1. A balanced high-frequency filter comprising:
a balanced high-frequency element having at least one balanced terminal; and
a phase-shifting circuit,
wherein the phase-shifting circuit is a series resonance circuit which is electrically connected between the balanced terminals and which resonates with common-mode signal components at a predetermined frequency;
a resonance frequency of the series resonance circuit is set in a second frequency band;
a first frequency band is a pass band of the balanced high-frequency element; and
the second frequency band is an attenuation band of the balanced high-frequency element.
2. The balanced high-frequency filter according to claim 1, wherein the first frequency band is a reception frequency band, and the second frequency band is a transmission frequency band.
3. The balanced high-frequency filter according to claim 1 or 2, wherein the phase-shifting circuit has a transmission line which has a length equal to about \xbd of a wavelength in the second frequency band; and
the phase-shifting circuit is connected between the balanced terminals.
4. The balanced high-frequency filter according to claim 3, wherein the phase-shifting circuit has at least two transmission lines;
one of the transmission lines has a length equal to about \xbd of a wavelength in the second frequency band;
the other of the transmission lines differs in length from said one of the transmission lines; and
the phase-shifting circuit is connected between the balanced terminals.
5. The balanced high-frequency filter according to claim 1 or 2, wherein the phase-shifting circuit has at least first, second and third impedance elements;
the first impedance element and the second impedance element are connected in series between the balanced terminals;
a connection point between the first impedance element and the second impedance element is grounded through the third impedance element;
the first impedance element and the third impedance element form a series resonance circuit; and
the second impedance element and the third impedance element form a series resonance circuit.
6. The balanced high-frequency filter according to claim 5, wherein each of the first and second impedance elements is a capacitor, and the third impedance element is an inductor.
7. The balanced high-frequency filter according to claim 5, wherein each of the first and second impedance elements is an inductor, and the third impedance element is a capacitor.
8. The balanced high-frequency filter according to claim 6, wherein the impedance of each of the first and second impedance elements in the first frequency band is set so that a value of the first or second impedance element normalized on a characteristic impedance value of one of the balanced terminals is equal to or larger than 3.
9. The balanced high-frequency filter according to claim 1 or 2, wherein the balanced high-frequency element is constituted by a surface acoustic wave filter.
10. The balanced high-frequency filter according to claim 1 or 2, wherein the balanced high-frequency element is constituted by a filter using an FBAR.
11. The balanced high-frequency filter according to claim 1 or 2, wherein the balanced high-frequency filter is connected to an input side of a low-noise amplifier having balanced terminals.
12. The balanced high-frequency filter according to claim 1 or 2, wherein the balanced high-frequency filter is connected to an input side of a mixer having balanced terminals.
13. An antenna duplexer comprising the balanced high-frequency filter according to claim 1 or 2.
14. An antenna duplexer according to claim 13, wherein the balanced high-frequency filter is a receiving filter in the antenna duplexer;
the first frequency band is a reception frequency band in the antenna duplexer; and
the second frequency band is a transmission frequency band in the antenna duplexer.
15. An antenna duplexer according to claim 14, wherein the antenna duplexer is connected to an input side of a low-noise amplifier having balanced terminals.
16. A balanced high-frequency circuit comprising:
a low-noise amplifier having balanced terminals;
a mixer having balanced terminals; and
a phase-shifting circuit,
wherein the phase-shifting circuit is a series resonance circuit which is electrically connected between the balanced terminals connecting the low-noise amplifier and the mixer to each other, and which resonates with common-mode signal components at a predetermined frequency;
a resonance frequency of the series resonance circuit is set in a second frequency band;
a first frequency band is the frequency band of desired waves; and
the second frequency band is the frequency band of interference waves.
17. The balanced high-frequency circuit according to claim 16, wherein the first frequency band is a reception frequency band, and the second frequency band is a transmission frequency band.
