WO2020012634A1 - Broadcast receiver device and broadcast reception method - Google Patents

Abstract

A broadcast receiver device (100) is provided with an analog sound generation unit (111) for generating a sound signal from a broadcast signal of an acquired analog broadcast, a digital sound generation unit (112) for generating a sound signal from a broadcast signal of an acquired digital broadcast, a synthesis mode determination unit (113) for determining a synthesis mode in accordance with the sound bit rate of the digital broadcast when the reception quality of the analog broadcast is good, and a sound signal synthesizing unit (114) for generating a synthesized sound signal in which the sound signal generated by the analog sound generation unit (111) and the sound signal generated by the digital sound generation unit (112) are synthesized on the basis of the synthesis mode determined by the synthesis mode determination unit (113).

Description

Broadcast receiving device and broadcast receiving method

<< The present invention relates to a broadcast receiving apparatus and a broadcast receiving method.

As for programs broadcasted by digital broadcasting such as DAB (Digital Audio Broadcast) and IBOC (In-band on-channel), the same programs are also broadcasted by analog broadcasting. Therefore, by adjusting the time difference between the respective audio signals in the same sound source between the audio signal generated from the received digital broadcast broadcast signal and the audio signal generated from the received analog broadcast broadcast signal, analog broadcast is performed. From digital broadcasting to digital broadcasting, or from digital broadcasting to analog broadcasting without interrupting the audio or without duplicating the audio.

For example, Patent Literature 1 discloses an analog demodulation unit that demodulates a first audio signal from a broadcast wave of an analog broadcast included in a predetermined frequency band, and a broadcast wave of a digital broadcast included in the frequency band and having the same content as the analog broadcast. A digital demodulation / decoding unit for demodulating and decoding a second audio signal from the first, a delay unit for delaying at least one of the first and second audio signals, and outputting them as third and fourth audio signals, respectively, A reception state detection unit that outputs an analog reception state signal indicating a reception state of a wave, and controls at least one of the volume and the sound quality of the third quarter audio signal in accordance with the analog reception state signal, thereby forming a fifth / sixth audio signal. A fifth audio signal and a sixth audio signal according to a reception state of at least one of analog broadcast waves and digital broadcast airwaves; Receiving apparatus is disclosed having a mixing processing unit and outputting the mixed bets at a predetermined ratio.

The receiving apparatus disclosed in Patent Document 1 outputs an audio signal obtained from a digital broadcast broadcast wave when the digital broadcast broadcast wave reception state is better than a predetermined first state, and outputs the digital broadcast broadcast wave. If the reception state is worse than the first predetermined state and better than the second predetermined state, the audio signal obtained from the broadcast wave of the digital broadcast and the audio signal obtained from the broadcast wave of the analog broadcast are Mixing and outputting according to the reception state of the digital broadcast broadcast wave, and outputting the audio signal obtained from the analog broadcast broadcast wave when the digital broadcast broadcast wave reception state is worse than the predetermined second state. Things.

JP 2010-219649 A

However, audio signals obtained from digital broadcast waves may have lower sound quality than audio signals obtained from analog broadcast waves in terms of standards. The receiving apparatus disclosed in Patent Document 1 outputs an audio signal obtained from a digital broadcast wave having lower sound quality than an audio signal obtained from an analog broadcast wave when the reception state of the digital broadcast wave is good. There was a problem that would.

SUMMARY OF THE INVENTION The present invention is directed to solving the above-described problems, and is a broadcast receiving apparatus capable of outputting an audio signal having higher sound quality than an audio signal obtained from a received digital broadcast broadcast wave when analog broadcast reception quality is good. The challenge is to provide

A broadcast receiving apparatus according to the present invention includes: an analog audio generation unit configured to generate an audio signal from an acquired analog broadcast signal; a digital audio generation unit configured to generate an audio signal from an acquired digital broadcast signal; If the reception quality is good, the synthesis mode determination unit that determines the synthesis mode according to the audio bit rate of the digital broadcast, the audio signal generated by the analog audio generation unit, and the audio signal generated by the digital audio generation unit An audio signal synthesis unit that generates a synthesized audio signal synthesized based on the synthesis mode determined by the synthesis mode determination unit.

According to the present invention, it is possible to output an audio signal having higher sound quality than an audio signal obtained from a digital broadcast wave when the reception quality of the analog broadcast is good.

FIG. 1 is a block diagram illustrating a main part of an in-vehicle audio device to which the broadcast receiving device according to Embodiment 1 is applied. 2A and 2B are diagrams illustrating an example of a hardware configuration of the broadcast receiving device according to the first embodiment. FIG. 3 is a block diagram showing a main part of a combining mode determining unit in the broadcast receiving apparatus according to Embodiment 1. FIG. 4 is a block diagram showing a main part of an audio signal synthesis unit in the broadcast receiving apparatus according to Embodiment 1. FIG. 5 is a flowchart illustrating processing of the broadcast receiving device according to the first embodiment. FIG. 6 is a flowchart illustrating a process of the combining mode determination unit in the broadcast receiving device according to the first embodiment. FIG. 7 is a flowchart illustrating a process of the audio signal combining unit in the broadcast receiving device according to the first embodiment. FIG. 8 is a block diagram showing a main part of an in-vehicle audio device to which the broadcast receiving device according to Embodiment 2 is applied. FIG. 9 is a block diagram showing a main part of a combining mode determining unit in the broadcast receiving apparatus according to Embodiment 2. FIG. 10 is a block diagram showing a main part of an audio signal synthesizing unit in the broadcast receiving apparatus according to Embodiment 2. FIG. 11 is a flowchart illustrating a process of the broadcast receiving device according to the second embodiment. FIG. 12 is a flowchart illustrating a process of the combining mode determining unit in the broadcast receiving apparatus according to Embodiment 2. FIG. 13A is a flowchart illustrating a part of the process of the audio signal combining unit in the broadcast receiving device according to Embodiment 2. FIG. 13B is a flowchart illustrating a part of the processing of the audio signal combining unit in the broadcast receiving device according to Embodiment 2.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1 FIG.
The broadcast receiving apparatus 100 according to the first embodiment will be described below as being applied to the on-vehicle audio apparatus 10 as an example.
FIG. 1 is a block diagram showing a main part of an on-vehicle acoustic device 10 to which a broadcast receiving device 100 according to Embodiment 1 is applied.

The on-vehicle acoustic device 10 is mounted on the vehicle 1.
The vehicle 1 includes a vehicle-mounted acoustic device 10, a voice output device 11, and an antenna 12.

The sound output device 11 converts a sound signal acquired from the on-vehicle sound device 10 described later into a sound wave and outputs the sound wave. The audio output device 11 is, for example, a speaker.
The antenna 12 receives broadcast waves of analog broadcast and digital broadcast, and outputs the received broadcast wave as a broadcast signal, which is an electric signal, to the on-vehicle acoustic device 10 described later.
More specifically, the antenna 12 includes an antenna 12a for receiving an analog broadcast wave and an antenna 12b for receiving a digital broadcast wave. When both the analog broadcast wave and the digital broadcast wave can be received by one antenna 12, the antennas 12 do not need to be two antennas 12a and 12b.
The on-vehicle acoustic device 10 appropriately amplifies a synthesized audio signal acquired from a broadcast receiving device 100 described later, and outputs the amplified audio signal to the audio output device 11.

音響 The in-vehicle acoustic device 10 includes a broadcast receiving device 100, an operation receiving unit 101, and an amplifying unit 102.

The operation receiving unit 101 receives operation information from an operation input device (not shown), and appropriately outputs the operation information to the broadcast receiving device 100 and the amplification unit 102 based on the received operation information. The operation information includes, for example, information for setting an amplification value in the amplification unit 102, information for setting a broadcast frequency corresponding to a broadcast station for analog broadcasting and digital broadcasting, and the on-vehicle acoustic device 10 or a broadcast described later. This is information for turning the power of the receiving apparatus 100 on and off.
The broadcast frequency is set, for example, based on the operation information acquired by the operation reception unit 101.
More specifically, for example, when the operation receiving unit 101 sets a broadcast frequency corresponding to one of the analog broadcast and the digital broadcast based on the operation information, the operation accepting unit 101 selects one of the analog broadcast and the digital broadcast. As for the other broadcast frequency, a broadcast frequency corresponding to the broadcast station is set. Hereinafter, in the case where the broadcast station of the analog broadcast and the broadcast station of the digital broadcast are the same, description will be made assuming that the same broadcast program is being broadcast.

