio.

[0099] In addition, in the radio device, the analog radio audio and the digital radio audio may be stereo signals, and the evaluation unit may convert each of the analog radio audio and the digital radio audio into a monaural signal before evaluating the sound quality. This configuration makes it possible to reduce the processing load and processing time involved in evaluating the sound quality of the analog radio audio, which is a stereo signal.

[0100] In addition, in the radio device, the switching unit may switch to either analog radio audio or IP radio audio based on a sound quality evaluation when the reception conditions of the digital radio broadcast deteriorate. With this configuration, the higher quality digital radio broadcast is normally output as audio priority, and when the reception conditions of the digital radio broadcast deteriorate, the switching unit switches to another radio broadcast, thereby improving the performance of the radio device for the user.

[0101] In addition, in the radio device, the switching unit may switch to analog radio audio when the reception conditions for digital radio broadcasting, analog radio broadcasting, and IP radio broadcasting have all deteriorated. With this configuration, it is possible to prevent silent audio output even when the reception conditions for any radio broadcast have deteriorated.

[0102] <Other embodiments> In the above embodiment, switching from digital radio audio to another radio audio has been described as an example. However, this is not limiting and other switching applications are also possible. For example, the present invention may be applied to switching when an IP radio broadcast is being output. The radio audio of an analog radio broadcast that is simulcast with the IP radio broadcast being output may be compared with the IP radio audio, and control may be exercised as to whether to switch to the analog radio audio. This makes it possible to seamlessly switch to another simulcast based on audio quality, for example, when it is desirable to minimize the payment of fees for IP radio use.

[0103] In addition, the functions of one or more of the above-described embodiments can be realized by supplying a program and application to a system or device via a network or storage medium, and having one or more processors in the computer of the system or device read and execute the program.

[0104] Alternatively, the functions may be realized by a circuit that realizes one or more functions (for example, an Application Specific Integrated Circuit (ASIC) or a Field Programmable Gate Array (FPGA)).

[0105] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present disclosure is not limited to these examples. It is clear to those skilled in the art that various modifications, alterations, substitutions, additions, deletions, and equivalents may be made within the scope of the claims, and it is understood that these also fall within the technical scope of the present disclosure. Furthermore, the components of the various embodiments described above may be combined in any manner without departing from the spirit of the invention.

[0106] (Addendum) The above description of the embodiments discloses the following techniques. (Technology 1) a receiving unit that receives a digital radio signal that is a radio signal for digital radio broadcasting, an analog radio signal that is a radio signal for analog radio broadcasting, and an IP radio signal that is a radio signal for IP radio broadcasting, all of which are in a simulcast relationship; an evaluation unit that evaluates the sound quality of the analog radio audio using digital radio audio based on the digital radio signal and analog radio audio based on the analog radio signal; a switching unit that switches the audio output of the digital radio audio to either the analog radio audio or the IP radio audio based on the IP radio signal based on the sound quality evaluation; A radio device having: According to this configuration, it becomes possible to evaluate the audio quality of radio broadcasts and appropriately switch radio audio in a car-mounted radio device or the like.

[0107] (Technology 2) The switching unit is If the sound quality evaluation determines that the sound quality of the analog radio sound is good, switching to the analog radio sound; The radio device according to technology 1, wherein if the sound quality evaluation determines that the sound quality of the analog radio audio is poor, the radio device switches to the IP radio audio. According to this configuration, when the quality of the analog radio audio is degraded, it is possible to skip switching the audio output to analog radio audio and switch directly to IP radio audio.

[0108] (Technology 3) The radio device according to technology 2, wherein the evaluation unit derives a degree of match between the analog radio audio and the digital radio audio, and if the degree of match is equal to or greater than a predetermined threshold, evaluates that the sound quality of the analog radio audio is good. According to this configuration, by using the degree of coincidence between analog radio audio, which is more likely to contain noise, and digital radio audio, it is possible to appropriately evaluate the audio quality of analog radio audio.

