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DESCRIPTION JP2011114663

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DESCRIPTION JP2011114663
PROBLEM TO BE SOLVED: To prevent a decrease in usage efficiency of a circuit that makes it
difficult to distort an audio signal even when the amplitude of the audio signal increases when
generating audio data of the first number of channels. SOLUTION: When audio data of a first
number of channels is generated, a part of a circuit that makes the audio signal less likely to be
distorted even if the amplitude of the audio signal is increased is shared, and is more than the
first channel number. Audio data of the second channel number having a large number of
channels is generated. [Selected figure] Figure 2
Audio signal processing device
[0001]
The present invention relates to an audio signal processing apparatus, and more particularly to
an audio signal processing apparatus that converts an analog audio signal indicating acquired
audio into a digital signal.
[0002]
2. Description of the Related Art Conventionally, as an apparatus for processing an audio signal,
an imaging apparatus for recording an image signal and recording an audio signal is known.
In these imaging devices, external sound obtained by the microphone is converted into an
electric signal to obtain an analog sound signal. Then, in order to perform various digital signal
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1
processing and to record on a recording medium, the A / D converter converts an analog voice
signal amplified by a predetermined amount into a digital voice signal. However, in an AD
converter used for an imaging device or the like, for example, since the dynamic range is about
90 dB, the waveform of the digital audio signal when audio at an audio level higher than that set
by the AD converter is input to the microphone I will be distorted.
[0003]
Conventionally, such a problem has been addressed by using a technique as disclosed in Patent
Document 1. That is, the input analog voice signal is branched, one analog voice signal is
converted into a digital voice signal without attenuation of the amplitude, and the other analog
voice signal is converted into a digital signal after the amplitude is attenuated, The previously
attenuated signal is amplified as a digital signal. Then, the level of the analog voice signal is
monitored, and when the amplitude of the analog voice signal becomes larger than a
predetermined level, the other analog voice signal (a signal obtained by attenuating the
amplitude of the analog voice signal) is used. By doing so, distortion of the digital audio signal
converted from the analog audio signal is reduced.
[0004]
Japanese Patent Application Publication No. 07-86943
[0005]
In the technique of Patent Document 1, in order to convert one analog audio signal into a digital
audio signal, the analog audio signal is branched into two and recombined after digital
conversion.
Therefore, it has been necessary to prepare a circuit for converting an analog voice signal to a
digital voice signal twice as much as the input analog voice signal. However, it has not been
disclosed that this circuit is used for applications other than reducing distortion when converting
an analog audio signal of a level higher than a predetermined level into a digital audio signal.
[0006]
Therefore, an object of the present invention is to provide an audio signal processing apparatus
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capable of increasing the number of channels of audio data to be obtained by using a circuit for
reducing distortion of a digital audio signal for other audio processing. I assume.
[0007]
In order to achieve the above object, the audio signal processing device of the present invention
is amplified by an input unit for inputting an analog audio signal, an amplification unit for
amplifying an analog audio signal input by the input unit, and the amplification unit. Digital audio
signal of n channels and digital audio signal of m channels (m> n) using AD conversion means for
converting an analog audio signal into a digital audio signal and the digital audio signal
outputted from the AD conversion means A first mode in which the input means generates a first
predetermined number of analog audio signals, and the audio processing means generates the nchannel digital audio signals; Means for inputting a second predetermined number of said analog
speech signals more than a first predetermined number of analog speech signals, said speech
processing means comprising Mode selecting means for selecting one of the second modes for
generating the digital audio signal of the loop, the amplification means, the AD conversion
means, and the audio processing means according to the mode selected by the mode selecting
means Control means for controlling the first audio signal and the second audio signal in the first
mode, each of the first predetermined number of analog audio signals input by the input means,
The A / D converter controls the amplification means to amplify and output the signal at a
second amplification factor smaller than the amplification factor of 1, and converts the analog
audio signal output from the amplification means into a digital audio signal. Means for
controlling the digital audio signal output from the AD conversion means when the level of the
analog audio signal input by the input means is greater than a predetermined level The n-channel
digital audio signal is generated using the first predetermined number of digital audio signals
amplified by the second amplification factor, and the level of the analog audio signal input by the
input unit is the predetermined The digital audio signal of the n channel is generated using the
first predetermined number of digital audio signals amplified by the first amplification factor
among the digital audio signals output from the AD conversion means when the level is lower
than the level To control the audio processing means so that, in the second mode, each of the
second predetermined number of analog audio signals input by the input means is amplified at a
predetermined amplification factor and output. Controlling the amplification means and
controlling the A / D conversion means to convert the analog sound signal output from the
amplification means into a digital sound signal, respectively; The audio processing means is
controlled to generate the m-channel digital audio signal using the second predetermined
number of digital audio signals output from the AD conversion means.
