close

Вход

Забыли?

вход по аккаунту

?

JP2006279508

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2006279508
An object of the present invention is to improve the sound quality of sound output from a
speaker. According to the present invention, an audio signal S1 is amplified by a power amplifier
12 to generate an amplified audio signal S3, and a current detection resistor 13 and a differential
amplifier 14 provided between the power amplifier 12 and the speaker 2. Thus, when the
amplified audio signal S3 is supplied as the output audio signal S4 to the speaker 2, the current
waveform of the amplified audio signal S3 and the output audio signal S4 on which the distortion
component is superimposed due to the influence of the speaker 2 is the The distortion
component signal S6 is detected based on the difference between the current detection signal S5
and the audio signal S1, and the distortion component adder 11 adds the distortion component
signal S6 to the audio signal S1 to obtain the addition result as a power amplifier. It was supplied
to 12. [Selected figure] Figure 1
Audio signal amplifier and distortion correction method
[0001]
The present invention relates to an audio signal amplification apparatus and a distortion
correction method, and is suitably applied to an audio apparatus that amplifies an externally
supplied audio signal and sends it to an external speaker, for example.
[0002]
Conventionally, in an audio apparatus, an audio signal supplied from an external CD (Compact
Disc) player or the like is amplified and sent out to an external speaker, whereby a sound
corresponding to the audio signal is output from the speaker. What has been done is widespread.
08-05-2019
1
[0003]
Here, in general, a speaker generates a magnetic force by flowing an amplified audio signal
supplied from an audio device, that is, an electric signal to a voice coil to vibrate a diaphragm,
but the general nature of the coil causes When an electric signal flows through the voice coil, a
back electromotive force is generated.
[0004]
Therefore, the audio apparatus has a problem that distortion is generated in the amplified audio
signal supplied to the speaker by the back electromotive force from the speaker, and the sound
quality of the sound output from the speaker is degraded.
[0005]
In order to solve this problem, a low distortion speaker device has been proposed as an audio
device that employs a negative feedback method for reducing distortion components of the
current waveform flowing through the voice coil of the speaker (see, for example, Patent
Document 1).
JP-A-62-120195 (pages 1-2, FIG. 4)
[0006]
However, in the audio device having such a configuration, since the current detection resistor is
connected between the ground and the speaker, noise is generated from the power supply circuit
or the like in the audio device, and the current detection resistor is So-called regenerative current
may flow.
[0007]
In this case, since the audio apparatus can not correctly detect only the current flowing to the
speaker due to the influence of the regenerative current, the distortion component due to the
back electromotive force can not be correctly extracted, and the distortion due to the back
electromotive force is completely eliminated. There is a problem that the sound quality of the
sound output from the speaker is lowered without being able to
08-05-2019
2
[0008]
The present invention has been made in consideration of the above points, and an object of the
present invention is to propose an audio signal amplification device and a distortion correction
method capable of improving the sound quality of the sound output from the speaker.
[0009]
In order to solve such problems, in the present invention, an audio signal is amplified by an
amplifier to generate an amplified audio signal, and before the audio signal amplified by the
amplifier is supplied to a speaker, distortion components are generated by the influence of the
speaker. A current waveform of the superimposed audio signal is detected, a distortion
component is calculated based on a difference between the current waveform and the signal
waveform of the audio signal, and an addition result obtained by adding the distortion
component to the audio signal is supplied to the amplifier. did.
[0010]
Thereby, only the distortion component superimposed on the amplified audio signal due to the
influence of the speaker is accurately calculated without being affected by the noise wraparound,
and the distortion component generated due to the influence of the speaker and the distortion
component added to the audio signal are Since it is possible to cancel out, it is possible to output
a sound faithful to the audio signal from the speaker.
[0011]
In the present invention, an audio signal amplifier for transmitting a plurality of amplified audio
signals obtained by respectively amplifying audio signals of a plurality of channels to the
speakers of the respective channels via ground lines shared by the respective channels. An
amplifier that amplifies an audio signal for each channel to generate an amplified audio signal,
and is provided between the amplifier and the speaker for each channel, and when the amplified
audio signal is sent from the amplifier to the speaker, Current detection means for respectively
detecting the current waveform in the amplified audio signal on which the distortion component
due to the influence and the influence from the other channel through the ground line is
superimposed, and the current waveform and the signal waveform of the audio signal for each
channel Distortion component calculation means for calculating distortion components based on
differences, and And an addition result obtained by adding the distortion component in the audio
signal to provide a distortion component adding means for supplying to the amplifier for each
channel.