[0109] (Technology 4) The radio device according to Technology 2 or Technology 3, wherein the evaluation unit evaluates the sound quality of the analog radio audio to be good when the signal strength of noise included in the error signal between the analog radio audio and the digital radio audio is smaller than a predetermined threshold. This configuration makes it possible to properly evaluate the audio quality of analog radio audio by using the error signal between analog radio audio and digital radio audio, which is more likely to contain noise. In particular, it makes it possible to properly capture residual noise contained in analog radio audio and evaluate audio quality.

[0110] (Technology 5) The radio device according to any one of Technology 2 to Technology 4, wherein the evaluation unit derives periodic noise included in an error signal between the analog radio audio and the digital radio audio, and evaluates that the sound quality of the analog radio audio is good if the periodic noise is smaller than a predetermined threshold. According to this configuration, it is possible to appropriately capture periodic noise contained in analog radio audio and evaluate audio quality.

[0111] (Technology 6) The radio device according to Technology 4 or Technology 5, wherein the evaluation unit calculates the error signal after correcting the frequency characteristics of the analog radio audio and the digital radio audio so that they match. According to this configuration, the accuracy of the evaluation can be improved by correcting the difference between the frequency characteristics of analog radio audio and the frequency characteristics of digital radio audio before evaluating the quality.

[0112] (Technology 7) The radio device according to technology 6, wherein the evaluation unit applies a low-pass filter corresponding to the analog radio audio to the digital radio audio, and then corrects the frequency characteristics. This configuration makes it possible to reduce the processing load and processing time required to correct the difference between the frequency characteristics of analog radio audio and the frequency characteristics of digital radio audio.

[0113] (Technology 8) the analog radio audio and the digital radio audio are stereo signals, The radio device according to any one of Technology 1 to Technology 7, wherein the evaluation unit converts each of the analog radio audio and the digital radio audio into a monaural signal, and then performs sound quality evaluation. This configuration makes it possible to reduce the processing load and processing time involved in evaluating the audio quality of analog radio audio, which is a stereo signal.

[0114] (Technology 9) The radio device according to any one of Technology 1 to Technology 8, wherein the switching unit switches to either the analog radio audio or the IP radio audio based on the sound quality evaluation when the reception conditions of the digital radio broadcast deteriorate. With this configuration, higher quality digital radio broadcasts are normally output as audio with priority, and when reception conditions deteriorate, the system switches to other radio broadcasts, thereby improving the performance of the user's radio device.

[0115] (Technology 10) The radio device according to any one of Technology 1 to Technology 9, wherein the switching unit switches to the analog radio audio when the reception conditions of the digital radio broadcast, the analog radio broadcast, and the IP radio broadcast all deteriorate. With this configuration, even if the reception condition of any radio broadcast deteriorates, it is possible to prevent a situation in which silent audio is output.

[0116] (Technology 11) a receiving step of receiving a digital radio signal that is a radio signal for digital radio broadcasting, an analog radio signal that is a radio signal for analog radio broadcasting, and an IP radio signal that is a radio signal for IP radio broadcasting, which are in a simulcast relationship; an evaluation step of evaluating the sound quality of the analog radio audio using the digital radio audio based on the digital radio signal and the analog radio audio based on the analog radio signal; a switching step of switching the audio output of the digital radio audio to either the analog radio audio or the IP radio audio based on the IP radio signal based on the sound quality evaluation; A method for controlling a radio device having the above configuration. According to this configuration, it becomes possible to evaluate the audio quality of radio broadcasts and appropriately switch radio audio in a car-mounted radio device or the like.

[0117] (Technology 12) On the computer, a receiving step of receiving a digital radio signal that is a radio signal for digital radio broadcasting, an analog radio signal that is a radio signal for analog radio broadcasting, and an IP radio signal that is a radio signal for IP radio broadcasting, which are in a simulcast relationship; an evaluation step of evaluating the sound quality of the analog radio audio using the digital radio audio based on the digital radio signal and the analog radio audio based on the analog radio signal; a switching step of switching the audio output of the digital radio audio to either the analog radio audio or the IP radio audio based on the IP radio signal based on the sound quality evaluation; A program that executes the following. According to this configuration, it becomes possible to evaluate the audio quality of radio broadcasts and appropriately switch radio audio in a car-mounted radio device or the like. [Industrial Applicability]

