JP7599790B2 - Speaker distortion correction device and speaker unit - Google Patents
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Description
本発明は、入力に対するスピーカの出力の歪みを補正する技術に関するものである。 The present invention relates to a technology for correcting distortion in speaker output relative to input.
種々のスピーカの等価回路や、等価回路に基づいてスピーカの駆動を制御する技術が知られている（非特許文献１、特許文献１）。
また、等価回路に基づいてスピーカの駆動を制御する技術としては、スピーカの等価回路に基づいて、入力に対するスピーカの出力の歪みが解消されるように、スピーカを駆動する音声信号を補正する技術も知られている（特許文献２）。
Various equivalent circuits for speakers and techniques for controlling the driving of speakers based on the equivalent circuits are known (Non-Patent Document 1, Patent Document 1).
Furthermore, as a technique for controlling the driving of a speaker based on an equivalent circuit, a technique is also known in which an audio signal that drives a speaker is corrected based on the speaker's equivalent circuit so as to eliminate distortion in the speaker output relative to the input (Patent Document 2).
また、スピーカの振動板の振動を検出するセンサを備え、センサで検出した振動に応じてスピーカの駆動を制御するモーショナルフィードバックの技術も知られている（たとえば、特許文献３、４）。 Motional feedback technology is also known, which uses a sensor to detect vibrations in the speaker's diaphragm and controls the speaker's operation in response to the vibrations detected by the sensor (see, for example, Patent Documents 3 and 4).
モーショナルフィードバックの技術を用い、スピーカの振動板の振動を検出し、検出した振動に応じて、スピーカの歪みが解消されるように、スピーカを駆動する音声信号を補正することが考えられる。 It is possible to use motional feedback technology to detect the vibration of the speaker's diaphragm and correct the audio signal that drives the speaker based on the detected vibration so as to eliminate speaker distortion.
また、この場合には、適応フィルタを音声信号の補正に適用し、理想の振動と検出した振動の差をエラーとして、エラーが最小となるように適応フィルタの係数を更新することにより、スピーカの歪みを解消することが考えられる。 In this case, it is possible to eliminate speaker distortion by applying an adaptive filter to correct the audio signal, and updating the coefficients of the adaptive filter so that the error is minimized, using the difference between the ideal vibration and the detected vibration as the error.
一方、スピーカの特性は、線形な特性と非線形な特性がある。
たとえば、図４に示すスピーカの等価回路においては、Bl、KMS、Le(x,i)などは、非線形な特性を示す。
なお、図４の等価回路は、上掲した非特許文献１で示される等価回路であり、
Re; Electrical Resistance
Le(x,i);Electrical Inductance
Bl(x); Force factor
Fm(x,i); Reluctance Force
Mms; Mechanical mass
Rms(v); Mechanical Resistance
Kms(x); Stiffness（剛性）
である。
On the other hand, the characteristics of a speaker are classified into linear characteristics and non-linear characteristics.
For example, in the equivalent circuit of the speaker shown in FIG. 4, Bl, KMS, Le(x, i) and the like exhibit nonlinear characteristics.
The equivalent circuit in FIG. 4 is the equivalent circuit shown in the above-mentioned non-patent document 1.
Re; Electrical Resistance
Le(x,i);Electrical Inductance
Bl(x); Force factor
Fm(x,i); Reluctance Force
Mms; Mechanical mass
Rms(v); Mechanical Resistance
Kms(x); Stiffness
It is.
そして、このようなスピーカの非線形な特性にも対応するように適応フィルタを構成する場合には、適応フィルタの処理や構成が大規模化し高コスト化を招く。
そこで、本発明は、適応フィルタを用いつつ、比較的簡易な構成でスピーカの出力の歪みを補正することを課題とする。
If an adaptive filter is configured to also accommodate the nonlinear characteristics of such speakers, the processing and configuration of the adaptive filter will become large-scale, resulting in high costs.
Therefore, an object of the present invention is to correct the distortion of the speaker output with a relatively simple configuration while using an adaptive filter.
