1. A filter element comprising:
a flat dielectric substrate;
a ground electrode on a back main surface of the dielectric substrate;
resonant lines each having a shorting end located in an area of a border between a side surface and the back main surface of the dielectric substrate and extending from the side surface to a front main surface of the dielectric substrate, wherein the ground electrode and the resonant lines constitute a plurality of strip-line resonators; and
an inputoutput terminal coupled to any of the plurality of strip-line resonators; wherein
in any of the plurality of strip-line resonators, a line width of substantially the entire portion of the resonant line on the front main surface is different from a line width of the resonant line of the strip-line resonator on the side surface; and
the line width of at least one of the resonant lines on the side surface is less than the line width of the resonator lines on the front surface, and the line width of at least another one of the resonator lines on the side surface is greater than the line width of the resonator lines on the on the front surface.
2. The filter element according to claim 1, wherein, among the plurality of strip-line resonators, a strip-line resonator coupled to the inputoutput terminal and a strip-line resonator adjacent thereto are comb-line coupled to each other, and at least another one of the strip-line resonators is interdigitally coupled to a strip-line resonator adjacent thereto.
3. The filter element according to claim 2, further comprising a comb-line coupling electrode that allows the comb-line coupled strip-line resonators to be in conductive contact with each other and that is adjacent to the shorting ends in the strip-line resonators.
4. The filter element according to claim 3, wherein the comb-line coupling electrode comprises an electrode on the front main surface of the dielectric substrate.
5. The filter element according to claim 1, wherein the center of the resonant line on the side surface in the width direction and the center of the resonant line on the front main surface in the width direction are not aligned with each other.
6. The filter element according to claim 1, wherein the electrode thickness of the resonant line on the side is larger than the electrode thickness of the resonant line on the front main surface.
7. The filter element according to claim 1, wherein the resonant line on the front main surface is composed of photosensitive conductive paste, and the resonant line on the side, the ground electrode, and the inputoutput terminal are composed of non-photosensitive conductive paste.
8. The filter element according to claim 1, wherein the line width of the at least one resonant line on the side surface having a line width less than the line width of the resonator lines on the front surface is in a range of about 0.5 times to less than about 1 times the line width of the resonant lines on the front main surface and the line width of at least another resonant line on the side surface having a line width greater than the line width of the resonator lines on the front surface is in a range of greater than about 1 times to about 1.1 times the line width of the resonant lines on the front main surface.
9. The filter element according to claim 1, wherein the front main surface of the dielectric substrate is overlaid with an insulating layer, and further comprising an insulating-layer side electrode disposed on a side of the insulating layer and extending from the resonant line on the side.
10. A method for manufacturing a filter element, the method comprising:
a dividing step of dividing a flat dielectric base substrate into a plurality of filter element bases, the dielectric base substrate including a front main surface on which resonant-line main-surface portions are formed and a back main surface on which a ground electrode is formed; and
a resonant-line forming step of forming resonant-line side portions on a side of each of the filter element bases produced in the dividing step from the resonant-line main-surface portions to the ground electrode using conductive paste through printing, drying, and firing such that substantially the entire resonant-line main-surface portions have a line width different from a line width of the resonant-line side portions and such that the resonant-line main-surface portions and the resonant-line side portions constitute resonant lines having a shorting end in an area of a border between a side of the filter element base and the back main surface; wherein
the line width of at least one of the resonant-line side portions is less than the line width of the resonant-line main-surface portions, and the line width of at least another one of the resonant-line side portions is greater than the line width of the resonant-line main-surface portions.
11. The method for manufacturing a filter element according to claim 10, wherein the resonant-line forming step is a step of forming the resonant-line side portions on a filter element base extracted from the plurality of filter element bases produced in the dividing step, optimizing the shape of the resonant-line side portions, and then forming the resonant-line side portions having the optimized shape on all the plurality of filter element bases.
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 coding apparatus using a band extension, the coding apparatus comprising:
a bandwidth extender for extracting auxiliary information relating to a characteristic of a high band signal using the high band signal and a low band signal; and
an encoder for encoding a residual high band signal obtained by subtracting auxiliary information acquired from the low band signal from auxiliary information acquired from the high band signal.