08-05-2019
3
[0012]
Thereby, only the distortion component superimposed on the amplified audio signal due to the
influence of the speaker and the influence from the other channel through the ground line is
accurately calculated, and the distortion component caused by the influence of the speaker and
the influence from the other channel And the distortion component previously added to the audio
signal can be canceled out, so that a sound faithful to the audio signal can be output from the
speaker.
[0013]
According to the present invention, only the distortion component superimposed on the
amplified audio signal due to the influence of the speaker is accurately calculated without being
affected by the noise wraparound, and the distortion component generated due to the influence
of the speaker and the distortion added to the audio signal Since the component can be offset, a
sound faithful to the audio signal can be output from the speaker, and thus an audio signal
amplifier and a distortion correction method can be realized which can improve the sound
quality of the sound output from the speaker. .
[0014]
Further, according to the present invention, it is possible to accurately calculate only the
distortion component superimposed on the amplified audio signal due to the influence of the
speaker and the influence from other channels through the ground line, and the distortion
component added in advance to the audio signal And an distortion component generated by the
influence of the speaker, so that an audio signal amplification device capable of outputting a
sound faithful to the audio signal from the speaker and thus improving the sound quality of the
sound output from the speaker Can be realized.
[0015]
Hereinafter, an embodiment of the present invention will be described in detail with reference to
the drawings.
[0016]
(1) First Embodiment (1-1) Configuration of Audio Device In FIG. 1, the audio device 1 according
to the first embodiment is supplied from an audio signal source 3 such as a CD (Compact Disc)
player, for example. By operating as a so-called audio amplifier that amplifies the audio signal S1
to be supplied to the speaker 2, a sound corresponding to the audio signal S1 is output from the
speaker 2.
08-05-2019
4
[0017]
Here, as shown in the cross-sectional view of FIG. 2, the speaker 2 has a cone-shaped diaphragm
21, and an edge 31 made of a resin material having flexibility at the front outer periphery of the
substantially mortar-shaped frame 22. The diaphragm 21 is attached via the above-mentioned,
and the diaphragm 21 can be freely moved (vibrated) in the front-rear direction with respect to
the frame 22.
[0018]
On the rear side of the frame 22, a substantially disc-like top plate 23, a magnet 24, and a back
plate 25 are attached, and a pole yoke 26 is provided so as to project forward from the central
portion of the back plate 25. .
The pole yoke 26 penetrates the magnet 24 and forms a magnetic circuit by forming a magnetic
gap 27 with the top plate 23.
[0019]
The voice coil bobbin 28 is made of a substantially cylindrical metal material, is pivotally
supported by the damper 30 and attached to the rear central portion of the diaphragm 21, and is
rotated so that the voice coil 29 is positioned within the magnetic gap 27. It is rolled.
The voice coil 29 is connected to a connection terminal (not shown) attached to the frame 22 via
a lead (not shown) so that the output audio signal S4 of an AC waveform is supplied from the
audio apparatus 1 It is done.
[0020]
That is, the speaker 2 generates an electromagnetic force corresponding to the current of the
output audio signal S4 when a current corresponding to the output audio signal S4 from the
audio apparatus 1 flows through the voice coil 29.
08-05-2019
5
At this time, the speaker 2 vibrates the surrounding air by vibrating the diaphragm 21, the voice
coil bobbin 28 and the voice coil 29 integrally with the other components such as the frame 22
by the electromagnetic force and vibrating the surrounding air. A sound corresponding to the
signal S4 can be generated.
[0021]
By the way, as shown in FIG. 3, the impedance of the speaker 2 changes according to the
frequency according to the property of the voice coil 29, the impedance becomes maximum at
the bass resonance frequency, and the impedance rises when the frequency rises from the bass
resonance frequency. It decreases to a minimum value, that is, a nominal impedance, and the
impedance gradually increases as the frequency increases.
[0022]
Further, when the output audio signal S4 flows through the voice coil 29, the speaker 2
generates a back electromotive force in the voice coil 29 due to the general nature of the coil, so
the current of the output audio signal S4 is generated by the back electromotive force. It distorts
the waveform and degrades the sound quality of the sound to be output.
[0023]
Therefore, the audio apparatus 1 (FIG. 1) is configured to amplify the audio signal S1 by the
power amplifier 12 and correct distortion caused by the influence of the voice coil 29 of the
speaker 2 by the distortion correction circuit 10.
[0024]
First, the distortion correction circuit 10 subtracts the distortion component signal S6 (described
in detail later) from the audio signal S1 by the distortion component adder 11 to generate an
addition audio signal S2 and supplies this to the power amplifier 12.
[0025]
The power amplifier 12 generates an amplified audio signal S3 by amplifying the addition audio
signal S2 at a predetermined amplification factor, and supplies the amplified audio signal S3 to
the current detection resistor 13 of the distortion correction circuit 10.