前記課題達成のために、本発明は、入力信号に対するスピーカの出力の歪みを補正する、スピーカの歪み補正装置に、前記スピーカの振動系の振動を検出するセンサと、前記入力信号を入力とする非線形部補正フィルタと、前記非線形部補正フィルタの出力を入力とし、前記スピーカを駆動する出力信号を出力する線形逆フィルタと、所定の適応アルゴリズムを実行し、前記センサで検出される振動が、前記入力信号に対して歪みのない振動となるように前記線形逆フィルタの伝達特性を更新する適応アルゴリズム実行部とを設け、前記非線形部補正フィルタには、前記スピーカの非線形な特性による当該スピーカの前記入力信号に対する出力の歪みを補正する伝達特性を設定したものである。 To achieve the above object, the present invention provides a speaker distortion correction device that corrects the distortion of a speaker's output in response to an input signal, the device comprising: a sensor that detects vibrations in the vibration system of the speaker; a nonlinear correction filter that receives the input signal; a linear inverse filter that receives the output of the nonlinear correction filter and outputs an output signal that drives the speaker; and an adaptive algorithm execution unit that executes a predetermined adaptive algorithm and updates the transfer characteristics of the linear inverse filter so that the vibrations detected by the sensor are vibrations that are undistorted in response to the input signal, and the nonlinear correction filter is set to a transfer characteristic that corrects the distortion of the speaker's output in response to the input signal due to the nonlinear characteristics of the speaker.
このようなスピーカの歪み補正装置の構成によれば、前記スピーカの非線形な特性による歪みについては非線形部補正フィルタで対応するので、線形逆フィルタと適応アルゴリズム実行部とよりなる適応フィルタを、前記スピーカの線形な特性によるによる歪みのみに対応するように構成することができる。 With this type of speaker distortion correction device configuration, distortion caused by the nonlinear characteristics of the speaker is handled by the nonlinear correction filter, so the adaptive filter consisting of a linear inverse filter and an adaptive algorithm execution unit can be configured to handle only distortion caused by the linear characteristics of the speaker.
よって、適応フィルタを用いつつ、比較的簡易な構成で、スピーカの非線形な特性によるものも含めスピーカの出力の歪みを補正することができる。
また、本発明は、前記課題達成のために、入力信号に対するスピーカの出力の歪みを補正する、スピーカの歪み補正装置に、前記入力信号を入力とする非線形部補正フィルタと、前記非線形部補正フィルタの出力を入力とし、前記スピーカを駆動する出力信号を出力する線形逆フィルタとを設け、前記非線形部補正フィルタには、前記スピーカの非線形な特性による当該スピーカの前記入力信号に対する出力の歪みを補正する伝達特性を設定し、前記線形逆フィルタに、前記スピーカの線形な特性による当該スピーカの前記入力信号に対する出力の歪みを補正する伝達特性を設定したものである。
Therefore, it is possible to correct the distortion of the speaker output, including that caused by the non-linear characteristics of the speaker, with a relatively simple configuration while using an adaptive filter.
In addition, in order to achieve the above-mentioned object, the present invention provides a speaker distortion correction device that corrects distortion of a speaker's output in response to an input signal, the device being provided with a nonlinear section correction filter which receives the input signal, and a linear inverse filter which receives the output of the nonlinear section correction filter as an input and outputs an output signal that drives the speaker, the nonlinear section correction filter being set with a transfer characteristic that corrects distortion of the speaker's output in response to the input signal due to the nonlinear characteristics of the speaker, and the linear inverse filter being set with a transfer characteristic that corrects distortion of the speaker's output in response to the input signal due to the linear characteristics of the speaker.
ここで、このようなスピーカの歪み補正装置の線形逆フィルタの伝達特性は、当該伝達特性の設定の際に上述したセンサと適応アルゴリズム実行部を付加することにより予め適応的に設定することができる。
よって、このようなスピーカの歪み補正装置によっても、適応フィルタを用いつつ、比較的簡易な構成でスピーカの歪みを補正することができる。
ここで、これらのスピーカの歪み補正装置に、周囲温度と前記スピーカの経年時間とのうちの少なくとも一方を環境として検知する環境検知手段と、前記非線形部補正フィルタの伝達特性を、前記環境検知手段が検知した環境から推定される前記スピーカの非線形な特性に適合する伝達特性に切り替える切替制御手段とをもうけてもよい。
Here, the transfer characteristic of the linear inverse filter of such a speaker distortion correction device can be adaptively set in advance by adding the above-mentioned sensor and adaptive algorithm execution unit when setting the transfer characteristic.