The amplifying unit 102 amplifies the synthesized audio signal acquired from the broadcast receiving device 100 described later based on the set amplification value, and outputs the amplified synthesized audio signal to the audio output device 11. The amplification value is set, for example, based on the operation information acquired by the operation receiving unit 101.

The broadcast receiving apparatus 100 extracts analog broadcast and digital broadcast broadcast signals of a set broadcast frequency from a broadcast signal acquired from the antenna 12, and synthesizes an audio signal generated from the extracted analog broadcast and digital broadcast broadcast signals. The synthesized speech signal is output to the amplifier 102.

The broadcast receiving apparatus 100 includes an analog audio generation unit 111, a digital audio generation unit 112, a synthesis mode determination unit 113, and an audio signal synthesis unit 114.

The analog audio generation unit 111 generates an audio signal from a broadcast signal of an analog broadcast acquired from the antenna 12a.
More specifically, the analog audio generation unit 111 extracts, for example, a broadcast signal of an analog broadcast having a broadcast frequency set based on the operation information obtained by the operation reception unit 101 in the broadcast signal obtained from the antenna 12a. . Further, the analog audio generation unit 111 generates an audio signal by demodulating the extracted analog broadcast signal. The analog audio generation unit 111 outputs the generated audio signal to a synthesis mode determination unit 113 and an audio signal synthesis unit 114 described below.
Hereinafter, the audio signal generated by the analog audio generation unit 111 is referred to as an analog audio signal.

The digital audio generation unit 112 generates an audio signal from a digital broadcast signal acquired from the antenna 12b.
More specifically, the digital audio generation unit 112 extracts, for example, a broadcast signal of a digital broadcast having a broadcast frequency set based on the operation information acquired by the operation reception unit 101 in the broadcast signal acquired from the antenna 12b. . Furthermore, the digital audio generation unit 112 generates an audio signal by demodulating the extracted digital broadcast broadcast signal and decoding the demodulated broadcast signal. The digital audio generation unit 112 outputs the generated audio signal to a synthesis mode determination unit 113 and an audio signal synthesis unit 114 described below.

Hereinafter, it is assumed that the broadcast signal is such that sound data compressed by the MP2 (MPEG-1 / 2 Audio-Layer-2) system at the broadcast station is modulated to a broadcast frequency corresponding to the broadcast station and output from the broadcast station. explain. The compression method at the broadcasting station is not limited to MP2, but may be a compression method different from MP2, such as MPEG-2 AudioBC (backward compatible) or MPEG-2 AAC (Advanced Audio Coding). That is, the digital audio generation unit 112 generates an audio signal by demodulating a broadcast signal of a digital broadcast, extracting audio data compressed by the MP2 system, and decoding the extracted audio data compressed by the MP2 system. . The digital audio generation unit 112 outputs the generated audio signal to a synthesis mode determination unit 113 and an audio signal synthesis unit 114 described below.

* Hereinafter, the audio signal generated by the digital audio generation unit 112 is referred to as a digital audio signal.

The combining mode determining unit 113 determines the combining mode according to the reception quality of the analog broadcast and the audio bit rate of the digital broadcast.
More specifically, the synthesis mode determination unit 113 determines the synthesis mode according to the reception quality of the analog broadcast and the audio bit rate of the digital broadcast, and outputs the determined synthesis mode to the audio signal synthesis unit 114. .
The synthesis mode is a mode in which an analog audio signal and a digital audio signal are synthesized in an audio signal synthesis unit 114 described later. The synthesis mode is, for example, information indicating a synthesis method when synthesizing an analog audio signal and a digital audio signal.
The details of the process of determining the synthesis mode by the synthesis mode determination unit 113 will be described later.

The audio signal synthesizing unit 114 generates a synthesized audio signal obtained by synthesizing the analog audio signal and the digital audio signal based on the synthesis mode determined by the synthesis mode determination unit 113.
More specifically, the audio signal synthesizing unit 114 generates a synthesized audio signal by synthesizing the analog audio signal and the digital audio signal based on the synthesis mode determined by the synthesis mode determining unit 113, and generates the synthesized audio signal. Is output to the amplifier 102.
The details of the process of generating a synthesized voice signal in the voice signal synthesis unit 114 will be described later.

With reference to FIG. 2A and FIG. 2B, a hardware configuration of a main part of broadcast receiving apparatus 100 according to Embodiment 1 will be described.
2A and 2B are diagrams illustrating an example of a hardware configuration of a main part of broadcast receiving device 100 according to Embodiment 1. FIG.

As shown in FIG. 2A, the broadcast receiving apparatus 100 is configured by a computer, and the computer has a processor 201 and a memory 202. The memory 202 stores a program for causing the computer to function as the analog audio generation unit 111, the digital audio generation unit 112, the synthesis mode determination unit 113, and the audio signal synthesis unit 114. When the processor 201 reads out and executes the program stored in the memory 202, the functions of the analog audio generation unit 111, the digital audio generation unit 112, the synthesis mode determination unit 113, and the audio signal synthesis unit 114 are realized.

{Circle around (2)} As shown in FIG. 2B, the broadcast receiving apparatus 100 may include a processing circuit 203. In this case, the functions of the analog audio generation unit 111, the digital audio generation unit 112, the synthesis mode determination unit 113, and the audio signal synthesis unit 114 may be realized by the processing circuit 203.

The broadcast receiving device 100 may be configured by a processor 201, a memory 202, and a processing circuit 203 (not shown). In this case, some of the functions of the analog sound generation unit 111, the digital sound generation unit 112, the synthesis mode determination unit 113, and the sound signal synthesis unit 114 are realized by the processor 201 and the memory 202, and the remaining functions are realized. May be realized by the processing circuit 203.

The processor 201 uses, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a microprocessor, a microcontroller, or a DSP (Digital Signal Processor).

The memory 202 uses, for example, a semiconductor memory or a magnetic disk. More specifically, the memory 202 includes a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Memory Only), and an EEPROM (Electrical Memory). State @ Drive) or HDD (Hard @ Disk @ Drive) or the like.

Processing circuit 203, for example, ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), FPGA (Field-Programmable Gate Array), SoC (System-on-a-Chip) or a system LSI (Large-Scale Integration) Is used.

With reference to FIG. 3, a description will be given of a process in which the combining mode determining unit 113 determines the combining mode.
FIG. 3 is a block diagram showing a main part of combining mode determining section 113 in broadcast receiving apparatus 100 according to Embodiment 1.
The combining mode determination unit 113 includes, for example, an analog reception quality determination unit 131, a bit rate determination unit 132, a mode output unit 133, and a reception error determination unit 134.

The analog reception quality determination unit 131 determines whether the reception quality of the analog broadcast wave is good.
More specifically, for example, the analog reception quality determination unit 131 determines whether the power of a noise signal such as white noise and pink noise included in the analog audio signal is smaller than a predetermined threshold. Then, it is determined whether or not the reception quality of the analog broadcast wave is good. The power of the noise signal included in the analog audio signal can be calculated, for example, by analyzing a power spectrum obtained by performing a discrete Fourier transform on the analog audio signal by a known technique. The predetermined threshold value may be, for example, a fixed value, or a value calculated based on the power of a signal obtained by removing a noise signal from an analog audio signal.

The bit rate determination unit 132 determines, for example, whether the audio bit rate of the digital broadcast is lower than a predetermined threshold.
More specifically, for example, the bit rate determination unit 132 acquires from the digital audio generation unit 112 information indicating the audio bit rate of the digital audio signal obtained when the broadcast signal demodulated by the digital audio generation unit 112 is decoded. I do. The information indicating the audio bit rate is stored in, for example, a TS (Transport Stream) header of the MP2 in the demodulated broadcast signal.

In the first embodiment, the description will be given on the assumption that the digital audio generation unit 112 outputs information indicating the audio bit rate of the digital audio signal obtained when decoding the demodulated broadcast signal to the bit rate determination unit 132.
That is, in Embodiment 1, the bit rate determination unit 132 acquires information indicating the audio bit rate of the digital audio signal from the digital audio generation unit 112, and sets information indicating the audio bit rate of the acquired digital audio signal in advance. By comparing with a predetermined threshold value, it is determined whether or not the audio bit rate of the digital broadcast is lower than a predetermined threshold value.