[0008]
According to the present invention, the number of channels of obtained audio data can be
increased by using a circuit for reducing distortion of a digital audio signal for other audio
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processing.
[0009]
It is a block diagram of an imaging device of this example.
FIG. 2 is a block diagram of a voice input unit 102
It is a graph which shows the audio | voice signal in each part of an imaging device.
[0010]
Hereinafter, embodiments of the present invention will be described in detail with reference to
the drawings.
[0011]
An imaging device capable of processing and recording an audio signal will be described.
[0012]
FIG. 1 is a block diagram showing the configuration of the imaging device 100 of the first
embodiment.
In FIG. 1, an imaging unit 101 captures an image of a subject to obtain image data.
The voice input unit 102 collects voices around the imaging device 100 with a microphone,
converts the obtained analog voice signal to analog to digital, controls amplitude (level control),
and generates stereo or multi-channel voice data. Do.
The operation of the voice input unit 102 will be described later. The memory 103 temporarily
stores image data obtained by the imaging unit 101 and voice data obtained by the voice input
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unit 102. The display control unit 104 causes the display unit 105 to display an image related to
image data obtained by the imaging unit 101, an operation screen of the imaging apparatus 100,
a menu screen, and the like. The encoding processing unit 106 reads out image data and audio
data temporarily stored in the memory 103, performs predetermined encoding, and generates
compressed image data, compressed audio data, and the like. The recording / reproducing unit
107 records the compressed image data, the compressed audio data, etc. generated by the
encoding processing unit 106 in the recording medium 108, the compressed image data
recorded in the recording medium 108, the compressed audio data, Read various data and
programs. The recording medium 108 includes any recording medium such as an optical disk, a
magnetic recording medium, and a semiconductor memory. The control unit 109 includes a CPU,
a memory, and the like, and outputs a control signal for controlling each block of the imaging
device 100. The operation unit 110 is an operation unit for inputting an instruction from the
user, and includes a button, a switch, a dial, and the like. The audio output unit 111 transmits
compressed audio data reproduced by the recording / reproducing unit 107, an audio signal
output by the control unit 109, and the like to the speaker 112 and an audio output terminal (not
shown). The speaker 112 is a speaker that outputs the audio signal output from the audio output
unit 111 as audio. The external output unit 113 can output the video and audio reproduced by
the recording and reproducing unit 107 to an external device. The data bus 114 supplies various
data such as audio data and image data and control signals to each block of the imaging device
100.
[0013]
Here, the normal operation of the imaging device 100 of the present embodiment will be
described. The imaging apparatus of this embodiment can select, for example, 5.1 ch or 2 ch
audio recording, and the number of channels is selected by the user's instruction. Also, the
setting of the number of channels may be changed according to the identification ID of the
connected microphone or the like.
[0014]
In response to the operation of the power switch of the operation unit 110, the control unit 109
instructs each block of the imaging apparatus to start up. When activation is instructed by the
control unit 109, it is detected whether the mode switch of the operation unit 110 is in the
shooting mode, the reproduction mode, or the audio only recording mode.
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[0015]
When the mode switch of the operation unit is in the shooting mode, the control unit 109
transmits a control signal to each block of the imaging device 100 to shift to the shooting
standby state. When shifting to the imaging standby state according to the control signal output
from the control unit 109, each block of the imaging device 100 operates as follows.
[0016]
The imaging unit 101 converts an optical image of a subject captured by a shooting lens into an
electrical signal by an imaging element, converts an obtained analog image signal into a digital
image signal, and performs various image processing to obtain image data. Then, the image data
is transmitted to the display control unit 104, and the image is displayed on the display unit 105.
The user determines the shooting angle of view while checking the image displayed on the
display unit 104. Further, the audio input unit 102 converts a plurality of analog audio signals
obtained by collecting surrounding sounds with a plurality of microphones into digital audio
signals. Then, control (level control) and the like of the amplitudes of the plurality of digital audio
signals are performed to obtain stereo or multi-channel audio data. The obtained audio data is
input to the audio output unit 111, and the audio is output from the connected speaker or
headphone. The user adjusts the volume at the time of shooting while checking the outputted
sound.