Therefore, such a speaker distortion correction device can also correct speaker distortion with a relatively simple configuration while using an adaptive filter.
Here, the distortion correction device for these speakers may be provided with an environment detection means for detecting at least one of the ambient temperature and the aging time of the speaker as the environment, and a switching control means for switching the transfer characteristic of the nonlinear section correction filter to a transfer characteristic that is compatible with the nonlinear characteristic of the speaker estimated from the environment detected by the environment detection means.
または、これらのスピーカの歪み補正装置に、前記スピーカの非線形な特性を計測する計測手段と、前記非線形部補正フィルタの伝達特性を、前記計測手段が計測した前記スピーカの非線形な特性に適合する伝達特性に切り替える切替制御手段とを設けてもよい。 Alternatively, the distortion correction device for these speakers may be provided with a measuring means for measuring the nonlinear characteristics of the speaker, and a switching control means for switching the transfer characteristics of the nonlinear correction filter to transfer characteristics that match the nonlinear characteristics of the speaker measured by the measuring means.
これらの切替制御手段を備えたスピーカの歪み補正装置によれば、スピーカの非線形な特性の変化が生じた場合に、非線形部補正フィルタの伝達特性を現在のスピーカの非線形な特性に対して適正な伝達特性に更新することができる。 With a speaker distortion correction device equipped with these switching control means, if a change occurs in the nonlinear characteristics of the speaker, the transfer characteristics of the nonlinear correction filter can be updated to transfer characteristics appropriate for the current nonlinear characteristics of the speaker.
ここで、これらのように前記切替制御手段を備えたスピーカの歪み補正装置に、音声信号を再生し前記入力信号として出力するオーディオ装置の状態を検知する状態検知手段を設け、前記切替制御手段において、所定のタイミングで、前記非線形部補正フィルタの伝達特性を切り替えると共に、前記所定のタイミングを、前記オーディオ装置が起動したタイミングと、前記オーディオ装置が有意な音声信号の再生を行っていないタイミングと、前記オーディオ装置が前記入力信号の出力レベルを変化させたタイミングと、再生する音声信号の音源を切り替えたタイミングとのうちの、少なくとも一つのタイミングを含むものとしてもよい。 Here, a speaker distortion correction device having the switching control means as described above may be provided with a state detection means for detecting the state of an audio device that reproduces an audio signal and outputs it as the input signal, and the switching control means may switch the transfer characteristics of the nonlinear section correction filter at a predetermined timing, and the predetermined timing may include at least one of the timing when the audio device is started up, the timing when the audio device is not reproducing a significant audio signal, the timing when the audio device changes the output level of the input signal, and the timing when the sound source of the audio signal to be reproduced is switched.
また、本発明は、併せて、スピーカの歪み補正装置と、前記スピーカとを、当該歪み補正装置と当該スピーカとが一体化された形態で備えているスピーカユニットも提供する。 The present invention also provides a speaker unit that includes a speaker distortion correction device and the speaker, with the distortion correction device and the speaker integrated together.
以上のように、本発明によれば、適応フィルタを用いつつ、比較的簡易な構成でスピーカの歪みを補正することができる。 As described above, according to the present invention, it is possible to correct speaker distortion using an adaptive filter with a relatively simple configuration.
以下、本発明の実施形態について、自動車に搭載される音響システムへの適用を例にとり説明する。
図１に、実施形態に係る音響システムの構成を示す。
図示するように、音響システムは、補正特性制御部１、スピーカ２、スピーカ２の振動系の振動/変位を検出するセンサ３、スピーカ２を駆動する音声信号である出力信号Soをスピーカ２に出力する補正装置４、音声信号である入力信号Siを出力するオーディオ装置５を備えている。
Hereinafter, an embodiment of the present invention will be described taking as an example an application to an audio system mounted in an automobile.
FIG. 1 shows the configuration of an audio system according to an embodiment.
As shown in the figure, the acoustic system includes a correction characteristic control unit 1, a speaker 2, a sensor 3 that detects vibration/displacement of the vibration system of the speaker 2, a correction device 4 that outputs an output signal So, which is an audio signal that drives the speaker 2, to the speaker 2, and an audio device 5 that outputs an input signal Si, which is an audio signal.
