System and method for extracting parameters of a speaker without using stimulus

Patent metadata

Field	Value
Publication number	US-9357302-B2
Application number	US-201414474646-A
Country	US
Kind code	B2
Filing date	Sep 2, 2014
Priority date	Feb 18, 2014
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

A system includes a plurality of channels, a parameter calculator, and an equalizer. Each channel receives a plurality of input signals that represent an input to a speaker. Each channel generates real and imaginary components of a transfer function of the speaker based on the plurality of input signals. The parameter calculator calculates a plurality of parameters of the speaker based on the real and imaginary components of the transfer function received from each channel. The equalizer adjusts the input to the speaker based on the parameters.

First claim

What is claimed is:

1. A system comprising:
a plurality of channels, wherein each channel receives a plurality of input signals that represent an input to a speaker, and wherein each channel generates real and imaginary components of a transfer function of the speaker based on the plurality of input signals;
a parameter calculator that calculates a plurality of parameters of the speaker based on the real and imaginary components of the transfer function received from each channel; and
an equalizer that adjusts the input to the speaker based on the parameters.

2. The system of claim 1 wherein the parameters include a resonance frequency of the speaker, a quality factor of the speaker, and a DC value of an impedance of the speaker.

3. The system of claim 1 wherein in response to the plurality of input signals being sampled at a sampling rate greater than or equal to a predetermined sampling rate, the transfer function is a continuous transfer function, and the parameters include a resonance frequency of the speaker, a quality factor of the speaker, and a DC value of an impedance of the speaker.

4. The system of claim 1 wherein in response to the plurality of input signals being sampled at a sampling rate less than or equal to a predetermined sampling rate, the transfer function is a discrete transfer function, and the parameters include a plurality of coefficients of the discrete transfer function.

5. The system of claim 4 wherein the parameter calculator calculates a resonance frequency of the speaker, a quality factor of the speaker, and a DC value of an impedance of the speaker based on the plurality of coefficients of the discrete transfer function.

6. The system of claim 1 wherein each channel.comprises:
a plurality of band-pass filters that respectively filter the plurality of input signals and that output a plurality of sine wave signals;
a cosine generator that generates a cosine wave signal based on one of the plurality of sine wave signals; and
a plurality of correlators that correlate the plurality of sine wave signals and the cosine wave signal and that generate the real and imaginary components of the transfer function of the speaker.

7. The system of claim 6 wherein the plurality of band-pass filters have a center frequency, and wherein the center frequency is different in each channel and is selected based on a resonance frequency of the speaker.

8. The system of claim 1 wherein the plurality of input signals include a voltage signal and a current signal received from an amplifier that drives the speaker, and wherein each channel comprises:
a first band-pass filter that filters the current signal and that outputs a first sine wave signal;
a second band-pass filter that filters the voltage signal and that outputs a second sine wave signal;
a cosine generator that generates a cosine wave signal based on the first sine wave signal;
a first correlator that correlates the first sine wave signal and the cosine wave signal and that generates first real and imaginary components of the transfer function; and
a second correlator that correlates the first and second sine wave signals and the cosine wave signal and that generates second real and imaginary components of the transfer function,
wherein the parameter calculator calculates the plurality of parameters of the speaker based on the first and second real and imaginary components of the transfer function.

9. The system of claim 8 wherein the first and second band-pass filters have a center frequency, and wherein the center frequency is different in each channel and is selected based on a resonance frequency of the speaker.

10. A method comprising:
receiving, in each of a plurality of channels, a plurality of input signals representing an input to a speaker;
generating, in each of the plurality of channels, real and imaginary components of a transfer function of the speaker based on the plurality of input signals;
calculating a plurality of parameters of the speaker based on the real and imaginary components of the transfer function received from each channel; and
adjusting the input to the speaker based on the parameters.

11. The method of claim 10 wherein the parameters include a resonance frequency of the speaker, a quality factor of the speaker, and a DC value of an impedance of the speaker.

12. The method of claim 10 wherein in response to the plurality of input signals being sampled at a sampling rate greater than or equal to a predetermined sampling rate, the transfer function is a continuous transfer function, and the parameters include a resonance frequency of the speaker, a quality factor of the speaker, and a DC value of an impedance of the speaker.

13. The method of claim 10 wherein in response to the plurality of input signals being sampled at a sampling rate less than or equal to a predetermined sampling rate, the transfer function is a discrete transfer function, and the parameters include a plurality of coefficients of the discrete transfer function.

14. The method of claim 13 further comprising calculating a resonance frequency of the speaker, a quality factor of the speaker, and a DC value of an impedance of the speaker based on the plurality of coefficients of the discrete transfer function.

15. The method of claim 10 further comprising, in each channel:
filtering, using a plurality of band-pass filters, the plurality of input signals and outputting a plurality of sine wave signals;
generating a cosine wave signal based on one of the plurality of sine wave signals; and
correlating the plurality of sine wave signals and the cosine wave signal and generating the real and imaginary components of the transfer function of the speaker.

16. The method of claim 15 further comprising selecting, based on a resonance frequency of the speaker, a different center frequency for the plurality of band-pass filters in each channel.

17. The method of claim 10 wherein the plurality of input signals include a voltage signal and a current signal received from an amplifier that drives the speaker, the method further comprising, in each channel:
filtering, using a first band-pass filter, the current signal and outputting a first sine wave signal;
filtering, using a second band-pass filter, the voltage signal and outputting a second sine wave signal;
generating a cosine wave signal based on the first sine wave signal;
correlating the first sine wave signal and the cosine wave signal and generating first real and imaginary components of the transfer function;
correlating the first and second sine wave signals and the cosine wave signal and that generating second real and imaginary components of the transfer function; and
calculating the plurality of parameters of the speaker based on the first and second real and imaginary components of the transfer function.

18. The method of claim 17 further comprising selecting, based on a resonance frequency of the speaker, a different center frequency for the first and second band-pass filters.

Assignees

• Maxim Integrated Products

Inventors

• Kiadeh Mansur
• Nigam Vivek

Classifications

• H03G5/005

  of digital signals · CPC title

• H03G5/165

  Equalizers; Volume or gain control in limited frequency bands · CPC title

• H04R3/04 Primary

  for correcting frequency response · CPC title