[0026]
08-05-2019
6
The current detection resistor 13 is a pure resistor having almost no reactance, and slightly
attenuates the amplified audio signal S3 supplied from the power amplifier 12 and sends it to the
speaker 2 as an output audio signal S4.
At this time, the current detection resistor 13 generates a potential difference between the
amplified audio signal S3 and the output audio signal S4 so that the magnitudes of the current
values in the amplified audio signal S3 and the output audio signal S4 are based on the potential
difference. To be detected.
Since the current detection resistor 13 is a pure resistance, the potential difference at both ends
is proportional only to the magnitude of the current flowing through the current detection
resistor 13.
[0027]
Incidentally, a relatively small resistance value of, for example, about 0.1 [Ω] is selected as the
current detection resistor 13, and power loss of the amplified audio signal S3 by the current
detection resistor 13 is minimized. .
[0028]
Here, since the distortion component signal S6 is “0” in the initial state, the addition audio
signal S2 has substantially the same waveform as the audio signal S1, but the amplification audio
signal S3 and the output audio signal S4 are of the above-described speaker 2 The waveform is
distorted due to the influence of the back electromotive force generated in the voice coil 29.
In practice, for example, when the audio signal S1 is a rectangular wave as shown in FIG. 4 (A),
the amplified audio signal S3 and the output audio signal S4 are audios as shown in FIGS. 4 (B)
and 4 (C). The waveform is distorted with respect to the signal S1 (FIG. 4A).
[0029]
The differential amplifier 14 is supplied with the amplified audio signal S3 and the output audio
signal S4, calculates the difference between the amplified audio signal S3 and the output audio
08-05-2019
7
signal S4, and amplifies the difference by a predetermined amplification factor to obtain a
current detection resistor. A current detection signal S5 (FIG. 4 (D)) representing the current
waveform flowing in 13 (that is, the current waveform in the amplified audio signal S3 and the
output audio signal S4) is generated and sent to the distortion component calculator 15.
[0030]
Incidentally, the differential amplifier 14 is configured to amplify to such an extent that the
signal level of the current detection signal S5 becomes substantially equal to the signal level of
the audio signal S1.
[0031]
The distortion component calculator 15 calculates only the distortion component contained in
the amplified audio signal S3 and the output audio signal S4 by calculating the difference
between the current detection signal S5 and the original audio signal S1 not containing the
distortion component. Are sent out to the distortion component adder 11 as a distortion
component signal S6 (FIG. 4 (E)).
[0032]
Here, the distortion component signal S6 corresponds to one in which only the distortion
component generated by the back electromotive force from the speaker 2 is extracted.
That is, the distortion correction circuit 10 is configured to detect a distortion component
included in the output audio signal S4 based on the potential difference between the amplified
audio signal S3 and the output audio signal S4.
[0033]
The distortion component adder 11 subtracts the distortion component signal S6 from the
original audio signal S1 containing no distortion component as described above, that is, inverts
and adds the phase of the distortion component signal S6 to the audio signal S1. Thus, as shown
in FIG. 4F, the addition audio signal S2 in which the distortion components are added in reverse
phase is generated and sent to the power amplifier 12.
[0034]
08-05-2019
8
In response to this, the power amplifier 12 amplifies the addition audio signal S2 in which the
distortion components are added in reverse phase as it is to generate an amplified audio signal
S3 and outputs the output audio signal S4 to the speaker 2 through the current detection resistor
13. Send out.
[0035]
At this time, although the amplified audio signal S3 and the output audio signal S4 have their
waveforms distorted by the back electromotive force generated in the voice coil 29 of the
speaker 2 as described above, they are added by the distortion component signal S6 of the
opposite phase added in advance. The distortion component due to the back electromotive force
is canceled out.
For this reason, the amplified audio signal S3 and the output audio signal S4 contain almost no
distortion component and are corrected to waveforms substantially the same as the original
audio signal S1.
[0036]
As described above, the audio apparatus 1 applies a negative current feedback via the system of
the current detection resistor 13, the differential amplifier 14, the distortion component
calculator 15, and the distortion component adder 11 to cause back electromotive force from the
voice coil 29. Since the output audio signal S4 corrected to a waveform substantially equivalent
to the original audio signal S1 can be output to the voice coil 29 of the speaker 2 regardless of
the influence of the power, based on the audio signal S1 from the speaker 2 High quality sound
can be output faithfully.