そして、補正装置４はオーディオ装置５が出力する入力信号Siを補正し出力信号Soとしてスピーカ２に出力する。
また、補正特性制御部１には、車室の温度や音響システムの経年時間（製造年と現在時刻等）等の情報が外部情報として入力する。また、補正特性制御部１には、オーディオ装置５から、曲再生中/曲非再生中等の再生状態や、入力信号Siを出力しているオーディオソース（ラジオ／CD等）の情報や、出力レベル（ボリューム等）等の情報が入力する。
The correction device 4 corrects the input signal Si output by the audio device 5 and outputs the corrected signal to the speaker 2 as an output signal So.
In addition, information such as the temperature in the vehicle cabin and the age of the audio system (year of manufacture, current time, etc.) are input as external information to the correction characteristic control unit 1. In addition, information such as the playback state (playing music/not playing music, etc.) and information on the audio source (radio/CD, etc.) outputting the input signal Si and the output level (volume, etc.) are input to the correction characteristic control unit 1 from the audio device 5.
次に、補正装置４は、非線形部補正フィルタ４１、線形逆フィルタ４２、適応アルゴリズム実行部４３、エラー算出部４４を備えている。
オーディオ装置５が出力する入力信号Siは、非線形部補正フィルタ４１を通って中間補正信号Smとして、線形逆フィルタ４２に入力し、線形逆フィルタ４２の出力は出力信号Soとしてスピーカ２に出力される。
Next, the correction device 4 includes a nonlinear correction filter 41 , a linear inverse filter 42 , an adaptive algorithm execution unit 43 , and an error calculation unit 44 .
An input signal Si output by the audio device 5 passes through a nonlinear correction filter 41 and is input to a linear inverse filter 42 as an intermediate correction signal Sm. The output of the linear inverse filter 42 is output to the speaker 2 as an output signal So.
非線形部補正フィルタ４１の伝達特性（フィルタ係数）は補正特性制御部１から切替可能であり、補正特性制御部１は、非線形部補正フィルタ４１の伝達特性を、非線形部補正フィルタ４１が出力する中間補正信号Smでスピーカ２を駆動した場合に入力信号Siに対するスピーカ２の非線形な特性によるスピーカ２の出力の歪みがキャンセルされる伝達特性、すなわち、スピーカ２の非線形な特性による歪みを補正する伝達特性に設定する。 The transfer characteristic (filter coefficient) of the nonlinear part correction filter 41 can be switched by the correction characteristic control unit 1, and the correction characteristic control unit 1 sets the transfer characteristic of the nonlinear part correction filter 41 to a transfer characteristic that cancels the distortion of the output of the speaker 2 caused by the nonlinear characteristics of the speaker 2 in response to the input signal Si when the speaker 2 is driven with the intermediate correction signal Sm output by the nonlinear part correction filter 41, that is, a transfer characteristic that corrects the distortion caused by the nonlinear characteristics of the speaker 2.
エラー算出部４４は、入力信号Siに対して歪みの無いスピーカ２の振動と、センサ３の出力が示す実際のスピーカ２の振動との差分を算出する。
適応アルゴリズム実行部４３と線形逆フィルタ４２は適応フィルタを構成しており、適応アルゴリズム実行部４３は中間補正信号Smを参照信号r、エラー算出部４４が算出した差分をエラーeとして、ＬＭＳアルゴリズム等によって、エラーeが最小化するように、FIRフィルタ等である線形逆フィルタ４２の伝達特性（フィルタ係数）を更新する。
The error calculation unit 44 calculates the difference between the vibration of the speaker 2 without distortion in response to the input signal Si and the actual vibration of the speaker 2 indicated by the output of the sensor 3 .
The adaptive algorithm execution unit 43 and the linear inverse filter 42 constitute an adaptive filter. The adaptive algorithm execution unit 43 uses the intermediate correction signal Sm as a reference signal r and the difference calculated by the error calculation unit 44 as an error e, and updates the transfer characteristics (filter coefficients) of the linear inverse filter 42, which is an FIR filter or the like, so as to minimize the error e by an LMS algorithm or the like.
