CN101420238B - Filtering device and method used for dual frequency band sensing circuit - Google Patents
Filtering device and method used for dual frequency band sensing circuit Download PDFInfo
- Publication number
- CN101420238B CN101420238B CN2007101678248A CN200710167824A CN101420238B CN 101420238 B CN101420238 B CN 101420238B CN 2007101678248 A CN2007101678248 A CN 2007101678248A CN 200710167824 A CN200710167824 A CN 200710167824A CN 101420238 B CN101420238 B CN 101420238B
- Authority
- CN
- China
- Prior art keywords
- signal
- band
- frequency
- filter
- low
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Abstract
The present invention relates to a filtering device for dual band sensing circuit and a method thereof. The present invention is characterized in that a dual band sensing unit provided on a filtering device is used for receiving signals from a different frequency band subsystem and performing frequency division, then, one or more frequency band detecting units are used for detecting energy of signals at the high frequency band and the low frequency band and converting the energy into voltage, and users can adjust the gain of a tunable gain amplifier through an external part, perform a comparison operation by using a comparison unit, and control the switch time of a radio frequency switch unit with the help of generated signals, therefore, an adaptive notch filter effect is achieved, the notch filter with a high frequency or a low frequency is started by judging the current interference intensity, thus, in-band wastage is reduced.
Description
Technical field
The present invention relates to a kind of filter and method that is used in dual frequency band sensing circuit, be meant especially, and then decision is with the unlatching of refusing filter to reach the filter effect of effective inhibition interference opportunity by the gain of external control signal.
Background technology
Generally when design high frequency communication module, can normally utilize radio-frequency filter (RF filter) to filter needed frequency range at this moment according to the frequency range of Demand Design running.If the frequency range that need filter or energy are higher, the exponent number (order) of the filter that needs is healed high, and different designs has different exponent number demands.But the exponent number of filter is higher, and then the loss meeting in the module is bigger, and just, though can reach required energy requirement, because circuit area is bigger, the path of radio frequency is longer, causes decay also bigger.
And; If be applied to high frequency communication module of the prior art; Like WLAN (like WLAN, WiMax etc.), mobile communication technology (like GSM, 3G etc.), in design if need and alien frequencies cross-talk coexistence of systems, such as the design of different frequency range (1.8GHz, 5GHz etc.) coexistence; Usually need add that the filter with additional transmissions zero point (transmission zero) avoids interference; But, increase transmission zero and can increase the circuit design in the module, then can increase the loss of (In-band) in the band.
Except the filter use of above-mentioned frequency range, or the intersegmental application of alien frequencies, in fact, even the annoyance level of above-mentioned different frequency range subsystem start simultaneously also may not be certain and can cause significant impact to the whole system that is disturbed; And, these alien frequencies cross-talk systems and may not be certain together with the time start, but therefore alternately running optionally, uses general radio-frequency filter to seem that just flexibility is not enough.
In field of wireless communication; Then use a kind of self adaptation band to refuse filter (Adaptive Notch Filter) in addition; When it is arranged on RF signal (RF signal) path; The frequency range of control filters and filter specific frequency range simply, and reflect required signal, be different from the effect of general filter through this generation.
It is a kind of of filter that above-mentioned self adaptation band is refused filter; General filter all is to carry out LPF (low pass) or high-pass filtering (high pass); Just filter high or filter low frequency range, it then is to be divided into two to signal partly that the self adaptation band is refused filter, and a part of part with low-frequency range leaches; Another then is the part that leaches high band partly, is mixed two frequency ranges more afterwards.
In wideband communication, utilize the self adaptation band to refuse filter and eliminate background technology such as the United States Patent (USP) the 6th that narrow frequency disturbs; The technology that is disclosed for 704, No. 378, wherein to refuse filter be optionally to filter out the wideband communication signal that receives to the self adaptation band; To eliminate the interference that narrow frequency signal causes communication signal; For the existence that will judge that narrow frequency signal disturbs, this self adaptation band is refused filter will scan the different passages in the wideband signal frequency spectrum, find interference source through judging the signal strength size.
