1. A system that extends the high-frequency spectrum of a narrowband audio signal in the time domain comprising:
an interface configured to receive a narrowband audio signal;
a controller that extends the harmonics of vowels by introducing a non linearity in the received narrowband audio signal in the time domain; and
a random noise generator that generates consonants by introducing random-noise in the received narrowband audio signal in the time domain,
where the controller comprises a squaring circuit that squares a segment of the narrowband audio signal.
2. The system of claim 1 further comprising a plurality of filters that pass a portion of frequencies of the non-linearity and the random-noise, respectively.
3. The system of claim 1 further comprising a plurality of amplifiers that increase magnitudes of the non-linearity and the random-noise.
4. The system of claim 1 further comprising a plurality of mixers that select a portion of the non-linearity generated by the controller and a portion of the random-noise generated by the random-noise generator.
5. The system of claim 1 further comprising a summing circuit that sums a portion of the non-linearity generated by the controller and a portion of the random-noise generated by the random-noise generator.
6. The system of claim 1 further comprising a summing circuit that sums a portion of the non-linearity generated by the controller, a portion of the random-noise generated by the random-noise generator and the narrowband audio signal received through the interface.
7. The system of claim 6 further comprising an adaptive filter configured to dampen a background noise detected in an upper frequency of the summed signal.
8. The system of claim 6 further comprising an adaptive filter configured to vary the spectral shape of a portion of the summed signal.
9. The system of claim 1 further comprising:
a plurality of filters that pass a portion of frequencies of the non-linearity generated by the controller and the random-noise generated by the random-noise generator, respectively,
a plurality of amplifiers that increase magnitudes of the non-linearity and random-noise;
a plurality of mixers that select a portion of the non-linearity generated by the controller and a portion of the random-noise generated by the random-noise generator;
a first summing circuit that sums the portion of the non-linearity generated by the controller and the portion of the random-noise generated by the random-noise generator; and
a second summing circuit that sums the portion of the combined non-linearity and the random-noise with the narrowband audio signal.
10. The system of claim 9 further comprising:
a first adaptive filter configured to dampen a background noise detected in an upper frequency of the second summed signal; and
a second adaptive filter configured to vary the spectral shape of a portion of the second summed signal.
11. A method that extends a high-frequency spectrum of a narrowband signal comprising:
determining if a portion of a signal represents a vowel or a consonant;
generating a first portion of a high frequency spectrum in a time domain by squaring a portion of a narrow band signal if the that portion of the narrowband signal represents the vowel;
generating a second portion of the high frequency spectrum in the time domain by generating a random signal if the portion of the narrowband signal represents the consonant; and
filtering the generated high frequency signals to adjust spectral shapes and magnitude.
12. The method of claim 11 further comprising combing the generated high frequency signals with the narrowband signal.
13. The method of claim 11 further comprising conditioning the first portion of the high frequency spectrum and conditioning the second portion of the high frequency spectrum.
14. The method of claim 11 further comprising dampening the background noise in the generated high frequency spectrums.
15. The method of claim 11 further comprising adding the first portion of the high frequency spectrum to the second portion of the high frequency spectrum before filtering the summed signal.
16. The method of claim 11 further comprising:
adding the first portion of the high frequency spectrum to the second portion of the high frequency spectrum;
conditioning the first portion of the high frequency spectrum and conditioning the second portion of the high frequency spectrum;
adding the conditioned first portion of the high frequency spectrum to the conditioned second portion of the high frequency spectrum; and
adding the combined first portion of the high frequency spectrum and the second portion of the high frequency spectrum to the narrowband signal.
17. The method of claim 16 further comprising dampening at least a portion of the background noise in the combined high frequency spectrum and the narrowband signal.
18. A system that extends the high-frequency spectrum of a narrowband audio signal in the time domain comprising:
an interface configured to receive a narrowband audio signal;
a controller that extends the harmonics of vowels by introducing a non linearity in the received narrowband audio signal in the time domain;
a random noise generator that generates consonants by introducing random-noise in the received narrowband audio signal in the time domain,
a plurality of filters that pass a portion of frequencies of the non-linearity generated by the controller and the random-noise generated by the random-noise generator, respectively,
a plurality of amplifiers that increase magnitudes of the non-linearity and random-noise;
a plurality of mixers that select a portion of the non-linearity generated by the controller and a portion of the random-noise generated by the random-noise generator;
a first summing circuit that sums the portion of the non-linearity generated by the controller and the portion of the random-noise generated by the random-noise generator;
a second summing circuit that sums the portion of the combined non-linearity and the random-noise with the narrowband audio signal
a first adaptive filter configured to dampen a background noise detected in an upper frequency of the second summed signal; and
a second adaptive filter configured to vary the spectral shape of a portion of the second summed signal,
where the controller comprises a squaring circuit that squares a segment of the narrowband audio 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.