この更新の結果、前記スピーカ２の線形な特性によるスピーカ２の入力信号Siに対する出力の歪みを補正する伝達特性が線形逆フィルタ４２に設定される。
次に、補正特性制御部１が、非線形部補正フィルタ４１の伝達特性の切替のために音響システムの起動時に開始する補正特性制御処理について説明する。
図２に、この補正特性制御処理の手順を示す。
図示するように、音響システムが起動すると、補正特性制御処理は、まず、外部情報が示す車室の温度や音響システムの経年時間やオーディオ装置５の出力レベルなどの環境が、非線形部補正フィルタ４１の伝達特性を前回切り替えたときの値から、所定レベル以上大きく変化しているかどうかを調べ（ステップ２０２）、変化していなければ、ステップ２０８に進む。
As a result of this updating, a transfer characteristic that corrects the distortion of the output of the speaker 2 with respect to the input signal Si due to the linear characteristic of the speaker 2 is set in the linear inverse filter 42 .
Next, a correction characteristic control process that the correction characteristic control unit 1 starts at the start of the acoustic system in order to switch the transfer characteristic of the nonlinear section correction filter 41 will be described.
FIG. 2 shows the procedure for this correction characteristic control process.
As shown in the figure, when the acoustic system is started, the correction characteristic control process first checks whether the environment, such as the temperature in the vehicle cabin, the age of the acoustic system, and the output level of the audio device 5, indicated by the external information, has changed by a predetermined level or more from the values when the transfer characteristics of the nonlinear correction filter 41 were last switched (step 202), and if no change has occurred, the process proceeds to step 208.
一方、所定レベル以上大きく変化している場合には、スピーカ２の現在の非線形特性を推定する（ステップ２０４）。
この推定は、車室の温度や音響システムの経年時間やオーディ装置の出力レベルの組み合わせ毎に、その組み合わせとなったときの非線形特性を予め求めてライブラリとして記憶しておき、ライブラリから現在の環境に対応する非線形特性をスピーカ２の現在の非線形特性として推定することにより行う。
On the other hand, if there is a change greater than the predetermined level, the current nonlinear characteristics of the speaker 2 are estimated (step 204).
This estimation is performed by determining in advance the nonlinear characteristics for each combination of vehicle cabin temperature, age of the acoustic system, and output level of the audio device, storing those characteristics as a library, and then estimating the nonlinear characteristics corresponding to the current environment from the library as the current nonlinear characteristics of speaker 2.
または、この推定は、スピーカ２の挙動を計測し、計測値からスピーカ２の現在の非線形特性を算定することにより行ってもよい。
たとえば、図４に示したスピーカ２の等価回路のKms(x); Stiffness（剛性）であれば、この計測値に基づく算定は、次のように行うことができる。
すなわち、テスト信号や音楽信号や音響透かし信号などの適当な出力信号Soをスピーカ２に出力しながら、スピーカ２に流れる電流i、スピーカ２の入力電圧uを計測し、計測した電流iと入力電圧uから、スピーカ２のインピーダンスZ=u/iの共振周波数fsを検出する。そして、Mms; Mechanical massを用いて、
Kms(x)=（2πfs）2Mms
を算出し、センサ３が出力するスピーカ２の振動系の変位xと、Kms(x)との関係を求め、求めた関係に従って非線形なKms(x)の特性を算定する。ここで、Kms(x)の非線形特性の算定は、予めKms(x)の非線形特性のパターンを複数用意しておき、求めた変位xとKms(x)との関係にマッチするパターンを、Kms(x)の非線形特性として算定することにより行ってもよい。
Alternatively, this estimation may be performed by measuring the behavior of the speaker 2 and calculating the current nonlinear characteristics of the speaker 2 from the measured values.
For example, in the case of Kms(x); Stiffness of the equivalent circuit of the speaker 2 shown in FIG. 4, calculation based on this measurement value can be performed as follows.
That is, while outputting an appropriate output signal So such as a test signal, music signal, or audio watermark signal to the speaker 2, the current i flowing through the speaker 2 and the input voltage u of the speaker 2 are measured, and the resonance frequency fs of the impedance Z=u/i of the speaker 2 is detected from the measured current i and input voltage u. Then, using Mms; mechanical mass,
Kms(x) = (2πfs) 2 Mms
The relationship between the displacement x of the vibration system of the speaker 2 output by the sensor 3 and Kms(x) is calculated, and the nonlinear characteristics of Kms(x) are calculated according to the relationship thus calculated. Here, the calculation of the nonlinear characteristics of Kms(x) may be performed by previously preparing a plurality of patterns of the nonlinear characteristics of Kms(x), and calculating a pattern that matches the relationship between the obtained displacement x and Kms(x) as the nonlinear characteristics of Kms(x).