The audio bit rate of digital broadcasting is, for example, from 8 kbps (kilo bits per second) to 384 kbps in DAB, and from 20 kbps to 40 kbps, or from 25 kbps to 300 kbps in IBOC.
The predetermined threshold is, for example, an audio bit rate estimated from a broadcast type of analog broadcast. In the first embodiment, the predetermined threshold is described as being the audio bit rate estimated from the broadcast type of the analog broadcast. However, the predetermined threshold may be a fixed value appropriately determined. good.
The broadcast type of the analog broadcast can be determined from the broadcast frequency set in the analog audio generation unit 111 based on the operation information acquired by the operation reception unit 101, for example. The broadcast frequency set in the analog audio generation unit 111 can be acquired from the analog audio generation unit 111, for example.

In the first embodiment, description will be given assuming that analog audio generation section 111 outputs the set broadcast frequency to bit rate determination section 132.
That is, the bit rate determination unit 132 will be described as acquiring the broadcast frequency from the analog audio generation unit 111. However, the bit rate determination unit 132 determines that the operation reception unit 101 broadcasts the broadcast frequency to the analog audio generation unit 111 based on the operation information. When setting the frequency, the broadcast frequency may be acquired from the operation reception unit 101.

{More specifically, for example, when the value of the acquired broadcast frequency is between 47 MHz (megahertz) and 108 MHz, the bit rate determining unit 132 determines that the broadcast type is FM (Frequency Modulation) broadcast. When the broadcast type is FM broadcast, the estimated general audio bit rate is 96 kbps for FM stereo broadcast and 48 kbps for FM monaural broadcast. Further, for example, when the value of the acquired broadcast frequency is between 526.5 kHz (kilohertz) and 1606.5 kHz, the bit rate determining unit 132 determines that the broadcast type is AM (Amplitude @ Modulation) broadcast. When the broadcast type is AM broadcast, the estimated general audio bit rate is 32 kbps.

The reception error determination unit 134 determines whether a digital broadcast signal acquired from the antenna 12b has a bit error.
More specifically, for example, the reception error determination unit 134 converts the digital broadcast signal acquired from the antenna 12b based on information indicating whether or not the digital audio signal acquired from the digital audio generation unit 112 has been successfully generated. It is determined whether there is a bit error.
Note that reception error determination section 134 is not an essential component in broadcast receiving apparatus 100 according to Embodiment 1, and reception error determination section 134 is added or deleted from broadcast reception apparatus 100 according to Embodiment 1 as appropriate. can do.

Mode output section 133 determines a synthesis mode based on the result determined by analog reception quality determination section 131 and the result determined by bit rate determination section 132, and outputs the result to audio signal synthesis section 114.
More specifically, for example, the mode output unit 133 determines that the reception quality of the broadcast wave of the analog broadcast is good by the analog reception quality determination unit 131 and that the audio bit rate of the digital broadcast is If the digital audio signal is determined to be lower than the predetermined threshold, it is estimated that some frequency components in the digital audio signal are not present in the digital audio signal even though they are present in the analog audio signal. A synthesis mode is determined so that a signal having a weak frequency component in the signal is complemented by a signal having a frequency component having the same frequency as the frequency component in the analog audio signal to generate a synthesized audio signal (hereinafter, referred to as “aspect C”). I do.

Further, for example, the mode output unit 133 determines that the reception quality of the broadcast wave of the analog broadcast is good by the analog reception quality determination unit 131, and determines the audio bit rate of the digital broadcast by the bit rate determination unit 132 in advance. If it is not lower than the threshold, that is, if it is determined that the audio bit rate of the digital broadcast is equal to or higher than a predetermined threshold, it is estimated that the sound quality of the digital audio signal is better than the sound quality of the analog audio signal. The synthesis mode is determined so that the digital audio signal is used as the synthesized audio signal without combining the audio signal and the digital audio signal (hereinafter, referred to as “aspect A”).

Further, for example, when the analog reception quality determination unit 131 determines that the reception quality of the broadcast wave of the analog broadcast is not good, that is, the analog output quality determination unit 131 determines that the reception quality of the broadcast wave of the analog broadcast is bad, Since it is assumed that the sound quality is unacceptable for listening, the combining mode is determined to be mode A without depending on the result determined by the bit rate determining unit 132. When the analog reception quality determination unit 131 determines that the reception quality of the broadcast wave of the analog broadcast is poor, the analog reception quality determination unit 131 determines the audio bit rate of the digital broadcast by the bit rate determination unit 132 in advance, for example. The bit rate determination unit 132 may be controlled so as not to execute the process of determining whether the value is lower than the threshold.

In addition, for example, the mode output unit 133 is such that the combining mode determination unit 113 includes the reception error determination unit 134, the analog reception quality determination unit 131 determines that the reception quality of the broadcast wave of the analog broadcast is good, and If it is determined by the unit 134 that the digital broadcast signal acquired from the antenna 12b has a bit error, it is estimated that a digital audio signal has not been generated, so that the analog audio signal and the digital audio signal are combined. Instead, the synthesis mode is determined so that the analog voice signal is used as the synthesized voice signal (hereinafter, referred to as “mode B”).

Note that the analog reception quality determination unit 131, the bit rate determination unit 132, and the reception error determination unit 134 do not necessarily need to be provided in the combining mode determination unit 113 as long as they are provided in the broadcast receiving device 100.

With reference to FIG. 4, a process of generating a synthesized voice signal in voice signal synthesis section 114 will be described.
FIG. 4 is a block diagram showing a main part of audio signal combining section 114 in broadcast receiving apparatus 100 according to Embodiment 1.
The audio signal synthesis unit 114 includes, for example, a delay control unit 141, an analog delay adjustment unit 142, a digital delay adjustment unit 143, a volume adjustment unit 144, a frequency component extraction unit 145, and a synthesis unit 146.

The delay control unit 141 detects a time lag of the same sound source between the analog audio signal and the digital audio signal, and controls an analog delay adjustment unit 142 and a digital delay adjustment unit 143 described later according to the detected time lag. .
More specifically, for example, the delay control unit 141 compares the shape of the audio signal having the same frequency component between the analog audio signal and the digital audio signal, and detects a temporal position where the shape matches, thereby obtaining the digital signal. A time lag between the same sound source and an audio signal is detected. The same frequency component is, for example, 1 kHz. The same frequency component is not limited to 1 kHz, and may be in a frequency band included in both the analog audio signal and the digital audio signal. Further, the same frequency component whose shape is compared by the delay control unit 141 is not limited to one, and the delay control unit 141 uses the shape of the audio signal in the analog audio signal and the digital audio signal in the plurality of frequency components based on the shape of the audio signal. Alternatively, the time lag of the same sound source may be detected.

In addition, the delay control unit 141 outputs information indicating the time lag to an analog delay adjustment unit 142 or a digital delay adjustment unit 143 described below based on the detected time lag, for example, so that the analog delay adjustment unit 142 and the digital delay adjuster 143.
More specifically, for example, when the analog audio signal precedes the digital audio signal, the delay control unit 141 outputs information indicating a time lag to the analog delay adjustment unit 142. Further, when the digital audio signal precedes the analog audio signal, the delay control unit 141 outputs information indicating a time lag to the digital delay adjustment unit 143.
Note that the delay control unit 141 may acquire the synthesis mode from the synthesis mode determination unit 113, and perform the above-described processing only when the obtained synthesis mode is neither the mode A nor the mode B.

The analog delay adjustment unit 142 outputs an analog audio signal obtained by delaying the analog audio signal acquired from the analog audio generation unit 111 for a predetermined period.
More specifically, for example, based on the information indicating the time lag acquired from the delay control unit 141, the analog delay adjustment unit 142 Output an analog audio signal delayed by a predetermined period. Further, for example, when the analog delay adjustment unit 142 does not acquire information indicating a time lag from the delay control unit 141, the analog delay adjustment unit 142 converts the analog audio signal acquired from the analog audio generation unit 111 without delaying the analog audio signal. Output as is.
Note that the analog delay adjusting unit 142 may acquire the combining mode from the combining mode determining unit 113, and perform the above-described processing only when the obtained combining mode is neither the mode A nor the mode B. When not performing the above-described processing, the analog delay adjustment unit 142 outputs the analog audio signal as it is without delaying the analog audio signal acquired from the analog audio generation unit 111, for example.