2. The coding apparatus of claim 1, wherein the bandwidth extender acquires the auxiliary information from the low band signal using past pre-coded high band auxiliary information and auxiliary information acquired from the low band signal.
3. The coding apparatus of claim 1, further comprising:
a filter factor calculator for, after the low band signal is encoded, determining filter factors to increase mutual information of the high band signal and the encoded low band signal;
a high band mutual information filter for processing to increase the mutual information of the high band signal using the determined filter factors; and
a low band mutual information filter for processing to increase the mutual information of the low band signal using the determined filter factors.
4. The coding apparatus of claim 3, further comprising:
a high band estimator for estimating a high band signal using the low band signal of the increased mutual information and for processing to output a residual high band signal by subtracting the estimated high band signal and the high band signal of the increased mutual information; and
a quantizer for quantizing and outputting the residual high band signal.
5. The coding apparatus of claim 3, wherein the filter factors for increasing the mutual information reproduce an original signal Y from a converted signal Y2, establish the mutual information IX;Y2>IX;Y, and make a dynamic range of Y2 not be greater than at least a dynamic range of Y in a statistical sense, where X denotes the low band signal, Y denotes the high band signal, H denotes the high band mutual information filter, H\u22121 denotes a high band mutual information inverse filter, and Y2 denotes a high band signal converted by H .
6. The coding apparatus of claim 3, wherein the filter factors for increasing the mutual information are determined using a decoded high band signal and a decoded low band signal.
7. The coding apparatus of claim 3, wherein the mutual information of one of the high band signal and the low band signal is increased.
8. A coding method using a band extension, the coding method comprising:
extracting auxiliary information relating to a characteristic of a high band signal using the high band signal and a low band signal;
subtracting auxiliary information, acquired from the low band signal, from auxiliary information acquired from the high band signal; and
encoding the subtracted residual high band signal.
9. The coding method of claim 8, further comprising acquiring the auxiliary information from the low band signal using past pre-coded high band auxiliary information and auxiliary information acquired from the low band signal.
10. The coding method of claim 8, further comprising:
after the low band signal is encoded, determining filter factors to increase mutual information of the high band signal and the encoded low band signal; and
converting a signal using the increased mutual information of the high band signal and the low band signal using the determined filter factors.
11. The coding method of claim 10, further comprising:
estimating a high band signal using the low band signal of the increased mutual information;
outputting a residual high band signal from which the estimated high band signal and the high band signal of the increased mutual information are subtracted; and
transmitting the output residual high band signal.
12. The coding method of claim 10, wherein the filter factors for increasing the mutual information reproduce an original signal Y from a converted signal Y2, establish the mutual information IX;Y2>IX;Y, and make a dynamic range of Y2 not be greater than at least a dynamic range of Y in a statistical sense, where X denotes the low band signal, Y denotes the high band signal, H denotes the high band mutual information filter, H\u22121 denotes a high band mutual information inverse filter, and Y2 denotes a high band signal converted by H .
13. The coding method of claim 10, wherein the filter factors for increasing the mutual information are determined using a decoded high band signal and a decoded low band signal.
14. The coding method of claim 10, wherein the mutual information of one of the high band signal and the low band signal is increased.
15. A coding apparatus comprising:
a predictor for estimating a high band signal using a pre-decoded high band signal;
a bandwidth extender for receiving an encoded low band signal and for estimating a high band signal using the received encoded low band signal;
a low band encoder for encoding a received low band signal and for providing the encoded low band signal to the bandwidth extender; and
an encoder for providing an encoded high band signal.
16. The coding apparatus of claim 15, further comprising a first subtractor for generating a first residual high band signal by subtracting the estimated high band signal of the predictor from the pre-decoded high band signal.
17. The coding apparatus of claim 16, further comprising a second subtractor for generating a second residual high band signal by subtracting the estimated high band signal of the bandwidth extender from the first residual high band signal.
18. The coding apparatus of claim 17, wherein the encoder encodes the second residual high band signal.