そして、推定したスピーカ２の現在の非線形特性に対応する伝達特性に非線形部補正フィルタ４１の伝達特性を切り替え（ステップ２０６）、ステップ２０８に進む。非線形特性に対応する伝達特性とは、その非線形特性による歪みを補正する伝達特性であり、ステップ２０６では、推定した非線形特性を反映したスピーカモデルを用いて対応する伝達特性を算定してもよいし、予め非線形特性毎に対応する伝達特性を求めて記憶しておき、推定した非線形特性に対応する伝達特性をスピーカ２の現在の非線形特性に対応する伝達特性として求めてもよい。 Then, the transfer characteristic of the nonlinear section correction filter 41 is switched to the transfer characteristic corresponding to the estimated current nonlinear characteristic of the speaker 2 (step 206), and the process proceeds to step 208. The transfer characteristic corresponding to the nonlinear characteristic is a transfer characteristic that corrects the distortion caused by the nonlinear characteristic, and in step 206, the corresponding transfer characteristic may be calculated using a speaker model that reflects the estimated nonlinear characteristic, or a transfer characteristic corresponding to each nonlinear characteristic may be obtained and stored in advance, and the transfer characteristic corresponding to the estimated nonlinear characteristic may be obtained as the transfer characteristic corresponding to the current nonlinear characteristic of the speaker 2.
または、車室の温度や音響システムの経年時間やオーディ装置の出力レベルの組み合わせ毎に、その組み合わせとなったときの非線形特性に対応する伝達特性を予め求めてライブラリとして記憶しておき、ステップ２０４は行わずステップ２０６において、ライブラリから現在の環境に対応する伝達関数をスピーカ２の現在の非線形特性に対応する伝達特性として選定し、選定した伝達特性に非線形部補正フィルタ４１の伝達特性を切り替えるようにしてもよい。 Alternatively, for each combination of vehicle cabin temperature, age of the audio system, and output level of the audio device, the transfer characteristic corresponding to the nonlinear characteristic for that combination may be determined in advance and stored as a library, and step 204 may not be performed. In step 206, a transfer function corresponding to the current environment may be selected from the library as the transfer characteristic corresponding to the current nonlinear characteristic of speaker 2, and the transfer characteristic of nonlinear section correction filter 41 may be switched to the selected transfer characteristic.
さて、以上のようにしてステップ２０２またはステップ２０６から、ステップ２０８に進んだならば、補正装置４に、オーディオ装置５からの入力信号Siを補正装置４で補正した出力信号Soのスピーカ２への出力を開始させる。 Now, if the process proceeds from step 202 or step 206 to step 208 as described above, the correction device 4 is caused to start outputting to the speaker 2 the output signal So, which is the input signal Si from the audio device 5 corrected by the correction device 4.
そして、上述したスピーカ２の現在の非線形特性の推定（ステップ２１０）を、更新タイミングが到来するまで（ステップ２１２）繰り返す。
ここで、更新タイミングの検出は、オーディオ装置５が曲の再生を終了したタイミングや、オーディオ装置５が入力信号Siを出力しているオーディオソースが切り替わったタイミングや、オーディオ装置５が出力レベル（ボリューム等）を変更したタイミングを、オーディオ装置５からの情報に基づいて更新タイミングとして検出することにより行う。
Then, the estimation of the current nonlinear characteristics of the speaker 2 (step 210) is repeated until the update timing arrives (step 212).
Here, the detection of the update timing is performed by detecting, as the update timing, the timing when the audio device 5 finishes playing a song, the timing when the audio device 5 switches the audio source from which the audio device 5 outputs the input signal Si, or the timing when the audio device 5 changes the output level (volume, etc.) based on information from the audio device 5.
そして、更新タイミングが到来したならば（ステップ２１２）、非線形部補正フィルタ４１の伝達特性の切替が必要かどうかを判定し（ステップ２１４）、切替が必要なければステップ２１０からの処理に戻る。ここで、ステップ２１４では、スピーカ２の現在の非線形特性に対応する伝達特性が、非線形部補正フィルタ４１に現在設定されている伝達特性と異なる場合に、線形部補正フィルタの伝達特性の切替が必要であると判定する。 When the update timing arrives (step 212), it is determined whether or not the transfer characteristic of the nonlinear part correction filter 41 needs to be switched (step 214), and if switching is not required, the process returns to step 210. Here, in step 214, if the transfer characteristic corresponding to the current nonlinear characteristic of the speaker 2 differs from the transfer characteristic currently set in the nonlinear part correction filter 41, it is determined that switching of the transfer characteristic of the linear part correction filter is required.