The digital delay adjuster 143 outputs a digital audio signal obtained by delaying the digital audio signal obtained from the digital audio generator 112 for a predetermined period.
More specifically, for example, the digital delay adjustment unit 143 adjusts the digital audio signal acquired from the digital audio generation unit 112 based on the information indicating the temporal deviation acquired from the delay control unit 141, according to the temporal deviation. Output a digital audio signal delayed by a predetermined period. Further, for example, when the digital delay adjustment unit 143 does not acquire the information indicating the time lag from the delay control unit 141, the digital delay adjustment unit 143 converts the digital audio signal acquired from the digital audio generation unit 112 without delaying the digital audio signal. Output as is.
Note that the digital delay adjustment unit 143 may acquire the combining mode from the combining mode determining unit 113, and perform the above-described processing only when the obtained combining mode is neither the mode A nor the mode B. When the above processing is not performed, the digital delay adjusting unit 143 outputs the digital audio signal as it is without delaying the digital audio signal acquired from the digital audio generation unit 112, for example.

The volume adjusting unit 144 adjusts the volume of the analog audio signal acquired from the analog delay adjusting unit 142 so as to be similar to the volume of the digital audio signal acquired from the digital delay adjusting unit 143, and adjusts the analog volume. Output audio signal.
More specifically, for example, the volume adjustment unit 144 determines that the amplitude of the predetermined frequency in the analog audio signal acquired from the analog delay adjustment unit 142 is the same as the amplitude of the predetermined frequency in the digital audio signal acquired from the digital delay adjustment unit 143. The analog audio signal is amplified to the extent that the analog audio signal is in the range. The predetermined frequency is, for example, 1 kHz. The predetermined frequency is not limited to 1 kHz, and may be in a frequency band included in both the analog audio signal and the digital audio signal. In addition, the predetermined frequency is not limited to one, and the volume control unit 144 may amplify the analog audio signal based on the amplitudes of the analog audio signal and the digital audio signal at a plurality of predetermined frequencies.

Note that the volume adjustment unit 144 may obtain the synthesis mode from the synthesis mode determination unit 113 and perform the above-described processing only when the obtained synthesis mode is neither the mode A nor the mode B. When not performing the above-described processing, the volume adjustment unit 144 outputs the analog audio signal as it is without adjusting the volume of the analog audio signal acquired from the analog delay adjustment unit 142, for example.

The frequency component extraction unit 145 extracts a frequency component having the same frequency as a weak frequency component in digital audio from the analog audio signal acquired from the volume adjustment unit 144.
More specifically, for example, the frequency component extraction unit 145 detects a weak frequency component of the digital audio by analyzing a power spectrum obtained by performing a discrete Fourier transform on the digital audio by a known technique. Further, the frequency component extraction unit 145 extracts, from the analog audio signal acquired from the volume adjustment unit 144, a frequency component having the same frequency as the weak frequency component of the digital audio using a known technique such as a filter. The frequency component having a weak power is determined based on, for example, whether or not the power of the frequency component is weaker than a preset threshold. The preset threshold value may be a fixed value, for example, or may be determined based on the power of the frequency component having the strongest power.

The weak frequency component of the digital audio is generated by omitting a specific frequency component when the audio signal is encoded by a compression method such as MP2 in a broadcasting station. The weak frequency component of the digital audio power becomes more prominent as the compression rate when the audio signal is encoded by a compression method such as MP2 increases, that is, as the audio bit rate of the digital broadcast decreases.

周波 数 Further, the frequency component extraction unit 145 may acquire the synthesis mode from the synthesis mode determination unit 113 and perform the above-described processing only when the obtained synthesis mode is neither the mode A nor the mode B. When the above processing is not performed, the frequency component extraction unit 145 outputs the analog audio signal as it is without extracting a specific frequency component from the analog audio signal acquired from the volume control unit 144, for example.

The synthesis unit 146 synthesizes the analog audio signal obtained from the frequency component extraction unit 145 and the digital audio signal obtained from the digital delay adjustment unit 143 based on the synthesis mode determined by the synthesis mode determination unit 113. And outputs the generated synthesized speech signal to the amplification unit 102.

More specifically, for example, when the synthesizing mode obtained from the synthesizing mode determining unit 113 is the mode C, the synthesizing unit 146 adds the frequency component extracting unit 145 to the digital audio signal obtained from the digital delay adjusting unit 143. A synthesized audio signal is generated by synthesizing the signal of the frequency component in the extracted analog audio signal.
Further, for example, when the synthesis mode obtained from the synthesis mode determination unit 113 is the mode A, the synthesis unit 146 does not synthesize the analog audio signal and the digital audio signal and outputs the digital audio signal obtained from the digital audio generation unit 112. The audio signal is output to the amplifier 102 as a synthesized audio signal.
Further, for example, when the synthesis mode obtained from the synthesis mode determination unit 113 is the mode B, the synthesis unit 146 does not synthesize the analog audio signal and the digital audio signal, and outputs the analog audio signal obtained from the analog audio generation unit 111. The audio signal is output to the amplifier 102 as a synthesized audio signal.

Note that the delay control unit 141, the analog delay adjustment unit 142, the digital delay adjustment unit 143, the volume adjustment unit 144, and the frequency component extraction unit 145 are not necessarily included in the audio signal synthesis unit 114 if provided in the broadcast receiving apparatus 100. It doesn't have to be.

The operation of broadcast receiving apparatus 100 according to Embodiment 1 will be described with reference to FIG.
FIG. 5 is a flowchart illustrating processing of broadcast receiving apparatus 100 according to Embodiment 1.

First, in step ST501, as described above, the analog audio generation unit 111 generates an audio signal from a broadcast signal of an analog broadcast acquired from the antenna 12a.
Next, in step ST502, digital audio generation section 112 generates an audio signal from the digital broadcast signal acquired from antenna 12.
Note that the processing in step ST501 and the processing in step ST502 are appropriately repeated in the background processing while the flowchart illustrated in FIG. 5 is being executed. Further, the processing of step ST501 and the processing of step ST502 may be performed first, or may be performed simultaneously.

Next, in step ST503, broadcast receiving apparatus 100 determines whether or not operation information for terminating the reception of the broadcast signal has been obtained from operation reception unit 101. The operation information for terminating the reception of the broadcast signal is, for example, operation information for turning off the power of the broadcast receiving device 100.
In step ST503, when the operation information for terminating the reception of the broadcast signal has been acquired from operation accepting section 101 (step ST503: YES), broadcast receiving apparatus 100 ends the processing of the flowchart illustrated in FIG.
In step ST503, when the operation information for terminating the reception of the broadcast signal has not been acquired from operation accepting section 101 (step ST503: NO), in step ST504, combining mode determining section 113 performs the combining mode as described above. To determine. Details of the process of step ST504 will be described later.

Next, in step ST505, the audio signal synthesizing unit 114 generates a synthesized audio signal obtained by synthesizing the analog audio signal and the digital audio signal based on the synthesis mode as described above, and amplifies the generated synthesized audio signal. Output to 102. Details of the process of step ST505 will be described later.
After the process of step ST505, the broadcast receiving device 100 returns to the process of step ST503. Specifically, for example, the broadcast receiving apparatus 100 repeatedly executes the processing of steps ST504 and ST505 until obtaining operation information for terminating the reception of the broadcast signal from the operation receiving unit 101. More specifically, when the access unit of the broadcast signal encoded by MP2 or the like in digital broadcasting is, for example, 125 milliseconds, the processing of steps ST504 and ST505 is repeatedly performed every 125 milliseconds. . The access unit is a unit for decoding a broadcast signal encoded by MP2 or the like.

Referring to FIG. 6, the operation of combining mode determining section 113 according to Embodiment 1 in step ST504 will be described.
FIG. 6 is a flowchart illustrating a process performed by combining mode determining section 113 in broadcast receiving apparatus 100 according to Embodiment 1.

First, in step ST601, analog reception quality determination section 131 determines whether or not the reception quality of an analog broadcast wave is good, as described above.
In step ST601, when analog reception quality determination section 131 determines that the reception quality of the analog broadcast wave is not good, that is, the reception quality of the analog broadcast wave is bad (step ST601: NO), step ST602. As described above, the mode output unit 133 determines the synthesis mode to be mode A, as described above. After step ST602, the combining mode determining unit 113 ends the processing of the flowchart illustrated in FIG.
In step ST601, when analog reception quality determination section 131 determines that the reception quality of the broadcast wave of the analog broadcast is good (step ST601: YES), in step ST603, reception error determination section 134 acquires from antenna 12b. It is determined whether there is a bit error in the broadcast signal of the digital broadcast.

