Speaker distortion correction device

Patent metadata

Field	Value
Publication number	US-12567838-B2
Application number	US-202418606415-A
Country	US
Kind code	B2
Filing date	Mar 15, 2024
Priority date	Apr 3, 2023
Publication date	Mar 3, 2026
Grant date	Mar 3, 2026

Abstract

A speaker distortion correction device includes an amplifier configured to drive a speaker; and a distortion corrector. An input signal is input to the distortion corrector, and an output of the distortion corrector is input to the amplifier. The distortion corrector includes a nonlinear distortion controller configured to generate a corrected signal obtained by performing a nonlinear distortion correction process on the input signal so that nonlinear distortion of the speaker is suppressed when the corrected signal is input to the amplifier; a maximum value calculating section configured to calculate a maximum output value of the amplifier to be obtained when the corrected signal is input to the amplifier, based on at least the input signal; and a selector configured to select the corrected signal when the maximum output value does not exceed a predetermined threshold and select the input signal when the maximum output value exceeds the predetermined threshold.

First claim

What is claimed is:

1 . A speaker distortion correction device comprising:
an amplifier configured to drive a speaker; a distortion corrector, an input signal being input to the distortion corrector, and an output of the distortion corrector being input to the amplifier; and a displacement detector configured to detect displacement of a vibration system of the speaker, wherein the distortion corrector includes:
a nonlinear distortion controller configured to generate a corrected signal obtained by performing a nonlinear distortion correction process on the input signal to correct the input signal so that nonlinear distortion of the speaker is suppressed when the corrected signal is input to the amplifier;
a maximum value calculating section configured to calculate a maximum output value of the amplifier to be obtained when the corrected signal generated by the nonlinear distortion controller is input to the amplifier, based on at least the input signal and a gain of the amplifier, the gain of the amplifier being calculated based on the displacement detected by the displacement detector; and
a selector configured to select, as the output of the distortion corrector, the corrected signal generated by the nonlinear distortion controller when the maximum output value calculated by the maximum value calculating section does not exceed a predetermined threshold and select, as the output of the distortion corrector, the input signal on which the nonlinear distortion correction process is not performed by the nonlinear distortion controller when the maximum output value calculated by the maximum value calculating section exceeds the predetermined threshold.

2 . The speaker distortion correction device as claimed in claim 1 , wherein the predetermined threshold is a maximum output value of the amplifier at which it is guaranteed that no abnormality of the speaker occurs, the abnormality of the speaker including clipping of an output of the speaker, destruction, or a bottom contact.

3 . The speaker distortion correction device as claimed in claim 1 ,
wherein the nonlinear distortion controller includes:
a nonlinear part correction filter, a target signal being input to the nonlinear part correction filter, the target signal being a signal on which the nonlinear distortion correction process is performed, and a transfer characteristic for correcting distortion due to a nonlinear characteristic of the speaker with respect to the target signal being set in the nonlinear part correction filter;
a linear inverse filter, an output of the nonlinear part correction filter being input to the linear inverse filter; and
an adaptive algorithm executing section configured to adapt a transfer function of the linear inverse filter so that the displacement detected by the displacement detector becomes a displacement having no distortion with respect to the target signal.

4 . The speaker distortion correction device as claimed in claim 1 , wherein the maximum value calculating section calculates, as the maximum output value, a maximum value of a signal obtained by multiplying a signal obtained by performing a process the same as the nonlinear distortion correction process on the input signal by a gain of the amplifier.

5 . The speaker distortion correction device as claimed in claim 1 , wherein the maximum value calculating section calculates the maximum output value from a maximum value of the input signal in accordance with a preset relationship between the maximum value of the input signal and the maximum output value.

6 . The speaker distortion correction device as claimed in claim 1 , wherein the maximum value calculating section obtains a maximum value of displacement of a vibration system of the speaker by applying the input signal to an equivalent model of a linear speaker from which a nonlinear characteristic of the speaker is excluded, and calculates the maximum output value from the obtained maximum value of the displacement in accordance with a preset relationship between the maximum value of the displacement and the maximum output value.

7 . A speaker distortion correction device comprising:
an amplifier configured to drive a speaker; a distortion corrector, an input signal being input to the distortion corrector, and an output of the distortion corrector being input to the amplifier; and a displacement detector configured to detect displacement of a vibration system of the speaker, wherein the distortion corrector includes:
an attenuator configured to generate an attenuated input signal by attenuating the input signal with a variable attenuation amount;
a nonlinear distortion controller configured to generate a corrected signal obtained by performing a nonlinear distortion correction process on the input signal or the attenuated input signal to correct the input signal or the attenuated input signal so that nonlinear distortion of the speaker is suppressed when the corrected signal is input to the amplifier;
a maximum value calculating section configured to calculate a maximum output value of the amplifier to be obtained when the corrected signal obtained by performing the nonlinear distortion correction process on the input signal is input to the amplifier, based on at least the input signal and a gain of the amplifier, the gain of the amplifier being calculated based on the displacement detected by the displacement detector; and
a selector configured to select, as the output of the distortion corrector, the corrected signal obtained by performing the nonlinear distortion correction process on the input signal when the maximum output value calculated by the maximum value calculating section does not exceed a predetermined threshold, and select, as the output of the distortion corrector, the corrected signal obtained by performing the nonlinear distortion correction process on the attenuated input signal generated by the variable attenuation amount being set so that a level of the attenuated input signal is less than or equal to a predetermined level when the maximum output value calculated by the maximum value calculating section exceeds the predetermined threshold.

8 . The speaker distortion correction device as claimed in claim 7 , wherein the predetermined level is a level of the attenuated input signal at which it is guaranteed that no abnormality of the speaker occurs when the corrected signal obtained by the nonlinear distortion controller performing the nonlinear distortion correction process on the attenuated input signal is input to the amplifier, the abnormality of the speaker including clipping of an output of the speaker, destruction, or a bottom contact.

9 . A speaker distortion correction device comprising:
an amplifier configured to drive a speaker; a distortion corrector, an input signal being input to the distortion corrector, and an output of the distortion corrector being input to the amplifier; and a displacement detector configured to detect displacement of a vibration system of the speaker, wherein the distortion corrector includes:
a band divider configured to divide the input signal into a plurality of band input signals for a plurality of bands;
a plurality of band distortion correctors provided respectively corresponding to the plurality of bands, and the plurality of band input signals being respectively input to the plurality of band distortion correctors; and
a mixer configured to synthesize outputs of the plurality of band distortion correctors as the output of the distortion corrector,
wherein each of the plurality of band distortion correctors includes:
a nonlinear distortion controller configured to generate a corrected signal obtained by performing a nonlinear distortion c

Assignees

• Alps Alpine Co Ltd

Inventors

• Saito Yuji

Classifications

• H04R3/007 Primary

  Protection circuits for transducers · CPC title

• H03F2201/3236

  A generated signal, e.g. a pulse or an inverted synchronous signal, being added to avoid certain conditions, e.g. clipping · CPC title

• H03F2200/03

  the amplifier being designed for audio applications · CPC title

• H03F3/21

  with semiconductor devices only {(H03F3/245 takes precedence)} · CPC title

• H03F3/183

  with semiconductor devices only · CPC title