CN201327861Y - Band-pass filter - Google Patents
Band-pass filter Download PDFInfo
- Publication number
- CN201327861Y CN201327861Y CNU2008202232056U CN200820223205U CN201327861Y CN 201327861 Y CN201327861 Y CN 201327861Y CN U2008202232056 U CNU2008202232056 U CN U2008202232056U CN 200820223205 U CN200820223205 U CN 200820223205U CN 201327861 Y CN201327861 Y CN 201327861Y
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- filter
- inner wire
- resonant cavity
- coaxial
- adjustable
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Abstract
The utility model discloses a band-pass filter which comprises a tuning device, wherein the tuning device comprises a coaxial tuned cavity, a basic inner conductor and an adjustable inner conductor, wherein the length of the adjustable inner conductor can be continuously changed along the axial line of the inner conductor; and the basic inner cavity can be electrically connected with the adjustable inner conductor by a contact reed. The band-pass filter has small insertion consumption, high selectivity and large power capacity, which can meet filter requirements of narrow band, high power and high selectivity of modern communication.
Description
Technical field
The utility model relates to communication technical field, is the filter in the digital TV transmitter especially.
Background technology
The main effect of high power digital band pass filter in the radio and television emission system is idle component outside the inhibition zone.Figure 1 shows that a kind of structural formula shape of conventional fixed frequency band pass filter, the coupling mechanism 3 of the fixed coupling coefficient between the coaxial inner conductor 2, resonant cavity that comprises coaxial resonant cavity cavity 1, fixed frequency and the resonant cavity, the input/output unit 4 that is connected with resonant cavity.Conventional fixed frequency band pass filter goes out the coupling window that the coupling coefficient between each resonant cavity cavity and resonant cavity and the resonant cavity is fixed with aluminum profile extrusion usually, and its tuning characteristic is bad, temperature stability is poor, power capacity is little, selectivity is not high.
The utility model content
The purpose of this utility model provides a kind of tunable filter, this filter has a tuner, tuner comprises coaxial tunning chamber, basic inner wire and can continuously change the adjustable inner wire of length along the inner wire axis direction, realizes being electrically connected with contact spring between basic inner wire and the adjustable inner wire.Basic inner wire and adjustable inner wire are made by conduction conductors such as copper or aluminium, are preferably brass material turning processing after silver-plated forming.Adopt this design, coaxial inner conductor can continuously change length in the coaxial resonant cavity cavity, thereby makes coaxial resonant cavity change resonance frequency in wider frequency, is implemented in whole uhf band continuous tuning.
Tuner also comprises temperature compensation means, this temperature compensation means also is the fixture of adjustable-length coaxial inner conductor, as long as varying with temperature, the length of temperature compensation means keep weighing apparatus fixed constant, perhaps change very little, then the length of adjustable-length coaxial inner conductor in coaxial resonant cavity varies with temperature the maintenance weighing apparatus is decided, or change very little, the resonance frequency of coaxial resonant cavity will vary with temperature and keep weighing apparatus fixed simultaneously, perhaps change very little, thereby protect just high-power coaxial cavity narrow band filter under high-power condition, frequency change-the Wen that causes because of variations in temperature wafts, and within permissible range, has promptly realized temperature-compensating.
Temperature compensation means and adjustable-length coaxial inner conductor organically combine, and simple and reliable for structure, cost is low, makes coaxial resonant cavity realize both can changing resonance frequency in wider frequency, has higher resonance frequency stability again.
A coupling device that can continuously change coupling coefficient is arranged between resonant cavity and the resonant cavity.Wherein coupling device plays the effect of transmitting microwave energy between two chambeies between adjacent two coaxial resonant cavities.Coupling device is a kind of coupling loop that continuously changes coupling coefficient, increase or reduce insertion depth between adjacent two coaxial resonant cavities, increase that can be continuous or reduce coupling coefficient between the chamber, thus realize the requirement that coupling coefficient continuously changes between adjacent two coaxial resonant cavities.
For increasing the power capacity of filter, selected the coaxial resonant cavity of larger volume, the diameter of coaxial resonant cavity can reduce the microwave energy in the unit space in the coaxial resonant cavity like this greater than 130 millimeters, guarantees not take place the phenomenon that microwave energy punctures air dielectric in the chamber; Because resonant cavity has repeatedly resonance characteristic, in order to protect just in the 450MHz-900MHz tuning range, the secondary of all working channel, triple-frequency harmonics do not drop on the parasitic passband of coaxial resonant cavity, determine the radial dimension D of coaxial resonant cavity and the ratio of axial dimension L through experiment repeatedly: i.e. D/L<0.8; In order to protect the maximum quality factor of positive coaxial resonant cavity, have less insertion loss thereby protect just high-power coaxial cavity narrow band filter, the characteristic impedance of determining the coaxial resonant cavity resonant cavity is 75.5 Europe.Be to improve the radiating effect of filter, this filter forms the resonant cavity cavity after adopting thickness greater than the aluminium sheet of 5mm or copper coin Combination Welding, and then pastes radiator in the cavity outside.