[0118] The present disclosure is useful as a radio device, a control method for a radio device, and a program. [Explanation of symbols]

[0119] 100...Radio equipment 101, 104, 107...antennas 102...Analog radio receiver 103...Analog demodulation section 105...Digital radio receiver 106...Digital demodulation section 108...IP radio receiver 109…IP demodulation section 110...Speech quality evaluation unit 111...Sound source switching section 112...Audio output unit 201...Time lag correction unit 202...Correlation derivation unit 203...Threshold value determination unit

Claims

1. a receiving unit that receives a digital radio signal that is a radio signal for digital radio broadcasting, an analog radio signal that is a radio signal for analog radio broadcasting, and an IP radio signal that is a radio signal for IP radio broadcasting, all of which are in a simulcast relationship; an evaluation unit that evaluates the sound quality of the analog radio audio using digital radio audio based on the digital radio signal and analog radio audio based on the analog radio signal; a switching unit that switches the audio output of the digital radio audio to either the analog radio audio or the IP radio audio based on the IP radio signal based on the sound quality evaluation; A radio device having:

2. The switching unit is If the sound quality evaluation determines that the sound quality of the analog radio sound is good, switching to the analog radio sound; The radio device according to claim 1 , wherein if the sound quality evaluation determines that the sound quality of the analog radio sound is poor, the radio device switches to the IP radio sound.

3. The radio device according to claim 2 , wherein the evaluation unit derives a degree of match between the analog radio audio and the digital radio audio, and evaluates the sound quality of the analog radio audio as good if the degree of match is equal to or greater than a predetermined threshold.

4. 3. The radio device according to claim 2, wherein the evaluation unit evaluates the sound quality of the analog radio audio as good when a signal strength of noise included in an error signal between the analog radio audio and the digital radio audio is smaller than a predetermined threshold.

5. 3. The radio device according to claim 2, wherein the evaluation unit derives periodic noise contained in an error signal between the analog radio audio and the digital radio audio, and evaluates the sound quality of the analog radio audio as good if the periodic noise is smaller than a predetermined threshold.

6. The radio device according to claim 4 , wherein the evaluation unit calculates the error signal after correcting the frequency characteristics of the analog radio audio and the digital radio audio so that they match.

7. The radio device according to claim 6 , wherein the evaluation unit applies a low-pass filter corresponding to the analog radio audio to the digital radio audio, and then performs the correction of the frequency characteristics.

8. the analog radio audio and the digital radio audio are stereo signals, The radio device according to claim 1 , wherein the evaluation unit performs sound quality evaluation after converting each of the analog radio sound and the digital radio sound into a monaural signal.

9. The radio device according to claim 1 , wherein the switching unit switches to either the analog radio audio or the IP radio audio based on the sound quality evaluation when the reception condition of the digital radio broadcast deteriorates.

10. The radio device according to claim 1 , wherein the switching unit switches to the analog radio audio when reception conditions for the digital radio broadcast, the analog radio broadcast, and the IP radio broadcast are all deteriorating.

11. a receiving step of receiving a digital radio signal that is a radio signal for digital radio broadcasting, an analog radio signal that is a radio signal for analog radio broadcasting, and an IP radio signal that is a radio signal for IP radio broadcasting, which are in a simulcast relationship; an evaluation step of evaluating the sound quality of the analog radio audio using the digital radio audio based on the digital radio signal and the analog radio audio based on the analog radio signal; a switching step of switching the audio output of the digital radio audio to either the analog radio audio or the IP radio audio based on the IP radio signal based on the sound quality evaluation; A method for controlling a radio device having the above configuration.

12. On the computer, a receiving step of receiving a digital radio signal that is a radio signal for digital radio broadcasting, an analog radio signal that is a radio signal for analog radio broadcasting, and an IP radio signal that is a radio signal for IP radio broadcasting, which are in a simulcast relationship; an evaluation step of evaluating the sound quality of the analog radio audio using the digital radio audio based on the digital radio signal and the analog radio audio based on the analog radio signal; a switching step of switching the audio output of the digital radio audio to either the analog radio audio or the IP radio audio based on the IP radio signal based on the sound quality evaluation; A program that executes the following.

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