[0017]
In the imaging standby state, when the user operates the operation unit 110 to instruct imaging
start, the control unit 109 transmits a control signal of imaging start to each block of the imaging
device 100. When imaging is started, each block of the imaging device 100 operates as follows.
[0018]
The imaging unit 101 converts an optical image of a subject captured by a shooting lens into an
electrical signal by an imaging element, converts an obtained analog image signal into a digital
image signal, and performs various image processing to obtain image data. Then, the control unit
109 temporarily stores the image signal obtained by the imaging unit 101 in the memory 103,
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and the encoding processing unit 106 encodes the image data stored in the memory to generate
compressed image data.
[0019]
On the other hand, the voice input unit 102 converts a plurality of analog voice signals obtained
by collecting surrounding sounds with a plurality of microphones into digital voice signals. Then,
control (level control) and the like of the amplitudes of the plurality of digital audio signals are
performed to obtain stereo or multi-channel audio data. The control unit 109 temporarily stores
the voice data obtained by the voice input unit 102 in the memory 103. The encoding processing
unit 106 encodes the audio data stored in the memory to generate compressed audio data.
[0020]
Then, the control unit 109 combines the compressed image data and the compressed audio data
to form a data stream, and outputs the data stream to the recording and reproducing unit 107.
The recording / reproducing unit 107 writes the data stream as one moving image file on the
recording medium 108 under file system management such as UDF or FAT based on an
instruction from the control unit 109. During shooting, image data obtained by the imaging unit
101 is transmitted to the display control unit 104 as necessary, and an image related to the
image data is displayed on the display unit 105.
[0021]
Here, when the user operates the shooting end button of the operation unit 110, the control unit
109 transmits a control signal of shooting end to the imaging unit 101, the voice input unit 102,
the encoding processing unit 106, the recording and reproducing unit 107, and the like. Stop
shooting. When receiving the control signal for ending the shooting, the imaging unit 101 and
the audio input unit 102 stop generating the image data and the audio data. Further, the
recording / reproducing unit 107 ends the recording operation after recording the compressed
image data from the start to the end of shooting and the compressed image data as one file on
the recording medium 108. Then, the control unit 109 causes the imaging device 100 to shift to
the imaging standby state again.
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[0022]
When the mode switch of the operation unit 107 is in the reproduction mode, the control unit
109 transmits a control signal for reproducing the image to each block of the imaging device
100. The imaging apparatus 100 according to the present embodiment can record audio data in
addition to the still image file and the moving image file reproduced in the reproduction mode.
When transitioning to the reproduction mode, each block of the imaging device 100 performs
the following operation.
[0023]
The recording / reproducing unit 107 reads the file consisting of the compressed image data and
the compressed audio data recorded on the recording medium 108, and the read compressed
image data and the compressed audio data are sent to the encoding processing unit 106. The
encoding processing unit 106 decodes the compressed image data and the compressed audio
data, and transmits them to the display control unit 104 and the audio output unit 111,
respectively.
[0024]
At this time, when the user operates the operation unit 110, additional recording of audio data is
possible. In that case, the control unit 109 sends a control signal for recording voice to the voice
input unit 102, the coding processing unit 106, etc., and sends the compressed voice data
generated as described above to the recording / playback unit 107. , Relating to the file being
reproduced and recorded on the recording medium 108. When the user instructs the end of the
voice from the control unit 109 by operating the operation unit 110, the compressed voice data
generated so far is recorded on the recording medium 108, and then the recording is ended.
[0025]
Also in the case of the audio only recording mode, the control unit 109 transmits a control signal
for recording the audio to the audio input unit 102, the encoding processing unit 106, etc., and
the compressed audio data generated as described above Are transmitted to the recording /
reproducing unit 107 and recorded on the recording medium 108.
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[0026]
In the present embodiment, when the voice input unit 102 obtains a voice, processing to be
described later is performed.
This process may be performed constantly when capturing an audio, or may be performed only
when recording an audio.
[0027]
Here, the process performed in the voice input unit 102 will be described with reference to FIG.
In FIG. 2, the microphone unit 201 is composed of a plurality of omnidirectional microphone
elements that collect surrounding sound, convert sound vibration into an electrical signal, and
obtain a sound signal. In the present embodiment, four microphone elements are used, but the
number of microphone elements may be two or more. The microphone unit may be built in the
imaging device 100 or may be a detachable external microphone unit connected to the
microphone terminal of the imaging device 100.
