Armature-based acoustic receiver having improved output and method

Patent metadata

Field	Value
Publication number	US-11012786-B2
Application number	US-201716342383-A
Country	US
Kind code	B2
Filing date	Oct 17, 2017
Priority date	Oct 17, 2016
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

A pre-distorted electrical excitation signal is generated for an acoustic transducer having an armature and a non-linear transfer characteristic by applying an electrical input signal (x) representative of a desired acoustic output to a computable non-linear function that is a function of the electrical input signal (x). When applied to an input of the transducer, the pre-distorted electrical excitation signal results in an improved acoustic output signal.

First claim

The invention claimed is:

1. An acoustic receiver having an armature and a non-linear transfer characteristic, the receiver comprising:
a coil disposed about an armature, a portion of the armature free to deflect between magnets of the receiver in response to application of a pre-distorted electrical excitation signal to the coil,
the pre-distorted electrical excitation signal is an output of a computable non-linear function of an electrical input signal (x) representative of a desired acoustic output;
an output port capable of producing an acoustic output in response to application of the pre-distorted electrical excitation signal to the coil,
wherein, for a specified acoustic sound pressure level, the acoustic output produced in response to the pre-distorted electrical excitation signal has less distortion than an acoustic output that would be produced in response to the electrical input signal (x) without pre-distortion.

2. The receiver of claim 1 further comprising
a diaphragm with a movable portion linked to the armature, wherein movement of the armature translates into movement of the diaphragm,
a housing including the output port, the armature and the diaphragm disposed at least partially within housing,
wherein movement of the diaphragm causes the receiver to produce the acoustic output.

3. The receiver of claim 1 , the magnets having a magnetic field that applies a magnetic force to the movable portion of the armature, wherein the magnet force is stronger than a mechanical restoring force of the armature.

4. The receiver of claim 1 in combination with,
a processor coupled to memory, the computable non-linear function stored in the memory,
the processor configured to generate the pre-distorted electrical excitation signal by applying the electrical input signal (x) to the computable non-linear function.

5. The receiver of claim 1 , the computable non-linear function is a function that can be approximated by a function including at least one term that is proportional to x n where n is not equal to unity.

6. The receiver of claim 4 ,
the processor configured to generate an updated pre-distorted electrical excitation signal using a computable non-linear function that is updated based on information indicative of a change in characteristic of the receiver;
an amplifier having an output coupled to the coil of the receiver,
wherein the updated pre-distorted electrical excitation signal compensates for the change in characteristic of the receiver when the updated pre-distorted electrical excitation signal is applied to the coil.

7. The receiver of claim 6 , the change in characteristic of the receiver is a change in balance of the receiver.

8. The receiver of claim 6 , the change in characteristic of the receiver is a change in frequency response of the receiver.

9. The apparatus of claim 4 , the processor configured to generate the computable non-linear function using a process that iterates until distortion at an output of the receiver is reduced to a specified level.

10. An apparatus for configuring an acoustic receiver to generate a pre-distorted electrical excitation signal from an electrical input signal (x) representative of a desired acoustic output, the receiver having an armature and a non-linear transfer characteristic attributable to the armature, the apparatus comprising:
an interface connectable to memory associated with the receiver;
a processor configured to optimize a computable non-linear function for the receiver,
the computable non-linear function is a function of the electrical input signal (x),
the optimized computable non-linear function capable of outputting a pre-distorted electrical excitation signal in response to the electrical input signal (x),
the processor configured to provide the optimized computable non-linear function to the interface connectable to the memory associated with the receiver.

11. The apparatus of claim 10 ,
the processor configured optimize the computable non-linear function by generating a set of one or more parameters for the computable non-linear function,
the computable non-linear function is a function that can be approximated by a function including at least one term that is proportional to x n where n is not equal to unity.

12. The apparatus of claim 11 ,
the processor configured generate the optimized set of one or more parameters by iteratively applying intermediate pre-distorted electrical excitation signals to a device representative of the receiver until distortion at an output of the device representative of the receiver is reduced to a specified level,
during each iteration, the processor configured to generate each intermediate pre-distorted electrical excitation signal by applying the electrical input signal (x) to the computable non-linear function with a corresponding intermediate set of one or more parameters.

13. The apparatus of claim 12 , the processor configured to optimize the set of one or more parameters using a gradient descent algorithm.

14. The apparatus of claim 12 , for each iteration, a processor configured to determine the distortion at the output of the device representative of the receiver before determining a new intermediate set of one or more parameters.

15. The apparatus of claim 12 , the device representative of the receiver is an actual receiver, an amplifier having an input coupled to an output of the processor, wherein the amplifier applies the intermediate pre-distorted electrical excitation signals to the actual receiver when an output of the amplifier is coupled to an input of the receiver.

16. The apparatus of claim 15 , the amplifier is a current amplifier.

17. The apparatus of claim 12 , the device representative of the receiver is a numerically implemented model of the receiver implemented by the processor, the processor configured to implement a virtual amplifier and to apply the intermediate pre-distorted electrical excitation signals to the numerically implemented model of the receiver using the virtual amplifier.

18. The apparatus of claim 11 , the computable non-linear function is a rational polynomial.

19. The apparatus of claim 11 , the computable non-linear function is a hyperbolic trigonometric function approximated by a polynomial function.

20. The apparatus of claim 10 , the computable non-linear function is a function that can be approximated by a function including at least one term that is proportional to where n is not equal to unity.

Assignees

• Knowles Electronics Llc

Inventors

• King Charles
• Unruh Andrew
• Warren Daniel

Classifications

• H04R3/04 Primary

  for correcting frequency response · CPC title

• H04R11/02

  Loudspeakers · CPC title

• H04R1/04

  Structural association of microphone with electric circuitry therefor (in electric hearing aids H04R25/00) · CPC title

• H04R11/04 Primary

  Microphones · CPC title