Wireless communication apparatus as shown in Figure 1; Wherein comprise antenna 10,, the signal that receives is sent to the frequency divider (splitter) 14 that couples with the low noise amplifier that is connected antenna 10 12; To be divided into different signal paths; Wherein have to transfer to the part that the self adaptation band is refused filter module 16, another part then transfers to a narrow frequency receiver 18, and the self adaptation band is refused the signal that filter module 16 exported and then is passed to a wideband receiver 19 again.
Above-mentioned narrow frequency and wideband can refer to the communication channel of two kinds of different frequency ranges; Indivedual output signals that produced will together be passed to other system; In this example, the self adaptation band refuse filter 16 except the signal through scanning each passage with the interference source that filters narrow frequency, also can be coupled to other control device or other system; Like network system, telephone system etc., narrow frequency receiver 18 then can be coupled to interchanger (switch) again.
Summary of the invention
The objective of the invention is to; Because prior art is when the application that requires between different radio communication frequency band or different frequency range; The design of filter will produce above-mentioned puzzlement with use; The present invention then discloses a kind of filter and method that is used in dual frequency band sensing circuit; Not only can promote the flexibility ratio of filter, also can promote the usefulness of various frequency ranges running, more can control the high band band exactly and refuse the unlatching opportunity that filter (High Band Notch) or low-frequency range band are refused filter (Low Band Notch); So that make an adjustable voltage/gain amplifier (tunable voltage amplifier) wherein be adjusted to suitable gain (gain), with the switching of the RF switch of controlling this communication module.
The present invention refuses filter except the application self-adapting band and can effectively eliminate the characteristic of disturbing in the communication signal, more utilizes this filter to launch high frequency or the trap of low frequency (Notch) through judging interference strength, carries out radio frequency and switches, and reduces the loss in the band.
For reaching above-mentioned purpose; The present invention provides a kind of filter that is used in dual frequency band sensing circuit, and it comprises: a two-band sensing cell, through the signal of connectivity port reception alien frequencies cross-talk system; And execution frequency division; Wherein this two-band sensing cell has a plurality of splicing ears, to connect the sensing circuit of many different frequency ranges, comprises the sense path of a high band, the sense path of a low-frequency range and the sense path of a primary band; Wherein the sense path of this high band is provided with an open circuit stub or step impedance open circuit stub at least, is used to filter out the signal than low frequency; The sense path of this low-frequency range is provided with step impedance open circuit stub, to control the frequency of two or more transmission zeros, is used to filter the signal of primary band and high band; One or more frequency range detecting unit is coupled to this two-band sensing cell, comprises the detecting ability of high band and low-frequency range at least, detects the energy of the signal of this reception, converts voltage again into; One or more adjustable gain amplifier; Be coupled to this frequency range detecting unit; Receive the voltage of this frequency range detecting unit conversion, and receive the effect of the gain amplification of outside this voltage of controlling signal adjustment, wherein this high band and this low-frequency range sense path all are provided with this adjustable gain amplifier; One or more comparing unit couples this adjustable gain amplifier, and this comparing unit is introduced a reference voltage, carries out a comparison operation with this voltage after gain is amplified; An and radio frequency switch unit; Be coupled to this comparing unit; Comprise a plurality of switchs, utilize to receive the open and close of these a plurality of switchings of signal control after this comparison operation, control the unlatching opportunity that the band of high-frequency signals and low-frequency signal in this radio frequency switch unit is refused filter in view of the above.This preferred embodiment that is used in the filter of dual frequency band sensing circuit comprises a connectivity port, and it connects the communication module of an alien frequencies cross-talk coexistence of systems; Comprise a two-band sensing cell, the signal that receives is carried out frequency division, as divide into a plurality of sense path such as high band, primary band and low-frequency range; Comprise a detecting unit,, convert voltage again into the energy of detection signal; Comprise an adjustable gain amplifier, the interference cases of cooperating equipment is adjusted above-mentioned voltage, produces suitable gain; Comprise a comparator, carry out voltage and the comparison operation of reference voltage after the gain amplification; Can accurately control the unlatching opportunity that band is refused filter, and then effectively filtering and inhibition interference.