In step ST603, when the reception error determination unit 134 determines that the digital broadcast signal acquired from the antenna 12b has a bit error (step ST603: YES), in step ST604, the mode output unit 133 performs As described above, the synthesis mode is determined to be mode B. After step ST604, the combining mode determination unit 113 ends the processing of the flowchart illustrated in FIG.
In step ST603, when it is determined by reception error determining section 134 that there is no bit error in the digital broadcast signal acquired from antenna 12b (step ST603: NO), in step ST605, bit rate determining section 132 As described above, it is determined whether or not the audio bit rate of the digital broadcast is lower than a predetermined threshold.

In step ST605, when the bit rate determination unit 132 determines that the audio bit rate of the digital broadcast is not lower than the predetermined threshold, that is, that the audio bit rate of the digital broadcast is equal to or higher than the predetermined threshold ( (Step ST605: NO), the mode output unit 133 performs the process shown in step ST602 as described above.
In step ST605, when the bit rate determination unit 132 determines that the audio bit rate of the digital broadcast is lower than a predetermined threshold (step ST605: YES), in step ST606, the mode output unit 133 performs the processing described above. As described above, the synthesis mode is determined as mode C. After step ST606, the combining mode determination unit 113 ends the processing of the flowchart illustrated in FIG.

Referring to FIG. 7, the operation of audio signal synthesis section 114 according to Embodiment 1 in step ST505 will be described.
FIG. 7 is a flowchart illustrating a process of audio signal combining section 114 in broadcast receiving apparatus 100 according to Embodiment 1.

First, in step ST701, as described above, the delay control unit 141 detects a time lag of the same sound source between the analog audio signal and the digital audio signal.
Next, in step ST702, the analog delay adjustment unit 142 converts the analog audio signal acquired from the analog audio generation unit 111 into the time based on the information indicating the time lag acquired from the delay control unit 141, as described above. An analog audio signal delayed by a period corresponding to the deviation is output. If the analog delay adjusting unit 142 has not obtained the information indicating the time lag from the delay control unit 141, the analog delay adjusting unit 142 outputs the analog audio signal obtained from the analog audio generating unit 111 without delay.

Next, in step ST703, the digital delay adjustment unit 143 converts the digital audio signal acquired from the digital audio generation unit 112 to the time based on the information indicating the time lag acquired from the delay control unit 141, as described above. A digital audio signal delayed by a period corresponding to the deviation is output. When the information indicating the time lag is not obtained from the delay control unit 141, the digital delay adjustment unit 143 outputs the digital audio signal as it is without delaying the digital audio signal obtained from the digital audio generation unit 112.
Note that step ST702 and step ST703 may be performed first, or may be performed simultaneously.

Next, in step ST704, as described above, volume adjusting section 144 sets the volume of the analog audio signal acquired from analog delay adjusting section 142 to the same volume as the digital audio signal acquired from digital delay adjusting section 143. And output an analog audio signal whose volume has been adjusted.
Next, in step ST705, the frequency component extraction unit 145 extracts a frequency component having the same frequency as the weak frequency component in the digital audio from the analog audio signal acquired from the volume adjustment unit 144, as described above.

Next, in step ST706, combining section 146 determines whether or not the combining mode acquired from combining mode determining section 113 is mode C.
In step ST706, when the combining unit 146 determines that the combining mode is mode C (step ST706: YES), in step ST707, combining unit 146 acquires from digital delay adjusting unit 143 as described above. A synthetic audio signal is generated by synthesizing the digital audio signal and a frequency component having the same frequency as the weak frequency component in the digital audio extracted from the analog audio signal by the frequency component extracting unit 145, and the generated synthetic audio signal is amplified by the amplifying unit 102. Output to After step ST707, audio signal synthesis section 114 ends the processing of the flowchart shown in FIG.
In step ST706, when the combining unit 146 determines that the combining mode is not mode C (step ST706: NO), in step ST708, combining unit 146 sets the combining mode acquired from combining mode determining unit 113 to mode A. It is determined whether or not.

In step ST708, when the synthesizing unit 146 determines that the synthesizing mode is mode A (step ST708: YES), in step ST709, synthesizing unit 146 converts the analog audio signal and the digital audio signal as described above. , And outputs the digital audio signal obtained from the digital audio generation unit 112 to the amplification unit 102 as a synthesized audio signal. After step ST709, the audio signal synthesis unit 114 ends the processing of the flowchart illustrated in FIG.
In step ST708, when the combining unit 146 determines that the combining mode is not mode A (step ST708: NO), in step ST710, combining unit 146 determines that the combining mode is mode B, for example. After step ST710, in step ST711, the synthesizing unit 146 outputs the analog audio signal obtained from the analog audio generation unit 111 to the amplification unit 102 as a synthesized audio signal without synthesizing the analog audio signal and the digital audio signal. I do. After step ST711, the audio signal synthesis unit 114 ends the processing of the flowchart illustrated in FIG.

Note that the audio signal synthesizing section 114 may perform the processing from step ST701 to step ST705 only when the synthesis mode is neither mode A nor mode B.

As described above, the broadcast receiving apparatus 100 includes the analog audio generation unit 111 that generates an audio signal from the acquired analog broadcast signal, the digital audio generation unit 112 that generates an audio signal from the acquired digital broadcast signal, If the reception quality of the analog broadcast is good, the synthesis mode determination unit 113 that determines the synthesis mode according to the audio bit rate of the digital broadcast, the audio signal generated by the analog audio generation unit 111, and the digital audio generation unit 112 An audio signal synthesizing unit 114 that generates a synthesized audio signal by synthesizing the generated audio signal based on the synthesis mode determined by the synthesis mode determination unit 113.
With this configuration, the broadcast receiving apparatus 100 can output an audio signal having higher sound quality than an audio signal obtained from a digital broadcast wave when the reception quality of the analog broadcast is good.

Embodiment 2 FIG.
The broadcast receiving apparatus 100a according to the second embodiment will be described below as being applied to, for example, an on-vehicle audio apparatus 10a.

FIG. 8 is a block diagram showing a main part of an in-vehicle acoustic device 10a to which the broadcast receiving device 100a according to Embodiment 2 is applied.
FIG. 9 is a block diagram showing a main part of the combining mode determining unit 113a in broadcast receiving apparatus 100a according to Embodiment 2.
FIG. 10 is a block diagram showing a main part of audio signal synthesis section 114a in broadcast receiving apparatus 100a according to Embodiment 1.

Broadcast receiving apparatus 100a according to Embodiment 2 is different from broadcast receiving apparatus 100 according to Embodiment 1 in that broadcast mode determining section 113a and audio signal synthesizing section 114a in broadcast receiving apparatus 100a according to Embodiment 2. The configuration is different from the configuration of the synthesis mode determination unit 113 and the audio signal synthesis unit 114 according to the first embodiment in the broadcast receiving apparatus 100.
In other configurations of the broadcast receiving device 100a according to the second embodiment, the same components as those of the broadcast receiving device 100 according to the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. That is, the description of the configurations in FIGS. 8, 9, and 10 to which the same reference numerals as those in FIGS. 1, 2, and 3 are attached is omitted.

The vehicle-mounted acoustic device 10a includes a broadcast receiving device 100a, an operation receiving unit 101, and an amplifying unit 102.
The broadcast receiving device 100a includes an analog audio generation unit 111, a digital audio generation unit 112, a synthesis mode determination unit 113a, and an audio signal synthesis unit 114a.

When the reception quality of the analog broadcast is good, the synthesis mode determination unit 113a determines the synthesis mode according to the audio bit rate of the digital broadcast and the frequency characteristics of the digital audio signal.
The combining mode determination unit 113a includes, for example, an analog reception quality determination unit 131, a bit rate determination unit 132, a mode output unit 133a, a reception error determination unit 134, and a frequency characteristic determination unit 135.
Note that, like broadcast receiving apparatus 100 according to the first embodiment, reception error determining section 134 is not an essential component in broadcast receiving apparatus 100a according to the second embodiment. 2 can be appropriately added or deleted from the broadcast receiving apparatus 100a according to the second embodiment.

The frequency characteristic determination unit 135 determines, for example, whether the frequency characteristic of the digital audio signal is lower than a predetermined threshold.
The frequency characteristic of the digital audio signal is an upper limit value of a frequency having a frequency component in the digital audio signal. That is, to determine whether the frequency characteristic of the digital audio signal is lower than a predetermined threshold means that the upper limit value of the frequency having the frequency component in the digital audio signal is lower than the predetermined frequency. Is determined.