[0037]
(1-2) Operation and Effect In the above configuration, the distortion correction circuit 10 of the
audio device 1 is provided with the current detection resistor 13 between the power amplifier 12
and the speaker 2, and an output audio signal to be sent to the speaker 2 The current waveform
of S4 is detected as a current detection signal S5 by the current detection resistor 13 and the
differential amplifier 14, and the distortion component signal S6 is extracted by calculating the
difference between the current detection signal S5 and the audio signal S1. The distortion
component signal S6 is added to the original audio signal S1 in reverse phase.
08-05-2019
9
[0038]
As a result, since the distortion correction circuit 10 applies negative current feedback to the
audio signal S1, the distortion component of the output audio signal S4 due to the back
electromotive force generated in the voice coil 29 of the speaker 2 can be canceled out. The
output audio signal S4 in a state in which no distortion component is included can be supplied to
the speaker 2.
[0039]
In response to this, the speaker 2 supplies the voice coil 29 with the current of the output audio
signal S4 having substantially the same signal waveform as the original audio signal S1
containing no distortion component. A faithful sound can be output.
[0040]
Note that the distortion correction circuit 10 applies negative current feedback to the audio
signal S1, so that it is a case where no distortion occurs or no distortion occurs in the output
audio signal S4. Even in this case, the output audio signal S4 can be corrected in accordance with
the signal waveform of the original audio signal S1.
[0041]
Further, since the distortion correction circuit 10 always applies negative current feedback to the
audio signal S1, no matter when any distortion occurs in the output audio signal S4, the
distortion correction circuit 10 immediately transmits the audio signal S1. Since the correction in
consideration of the distortion component can be performed, it is possible to always output highquality sound from the speaker 2.
[0042]
Here, frequency characteristics of voltage and current in a conventional audio apparatus (not
shown) using only the power amplifier 12 without using the distortion correction circuit 10 are
shown in FIGS. 5A and 5B.
The conventional audio device has substantially flat gain and phase with respect to voltage in the
audio band (about 20 Hz to 20 kHz) and exhibits good characteristics (FIG. 5A), but gain and
phase with respect to current It fluctuates largely depending on the frequency (Fig. 5 (B)).
08-05-2019
10
In this case, since the speaker 2 generates an electromagnetic force proportional to the current
flowing through the voice coil 29, the frequency characteristic of the sound to be output is
deteriorated according to the frequency characteristic of the current, and the sound quality is
deteriorated.
[0043]
On the other hand, the distortion correction circuit 10 of the audio apparatus 1 according to the
present invention detects the current waveform which actually flows through the speaker 2 as
the current detection signal S5 by the current detection resistor 13 and the differential amplifier
14, and outputs the current detection signal S5. The signal waveform of the output audio signal
S4 is corrected to the input audio signal S1 by negative current feedback based on it.
[0044]
As a result, as shown in FIGS. 6 (A) and 6 (B), the audio apparatus 1 of the present invention is
characterized in that the gain and phase characteristics are disturbed with respect to voltage
(FIG. 6 (A)). The characteristic of the phase becomes almost flat, and a good frequency
characteristic is obtained (FIG. 6 (B)).
Therefore, the audio device 1 can output a sound with good sound quality from the speaker 2.
[0045]
Furthermore, as shown in FIG. 7, the voltage (V) and the current when the distortion component
is corrected by the distortion correction circuit 10 in the audio apparatus 1 of the present
invention and when the distortion component is not corrected in the conventional audio
apparatus Comparing the distortion factor characteristics of (I), in the audio apparatus 1, the
distortion correction circuit 10 increases (that is, deteriorates) the total harmonic distortion
factor (THD: total harmonic distortion, hereinafter simply referred to as distortion factor) of the
voltage (V) The distortion factor of the current (I) is reduced and improved.
That is, the audio apparatus 1 can improve the frequency characteristic of the sound output from
the speaker 2 to significantly improve the sound quality.
08-05-2019
11
[0046]
Also, assuming that the regenerative current IT is generated via the ground due to the influence
of the current from another circuit such as a power supply circuit, for example, the current
detection resistor 13 is connected to the ground as shown in FIG. In the case of the audio device
40, although the current feedback is applied through the distortion component adder (not
shown), the impedance ZG on the ground line is caused by the influence of the regenerative
current IT from other circuits (not shown). Thus, the potential at the point P1 fluctuates, and the
voltage eo is affected by the regenerative current IT.
[0047]
At this time, in the audio device 40, the voltage eo is different from the potential difference at
both ends of the current detection resistor 13, and the distortion component due to the back
electromotive force generated in the voice coil 29 of the speaker 2 can not be accurately
calculated. The distortion of the flowing signal current IS can not be corrected correctly.