For reaching above-mentioned purpose; The present invention also provides a kind of filter that is used in dual frequency band sensing circuit; It comprises: a two-band sensing cell; Receive the signal of alien frequencies cross-talk system through a connectivity port, signal region is divided into the signal of high band, primary band and low-frequency range, connect a high band sense path, a primary band sense path and a low-frequency range sense path through a plurality of splicing ears; Wherein the sense path of this high band is provided with an open circuit stub or step impedance open circuit stub at least, is used to filter out the signal than low frequency; This low-frequency range sense path is provided with step impedance open circuit stub, to control the frequency of two or more transmission zeros, is used to filter the signal of primary band and high band; One high band detecting unit is arranged on this high band sense path, is coupled to this two-band sensing cell through one of these a plurality of splicing ears, is used to detect the high band signal and converts voltage signal into; One low-frequency range detecting unit is arranged on this low-frequency range sense path, is coupled to this two-band sensing cell through one of these a plurality of splicing ears, is used to detect the low-frequency range signal and converts voltage signal into; One or more adjustable gain amplifier is coupled to this high band detecting unit and this low-frequency range detecting unit, is used to adjust the gain of this voltage signal; One or more terminal is through the gain of this terminal by this adjustable gain amplifier of outside adjustment; One or more comparing unit is coupled to this adjustable gain amplifier, carries out this through the voltage signal of gain amplification and the comparison operation of a reference voltage; One radio frequency switch unit; Comprising being arranged, a plurality of switchs and one or more band refuse filter; These a plurality of switchs include a plurality of positive logic radio frequency switchs and negative logic radio frequency switch; Receive conducting that result after this comparison operation controls each switch and end, and then control the unlatching opportunity that this band is refused filter.
For reaching above-mentioned purpose, the present invention provides a kind of filtering method that is used in dual frequency band sensing circuit in addition, and it comprises: receive signal, this signal is the signal that an alien frequencies cross-talk system is produced, and comprises plural frequency range at least; Carry out the filtering frequency division through a two-band sensing cell; Wherein this double frequency sensing cell is provided with an open circuit stub or step impedance open circuit stub at least; Be used to filter out signal, or use the frequency of two or more transmission zeros of control, be used to filter the signal of primary band and high band than low frequency; Respectively by a high band detecting unit or a low-frequency range detecting unit detection signal energy; Changing this energy is a voltage signal; By the gain of this voltage signal of adjustable gain amplifier adjustment, this gain is controlled by an external control signal; Use a comparing unit to carry out this comparison operation through gain an adjusted voltage signal and a reference voltage; Produce the signal that a plurality of switchs of control open and close opportunity; Control the unlatching opportunity that one or more height frequency range band is refused filter; Carry out filtering; And output signal.The preferred embodiment of this filtering method comprises reception signal earlier, refers in particular to the signal that alien frequencies cross-talk system is produced, and carries out frequency division afterwards; The filtering mode that adopts the height frequency range to separate; Afterwards, high band and low-frequency range are passed through frequency range detecting unit detection signal energy respectively, and transfer voltage signal to.Then, the user is through external control, produces controlling signal, and amplifications that gain of adjustment adjustable gain amplifier is adjusted to suitable gain, compares computing in comparing unit, controls the switch open and close signal on opportunity with this.At last the band of control height frequency range unlatching opportunity of refusing filter, refuse filter implementation rate ripple, avoid being with internal loss, at last again through the antenna output signal through band.