一方、非線形部補正フィルタ４１の伝達特性の切替が必要と判定した場合には（ステップ２１４）、補正装置４のスピーカ２への出力をミュートし（ステップ２１６）、スピーカ２の現在の非線形特性に対応する伝達特性に非線形部補正フィルタ４１の伝達特性を切り替える（ステップ２１８）。 On the other hand, if it is determined that the transfer characteristics of the nonlinear correction filter 41 need to be switched (step 214), the output of the correction device 4 to the speaker 2 is muted (step 216), and the transfer characteristics of the nonlinear correction filter 41 are switched to the transfer characteristics corresponding to the current nonlinear characteristics of the speaker 2 (step 218).
そして、スピーカ２への出力のミュートを解除し（ステップ２２０）、ステップ２１０からの処理に戻る。
以上、補正特性制御部１が行う補正特性制御処理について説明した。
ところで、以上の実施形態は、非線形部補正フィルタ４１と線形逆フィルタ４２の一方もしくは両方を、伝達特性（フィルタ係数）を固定したフィルタとして適用してもよい。
Then, the output to the speaker 2 is unmuted (step 220), and the process returns to step 210.
The correction characteristic control process performed by the correction characteristic control unit 1 has been described above.
In the above embodiment, one or both of the nonlinear part correction filter 41 and the linear inverse filter 42 may be applied as filters with fixed transfer characteristics (filter coefficients).
図３ａは、非線形部補正フィルタ４１と線形逆フィルタ４２の双方を、伝達特性を固定したフィルタとした場合の音響システムの構成を示しており、この場合、センサ３と適応アルゴリズム実行部４３とエラー算出部４４と補正特性制御部１は設ける必要はない。 Figure 3a shows the configuration of an acoustic system in which both the nonlinear correction filter 41 and the linear inverse filter 42 are filters with fixed transfer characteristics. In this case, there is no need to provide the sensor 3, adaptive algorithm execution unit 43, error calculation unit 44, and correction characteristic control unit 1.
ただし、この場合、線形逆フィルタ４２に固定的に設定する伝達特性は、予め、図３ｂに示すセンサ３と適応アルゴリズム実行部４３とエラー算出部４４を設けた構成においてエラーeが最小となるように適応させた伝達特性とする。また、この場合、非線形部補正フィルタ４１に固定的に設定する伝達特性は、標準的な環境下においてスピーカ２の非線形な特性による歪みを補正する伝達特性とする。 However, in this case, the transfer characteristic fixedly set in the linear inverse filter 42 is a transfer characteristic that is adapted in advance so as to minimize the error e in the configuration in which the sensor 3, adaptive algorithm execution unit 43, and error calculation unit 44 shown in FIG. 3b are provided. Also, in this case, the transfer characteristic fixedly set in the nonlinear part correction filter 41 is a transfer characteristic that corrects distortion due to the nonlinear characteristics of the speaker 2 in a standard environment.
以上、本発明の実施形態について説明した。
以上のように本実施形態によれば、スピーカ２の非線形な特性による歪みについては非線形部補正フィルタ４１で対応するので、線形逆フィルタ４２と適応アルゴリズム実行部４３とよりなる適応フィルタを、前記スピーカ２の線形な特性によるによる歪みのみに対応するように構成することができ、この結果、比較的簡易な構成で、スピーカ２の非線形な特性によるものも含めスピーカ２の出力の歪みを補正することができる。
The embodiment of the present invention has been described above.
As described above, according to this embodiment, distortion due to the nonlinear characteristics of the speaker 2 is dealt with by the nonlinear section correction filter 41, so that the adaptive filter consisting of the linear inverse filter 42 and the adaptive algorithm execution unit 43 can be configured to deal with only distortion due to the linear characteristics of the speaker 2. As a result, with a relatively simple configuration, distortion in the output of the speaker 2, including that due to the nonlinear characteristics of the speaker 2, can be corrected.