[0048]
On the other hand, in the audio apparatus 1 of the present invention, as shown in FIG. 8B, the
current detection resistor 13 is connected between the power amplifier 12 and the speaker 2 (ie,
on the signal line side). Voltage eo representing the potential of detection signal S5 is not
affected by regenerative current IT.
[0049]
Therefore, the audio apparatus 1 can correctly detect the potential difference at both ends of the
current detection resistor 13 by the current detection signal S5, and therefore the distortion
component can be calculated with high accuracy without being affected by the regenerative
current IT to output the audio signal The distortion generated in S4 can be accurately corrected.
[0050]
Furthermore, assuming that the ends of the current detection resistor 13 are affected by
disturbance due to electromagnetic waves or the like, for example, as shown in FIG. 9A, in the
case of the audio device 40, signal waveforms at both ends of the current detection resistor 13
Like G1 and G2, the disturbance noise components N1 and N2 at the same level are
superimposed on the audio signal by the disturbance, respectively.
08-05-2019
12
[0051]
In this case, in the audio device 40, the noise component N2 of the audio signal becomes smaller
than the noise component N1 because the impedance on the ground side is low, and the voltage
eo when the difference is calculated by the differential amplifier 14 as in the signal waveform G3.
The noise component N3 which is the difference between the noise components N1 and N2 is
superimposed on the signal, and the potential difference at both ends of the current detection
resistor 13 can not be detected correctly.
[0052]
On the other hand, in the audio apparatus 1 according to the present invention, as shown in FIG.
9B, when both ends of the current detection resistor 13 are affected by the disturbance, the
impedances at both ends of the current detection resistor 13 are substantially equal. As in the
signal waveforms G11 and G12, the magnitudes of the noise components N11 and N12
respectively superimposed on the amplified audio signal S3 and the output audio signal S4
flowing at both ends of the current detection resistor 13 become substantially equal.
[0053]
As a result, as shown by the signal waveform G13, when the difference is calculated by the
differential amplifier 14, the audio device 1 hardly overlaps noise components as the voltage eo.
As a result, the audio apparatus 1 can correctly detect the potential difference between both ends
of the current detection resistor 13, calculate the distortion component with high accuracy, and
correct the distortion generated in the output audio signal S4 accurately.
[0054]
Moreover, even if the cable connecting the audio device 1 and the speaker 2 is affected by
disturbance or the like, and the noise is superimposed on the output audio signal S4, the audio
device 1 can not change the original audio signal by the distortion correction circuit 10. Only the
distortion component different from S1 can be extracted and the distortion component generated
in the output audio signal S4 can be corrected. Therefore, the speaker 2 outputs the sound
faithfully reproducing the audio signal S1 regardless of the influence of the disturbance. It can be
done.
[0055]
08-05-2019
13
According to the above configuration, the distortion correction circuit 10 of the audio apparatus
1 includes the current detection resistor 13 between the power amplifier 12 and the speaker 2
and calculates the distortion component by the current detection resistor 13 and the differential
amplifier 14. Distortion of the output audio signal S4 generated by the back electromotive force
generated in the voice coil 29 of the speaker 2 by adding to the original audio signal S1 in
reverse phase, and the output audio signal S4 is not distorted A signal waveform equivalent to
that of the input audio signal S1 can be corrected, and thus the sound quality of the speaker 2
can be significantly improved.
[0056]
(2) Second Embodiment (2-1) Configuration of Audio Device In FIG. 10 in which parts
corresponding to those in FIG. 1 are assigned the same reference numerals, an audio device 60
according to the second embodiment is, for example, portable. It is a CD (Compact Disc) player.
The audio device 60 amplifies the audio signals S11R and S11L of the two left and right channels
supplied from the audio signal sources 63R and 63L constituting the CD reproducing unit by the
power amplifiers 72R and 72L, respectively, and outputs the headphones via the three-pole
connector 62. By transmitting to the side 61, the right and left sounds are outputted from the
right side sound unit 77R and the left side sound unit 77L of the headphone 61, respectively.
[0057]
The audio device 60 has distortion correction circuits 70R and 70L for left and right channels
corresponding to the distortion correction circuit 10 as compared to the audio device 1 (FIG. 1),
and the right sound of the headphones 61 corresponding to the speaker 2 It has a common
configuration except that the unit 77R and the left acoustic unit 77L are connected by a threecore cable 76 sharing the ground line 76C.
[0058]
Here, the 3-core cable 76 connects the distortion correction circuit 70R and the right acoustic
unit 77R by the right signal line 76R, connects the distortion correction circuit 70L and the left
acoustic unit 77L by the left signal line 76L, and The ground line 76C is shared by the line 76R
and the left signal line 76L.