Description of drawings
Fig. 1 is a prior art wireless communication apparatus sketch map;
Fig. 2 is used in the embodiment sketch map of the filter of dual frequency band sensing circuit for the present invention;
Fig. 3 is the embodiment sketch map of filter of the present invention;
Shown in Figure 4 for the embodiment sketch map of two-band sensing cell of the present invention;
Fig. 5 shows the frequency response curve of filter of the present invention;
Fig. 6 shows the flow chart of filtering method of the present invention.
Symbol description among the figure
10 antennas, 12 low noise amplifiers
14 frequency dividers, 16 self adaptation bands are refused filter module
18 narrow frequency receiver 19 wideband receivers
201,202 connectivity ports, 21 two-band sensing cells
22 high band detecting units, 23 low-frequency range detecting units
24,25 adjustable gain amplifiers
203,204,205,206 terminals, 26 first comparing units
27 second comparing units, 28 radio frequency switch units
281,282 bands are refused filter 1,2,3,4,5,6 splicing ears
301 first switchs, 302 second switchs
303 the 3rd switchs 304 the 4th switch
305 the 5th switchs 306 the 6th switch
31 high band bands are refused filter 32 low-frequency range bands and are refused filter
41,42 open circuit stub A, B, C, D, E element
501,502,503 connecting curves
Embodiment
To refuse filter (Notch Filter) be a kind of of filter to band, and it is that signal with certain special frequency filters out that band is refused filter.The present invention then provides a kind of filter and method that is used in dual frequency band sensing circuit in field of wireless communication; When a self adaptation band is refused filter (Adaptive Notch Filter) and is arranged on RF signal (RF signal) path; Can judgement interference strength instantly refuse filter with the band of launching high frequency or low frequency; The frequency range of control filters and filter specific frequency range reduces the loss in the band, and reflects required signal simply.
See also Fig. 2, wherein be depicted as the embodiment that the present invention is used in the filter of dual frequency band sensing circuit, filter connects an outside signal source through a connectivity port 201, and preferred embodiment is the communication module that connects alien frequencies cross-talk coexistence of systems.In this example; When transmitting through connectivity port 201, signal gets into this filter; Earlier through a two-band sensing cell (Dual Band Sensing Unit) 21; Carry out the action of frequency division, the low-and high-frequency of signal is made a distinction, as divide into high band (high band), primary band (main band) and low-frequency range a plurality of sense path (sensing path) such as (low band).Wherein, because through its middle impedance adjustment, can control the width of the frequency range of desire filtration easily, effectively filtering also suppresses to disturb.
After the frequency division; The signal of high band will have the high band detecting unit 22 that high band is detected ability through one; This high band detecting unit 22 is coupled to this two-band sensing cell 21; The energy of elder generation's detection signal converts voltage again into, then is sent to the adjustable gain amplifier (tunable gain amplifier) 24 that a detecting unit couples.At the filter circuit of high band signal and the filter circuit of low-frequency range adjustable gain amplifier 24,25 is set all respectively among the present invention, need be directed against the running that whole signal amplifies with this mode of adjusting gain, so can not have influence on the signal of primary band.
This adjustable gain amplifier 24 can receive the outside controlling signal of this filter; Be that the user can be by terminal 203 input controlling signal; To this adjustable gain amplifier 24 of interference cases adjustment of the equipment that cooperates, after cooperating the reference voltage that will compare suitable amplifying voltage is provided, each switch has the characteristic of cut-in voltage separately; So can set by the user; Control the open and close of each switch in this filter on this basis, and control to open or close to be with and refuse filter 281,282; Required signal is passed through connectivity port 202, reach the present invention and utilize the self adaptation band to refuse the customized filter effect that filter reaches.