Transmission zero cross-couplings device is between input resonator and output cavity, be discoid capacitance structure, the position of this discoid capacitive coupling device in input, output cavity can change along the cavity axis direction, two transmission zeros position far away from the passband both sides of filter passband both sides moved to nearer position, passband both sides, thereby the selectivity of filter is improved.
This filter has bigger tuning range, can be in the 450MHz-900MHz frequency range continuous tuning; Have frequency selectivity preferably, can satisfy digital TV transmitter to optionally requirement of band pass filter, have higher temperature stability, temperature drift is less than 1KHz/1 ℃; Have bigger power capacity, bear power greater than 1KW.
This band pass filter has less insertion loss, selectivity preferably, and bigger power capacity can satisfy the demand of modern communications to arrowband, high-power, highly selective filter.
Description of drawings
The utility model will illustrate by example and with reference to the mode of accompanying drawing, wherein:
Fig. 1 is conventional fixed frequency band pass filter;
Fig. 2 is the utility model band pass filter;
Fig. 3 is the tuner with temperature-compensating in the utility model band pass filter;
Fig. 4 is a coupled structure between chamber in the utility model band pass filter;
Fig. 5 is the resonant cavity cavity in the utility model band pass filter;
Fig. 6 is a transmission zero cross-couplings device between input cavity and the output cavity in the utility model band pass filter;
Embodiment
Figure 2 shows that a kind of high-power coaxial chamber narrow band filter that has the wide tunable range of temperature compensation mechanism.Comprise the tunable high-power coaxial resonant cavity 1 that has temperature compensation mechanism, the input/output unit 3 that is connected with resonant cavity, the adjustable coupling mechanism 4 between resonant cavity and the resonant cavity, high-power coaxial chamber number are 6 chambeies; Coaxial inner conductor 2 has a HIGH-POWERED MICROWAVES structure that temperature compensation means and broad tuning device combine for shown in Figure 3; Have the discoid capacitive cross coupling device 5 that adapts to high-power environment between the input and output chamber, the position of discoid capacitive cross coupling device in input, output cavity can change along the cavity axis direction.
This filter has big tuning range, can be in the 450MHz-900MHz frequency range continuous tuning; Have frequency selectivity preferably, can satisfy digital TV transmitter output to optionally requirement of band pass filter, have temperature stability preferably, temperature drift is less than 1KHz/1 ℃; Have bigger power capacity, by power greater than 1KW.
This band pass filter has less insertion loss, selectivity preferably, and bigger power capacity can satisfy the demand of modern communications to arrowband, high-power, high selectivity filtering.
Figure 3 shows that the tuner that has temperature compensation means, this device comprises coaxial tunning chamber 1, basic inner wire 2 and can continuously change the adjustable inner wire 3 of length along the inner wire axis direction, adopts contact spring to realize being electrically connected between basic inner wire 2 and the adjustable inner wire 3.Basic inner wire 2 and adjustable inner wire 3 are made by copper or aluminium electric conductor, are preferably brass material turning processing after silver-plated forming.Adopt this design, coaxial inner conductor can continuously change length in coaxial resonant cavity, thereby makes coaxial resonant cavity change resonance frequency in wider frequency, is implemented in whole uhf band continuous tuning.
Tuner among Fig. 3 also comprises temperature compensation means 4, this temperature compensation means 4 also is the fixture of adjustable-length coaxial inner conductor 3, as long as varying with temperature, the length of temperature compensation means 4 keeps weighing apparatus, perhaps change very little, then the length of adjustable-length coaxial inner conductor 3 in coaxial resonant cavity varies with temperature the maintenance weighing apparatus fixed constant, perhaps change very little, the resonance frequency of coaxial resonant cavity will vary with temperature and keep weighing apparatus fixed constant simultaneously, perhaps change very little, thereby guarantee the coaxial cavity narrow band filter under high-power condition, waft within permissible range because of cavity temperature changes the frequency change-Wen that causes.For this reason, only need select invar material temperature compensation means 4 for use, the temperature line coefficient of expansion of this material is minimum or for negative. in-50 ℃ to+150 ℃ range of temperature, it is fixed to guarantee that the length of coaxial inner conductor in resonant cavity varies with temperature the basic weighing apparatus of maintenance, perhaps change very little. thereby the resonance frequency of assurance coaxial resonant cavity varies with temperature and keeps weighing apparatus fixed constant, perhaps changes very little.Promptly realized temperature-compensating.
Temperature compensation means 4 organically combines with adjustable-length coaxial inner conductor 3, and simple and reliable for structure, cost is low, makes coaxial resonant cavity realize both can changing resonance frequency in wider frequency, has the higher resonance frequency thermal stability again.
Figure 4 shows that coupling device structural representation between resonant cavity and the resonant cavity, comprise the coupling device 2 resonant cavity cavitys 1 that can continuously change coupling coefficient.Wherein coupling device 2 plays the effect of transmitting microwave energy between two chambeies between adjacent two coaxial resonant cavities.Coupling device 2 is a kind of coupling loops that continuously change coupling coefficient, increase or reduce insertion depth between adjacent two coaxial resonant cavities, increase that can be continuous or reduce coupling coefficient between the resonant cavity, thus realize the requirement that the coupling coefficient between each adjacent two resonant cavity of broad tuning band pass filter continuously changes.