[0059]
08-05-2019
14
The distortion correction circuit 70R (right (R) channel) of the audio apparatus 60 receives the
distortion component signal S16R from the audio signal S11R by the distortion component adder
71 as in the distortion correction circuit 10R of the audio apparatus 1 (FIG. 1) described above.
By subtracting, the addition audio signal S12R is generated and supplied to the power amplifier
72R.
[0060]
Similar to the power amplifier 12 (FIG. 1), the power amplifier 72R amplifies the addition audio
signal S12R to form an amplified audio signal S13R, which is supplied to the current detection
resistor 73R.
[0061]
The current detection resistor 73R is a pure resistor and slightly attenuates the amplified audio
signal S3 supplied from the power amplifier 72R to make an output audio signal S14R, and this is
output via the three-pole connector 62 and the three-core cable 76 of the headphone 61. The
sound is supplied to the right sound unit 77R.
[0062]
At this time, the distortion correction circuit 70R detects the current waveform of the output
audio signal S14R sent to the right acoustic unit 77R as a current detection signal S15R by the
current detection resistor 73R and the differential amplifier 74R, and the current detection signal
S15R and the audio signal S11R. The distortion component signal S16R is extracted by
calculating the difference between them and the distortion component signal S16R is added to
the original audio signal S11R in reverse phase by the distortion component adder 71R.
[0063]
Thereby, the distortion of the output audio signal S14R due to the back electromotive force
generated in the voice coil 78R of the right acoustic unit 77R can be corrected in advance by the
distortion correction circuit 70R, so the audio device 60 is substantially equivalent to the original
audio signal S11R. The output audio signal S14R corrected to the signal waveform can be fed to
the voice coil 78R of the right acoustic unit 77R, and thus the right acoustic unit 77R can output
a sound faithful to the audio signal S11R.
[0064]
As for the distortion correction circuit 70L (left (L) channel) of the audio device 60, as with the
distortion correction circuit 70R (right channel), the output audio signal S14L corrected to a
08-05-2019
15
signal waveform substantially equivalent to the original audio signal S11L Since the voice coil
78L of the left acoustic unit 77L can be flowed, it is possible to output a sound faithful to the
audio signal S11L from the left acoustic unit 77L.
[0065]
(2-2) Operation and Effect In the above configuration, the distortion correction circuits 70R and
70L (FIG. 10) of the audio device 60 are the same as the distortion correction circuit 10 (FIG. 1)
of the audio device 1 in the first embodiment, Current detection resistors 73R and 73L are
provided between the power amplifiers 72R and 72L and the right acoustic unit 77R and left
acoustic unit 77L, respectively, and the output audio signals S14R and S14L are supplied to the
right acoustic unit 77R and left acoustic unit 77L. The current waveform is detected as the
current detection signals S15R and S15L by the current detection resistors 73R and 73L and the
differential amplifiers 74R and 74L, and distortion is calculated by calculating the difference
between the current detection signals S15R and S15L and the audio signals S11R and S11L.
Extract component signals S16R and S16L The so-called negative current feedback is applied by
adding the distortion component signals S16R and S16L to the original audio signals S11R and
S11L in reverse phase.
[0066]
As a result, the distortion correction circuits 70R and 70L apply negative feedback to the audio
signals S11R and S11L, respectively, so that back-occurrence occurs in the voice coil 78R of the
right acoustic unit 77R and the voice coil 78L of the left acoustic unit 77L. The distortion of the
output audio signals S14R and S14L due to the power can be canceled out, and the output audio
signals S14R and S14L hardly containing distortion components can be supplied to the right
acoustic unit 77R and the left acoustic unit 77L.
[0067]
In response to this, the right audio unit 77R and the left audio unit 77L supply the voice coils
78R and 78L with the output audio signals S14R and S14L that have substantially the same
signal waveform as the original audio signals S11R and S11L that do not contain distortion
components. Therefore, high-quality sound faithful to the original audio signals S11R and S11L
can be output.
[0068]
Further, distortion correction circuits 70R and 70L apply negative current feedback to audio
signals S11R and S11L, respectively, as in distortion correction circuit 10. Therefore, distortion
occurs in output audio signals S14R and S14L. The right audio unit 77R and the left audio unit of
08-05-2019
16
the output audio signals S14R and S14L are equivalent to the signal waveforms of the original
audio signals S11R and S11L, respectively, even if no distortion occurs. 77L can be supplied.
[0069]
Further, the influence of the leakage current to other channels due to the sharing of the ground
line 76C will be discussed.