[0028]
In the imaging apparatus of the present embodiment, the operation unit 110 includes a mode
selection unit for selecting an audio channel. When the user operates the mode selection unit of
the operation unit 110, the audio channel can be set to 5.1 channel mode or 2 channel mode.
Then, audio data of different number of channels can be generated according to the set number
of channels. The user operates the operation unit 110 to set the audio channel mode to the 5.1
channel mode or the 2 channel mode, the first channel number mode, and the second channel
number smaller than the first channel number. A number of modes can be selected.
[0029]
The selection unit 202 selects an analog audio signal obtained by the microphone unit 201
according to whether the set audio channel is in the 5.1 ch mode or the 2 ch mode. In the case of
5.1ch mode, 4 analog audio signals obtained by 4 microphone elements are selected as input
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signals, and in 2ch mode, 2 analog audio signals obtained by 2 microphone elements are
selected. The four branched analog audio signals are selected as input signals. In the microphone
unit 201 of this embodiment, four microphone elements are arranged in the front, rear, left, and
right with respect to the photographing optical axis direction. In the 2ch mode, four analog audio
signals obtained by branching analog audio signals obtained by two microphone elements
arranged on the left and right with respect to the imaging optical axis direction are selected as
inputs.
[0030]
The amplification unit 203 amplifies a plurality of analog audio signals input at a designated
amplification factor. The amplification unit 203 includes two amplification units A that amplify
an analog voice signal input at an amplification factor α. The amplification unit 203 further
includes two amplification units B that amplify at an amplification factor α when the selected
audio channel is 5.1 ch, but amplify at an amplification factor α / 10 when two channels are
selected. . The AD conversion unit 204 converts the input analog audio signal into a digital audio
signal with a predetermined dynamic range.
[0031]
The selection unit 205 transmits the signal obtained from the microphone element to the 5.1ch
processing unit 206 or the stereo processing unit 207 depending on whether the selected audio
channel is 5.1ch or 2ch. Select to send to.
[0032]
The 5.1ch processing unit 206 (second generation unit) generates 5.1ch audio data of more than
2ch from the input four digital audio signals.
The method of generating 5.1 ch audio data from the four audio signals uses the existing
technology, so the description is omitted. The stereo processing unit 207 (first generation unit)
generates 2ch of audio data from the two input digital audio signals. The method of generating
2ch audio data from 2 audio signals uses the existing technology, so the description is omitted.
[0033]
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Although the 5.1ch processing unit 206 and the stereo processing unit 207 are illustrated as
separate blocks in this embodiment, processing for generating 5.1ch audio data, processing for
generating 2ch audio data, and selection It may be a single audio processing unit that can be
executed.
[0034]
When the 5.1 ch mode is selected, the amplification unit 208 amplifies the digital signal
corresponding to the analog audio signal amplified at the amplification factor α / 10 by the
amplification unit B by k times.
The amplification unit 208 corresponds to a digital signal corresponding to an analog speech
signal amplified at an amplification factor α at an amplification part A of a predetermined
speech level and an analog speech signal amplified at an amplification factor α / 10 at an
amplification part B. The amplification factor k is determined so that the amount of change per
sample with the digital signal is the same. If it is an ideal A / D converter, etc., there is no error,
so it should be amplified 10 times, but since the A / D converter also generates an error
depending on the temperature etc., it has such a configuration . The selection unit 209 normally
selects a digital audio signal that has not passed through the amplification unit 208, and the
digital audio amplified by the amplification unit 208 when the level of the analog audio signal
obtained by the microphone is equal to or higher than a predetermined level. Select a signal. In
this embodiment, the level of the analog audio signal obtained by the microphone is equal to or
higher than a predetermined level. However, the level of the analog audio signal itself may be
measured. The level of the digital signal corresponding to the analog audio signal may be
measured. Alternatively, the level of a digital signal corresponding to an analog voice signal
amplified at amplification factor α / 10 by the amplification unit B may be measured by the
amplification unit 208 by a factor of k.
[0035]
Here, processing when the audio input unit 102 generates audio data of two channels will be
described.
[0036]
When 2ch audio is generated, a control signal indicating that 2ch recording is performed is
output from control unit 109, and selection unit 202, amplification unit 203, and selection unit
205 are operated as follows according to the control signal. .