ここで、以上の実施形態において、スピーカ２とセンサ３と補正装置４とは、スピーカユニットとして一体化されたものであってよい。 In the above embodiment, the speaker 2, the sensor 3, and the correction device 4 may be integrated into a speaker unit.
１…補正特性制御部、２…スピーカ、３…センサ、４…補正装置、５…オーディオ装置、４１…非線形部補正フィルタ、４２…線形逆フィルタ、４３…適応アルゴリズム実行部、４４…エラー算出部。 1... correction characteristic control unit, 2... speaker, 3... sensor, 4... correction device, 5... audio device, 41... nonlinear correction filter, 42... linear inverse filter, 43... adaptive algorithm execution unit, 44... error calculation unit.
Claims (5)
前記スピーカの振動系の振動を検出するセンサと、
前記入力信号を入力とする非線形部補正フィルタと、
前記非線形部補正フィルタの出力を入力とし、前記スピーカを駆動する出力信号を出力する線形逆フィルタと、
所定の適応アルゴリズムを実行し、前記センサで検出される振動が、前記入力信号に対して歪みのない振動となるように前記線形逆フィルタの伝達特性を更新する適応アルゴリズム実行部とを有し、
前記非線形部補正フィルタには、前記スピーカの非線形な特性による当該スピーカの前記入力信号に対する出力の歪みを補正する伝達特性が設定されていることを特徴とするスピーカの歪み補正装置。 A speaker distortion correction device that corrects distortion of a speaker output with respect to an input signal, comprising:
a sensor for detecting vibration of a vibration system of the speaker;
a nonlinear section correction filter to which the input signal is input;
a linear inverse filter that receives the output of the nonlinear section correction filter as an input and outputs an output signal that drives the speaker;
an adaptive algorithm execution unit that executes a predetermined adaptive algorithm and updates a transfer characteristic of the linear inverse filter so that a vibration detected by the sensor becomes a vibration without distortion with respect to the input signal;
The speaker distortion correction device, wherein the nonlinear section correction filter has a transfer characteristic set for correcting distortion of the output of the speaker in response to the input signal, the distortion being caused by the nonlinear characteristics of the speaker.
周囲温度と前記スピーカの経年時間とのうちの少なくとも一方を環境として検知する環境検知手段と、An environment detection means for detecting at least one of an ambient temperature and an age of the speaker as an environment;
前記非線形部補正フィルタの伝達特性を、前記環境検知手段が検知した環境から推定される前記スピーカの非線形な特性に適合する伝達特性に切り替える切替制御手段を有することを特徴とするスピーカの歪み補正装置。A speaker distortion correction device comprising: a switching control means for switching the transfer characteristic of the nonlinear correction filter to a transfer characteristic that matches the nonlinear characteristic of the speaker estimated from the environment detected by the environment detection means.
前記スピーカの非線形な特性を計測する計測手段と、A measuring means for measuring a nonlinear characteristic of the speaker;
前記非線形部補正フィルタの伝達特性を、前記計測手段が計測した前記スピーカの非線形な特性に適合する伝達特性に切り替える切替制御手段を有することを特徴とするスピーカの歪み補正装置。A speaker distortion correcting device comprising: a switching control means for switching a transfer characteristic of the nonlinear portion correction filter to a transfer characteristic that matches the nonlinear characteristic of the speaker measured by the measuring means.
音声信号を再生し前記入力信号として出力するオーディオ装置の状態を検知する状態検知手段を有し、a state detection means for detecting a state of an audio device which reproduces an audio signal and outputs the audio signal as the input signal;
前記切替制御手段は、所定のタイミングで、前記非線形部補正フィルタの伝達特性を切り替え、The switching control means switches the transfer characteristic of the nonlinear section correction filter at a predetermined timing,
前記所定のタイミングは、前記オーディオ装置が起動したタイミングと、前記オーディオ装置が有意な音声信号の再生を行っていないタイミングと、前記オーディオ装置が前記入力信号の出力レベルを変化させたタイミングと、再生する音声信号の音源を切り替えたタイミングとのうちの、少なくとも一つのタイミングを含むことを特徴とするスピーカの歪み補正装置。A speaker distortion correction device characterized in that the specified timing includes at least one of the following: a timing when the audio device is started up, a timing when the audio device is not playing a significant audio signal, a timing when the audio device changes the output level of the input signal, and a timing when the sound source of the audio signal to be played is switched.
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