1. An apparatus, comprising a hearing assistance device, the hearing assistance device including:
a first microphone input configured to receive a first microphone signal with a first reception profile over a frequency range;
a second microphone input configured to receive a second microphone signal with a second reception profile over the frequency range; and
a digital signal processor configured to include:
a compensation filter connected to the second microphone input and configured to output the second microphone signal with a third reception profile which substantially matches the first reception profile;
a mixing module connected to the first microphone input to receive the first microphone signal with the first reception profile and connected to compensation filter to receive the second microphone signal with the third reception profile, the mixing module configured to provide a mixing ratio (\u03b1(k)), for the first microphone signal with the first reception profile and the second microphone signal with the third reception profile based on relative signal strength and nature of the received signals;
a first multiplier configured to:
receive the first microphone signal with the first reception profile over the frequency range;
receive a first signal value of (1\u2212\u03b1(k)) from the mixing module; and
provide a first multiplier output;
a second multiplier configured to:
receive the second microphone signal with the third reception profile over the frequency range;
receive a second signal value of \u03b1(k) from the mixing module; and
provide a second multiplier output; and
a summing stage connected to the first multiplier and the second multiplier, and configured to sum the first multiplier output and the second multiplier output.
2. The apparatus of claim 1, further comprising an omnidirectional microphone connected to the first microphone input.
3. The apparatus of claim 2, further comprising a directional microphone connected to the second microphone input.
4. The apparatus of claim 1, further comprising a directional microphone connected to the first microphone input.
5. The apparatus of claim 4, further comprising an omnidirectional microphone connected to the second microphone input.
6. The apparatus of claim 1, wherein the mixing module is configured to:
take target sound measurements (TSMs) of both the first microphone signal with the first reception profile and the second microphone signal with the third reception profile,
take power measurements of both the first microphone signal with the first reception profile and the second microphone signal with the third reception profile,
use the TSMs and the power measurements as inputs to determine whether to operate in a first microphone signal mode or in a second microphone signal mode, wherein the first microphone signal mode has a first value for a compensation filter output (\u03b2(k)) and the second microphone mode as a second value for a compensation filter output (\u03b2(k)); and
derive a smoothed \u03b2(k) value to provide a switching weight factor \u03b1(k).
7. The apparatus of claim 1, wherein the hearing assistance device further comprises hearing assistance device processing configured to receive and further process the sum of the first multiplier output and the second multiplier output for a user of the device.
8. The apparatus of claim 1, wherein the mixing module is configured to provide the mixing ratio (\u03b1(k)) based on target sound measurements (TSMs) and power measurements of the first and second microphone signal.
9. The apparatus of claim 1, wherein the hearing assistance device is selected from a group of hearing assistance devices consisting of:
behind-the-ear hearing assistance device;
on-the-ear hearing assistance device;
in-the-ear hearing assistance device;
in-the-canal hearing assistance device; and
completely-in-the-canal hearing assistance device.
10. A method implemented in a hearing assistance apparatus that includes a digital signal processor, comprising:
receiving a first microphone signal with a first reception profile over a frequency range;
receiving a second microphone signal with a second reception profile over the frequency range, and
using the digital signal processor to:
convert the second microphone signal with the second reception profile into the second microphone signal with a third reception profile, the third reception profiles substantially matching the first reception profile;
determine a mixing ratio (\u03b1(k)) for the first microphone signal with the first reception profile and the second microphone signal with the third reception profile based on the relative signal strength and nature of the first microphone signal with the first reception profile and the second microphone signal with the third reception profile;
multiply a first signal value (1\u2212\u03b1(k)) and the first microphone signal with the first reception profile to provide a first multiplier output signal;
multiply a second signal value \u03b1(k) and the second microphone signal with the third reception profile to provide a second multiplier output signal; and
sum the first multiplier output signal and the second multiplier output signal.
11. The method of claim 10, wherein receiving the first microphone signal includes receiving an omnidirectional microphone signal.
12. The method of claim 11, wherein receiving the second microphone signal includes receiving a directional microphone signal.
13. The method of claim 10, wherein receiving the first microphone signal the first microphone signal includes receiving a directional microphone signal.
14. The method of claim 13, wherein receiving the second microphone signal includes receiving an omnidirectional microphone signal.