18. The balanced high-frequency circuit according to claim 16 or 17, wherein the phase-shifting circuit has a transmission line which has a length equal to about \xbd of a wavelength in the second frequency band; and
the phase-shifting circuit is connected between the balanced terminals.
19. The balanced high-frequency circuit according to claim 16 or 17, wherein the phase-shifting circuit has at least first, second and third impedance elements;
the first impedance element and the second impedance element are connected in series between the balanced terminals;
a connection point between the first impedance element and the second impedance element is grounded through the third impedance element;
the first impedance element and the third impedance element form a series resonance circuit; and
the second impedance element and the third impedance element form a series resonance circuit.
20. The balanced high-frequency circuit according to claim 19, wherein each of the first and second impedance elements is a capacitor, and the third impedance element is an inductor.
21. The balanced high-frequency circuit according to claim 19, wherein each of the first and second impedance elements is an inductor, and the third impedance element is a capacitor.
22. The balanced high-frequency circuit according to claim 20, wherein the impedance of each of the first and second impedance elements in the first frequency band is set so that a value of the first or second impedance element normalized on a characteristic impedance value of one of the balanced terminals is equal to or larger than 3.
23. A balanced high-frequency circuit comprising:
a circuit board having balanced lines; and
a phase-shifting circuit,
wherein the phase-shifting circuit is mounted on the circuit board;
the phase-shifting circuit is a series resonance circuit which is electrically connected between the balanced terminals, and which resonates with common-mode signal components at a predetermined frequency;
a resonance frequency of the series resonance circuit is set in a second frequency band;
a first frequency band is the frequency band of desired waves; and
the second frequency band is the frequency band of interference waves.
24. The balanced high-frequency circuit according to claim 23, wherein the first frequency band is a reception frequency band, and the second frequency band is a transmission frequency band.
25. The balanced high-frequency circuit according to claim 23 or 24, wherein the phase-shifting circuit has a transmission line, the transmission line has a length equal to about \xbd of a wavelength in the first frequency band; and
the phase-shifting circuit is connected between the balanced terminals.
26. The balanced high-frequency circuit according to claim 23 or 24, wherein the phase-shifting circuit has at least first, second and third impedance elements;
the first impedance element and the second impedance element are connected in series between the balanced terminals;
a connection point between the first impedance element and the second impedance element is grounded through the third impedance element;
the first impedance element and the third impedance element form a series resonance circuit; and
the second impedance element and the third impedance element form a series resonance circuit.
27. The balanced high-frequency circuit according to claim 26, wherein each of the first and second impedance elements is a capacitor, and the third impedance element is an inductor.
28. The balanced high-frequency circuit according to claim 26, wherein each of the first and second impedance elements is an inductor, and the third impedance element is a capacitor.
29. The balanced high-frequency circuit according to claim 27, wherein the impedance of each of the first and second impedance elements in the first frequency band is set so that a value of the first or second impedance element normalized on a characteristic impedance value of one of the balanced terminals is equal to or larger than 3.
30. A communication apparatus using the balanced high-frequency filter according to claim 1 or 2.
31. A communication apparatus using the antenna duplexer according to claim 13.
32. A communication apparatus using the antenna duplexer according to claim 14.
33. A communication apparatus using the balanced high-frequency circuit according to claim 16 or 17.
34. A communication apparatus using the balanced high-frequency circuit according to claim 23 or 24.
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 method of manufacturing a padded cover designed to cover seat parts, comprising:
cutting out, from a padded material of the three-dimensional foam type having elasticity at least in its thickness direction, a shaped piece adapted to cover a part of the seat to be covered;
at borders of said shaped piece, stitching at least two concentric lines along the entire periphery of the shaped piece in order to flatten a border area of said shaped piece;
cutting out, from a semi-transparent openwork mesh fabric, a piece with dimensions corresponding to those of the padded shaped piece;
placing the piece made of semi-transparent fabric on top of the padded shaped piece; and
fastening the piece made of semi-transparent fabric to the padded shaped piece at the flattened peripheral border area.