Afterwards; The voltage signal that amplifies through gain will be passed to a comparing unit 26; First comparing unit 26 couples above-mentioned adjustable gain amplifier 24; To introduce a reference voltage, and utilize first comparing unit 26 to carry out the comparison operation of above-mentioned voltage and reference voltage, the open and close action of each switch (switch) in the radio frequency switch unit 28 that determines thus to be coupled.This reference voltage will be by terminal 204 inputs; And in the radio frequency switch unit 28 that needs to couple according to first comparing unit 26 each switch (not being shown among the figure) design and determine; The decision of reference voltage will influence and above-mentioned comparison operation result through between the voltage after the gain amplification; As utilize voltage ratio to producing 1 (unlatching) or 0 signals such as (closing), and determine the operation situation of each switch, and then the accurate band of control height frequency range unlatching opportunity of refusing filter.
At least include in the above-mentioned radio frequency switch unit 28 and be applied to high-frequency signals or the band of low-frequency signal is refused filter 281,282, each band is refused filter 281; 282 can filter the signal of special frequency; Especially the running of each switch in the middle of the collocation, the unlatching opportunity that the control band is refused filter, thus; The band that can utilize interference strength in the judgment means to launch high frequency or low frequency is refused filter, lets the band internal loss of whole system reduce to minimum.
In like manner, the filter circuit of low-frequency range is similar with the filter circuit of above-mentioned high band, behind above-mentioned two-band sensing cell 21 frequency divisions; The signal of low frequency will transfer to the low-frequency range detecting unit 23 with low frequency detecting ability; The energy of elder generation's detection signal converts voltage again into, then is sent to another adjustable gain amplifier 25; This adjustable gain amplifier 25 also can receive the outside controlling signal of this filter; The user by the filter effect input controlling signal of terminal 205 to required low frequency, adjusts the effect that gain is amplified equally, can adjust the control voltage of input to the interference cases of the equipment that cooperates; Each switch has the characteristic of cut-in voltage separately, after cooperating the reference voltage that will compare suitable amplifying voltage is provided.
Afterwards; Second comparing unit 27 is introduced reference voltage by terminal 206, and this reference voltage need design to the characteristic of each switch (not being shown among the figure) in the radio frequency switch unit 28, and the user sets the effect that gain is amplified through controlling signal; Carry out comparison operation again; Control the open and close of each switch in this filter on this basis, reaching the customized filter effect that utilizes the self adaptation band to refuse filter, and the waste in the control device.
Fig. 3 then shows the embodiment sketch map of filter of the present invention.Preferred embodiment produces signal by the module of alien frequencies cross-talk coexistence of systems; As use the communication device of frequency ranges such as 1.8GHz, 2.4GHz, 5GHz simultaneously; Signal be except producing the signal of different frequency range through filtering, more need eliminate the interference between the subsystem of each frequency range.This signal is imported through connectivity port 201 by external module earlier; Carry out the action of frequency division through two-band sensing cell 21; Signal region is divided into the signal of high band, primary band and low-frequency range etc., will get rid of the signal of frequency range not through the filter effects in the middle of the two-band sensing cell thus 21.
Among the figure, two-band sensing cell 21 has a plurality of splicing ears 1,2; 3; 4,5,6; Each splicing ear in its sensing circuit corresponding shown in Figure 4 respectively, the characteristic of wherein utilizing adjustable step impedance open circuit stub (stepped impedance open stub) to produce transmission zero will detail in the explanation of Fig. 4.
Transfer out through each frequency range signals of two-band sensing cell 21 frequency divisions splicing ear 4,5,6 through wherein, wherein the signal of high band is received by the high band detecting unit that couples splicing ear 4 22, is voltage signal with the signal power conversion of being detected.Afterwards; The user can pass through terminal 203 transmitting control signal to adjustable gain amplifiers 24; In this example, (Voltage Controlled Amplifier VCA) implements adjustable gain amplifier 24 with a voltage-adjusting amplifier; This amplifier is through changing the circuit of voltage swing control frequency, can producing the effect of adjustment gain thus.The user can be by the gain effect of this voltage-adjusting amplifier circuit of external control; The high band signal that adjustment is originally small; Can be then carry out the comparison operation with a reference voltage by first comparing unit 26; This reference voltage is by terminal 204 input, and according to after each switch design demand and adjust.After the computing through first comparing unit 26, will produce 1 (like the high voltage signal, high) or 0 (like the low-voltage signal, controlling signal low).