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[0037]
The selection unit 202 selects a signal obtained by branching two analog audio signals obtained
by microphones disposed on the left and right with respect to the photographing optical axis
direction, and selects the analog audio signals as the amplifiers A and B. Switch the switch to
input to.
The amplification unit 203 amplifies one analog audio signal branched from one analog audio
signal at an amplification factor α and the other analog audio signal branched at an
amplification factor α / 10.
That is, the control unit 109 controls the amplification factor of the amplification unit B to be
amplified at the amplification factor α / 10. Then, the A / D conversion unit 203 converts each
of the output four audio signals into a digital audio signal. The control unit 109 performs switch
control of the selection unit 205 so as to lead four digital audio signals to the stereo processing
unit 207.
[0038]
The amplification unit 208 amplifies the signals after digital conversion corresponding to the
analog voice signal amplified by the amplification factor α / 10 by k times. Then, the selection
unit 209 selects the digital audio signal amplified by the amplification unit 208 when the level of
the input analog audio signal becomes equal to or higher than a predetermined level, and in the
other case, the amplification unit 208. Select a digital signal not amplified by.
[0039]
The stereo processing unit 207 generates audio data of 2ch based on the input two digital audio
signals by the above-described existing technology.
[0040]
In the following, as described above, the reason for amplifying an audio signal with different
amplification factors and selecting an audio signal amplified with a small amplification factor
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when the level of the audio signal becomes equal to or higher than a predetermined level This
will be described using 3.
[0041]
In FIG. 3, the horizontal axis represents time, and the vertical axis represents the amplitude level
(volume).
FIG. 3A shows an analog audio signal input from the microphone.
(B) shows a digital audio signal corresponding to the analog audio signal amplified at the
amplification factor α by the amplification unit A. (C) shows a digital audio signal corresponding
to the analog audio signal amplified by the amplification unit B at an amplification factor α / 10.
(D) shows a digital audio signal input to the stereo processing unit 207.
[0042]
In FIG. 3, (b) to (d) show a line 301 corresponding to the dynamic range of the A / D conversion
unit 204. The A / D converter 204 can not convert the signal of the volume exceeding the
dynamic range into a digital signal, and as shown in FIG. 3B, the digital audio signal clipped at
the maximum value of the dynamic range Become. If audio data of 2ch is generated with such a
signal as it is, noise will be generated at the time of reproduction. That is, distortion of the audio
signal occurs.
[0043]
Therefore, in the present embodiment, the analog voice signal amplified by the amplification
factor α / 10 is digitally converted by the A / D converter. In this case, since the amplification
factor is low, as shown in FIG. 3C, since the dynamic range of the A / D conversion unit 204 is
not exceeded, digital conversion can be performed normally.
[0044]
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Then, in the selection unit 209, when the level of the audio signal exceeds a predetermined level
(the audio signal amplified by the amplification factor α is an arbitrary value within a range not
exceeding the maximum value of the dynamic range), The audio signal re-amplified by k times by
the amplification unit 208 is selected. In FIGS. 3B and 3D, a line 302 indicating this
predetermined level is shown.
[0045]
By doing this, as shown in FIG. 3B, the digital signal of the audio signal amplified by the
amplification factor α by the amplification unit A and the audio signal amplified by the
amplification factor α / 10 by the amplification unit B Can be selectively input to the stereo
processing unit 207 as a signal obtained by amplifying the digital signal of the signal x by a
factor of k. That is, as long as the level of the audio signal is smaller than the predetermined level
(the level corresponding to the line 302), the digital audio signal corresponding to the output of
the amplification unit A is input to the stereo processing unit 207. Then, when the level of the
audio signal exceeds a predetermined level (the level corresponding to the line 302), the digital
audio signal corresponding to the output of the amplification unit B is amplified by k times by the
amplification unit 208 to a stereo processing unit Input at 207. In FIG. 3D, the waveform of the
solid line is a digital audio signal corresponding to the output of the amplification unit A, and the
waveform of the dashed line is the digital audio signal corresponding to the amplification unit B
amplified by k times by the amplification unit 208 It shows a digital audio signal.
[0046]
As understood from FIG. 3D, the above-described processing can reduce the possibility of
distortion of the digital audio signal when the audio volume is high.
[0047]
Subsequently, processing for generating 5.1 ch audio data will be described.