As shown in FIG. 11A, in the audio apparatus 80 having only the power amplifiers 72R and 72L
and not correcting the distortion component, for example, when the audio signal S11R is
supplied from the audio signal source 63R only to the right channel. Because the ground line
76C has the impedance ZC and the potential at the branch point P2 of the ground line 76C does
not become "0", the leakage current IL of the signal current IS flows to the left acoustic unit 77L
of the left channel and the left acoustic The sound of the right channel is output slightly from the
unit 77L, and so-called channel separation is deteriorated.
[0070]
On the other hand, as shown in FIG. 11B, in the case of the audio device 60 of the present
invention, when the audio signal S11R is supplied from the audio signal source 63R only to the
right channel, as in the case of the audio device 80, Due to the influence of the impedance ZC on
the ground line 76C, the potential of the branch point P2 does not become "0", and the leakage
current IL of the signal current IS flows to the left acoustic unit 77L of the left channel.
[0071]
However, in the audio apparatus 60, since the distortion correction circuit 70L of the left channel
corrects the signal waveform of the output audio signal S14L to match the signal waveform of
the original audio signal S11L, the leakage current IL of the signal current IS of the right channel
is distorted. An output audio signal S14L, which is detected as a component and added as the
opposite phase of the distortion component, can be supplied to the left acoustic unit 77L.
[0072]
As a result, the audio device 60 can offset the leakage current component by the output audio
signal S14L generated by the distortion correction circuit 70L of the left channel, so when
outputting the sound of the left channel from the left acoustic unit 77L, the right channel The
channel separation can be improved by preventing the sound due to the leak current IL from
08-05-2019
17
being superimposed and being output.
[0073]
The audio device 60 can also detect and correct the leakage current from the left channel to the
right channel as a distortion component as well as the leakage current IL from the right channel
to the left channel. Since it is possible to simultaneously detect and correct each other's leakage
current as a distortion component in the left channel, it is possible to improve channel separation
for both left and right channels.
[0074]
Here, measurement results of channel separation in the case of the audio device 80 (without
distortion correction) and in the case of the audio device 60 of the present invention (with
distortion correction) are shown in FIG.
In FIG. 12, with respect to both the right channel (R) to the left channel (L) and the left channel
(L) to the right channel (R), the channel separation is approximately about with distortion
correction compared to the case without distortion correction. An improvement of about 30 [dB]
has been shown, and it is shown that high-quality sound can be output from the right acoustic
unit 77R and the left acoustic unit 77L (FIG. 10).
[0075]
Incidentally, in FIG. 12, when distortion correction is performed, the output level due to the
leakage current from the right channel (R) to the left channel (L) and the output level due to the
leakage current from the left channel (L) to the right channel (R) Although there is a slight
difference, it is presumed that this is due to measurement error.
[0076]
Next, measurement results of distortion factor characteristics in the audio device 80 (without
distortion correction) and the audio device 60 of the present invention (with distortion
correction) are shown in FIG.
08-05-2019
18
In this FIG. 13, compared with the case without distortion correction, the distortion factor is
lower for both left and right channels when distortion is corrected, and the sound output from
the right acoustic unit 77R and the left acoustic unit 77L (FIG. 10) It is shown that the sound
quality of is improved by the distortion correction.
[0077]
Also, as in the audio device 90 shown in FIG. 14A, when the current detection resistor 93 is
connected to the shared ground side, the signal current of both the left and right channels flows
in the current detection resistor 93, so the left channel Also, since the current waveform flowing
to each of the right channel and the right channel can not be detected independently, that is, the
distortion component can not be accurately extracted because the distortion component can not
be extracted with high accuracy.
[0078]
On the other hand, as shown in FIG. 14B, the audio device 60 of the present invention has a
current detection resistor between the power amplifiers 72R and 72L and the right acoustic unit
77R and the left acoustic unit 77L (ie, on the signal line side). Since 73R and 73L are respectively
connected, the current detection resistors 73R and 73L can independently detect the current
waveform flowing to the left channel and the right channel respectively, and the distortion
components of the left channel and the right channel can be high. It is possible to accurately
extract the distortion component to extract it accurately.
[0079]
According to the above configuration, the distortion correction circuits 70R and 70L (FIG. 10) of
the audio device 60 have the current detection resistors 73R and 73L between the power
amplifiers 72R and 72L and the right acoustic unit 77R and the left acoustic unit 77L,
respectively. The distortion components of the left and right channels are calculated by the
current detection resistors 73R and 73L and the differential amplifiers 74R and 74L,
respectively, and added to the original audio signals S11R and S11L in reverse phase, thereby the
audio signal S11R. And S11L respectively, the distortion component added in the opposite phase,
and the back EMF generated in the voice coil 78R of the right acoustic unit 77R and the voice
coil 78L of the left acoustic unit 77L and the output audio signals S14R and S14L due to leakage
current from other channels. Distortion component of the To correct the output audio signals
S14R and S14L to signal waveforms equivalent to the original audio signals S11R and S11L, thus
improving the channel separation of the sound output from the right acoustic unit 77R and left
acoustic unit 77L. High quality sound.