In like manner; Low-frequency range signal in this example is by the low-frequency range detecting unit 23 that couples splicing ear 6; After converting voltage signal into, the user equally can be according to needing through terminal 205 transmitting control signal to adjustable gain amplifiers 25, to adjust the effect that gain is amplified; The preferred embodiment of this amplifier is implemented by voltage-adjusting amplifier (VCA), with the adjustment gain effect.After gain is amplified, the low-frequency range signal of input will compare computing with reference voltage in second comparing unit 27, produce the controlling signal of voltage high (level high) or voltage low (level low), with the running of each switch after the control.
After the signal route of above-mentioned signal route and low-frequency range by high band produces controlling signal, then there is the band of being responsible for the height frequency range to refuse filter and carries out filtering.Embodiment with this accompanying drawing; The radio frequency switch unit that connects antenna includes the contactor that a plurality of switchs (switch) are realized; Wherein each switch has different How It Works; Among the embodiment; The 5th switch 305 and the 6th switch 306 that are coupled to first switch 301 and second switch 302 of first comparing unit 26 and are coupled to second comparing unit 27 are a kind of positive logic radio frequency switch (positive logic RF switch), in the voltage height or signal is conducting in 1 o'clock (turn on), in voltage low or signal be 0 o'clock for by (cut off); And the 3rd switch 303 that is coupled to first comparing unit 26 is a kind of negative logic radio frequency switch (negative logic RF switch) with the 4th switch 304 that is coupled to second comparing unit 27; Low or signal is conducting in 0 o'clock (turn on) in voltage, be to end in 1 o'clock in voltage height or signal.
Please refer to the circuit among the figure, first comparing unit 26 is coupled to first switch 301, second switch 302 and the 3rd switch 303; And second comparing unit 27 is coupled to the 4th switch 304, the 5th switch 305 and the 6th switch 306; The present invention mainly be through each switch conducting with control the unlatching opportunity that band is wherein refused filter by opportunity, reach the effect that the self adaptation band is refused filter.
At the beginning of circuit comes into operation; The user need be directed against the effect that the different adjustment gain of demand (comprise filter effect and disturb inhibition) design is amplified; Respectively at terminal 203 and 205 outputs; After comparison operation, can control the unlatching opportunity of each switch, the band of the height frequency range in the radio frequency switch unit is refused filter and is then carried out filtering to required frequency range separately.
In this embodiment; After a high band signal passes through high band detecting unit 22, adjustable gain amplifier 24 and first comparing unit 26; Produce the high signal (or signal 1) of voltage; This is conducting first switch 301, second switch 302 (positive logic radio frequency switch), and by the 3rd switch 303 (negative logic radio frequency switch); At this moment; The interlock circuit of being responsible for processing low-frequency range signal then produces the low signal of voltage (or signal 0); Promptly second comparing unit 27 produces the low signal of voltage; By the 5th switch 305 and the 6th switch 306 (positive logic radio frequency switch), and conducting the 4th switch 304 (negative logic radio frequency switch).
Relatively; If the signal of input is low-frequency range signal (is the alien frequencies section with respect to high band); Then the filter circuit (this schemes the first half) of high band is produced the low or signal of signal 0 of voltage, will be by positive logic radio frequency switch, and make the conducting of negative logic radio frequency switch; But the filter circuit (this schemes Lower Half) to low-frequency range produces the voltage height or the signal of signal 1, makes the conducting of positive logic radio frequency switch, and by negative logic radio frequency switch.