More specifically, for example, the frequency characteristic determination unit 135 acquires from the digital audio generation unit 112 information indicating the sampling rate of the digital audio signal obtained when the broadcast signal demodulated by the digital audio generation unit 112 is decoded. . Information indicating the sampling rate of the digital audio signal is stored, for example, in the TS header of MP2 in the demodulated broadcast signal. In general, the frequency characteristic can be calculated by reducing the sampling rate to a half value. Therefore, the frequency characteristic of the digital audio signal is calculated from information indicating the sampling rate of the digital audio signal acquired from the digital audio generation unit 112.

サ ン プ リ ン グ The sampling rate of the digital audio signal is, for example, 48 kHz or 24 kHz in DAB. Therefore, the frequency characteristic of the digital audio signal is, for example, 24 kHz or 12 kHz in DAB. For example, when the frequency characteristic of a digital audio signal is 12 kHz, a high-frequency range of 12 kHz or more is omitted when encoded by a compression method such as MP2.

The predetermined threshold value is, for example, a frequency characteristic of analog broadcasting in which the sampling rate estimated from the broadcasting type of analog broadcasting is halved. The broadcast type of the analog broadcast can be determined from the broadcast frequency set in the analog audio generation unit 111 based on the operation information acquired by the operation reception unit 101, for example. The frequency characteristic determination unit 135 acquires, for example, the broadcast frequency set in the analog audio generation unit 111 from the analog audio generation unit 111. For example, if the broadcast frequency is between 47 MHz and 108 MHz, the broadcast type is determined to be FM broadcast. When the broadcast type is FM broadcast, the estimated general sampling rate is 33 kHz. Therefore, the frequency characteristic of analog broadcasting in FM broadcasting is 16.5 kHz. Also, for example, when the broadcast frequency is between 526.5 kHz and 1606.5 kHz, the broadcast type is determined to be AM broadcast. When the broadcast type is AM broadcast, the estimated general sampling rate is 22 kHz. Therefore, the frequency characteristic of analog broadcasting in AM broadcasting is 11 kHz.

The mode output unit 133a determines the synthesis mode based on the result determined by the analog reception quality determination unit 131, the result determined by the bit rate determination unit 132, and the result determined by the frequency characteristic determination unit 135, The signal is output to the audio signal synthesis unit 114a.

More specifically, for example, the mode output unit 133a determines that the reception quality of the broadcast wave of the analog broadcast is good by the analog reception quality determination unit 131 and that the audio bit rate of the digital broadcast is When it is determined that the frequency characteristic of the digital broadcast is lower than the predetermined threshold and the frequency characteristic determination unit 135 determines that the frequency characteristic of the digital broadcast is lower than the predetermined threshold, some of the frequency components in the digital audio signal are analog audio. Since it is presumed that the signal exists in the signal but does not exist in the digital audio signal, the synthesis mode is determined to be mode C.
In the second embodiment, the mode output unit 133a determines that the reception quality of the analog broadcast wave is good by the analog reception quality determination unit 131, and determines the audio bit rate of the digital broadcast by the bit rate determination unit 132 in advance. When the frequency characteristic of the digital broadcast is determined to be lower than the predetermined threshold and the frequency characteristic of the digital broadcast is determined to be lower than the predetermined threshold by the frequency characteristic determination unit 135, an example in which the combining mode is determined to the mode C will be described. Not as long.

For example, the mode output unit 133a determines that the reception quality of the broadcast wave of the analog broadcast is good by the analog reception quality determination unit 131, and that the bit rate determination unit 132 determines that the audio bit rate of the digital broadcast is higher than a predetermined threshold. If the frequency component is determined to be low and the frequency characteristic determination unit 135 determines that the frequency characteristic of the digital broadcast is lower than a predetermined threshold, a frequency component higher in frequency than the frequency characteristic of the digital audio signal is included in the analog audio signal. Since it is presumed that the signal does not exist in the digital audio signal despite its existence, the signal of the frequency component having a higher frequency than the frequency characteristics of the digital audio signal is complemented by the signal of the frequency component of the frequency in the analog audio signal. To generate a synthesized voice signal (hereinafter referred to as “mode D”). It may be determined.

Also, for example, the mode output unit 133a determines that the reception quality of the broadcast wave of the analog broadcast is good by the analog reception quality determination unit 131, and determines the audio bit rate of the digital broadcast by the bit rate determination unit 132 in advance. When it is determined that the frequency characteristic is lower than the threshold value and the frequency characteristic determination unit 135 determines that the frequency characteristic of the digital broadcast is lower than a predetermined threshold value, the combining mode is determined to be a mode combining the modes C and D. May be.

Also, for example, the mode output unit 133a determines that the reception quality of the broadcast wave of the analog broadcast is good by the analog reception quality determination unit 131, and determines the audio bit rate of the digital broadcast by the bit rate determination unit 132 in advance. If it is determined that the sound quality is lower than the threshold value and the frequency characteristic determination unit 135 determines that the frequency characteristic of the digital broadcast is lower than a predetermined threshold value, the sound quality of the analog audio signal is lower than the sound quality of the digital audio signal. Therefore, the combining mode may be determined to be the mode B.

Also, for example, the mode output unit 133a determines that the reception quality of the broadcast wave of the analog broadcast is good by the analog reception quality determination unit 131, and determines the audio bit rate of the digital broadcast by the bit rate determination unit 132 in advance. If the digital audio signal is determined to be lower than the threshold value and the frequency characteristic determination unit 135 determines that the frequency characteristic of the digital broadcast is equal to or greater than the predetermined threshold value, the digital audio signal may include a frequency component in a higher frequency range than the analog audio signal. Regardless, since the audio bit rate of the digital audio signal is lower than the audio bit rate of the analog audio signal, some frequency components in the digital audio signal are present in the digital audio signal despite being present in the analog audio signal. Since it is presumed not to be performed, the combining mode is determined to be mode C.

Also, for example, the mode output unit 133a determines that the reception quality of the broadcast wave of the analog broadcast is good by the analog reception quality determination unit 131, and determines the audio bit rate of the digital broadcast by the bit rate determination unit 132 in advance. When the frequency characteristic is determined to be equal to or more than the threshold value, and the frequency characteristic determination unit 135 determines that the frequency characteristic of the digital broadcast is lower than the predetermined threshold value, a frequency component having a frequency higher than the frequency characteristic of the digital audio signal is converted to the analog audio signal. It is presumed that although exists, it does not exist in the digital audio signal, so that the synthesis mode is determined as mode D.

Also, for example, the mode output unit 133a determines that the reception quality of the broadcast wave of the analog broadcast is good by the analog reception quality determination unit 131, and determines the audio bit rate of the digital broadcast by the bit rate determination unit 132 in advance. If the sound quality of the digital audio signal is determined to be higher than the threshold and the frequency characteristic of the digital broadcast is determined to be equal to or higher than the predetermined threshold by the frequency characteristic determination unit 135, it is estimated that the sound quality of the digital audio signal is better than the sound quality of the analog audio signal. Therefore, the synthesis mode is determined to be mode A.

Also, for example, when the analog reception quality determination unit 131 determines that the reception quality of the analog broadcast wave is not good, that is, the analog output quality determination unit 131 determines that the reception quality of the analog broadcast wave is bad, Since it is assumed that the sound quality is unacceptable for listening, the synthesis mode is determined to be mode A without depending on the result determined by the bit rate determination unit 132 and the result determined by the frequency characteristic determination unit 135. When the analog reception quality determination unit 131 determines that the reception quality of the broadcast wave of the analog broadcast is poor, the analog reception quality determination unit 131 determines the audio bit rate of the digital broadcast by the bit rate determination unit 132 in advance, for example. The bit rate determination unit 132 is set so that the process of determining whether the digital broadcast is lower than the threshold and the process of determining whether the frequency characteristic of the digital broadcast is lower than the predetermined threshold by the frequency characteristic determination unit 135 are not performed. It may be controlled.

In addition, for example, the mode output unit 133a includes a reception mode determination unit 134 in which the combining mode determination unit 113a includes the reception error determination unit 134. The analog reception quality determination unit 131 determines that the reception quality of the broadcast wave of the analog broadcast is good. When it is determined by the unit 134 that the digital broadcast signal acquired from the antenna 12b has a bit error, it is estimated that a digital audio signal has not been generated, so that the combining mode is determined to be mode B.

Note that the analog reception quality determination unit 131, the bit rate determination unit 132, the reception error determination unit 134, and the frequency characteristic determination unit 135 are not necessarily provided in the combining mode determination unit 113a if provided in the broadcast receiving device 100. No need to be.