15. The method of claim 10, wherein determining the mixing ratio (\u03b1(k)) includes:
taking target sound measurements (TSMs) of both the first microphone signal with the first reception profile and the second microphone signal with the third reception profile;
taking power measurements of both the first microphone signal with the first reception profile and the second microphone signal with the third reception profile;
using the TSMs and the power measurements as inputs to determine whether to operate in a first microphone signal mode or in a second microphone signal mode, wherein the first microphone signal mode has a first value for a compensation filter output (\u03b2(k)) and the second microphone mode as a second value for the compensation filter output (\u03b2(k));
deriving a smoothed value for the compensation filter output (\u03b2(k)) to provide a switching weight factor \u03b1(k);
multiplying a first signal value (1\u2212\u03b1(k)) and the first microphone signal with the first reception profile to provide a first multiplier output signal;
multiplying a second signal value \u03b1(k) and the second microphone signal with the third reception profile to provide a second multiplier output signal; and
summing the first multiplier output signal and the second multiplier output signal.
16. A method implemented in a hearing assistance apparatus that includes a digital signal processor, comprising:
receiving a first microphone signal with a first reception profile over a frequency range and a second microphone signal with a second reception profile over the frequency range;
using the digital signal processor to:
convert the second microphone signal with the second reception profile over the frequency range to the second microphone signal with a third reception profile over the frequency range, the third reception profile substantially matching the first reception profile;
take target sound measurements (TSMs) of both the first microphone signal with the first reception profile and the second microphone signal with the third reception profile;
take power measurements of both the first microphone signal with the first reception profile and the second microphone signal with the third reception profile;
use the TSMs and the power measurements as inputs to determine whether to operate in a first microphone signal mode or in a second microphone signal mode, wherein the first microphone signal mode has a first value for a compensation filter output (\u03b2(k)) and the second microphone mode as a second value for a compensation filter output (\u03b2(k));
derive a smoothed value for the compensation filter output (\u03b2(k)) to provide a switching weight factor \u03b1(k);
multiply a first signal value (1\u2212\u03b1(k)) and the first microphone signal with the first reception profile to provide a first multiplier output signal;
multiply a second signal value \u03b1(k) and the second microphone signal with the third reception profile to provide a second multiplier output signal; and
sum the first multiplier output signal and the second multiplier output signal.
17. The method of claim 16, wherein receiving the first microphone signal includes receiving an omnidirectional microphone signal.
18. The method of claim 17, wherein receiving the second microphone signal includes receiving a directional microphone signal.
19. The method of claim 16, wherein receiving the first microphone signal includes receiving a directional microphone signal.
20. The method of claim 19, wherein receiving the second microphone signal includes receiving an omnidirectional microphone signal.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. In a vertical double diffused MOSFET, said vertical double diffused MOSFET characterized in that a nitride film is used as an insulation layer interposed between a gate electrode and a metal interconnect layer.
2. A vertical double diffused MOSFET, comprising:
a semiconductor substrate;
an oxide film formed on said semiconductor substrate;
a gate electrode formed on said oxide film and having at least one window;
a nitride film formed on said oxide film and said gate electrode;
an ion implant window formed through said nitride film at a center of said window, ions of a first conductivity type being implanted through said ion implant window to said semiconductor substrate and thermally diffused thereby forming a main diffusion region;
a thick walled portion formed by growing said oxide film in said ion implant window, wherein ions of the first conductivity type are implanted through as a mask said gate electrode and said nitride film on said gate electrode into said semiconductor substrate and thermally diffused to form a channel diffusion region, and ions of a second conductivity type being implanted through as a mask said thick walled portion, said gate electrode and said nitride film on said gate electrode into said semiconductor substrate and thermally diffused thereby forming a source diffusion region.
3. A vertical double diffused MOSFET according to claim 2, wherein said main diffusion region and said thick walled portion are substantially simultaneously formed in one heating process.
4. A method for manufacturing a vertical double diffused MOSFET, comprising the steps of:
(a) forming an oxide film on a substrate;
(b) forming a gate electrode having at least one window on said oxide film;
(c) forming a nitride film as an insulation layer on said oxide film and said gate electrode;
(d) forming an ion implant window through said nitride film at a center of said window;
(e) implanting ions of a first conductivity type through said ion implant window to said substrate;
(f) thermally diffusing said ions to form a main diffusion region and growing said oxide film inside said ion implant window to form a thick walled portion;
(g) implanting ions of the first conductivity type through as a mask said thick walled portion, said gate electrode and said nitride film on said gate electrode to said substrate and thermally diffused to form a channel diffusion region; and
(h) implanting ions of a second conductivity type through a mask of said thick walled portion, said gate electrode and said nitride film on said gate electrode to said substrate and thermally diffused to form a source diffusion region.
5. A manufacturing method according to claim 4, wherein said step (f) is substantially one heating step.