When 5.1-ch audio data is to be generated, an instruction signal indicating that 5.1-channel
recording is to be performed is output from the control unit 109, and the selection unit 202, the
amplification unit 203, and the selection unit 205 are respectively described below according to
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the instruction signal. Act like. The selection unit 202 switches switches so that the four analog
audio signals obtained by the microphones arranged at the front, rear, left, and right with respect
to the photographing optical axis direction are respectively input to the amplification unit A and
the amplification unit B. The amplification unit 203 amplifies each of the four types of input
analog audio signals at an amplification factor α. That is, when audio data of 2 ch is generated,
the control unit 109 controls the amplification unit B which has been amplified at the
amplification factor α / 10 to be amplified at the amplification factor α. Then, the A / D
conversion unit 203 converts each of the output four audio signals into a digital audio signal. The
selection unit 205 switches the switch so as to introduce four digital audio signals to the 5.1 ch
processing unit 206.
[0048]
Then, the 5.1ch processing unit 206 generates 5.1ch audio data based on the input four digital
audio signals by the existing technology as described above.
[0049]
As described above, in the two-channel mode, the audio input unit 102 of the present
embodiment respectively receives the analog audio signals of the two microphone elements as
the first amplification factor and the second amplification factor smaller than that in the
amplification section 203. To generate four analog audio signals amplified by.
Then, when the level of the audio signal is larger than the predetermined level, the analog audio
signal amplified by the second amplification factor is converted into a digital audio signal by the
AD conversion unit 204 and then amplified again using the digital audio signal. Generate 2ch
audio data. Also, when the level of the audio signal is less than or equal to (less than) a
predetermined level, 2 ch audio data is generated using the digital audio signal obtained by
converting the analog audio signal amplified by the first amplification factor by the AD converter
204. Do. Such a configuration can reduce the possibility of distortion of the waveform of the
digital audio signal by exceeding the dynamic range of the AD conversion unit 204 even when
the level of the audio signal increases. Then, in the 5.1 channel mode, the analog audio signals
from the four microphone elements are amplified at the same amplification factor to generate
four analog audio signals using the amplification unit 203 used in the two channel mode. Then,
the four analog audio signals are converted into digital audio signals by the AD conversion unit
204 used in the two-channel mode to generate 5.1 ch audio data.
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[0050]
With such a configuration, the amplification unit 203 and the AD conversion unit 204 can be
shared in the 2-channel mode and the 5.1-channel mode, so that the usage efficiency of the
circuit can be increased.
[0051]
Further, although the imaging apparatus has been described in the present embodiment, the
audio processing of the audio input unit 102 in the present embodiment may be any apparatus
as long as it is an apparatus that records or inputs external audio. Even if there is, it can be
applied.
For example, the present invention may be applied to an IC recorder, a mobile phone, a personal
computer and the like.
[0052]
Further, in the present embodiment, an example in which audio data of two channels and
multichannel audio data of 5.1 channels are generated has been described, but the present
invention is applied to the case of generating audio data of other channels. good. For example, an
analog audio signal input by one microphone is branched, amplified at amplification factors
different in magnitude, and then digital-converted to generate a digital audio signal. When the
level of the analog audio signal is equal to or higher than a predetermined level, a signal obtained
by amplifying a digital audio signal corresponding to the analog audio signal amplified at a small
amplification factor is used. Then, when the level of the analog audio signal is equal to or lower
than a predetermined level, a digital audio signal corresponding to the analog audio signal
amplified at a large amplification factor is used. In the audio processing apparatus capable of
generating a monaural audio signal in this manner, the analog audio signals input from the two
microphones are respectively amplified by a predetermined amplification factor and then
converted into digital signals, respectively. Generate Then, audio data of two channels (stereo)
can be generated based on the obtained two digital audio signals.
[0053]
As described above, as in the imaging apparatus of this embodiment, when generating audio data
of one channel (monaural), audio data of two channels more than one channel is shared by
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sharing a circuit that reduces the possibility of distortion of the audio signal. Can be generated.
[0054]
Similarly, in the first mode, a circuit for reducing distortion of a digital audio signal at a large
volume when generating audio data of n channels from analog audio signals obtained from a first
predetermined number of microphones. Share.
In the second mode, even in the case of an audio signal processing apparatus capable of
generating audio data of m channels more than n channels from analog audio signals obtained
from a second predetermined number of microphones larger than the predetermined number,
You can get the effect of
[0055]
Although the imaging apparatus has been described in this embodiment, any apparatus may be
used as long as it is not an imaging apparatus and can process audio.
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