Digital microphone and position-to-frequency converter

Patent metadata

Field	Value
Publication number	US-9503811-B2
Application number	US-201514615471-A
Country	US
Kind code	B2
Filing date	Feb 6, 2015
Priority date	Feb 18, 2014
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

A digital microphone includes: a cavity resonator operatable in a micrometer, millimeter, or electromagnetic waveband, the cavity resonator having a metal wall including a conductive membrane 32 that vibrates in response to incident acoustic waves and converts the shift of the membrane 32 into a resonance frequency of the cavity resonator; an FM-signal generator that modulates the resonance frequency of the cavity resonator in response to the shift of the membrane 32 and outputs FM signals from the metal wall other than the membrane; and a ΔΣ-modulated-signal generator that generates ΔΣ-modulated signals from the FM signals. The FM-signal generator includes a slot 36 , a micro-strip line 38 , and a negative resistive element 40 . The ΔΣ-modulated-signal generator includes an edge detector 42.

First claim

What is claimed is:

1. A digital microphone comprising:
a cavity resonator operatable in a micrometer, millimeter, or electromagnetic waveband, the cavity resonator comprising a metal wall comprising a conductive membrane that vibrates in response to incident acoustic waves and converts vibration of the membrane into a resonance frequency of the cavity resonator;
an FM-signal generator that modulates the resonance frequency of the cavity resonator in response to the vibration of the membrane and outputs FM signals from a position on the cavity resonator other than the membrane; and
a ΔΣ-modulated-signal generator that generates ΔΣ-modulated signals from the FM signals.

2. The digital microphone according to claim 1 , wherein the ΔΣ-modulated-signal generator comprises a single-bit quantizer that samples the FM signals with high-frequency clock signals and outputs single-bit quantized signals.

3. The digital microphone according to claim 1 , wherein the FM-signal generator comprises:
a conductive plate disposed in an area other than the membrane in the cavity resonator;
a dielectric layer disposed on the conductive plate;
a slot in the conductive plate;
a micro-strip line that intersects the slot and is coupled with micrometer, millimeter, or electromagnetic waves in the cavity resonator; and
a negative resistive element that is connected to the micro-strip line.

4. The digital microphone according to claim 3 , wherein the dielectric layer is disposed on a surface of the conductive plate, the surface being remote from the membrane.

5. The digital microphone according to claim 1 , wherein the cavity resonator comprises a cylindrical waveguide having a first end covered with the membrane and a second end comprising the FM-signal generator.

6. The digital microphone according to claim 1 , wherein the cavity resonator comprises a prismatic waveguide having a first end covered with the membrane and a second end comprising the FM-signal generator.

7. The digital microphone according to claim 1 , wherein the cavity resonator comprises a prismatic waveguide, at least one side of the waveguide comprising the membrane, at least one of the other sides of the waveguide comprising the FM-signal generator.

8. The digital microphone according to claim 1 , wherein the cavity resonator comprises a prismatic waveguide, multiple sides of the waveguide each comprising the membrane, at least one of the other sides of the waveguide comprising the FM-signal generator.

9. A position-to-frequency converter comprising:
a cavity resonator operatable in a micrometer, millimeter, or electromagnetic waveband, the cavity resonator comprising a metal wall comprising a conductive movable structure that shifts in response to an incident external force and converts the shift of the conductive movable structure into a resonance frequency of the cavity resonator;
an FM-signal generator that modulates the resonance frequency of the cavity resonator in response to the shift of the movable structure and outputs FM signals from a position on the cavity resonator other than the movable structure; and
a ΔΣ-modulated-signal generator that generates ΔΣ-modulated signals from the FM signals.

10. The position-to-frequency converter according to claim 9 , wherein the ΔΣ-modulated-signal generator comprises a single-bit quantizer that samples the FM signals with high-frequency clock signals and outputs single-bit quantized signals.

11. The position-to-frequency converter according to claim 9 , wherein the FM-signal generator comprises:
a conductive plate disposed in an area other than the movable structure in the cavity resonator;
a dielectric layer disposed on the conductive plate;
a slot in the dielectric layer;
a micro-strip line that intersects the slot and is coupled with micrometer, millimeter, or electromagnetic waves in the cavity resonator; and
a negative resistive element that is connected to the micro-strip line.

12. The position-to-frequency converter according to claim 9 , wherein the cavity resonator comprises a cylindrical or prismatic waveguide, at least one surface of the waveguide comprising the movable structure, at least one of the other surfaces of the waveguide comprising the FM-signal generator.

Assignees

• Maezawa Koichi
• Tanoue Koichiro
• Audio Technica Kk
• Nat Univ Corp Univ Of Toyama

Inventors

• Maezawa Koichi
• Tanoue Koichiro

Classifications

• H04R1/08

  Mouthpieces; {Microphones;} Attachments therefor · CPC title

• H04R3/00 Primary

  Circuits for transducers (arrangements for producing a reverberation or echo sound G10K15/08; amplifiers H03F) · CPC title

• H04R1/04 Primary

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

• H04R23/00

  Transducers other than those covered by groups H04R9/00 - H04R21/00 {(diaphragms for transducers of the distributed-mode type H04R7/045)} · CPC title

• H03M3/43

  the quantiser being a single bit one · CPC title