1. A silicon substrate having a substrate plane orientation (100), comprising:
textures on one surface for receiving light; and
fine rectangular-shaped uneven portions in a ripple shape on another surface opposite to the one surface on which the textures are formed,
wherein the depth of concave portions in the uneven portions is 10 to 200 nm.
2. The silicon substrate according to claim 1,
wherein the depth of each of the unevenness formed in the ripple shape ranges from 10 nm to 100 nm.
3. The silicon substrate according to claim 1,
wherein the density of the unevenness on the another surface is 10 to 100000 pieces100 \u03bcm2.
4. The silicon substrate according to claim 1,
wherein the absorptivity of incident light (wavelength 0.5 to 10 \u03bcm) onto the silicon substrate is 80% or more.
5. A manufacturing method of a silicon substrate comprising:
preparing a silicon substrate having a substrate plane orientation (100); and
spraying an etching gas to the surface of the silicon substrate,
wherein the etching gas includes one or sore gases selected from the group consisting of ClF3, XeF2, BrF3, BrF5 and NF3 as well as a gas containing oxygen atoms in molecules,
the concentration of the gases selected from ClF3, XeF2, BrF3, BrF5 and NF3 with respect to the total flow rate during etching processing is 1 to 10%, and
the surface of the silicon substrate is processed by non-plasma.
6. The manufacturing method of the silicon substrate according to claim 5,
wherein the etching gas further includes an inert gas.
7. The manufacturing method of the silicon substrate according to claim 5,
wherein, in the etching gas, the concentration of the gas containing oxygen atoms in molecules with respect to the total flow rate during etching processing is 4 to 40%.
8. The manufacturing method of the silicon substrate according to claim 5,
wherein, in the etching gas, the ratio between the one or more gases selected from the group consisting of ClF3, XeF2, BrF3, BrF5 and NF3 and the gas containing oxygen atoms in molecules is 1:10 to 1:3.
9. The manufacturing method of the silicon substrate according to claim 5,
wherein the temperature of the silicon substrate is maintained to 130\xb0 C. or less.
10. The manufacturing method of the silicon substrate according to claim 5,
wherein the etching processing of the silicon substrate is performed under a reduced pressure condition.
11. The manufacturing method of the silicon substrate according to claim 5, further comprising:
washing the silicon substrate,
wherein the washing of the silicon substrate is performed by using flue-nitric acid.
12. The manufacturing method of the silicon substrate according to claim 5, further comprising:
washing the silicon substrate,
wherein the washing of the silicon substrate is performed by using sodium hydroxide.
13. The manufacturing method of the silicon substrate according to claim 6,
wherein, in the etching gas, the concentration of the gas containing oxygen atoms in molecules with respect to the total flow rate during etching processing is 4 to 40%.
14. The manufacturing method of the silicon substrate according to claim 13,
wherein, in the etching gas, the ratio between the one or more gases selected from the group consisting of ClF3, XeF2, BrF3, BrF5 and NF3 and the gas containing oxygen atoms in molecules is 1:10 to 1:3.
15. The manufacturing method of the silicon substrate according to claim 14,
wherein the temperature of the silicon substrate is maintained to 130\xb0 C. or less.
16. The manufacturing method of the silicon substrate according to claim 15, further comprising:
washing the silicon substrate,
wherein the washing of the silicon substrate is performed by using fluonitric acid.
17. The manufacturing method of the silicon substrate according to claim 15, further comprising:
washing the silicon substrate,
wherein the washing of the silicon substrate is performed by using sodium hydroxide.
18. The silicon substrate according to claim 2,
wherein the density of the unevenness on the other surface is 10 to 100000 pieces100 \u03bcm2.
19. The silicon substrate according to claim 2,
wherein the absorptivity of incident light (wavelength 0.5 to 10 \u03bcm) onto the silicon substrate is 80% or more.
20. The silicon substrate according to claim 18,
wherein the absorptivity of incident light (wavelength 0.5 to 10 \u03bcm) onto the silicon substrate is 80% or more.