2. The method of manufacturing a padded cover according to claim 1, wherein the padded shaped piece is covered with a plurality of concentric stitching lines at its borders.
3. The method of manufacturing a padded cover according to claim 1, wherein the padded shaped piece has a three-dimensional structure based on adjacent tubes extending axially along the thickness of the padded material.
4. The method of manufacturing a padded cover according to claim 3, wherein the piece made of semi-transparent fabric covers free edges of walls delimiting the adjacent tubes, at outlets of recesses that the tubes constitute.
5. The method of manufacturing a padded cover according to claim 4, wherein the free edges of the walls delimiting the tubes form identical adjacent motifs repeating over an entire surface of the padded shaped piece to be covered by the semi-transparent fabric.
6. The method of manufacturing a padded cover according to claim 5, wherein said adjacent motifs have a honeycomb configuration.
7. A method of assembling a padded cover, manufactured according to the method of claim 1, to a rigid or semi-rigid support of the seat parts including a seatback, a headrest, or an armrest type, further comprising:
manufacturing a padded cover having peripheral stitching lines whose shape corresponds essentially to that of the support, an innermost line of the peripheral stitching lines being disposed to approximately follow a contour of said support;
disposing the padded cover on a front face of the support to be covered, centering the padded cover inside a flattened area of the stitching lines;
folding the flattened borders around the stitching lines around edges of the support to apply them to a rear face of said support; and
fastening said flattened borders to the rear face of the support.
8. The method of assembling a padded cover according to claim 7, wherein the flattened borders are stapled to the rear face of the rigid support.
9. A padded cover for covering seat parts of a seatback, headrest, or armrest type, obtained by the method of claim 1, the seat parts comprising:
a padded material having elasticity at least in its thickness direction, covered with a semi-transparent openwork mesh fabric, the padded material having a three-dimensional structure that is at least partially visible through said fabric and having recesses that define openings in contact with the fabric.
10. The padded cover according to claim 9, wherein the three-dimensional structure is comprised of adjacent tubes extending axially along the thickness of the material and whose free edges, disposed in contact with the mesh fabric, form identical motifs repeating over the entire surface of the padded material.
11. The padded cover according to claim 10, wherein the repeating motifs of the free edges of the tubular structure form a honeycomb configuration.
12. The padded cover according to claim 9, wherein the borders of the padded material are flattened by at least two concentric stitching lines, the mesh fabric being fastened to said material in this stitching area.
13. The padded cover according to claim 12, further comprising a plurality of stitching lines.
14. The padded cover according to claim 13, wherein the number of lines is between five and ten.
15. The padded cover according to claim 12, wherein the mesh fabric is fastened to the padded material by welding.
16. The padded cover according to claim 9, wherein the openwork mesh fabric deinfes openings of approximately 0.1 mm to 0.5 mm.
17. The padded cover according to claim 9, wherein the mesh fabric and the padded material are made of polyester.
18. Supports forming parts of a seat including a seatback, a headrest, or an armrest type, of the supports comprising:
a rigid or semi-rigid support;
a padded foam-type material having elasticity at least in its thickness direction, and having a three-dimensional structure provided with recesses that define openings; and
a semi-transparent openwork mesh fabric covering one face of the padded material in contact with the openings defined by said recesses;
whereby the padded material and the semi-transparent fabric form a padded cover to cover one side of the support structure.
19. The supports according to claim 18, wherein the three-dimensional structure of which the padded material is comprised is made of adjacent tubes extending axially along the thickness of the material, free edges of the adjacent tubes forming form identical motifs repeating over an entire surface of the padded material in contact with the semi-transparent fabric.
20. The supports according to claim 19, wherein that the repeating motifs of the free edges of the adjacent tubes form a honeycomb configuration.
21. The supports according to claim 18, wherein the openwork mesh fabric defines openings of approximately 0.1 to 0.5 mm.
22. The supports according to claim 18, wherein the mesh fabric and the padded material are made of polyester.