The audio signal synthesizing unit 114a generates a synthesized audio signal obtained by synthesizing the analog audio signal and the digital audio signal based on the synthesis mode determined by the synthesis mode determination unit 113a.
The audio signal synthesis unit 114a includes, for example, a delay control unit 141, an analog delay adjustment unit 142, a digital delay adjustment unit 143, a volume adjustment unit 144, a frequency component extraction unit 145, and a synthesis unit 146a.

The synthesizer 146a synthesizes the analog audio signal obtained from the frequency component extractor 145 and the digital audio signal obtained from the digital delay adjuster 143 based on the synthesis mode determined by the synthesis mode determiner 113a. And outputs the generated synthesized speech signal to the amplification unit 102.

More specifically, for example, when the synthesizing mode obtained from the synthesizing mode determining unit 113 is mode C, the synthesizing unit 146a adds the frequency component extracting unit 145 to the digital audio signal obtained from the digital delay adjusting unit 143. A synthesized audio signal is generated by synthesizing the signal of the frequency component in the extracted analog audio signal.

In addition, for example, when the synthesis mode obtained from the synthesis mode determination unit 113 is the mode A, the synthesis unit 146a does not synthesize the analog audio signal and the digital audio signal but outputs the digital audio signal obtained from the digital audio generation unit 112. The audio signal is output to the amplifier 102 as a synthesized audio signal.
Further, for example, when the synthesis mode obtained from the synthesis mode determination unit 113 is the mode B, the synthesis unit 146a does not synthesize the analog audio signal and the digital audio signal, and outputs the analog audio signal obtained from the analog audio generation unit 111. The audio signal is output to the amplifier 102 as a synthesized audio signal.
Further, for example, when the synthesis mode obtained from the synthesis mode determination unit 113 is the mode D, the synthesis unit 146a may output the digital audio signal obtained from the digital delay adjustment unit 143 and an analog voice higher than the frequency characteristics of the digital audio signal. A synthesized voice signal is generated by synthesizing the frequency component of the signal and the synthesized voice signal is output to the amplifier 102.

Note that the delay control unit 141, the analog delay adjustment unit 142, the digital delay adjustment unit 143, the volume adjustment unit 144, and the frequency component extraction unit 145 are not necessarily included in the audio signal synthesis unit 114a if provided in the broadcast receiving device 100a. No need to be provided.

Note that, in the second embodiment, the functions of the analog audio generation unit 111, the digital audio generation unit 112, the synthesis mode determination unit 113a, and the audio signal synthesis unit 114a are exemplified in FIGS. 2A and 2B in the first embodiment. It may be realized by the processor 201 and the memory 202 in the illustrated hardware configuration, or may be realized by the processing circuit 203.

The operation of broadcast receiving apparatus 100a according to Embodiment 2 will be described with reference to FIG.
FIG. 11 is a flowchart illustrating processing of broadcast receiving apparatus 100a according to Embodiment 2.
Note that the processing from step ST501 to step ST503 shown in FIG. 11 is the same as the processing from step ST501 to step ST503 shown in FIG. 5, and a description thereof will be omitted.

In step ST503, when the operation information for terminating the reception of the broadcast signal has not been acquired from operation accepting section 101 (step ST503: NO), in step ST1104, combining mode determining section 113a performs the combining mode as described above. To determine. Details of the process of step ST1104 will be described later.

Next, in step ST1105, the audio signal synthesizing unit 114a generates a synthesized audio signal obtained by synthesizing the analog audio signal and the digital audio signal based on the synthesis mode as described above, and amplifies the generated synthesized audio signal. Output to 102. Details of the process of step ST1105 will be described later.
After the process of step ST1105, the broadcast receiving device 100a returns to the process of step ST503 shown in FIG. Specifically, for example, the broadcast receiving apparatus 100a repeatedly executes the processing of steps ST1104 and ST1105 until obtaining operation information for terminating the reception of the broadcast signal from the operation reception unit 101. More specifically, when the access unit of the broadcast signal encoded by MP2 or the like in digital broadcasting is, for example, 125 milliseconds, the processing of steps ST1104 and ST1105 is repeatedly performed every 125 milliseconds. . The access unit is a unit for decoding a broadcast signal encoded by MP2 or the like.

Referring to FIG. 12, the operation of combining mode determining section 113a according to Embodiment 2 in step ST1104 will be described.
FIG. 12 is a flowchart illustrating a process of the combining mode determination unit 113a in the broadcast receiving device 100a according to Embodiment 2.
Note that the processing from step ST601 to step ST604 shown in FIG. 12 is the same as the processing from step ST601 to step ST604 shown in FIG. 6, and a description thereof will be omitted.
In the processing from step ST601 to step ST604 shown in FIG. 6, what is processed by the mode output unit 133 and the audio signal synthesis unit 114 is processed by the mode output unit 133a and the audio signal synthesis unit 114a in FIG. Shall be

In step ST603, when it is determined by reception error determination section 134 that the digital broadcast signal acquired from antenna 12b has no bit error (step ST603: NO), in step ST1205, frequency characteristic determination section 135 As described above, it is determined whether or not the frequency characteristic of the digital broadcast is lower than a predetermined threshold.

In step ST1205, when frequency characteristic determination section 135 determines that the frequency characteristic of digital broadcasting is not lower than the predetermined threshold, that is, the frequency characteristic of digital broadcasting is equal to or higher than the predetermined threshold (step ST1205) : NO), in step ST1206, bit rate determining section 132 determines whether or not the audio bit rate of the digital broadcast is lower than a predetermined threshold.

In step ST1206, when the bit rate determination unit 132 determines that the audio bit rate of the digital broadcast is not lower than the predetermined threshold, that is, that the audio bit rate of the digital broadcast is equal to or higher than the predetermined threshold ( (Step ST1206: NO), the mode output unit 133a performs the process shown in step ST602 as described above.
In step ST1206, when bit rate determining section 132 determines that the audio bit rate of the digital broadcast is lower than a predetermined threshold (step ST1206: YES), in step ST1207, mode output section 133a performs the above-described processing. As described above, the synthesis mode is determined as mode C. After step ST1207, the combining mode determining unit 113a ends the processing of the flowchart illustrated in FIG.

In step ST1205, when frequency characteristic determining section 135 determines that the frequency characteristic of the digital broadcast is lower than a predetermined threshold (step ST1205: YES), in step ST1208, bit rate determining section 132 sets digital broadcast Is determined whether or not the audio bit rate is lower than a predetermined threshold.

In step ST1208, when the bit rate determination unit 132 determines that the audio bit rate of the digital broadcast is not lower than the predetermined threshold, that is, the audio bit rate of the digital broadcast is equal to or higher than the predetermined threshold ( In step ST1208: NO), in step ST1209, the mode output unit 133a determines the synthesis mode to be mode D as described above. After step ST1209, the combining mode determining unit 113a ends the processing of the flowchart illustrated in FIG.
In step ST1208, when the bit rate determination unit 132 determines that the audio bit rate of the digital broadcast is lower than a predetermined threshold (step ST1208: YES), the mode output unit 133a returns to step ST1207 as described above. The following processing is performed.

With reference to FIG. 13A and FIG. 13B, the operation of audio signal synthesis section 114a according to Embodiment 2 in step ST1105 will be described.
FIGS. 13A and 13B are flowcharts illustrating a part of the processing of the audio signal combining unit 114a in the broadcast receiving apparatus 100a according to the second embodiment. The connector illustrated in FIG. 13A and the connector illustrated in FIG. Are connected, a series of processes of the audio signal synthesizing unit 114a in the broadcast receiving apparatus 100a according to the second embodiment is performed.
Note that the processing from step ST701 to step ST709 shown in FIG. 13A or 13B is the same as the processing from step ST701 to step ST709 shown in FIG. Also,
In steps ST701 to ST709 shown in FIG. 7, what is processed by the combining unit 146 and the combining mode determining unit 113 is performed by the combining unit 146a and the combining mode determining unit 113a in FIGS. 13A and 13B. Shall be processed.

In step ST708, when combining section 146a determines that the combining mode is not mode A (step ST708: NO), in step ST1310, combining section 146a sets the combining mode acquired from combining mode determining section 113a to mode D. It is determined whether or not.