08-05-2019
19
[0080]
(3) Other Embodiments In the above-described first embodiment, the current detection resistor
13 and the differential amplifier 14 are used to detect the current waveform flowing through the
speaker 2. The present invention is not limited to this, and for example, a solenoid coil or the like
may be used to detect the current waveform flowing through the speaker 2.
The same applies to the second embodiment.
[0081]
In the second embodiment described above, distortion components of both right and left
channels are respectively extracted in the audio apparatus 60 having the left and right two
channels and sharing the ground line 76C, and the distortion components are respectively
corrected. Although the case has been described, the present invention is not limited thereto. For
example, an audio apparatus having four channels to realize a surround system and sharing the
ground lines of the four channels may share an arbitrary number of ground lines of channels.
The distortion component of each channel may be extracted in the converted audio apparatus to
correct the distortion component.
[0082]
Furthermore, in the first embodiment described above, the case where the output audio signal S4
is supplied to the cone-shaped speaker 2 has been described, but the present invention is not
limited thereto. For example, a voice coil such as a dome-shaped speaker The output audio signal
S4 may be supplied to another type of speaker having any of the above, or to various types of
speakers that may distort the current waveform of the supplied output audio signal S4.
[0083]
Furthermore, in the first and second embodiments described above, the present invention is
applied to the audio apparatus 1 operating as an audio amplifier and the audio apparatus 60
formed of a portable CD player, but the present invention is limited thereto. For example, an
audio circuit unit mounted on a television receiver, an audio circuit unit of a personal computer
or a portable telephone, etc., an audio signal supplied from a predetermined audio signal source
is amplified and supplied to a speaker, a headphone, etc. The present invention may be applied to
various electronic devices having a signal amplification circuit.
08-05-2019
20
[0084]
Further, in the above embodiment, the power amplifier 12 as an amplifier, the current detection
resistor 13 and the differential amplifier 14 as current detection means, the distortion
component calculator 15 as distortion component calculation means, distortion component
addition means Although the case where the audio device 1 as an audio signal amplification
device is configured by the distortion component adder 11 as the present invention is described,
the present invention is not limited to this, and amplifiers having other various circuit
configurations, current detection means, The audio signal amplifier may be configured by the
distortion component calculation means and the distortion component addition means.
[0085]
The present invention can also be used in various electronic devices having an audio signal
amplifier circuit.
[0086]
FIG. 1 is a schematic circuit diagram showing a configuration of an audio device according to a
first embodiment.
It is an approximate line sectional view showing composition of a speaker.
It is a schematic diagram which shows the impedance characteristic of a speaker.
FIG. 5 is a schematic line waveform diagram showing a signal waveform.
It is a substantially linear waveform diagram which shows the frequency characteristic in the
case of no distortion correction.
It is a substantially linear waveform chart which shows the frequency characteristic in the case of
distortion correction existence.
It is a substantially linear waveform diagram which shows the distortion factor characteristic in
08-05-2019
21
1st Embodiment.
FIG. 6 is a schematic circuit diagram for describing the influence of regenerative current from
another circuit.
FIG. 6 is a schematic circuit diagram for describing the influence of disturbance.
FIG. 7 is a schematic circuit diagram showing a configuration of an audio device according to a
second embodiment.
FIG. 6 is a schematic circuit diagram for describing the influence of leakage current from other
channels.
FIG. 6 is a schematic waveform diagram showing channel separation characteristics.
It is a substantially linear waveform diagram which shows the distortion factor characteristic in
2nd Embodiment.
FIG. 5 is a schematic circuit diagram for describing connection points of current detection
resistors.
Explanation of sign
[0087]
1, 40, 60, 80, 90 ...... audio apparatus, 2 ...... speakers, 3, 63 ...... audio signal source, 10, 70 L, 70
R ...... distortion correction circuit 11, 11 R, 71 L ...... distortion component adder , 12, 72R, 72L ...
power amplifier, 13, 73R, 73L, 93 ... current detection resistor, 14, 74R, 74L ... differential
amplifier, 15, 75R, 75L ... distortion component calculator, 29, 78R 78L: voice coil 61:
headphones 62: three-pole connector 76: three-core cable 76C: ground wire 77R: right acoustic
unit 77L: left acoustic unit.
08-05-2019
22
Документ
Категория
Без категории
Просмотров
0
Размер файла
35 Кб
Теги
jp2006279508
1/--страниц
Пожаловаться на содержимое документа