Figure 5 shows that the resonant cavity cavity, consider that from power capacity selected the coaxial resonant cavity 1 of larger volume, the diameter of coaxial resonant cavity is greater than 130 millimeters, can reduce the microwave energy in the unit space in the coaxial resonant cavity like this, guarantee not take place the phenomenon that microwave energy punctures air dielectric in the chamber; Because resonant cavity has repeatedly resonance characteristic, in order to guarantee in the 450MHz-900MHz tuning range, the secondary of all working channel, triple-frequency harmonics do not drop on the parasitic passband of coaxial resonant cavity, the radial dimension D of coaxial resonant cavity and the ratio of axial dimension L: i.e. D/L<0.8; In order to protect the maximum quality factor of positive coaxial resonant cavity, thereby protect just high-power coaxial cavity narrow band filter less insertion loss is arranged, the characteristic impedance of determining the coaxial resonant cavity resonant cavity is 75.5 Europe.Be to improve the radiating effect of filter, this filter adopts with thickness and forms the resonant cavity cavity after greater than the aluminium sheet of 5mm or copper coin Combination Welding, and then pastes radiator in the cavity outside.
Figure 6 shows that the transmission zero cross-couplings device between input cavity and the output cavity, this cross-couplings device is discoid capacitive form, the position of cross-couplings device in input, output cavity can change along the cavity axis direction, two transmission zeros of filter passband both sides can be moved to transmission nearer position, passband both sides position far away from the passband both sides, the selectivity of filter is improved.
Disclosed all features in this specification, or the step in disclosed all methods or the process except mutually exclusive feature and/or step, all can make up by any way.
Disclosed arbitrary feature in this specification (comprising any accessory claim, summary and accompanying drawing) is unless special narration all can be replaced by other equivalences or the alternative features with similar purpose.That is, unless special narration, each feature is an example in a series of equivalences or the similar characteristics.
The above only is preferred embodiment of the present utility model; not in order to restriction the utility model; all any modifications of within spirit of the present utility model and principle, being done, be equal to and replace and improvement etc., all should be included within the protection range of the present utility model.
Claims (9)
1, a kind of filter, comprise tuner, it is characterized in that: this tuner comprises coaxial tunning chamber, basic inner wire and can continuously change the adjustable inner wire of length along the inner wire axis direction, realizes being electrically connected with contact spring between basic inner wire and the adjustable inner wire.
2, filter as claimed in claim 1 is characterized in that: basic inner wire and adjustable inner wire have by conducting metal to be made.
3, filter as claimed in claim 1 or 2 is characterized in that: basic inner wire and adjustable inner wire are processed after silver-plated forming by brass material turning.
4, filter as claimed in claim 1 is characterized in that: this filter also comprises temperature compensation means, and this this temperature compensation means also is the fixture of adjustable-length coaxial inner conductor.
5, filter as claimed in claim 1, it is characterized in that: this filter also comprises coupling device between the chamber, coupling device is a kind of coupling loop that continuously changes coupling coefficient, increase or reduce insertion depth between adjacent two coaxial resonant cavities, increase that can be continuous or reduce coupling coefficient between the chamber, coupling device is between adjacent two coaxial resonant cavities.
6, filter as claimed in claim 1 is characterized in that: the diameter of described coaxial resonant cavity is greater than 130 millimeters.
7, filter as claimed in claim 1 is characterized in that: ratio D/L<0.8 of the radial dimension D of described coaxial resonant cavity and axial dimension L.
8, filter as claimed in claim 1 is characterized in that: the characteristic impedance of described coaxial resonant cavity is 75.5 Europe.
9, filter as claimed in claim 1 is characterized in that: the minimum number of described coaxial resonant cavity is 3 chambeies, is no more than 12 chambeies at most.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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CNU2008202232056U CN201327861Y (en) | 2008-12-05 | 2008-12-05 | Band-pass filter |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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CNU2008202232056U CN201327861Y (en) | 2008-12-05 | 2008-12-05 | Band-pass filter |
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CN201327861Y true CN201327861Y (en) | 2009-10-14 |
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CNU2008202232056U Expired - Fee Related CN201327861Y (en) | 2008-12-05 | 2008-12-05 | Band-pass filter |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103296359A (en) * | 2012-02-29 | 2013-09-11 | 深圳光启创新技术有限公司 | Filter |
-
2008
- 2008-12-05 CN CNU2008202232056U patent/CN201327861Y/en not_active Expired - Fee Related
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103296359A (en) * | 2012-02-29 | 2013-09-11 | 深圳光启创新技术有限公司 | Filter |
CN103296359B (en) * | 2012-02-29 | 2017-05-24 | 深圳光启创新技术有限公司 | Filter |
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Legal Events
Date | Code | Title | Description |
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C14 | Grant of patent or utility model | ||
GR01 | Patent grant | ||
CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20091014 Termination date: 20171205 |
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CF01 | Termination of patent right due to non-payment of annual fee |