In step ST1310, when the combining unit 146a determines that the combining mode is mode D (step ST1310: YES), in step ST1311, the combining unit 146a acquires from the digital delay adjustment unit 143 as described above. A synthetic audio signal is generated by synthesizing the digital audio signal and a frequency component of the analog audio signal higher than the frequency characteristic of the digital audio signal, and outputs the synthesized audio signal to the amplifier 102. After step ST1311, the audio signal synthesis unit 114a ends the processing of the flowcharts illustrated in FIGS. 13A and 13B.
In step ST1310, when combining section 146a determines that the combining mode is not mode D (step ST1310: NO), combining section 146a determines that the combining mode is mode B, for example, in step ST1312. After step ST1312, in step ST1313, the analog audio signal obtained from the analog audio generation unit 111 is output to the amplification unit 102 as a synthesized audio signal without synthesizing the analog audio signal and the digital audio signal. After step ST1313, the audio signal synthesizing unit 114a ends the processing of the flowcharts shown in FIGS. 13A and 13B.

Note that the audio signal synthesizing unit 114a may perform the processing from step ST701 to step ST705 only when the synthesis mode is neither mode A nor mode B.

As described above, the broadcast receiving device 100a includes the analog audio generation unit 111 that generates an audio signal from the obtained analog broadcast signal, the digital audio generation unit 112 that generates an audio signal from the obtained digital broadcast signal, When the reception quality of the analog broadcast is good, the synthesis mode determination unit 113a that determines the synthesis mode according to the audio bit rate of the digital broadcast and the frequency characteristics of the audio signal generated by the digital audio generation unit 112; An audio signal synthesizing unit 114a that generates a synthesized audio signal by synthesizing the audio signal generated by the generation unit 111 and the audio signal generated by the digital audio generation unit 112 based on the synthesis mode determined by the synthesis mode determination unit 113a; , With.
With this configuration, the broadcast receiving apparatus 100a can output an audio signal with higher sound quality than an audio signal obtained from a digital broadcast wave when the reception quality of the analog broadcast is good.

In the present invention, within the scope of the invention, any combination of the embodiments can be freely selected, or any of the constituent elements of each of the embodiments can be modified, or any of the constituent elements can be omitted in each of the embodiments. .

The broadcast receiving device according to the present invention can be applied to an audio device.

1 vehicle, 10, 10a vehicle-mounted acoustic device, 11 audio output device, 12, 12a, 12b antenna, 100, 100a broadcast receiving device, 101 operation reception unit, 102 amplification unit, 111 analog audio generation unit, 112 digital audio generation unit , 113, 113a {synthesis mode determination section, 114, 114a} audio signal synthesis section, 131} analog reception quality determination section, 132} bit rate determination section, 133, 133a {mode output section, 134} reception error determination section, 135 # frequency characteristic determination section, 141 Delay control section, 142 analog delay adjustment section, 143 digital delay adjustment section, 144 volume control section, 145 frequency component extraction section, 146, 146a synthesis section, 201 processor, 202 memory, 203 processing circuit.

Claims (11)

1. An analog audio generation unit that generates an audio signal from the acquired analog broadcast signal;
   A digital audio generation unit that generates an audio signal from the acquired digital broadcast signal,
   When the reception quality of the analog broadcast is good, a synthesis mode determination unit that determines a synthesis mode according to the audio bit rate of the digital broadcast,
   Speech signal synthesis for generating a synthesized speech signal by synthesizing the audio signal generated by the analog audio generation unit and the audio signal generated by the digital audio generation unit based on the synthesis mode determined by the synthesis mode determination unit Department and
   A broadcast receiving device comprising:
2. When the audio bit rate of the digital broadcast is lower than the audio bit rate estimated from the broadcast type of the analog broadcast, the synthesis mode determination unit determines a signal of a weak frequency component in the audio signal generated by the digital audio generation unit. And determining the synthesis mode so as to generate the synthesized audio signal by complementing with a signal of a frequency component having the same frequency as the frequency component in the audio signal generated by the analog audio generation unit. 2. The broadcast receiving device according to 1.
3. When the reception quality of the analog broadcast is good, the synthesis mode determination unit sets the synthesis mode according to the audio bit rate of the digital broadcast and the frequency characteristics of the audio signal generated by the digital audio generation unit. The broadcast receiving device according to claim 1, wherein the broadcast receiving device is determined.
4. The synthesizing mode determination unit may be configured such that the audio bit rate of the digital broadcast is higher than an audio bit rate estimated from a broadcast type of the analog broadcast, and the frequency characteristic of the audio signal generated by the digital audio generation unit is the analog signal. When the frequency characteristic of the audio signal generated by the audio generation unit is worse than the frequency characteristic of the audio signal generated by the digital audio generation unit, a signal of a frequency component having a higher frequency than the frequency characteristic of the audio signal generated by the analog audio generation unit is output. The broadcast receiving apparatus according to claim 3, wherein the synthesis mode is determined so as to generate the synthesized audio signal by complementing with a signal of a frequency component of the frequency.
5. The synthesizing mode determining unit may be configured such that the audio bit rate of the digital broadcast is lower than the audio bit rate estimated from the broadcast type of the analog broadcast, and the frequency characteristic of the audio signal generated by the digital audio generator is the analog signal. If the frequency characteristic of the audio signal generated by the audio generation unit is better, the signal of the weak frequency component in the audio signal generated by the digital audio generation unit is set to the same frequency as the frequency component in the audio signal generated by the analog audio generation unit. The broadcast receiving apparatus according to claim 3, wherein the synthesizing mode is determined so as to generate the synthesized voice signal by complementing with the signal of the frequency component.
6. The synthesizing mode determination unit may be configured such that the audio bit rate of the digital broadcast is higher than an audio bit rate estimated from a broadcast type of the analog broadcast, and the frequency characteristic of the audio signal generated by the digital audio generation unit is the analog signal. When the frequency characteristic of the audio signal generated by the audio generation unit is better, a signal of a frequency component having a frequency higher than the frequency characteristic of the audio signal generated by the digital audio generation unit is output in the audio signal generated by the analog audio generation unit. Complemented by the signal of the frequency component of the frequency, further, the signal of the weak frequency component in the audio signal generated by the digital audio generation unit, the frequency of the same frequency as the frequency component in the audio signal generated by the analog audio generation unit The synthesis mode so as to generate the synthesized speech signal by complementing with a component signal Determining a broadcast receiving apparatus according to claim 3, characterized in that the.
7. The synthesizing mode determination unit may be configured such that the audio bit rate of the digital broadcast is higher than an audio bit rate estimated from a broadcast type of the analog broadcast, and the frequency characteristic of the audio signal generated by the digital audio generation unit is the analog signal. When the frequency characteristic of the audio signal generated by the audio generation unit is better than the audio signal generated by the analog audio generation unit and the audio signal generated by the digital audio generation unit, the digital audio generation unit The broadcast receiving apparatus according to claim 3, wherein the synthesis mode is determined so that the generated audio signal is used as the synthesized audio signal.
8. The synthesizing mode determining unit may be configured such that the audio bit rate of the digital broadcast is lower than the audio bit rate estimated from the broadcast type of the analog broadcast, and the frequency characteristic of the audio signal generated by the digital audio generator is the analog signal. If the frequency characteristic of the audio signal generated by the audio generation unit is worse than the audio signal generated by the analog audio generation unit and the audio signal generated by the digital audio generation unit, the analog audio generation unit The broadcast receiving apparatus according to claim 3, wherein the synthesis mode is determined so that the generated audio signal is used as the synthesized audio signal.
9. The synthesizing mode determining unit, when the reception quality of the analog broadcast is good and the acquired broadcast signal of the digital broadcast has a bit error, the audio signal generated by the analog audio generation unit, and the digital audio The synthesis mode is determined such that the audio signal generated by the analog audio generation unit is used as the synthesized audio signal without synthesizing the audio signal generated by the generation unit. Broadcast receiver.
10. When the reception quality of the analog broadcast is poor, the synthesis mode determination unit does not synthesize the audio signal generated by the analog audio generation unit and the audio signal generated by the digital audio generation unit, and outputs the digital audio. The broadcast receiving apparatus according to claim 1, wherein the synthesis mode is determined so that the synthesized audio signal is generated only from the audio signal generated by the generation unit.
11. An analog audio generation unit generates an audio signal from the acquired analog broadcast signal,
    A digital audio generation unit generates an audio signal from the acquired digital broadcast signal,
    When the reception quality of the analog broadcast is good, the synthesis mode determination unit determines the synthesis mode according to the audio bit rate of the digital broadcast.The audio signal synthesis unit outputs the audio signal generated by the analog audio generation unit. And generating a synthesized audio signal obtained by synthesizing the audio signal generated by the digital audio generation unit based on the synthesis mode determined by the synthesis mode determination unit.

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