Move according to above-mentioned each switch, when the signal of input is the signal of high band, the running of each switch of voltage signal control that then produces; Therefore signal transfers to the high band band via first switch 301 and refuses filter 31; Unwanted frequency range signal is filtered out, and this example promptly keeps the part of higher frequency band, because second switch 302 is switched on; The signal of this high band can successfully transfer to connectivity port 202, goes out through antenna transmission again.Specifically, because the 3rd switch 303 and the 5th switch 305 are for ending, so can't be disturbed by other internal circuit.
On the contrary, when the signal of input is the low-frequency range signal, the voltage signal that then produces makes the 5th switch 305 and the 6th switch 306 conductings (positive logic radio frequency switch); Signal is refused filter 32 through the low-frequency range band, filters the signal of no frequency range, simultaneously; The 3rd switch 303 that leads to antenna also is conducting (negative logic radio frequency switch); And by the 4th switch 304 (negative logic radio frequency switch), so signal can send through antenna smoothly, can't be disturbed by internal circuit.
Shown in Figure 4 then is the embodiment sketch map of above-mentioned two-band sensing cell (Dual Band Sensing Unit), shows three circuit of representing different frequency range and intercoupling (couple) among the figure, is different from the aspect of two coupling circuits of traditional low-and high-frequency; A plurality of splicing ears 1,2,3 are wherein arranged; 4,5, the 6 corresponding splicing ears 1 that connect two-band sensing cell 21 shown in Figure 3; 2,3,4; 5,6, the sense path of three kinds of frequency ranges of formation in this example; Wherein splicing ear 1 and 4 circuit form the sense path (high band sensing path) of high band, and this path is provided with an open circuit stub 41 (another embodiment can be step impedance open circuit stub), can filter the signal of special frequency; The sense path of this high band then is used to filter out the part than low frequency, comprises the part of low-frequency range and primary band, and element A then is the transmission line effect in the indication circuit.
Splicing ear 2 and 5 s' circuit forms the sense path of this routine primary band, except considering the electric effect of transmission line (representing with element B and D) etc., the noise that the coupling that also produces between the considered circuit causes.
Splicing ear 3 and 6 s' circuit then forms the sense path of low-frequency range; Except considering the electric effect of transmission line (representing) with element C and E; This path is provided with step impedance open circuit stub, can control the frequency of two or more transmission zeros arbitrarily, can effectively filter out no parts such as primary band and high band; This produces an adjustable transmission zero; So when the designed filters device, effect is controlled the position of transmission zero well thus, makes filter prevent that effectively unnecessary frequency is coupled.
Fig. 5 shows that the present invention uses the frequency response curve of the filter of two-band sensing cell shown in Figure 4, and this two-band sensing cell is arranged on the filter of the present invention with the enforcement aspect of module.
Wherein show three curves, represent the connecting curve 501 of primary band, the connecting curve 502 of high band and the connecting curve 503 of low-frequency range respectively.Because the present invention is through the suitable gain of the adjustment of the adjustable gain amplifier in the filter circuit that is arranged at high band and low-frequency range; Do not influence the signal of primary band; So curve 501 demonstration primary band signal institutes are influenced little among the figure, along with frequency raises, inserting loss only has variation a little.For instance, be marked with the some a of a plurality of frequency values among the figure, b, c, d, e, its mid point a represent frequency Xa=2.40GHz, insert loss Ya=-0.29, like the frequency range of WLAN (WLAN).
In the curve 502 of high band; In order partly to carry out filtering to high band; The signal of getting rid of primary band and low-frequency range, the some c shown in the figure then are because the transmission zero that the open circuit stub that is provided with on the sense path of high band shown in Figure 4 41 produces can filter the part of low-frequency range; The signal that suppresses low-frequency range disturbs the low-frequency signal represented like a b.
The step impedance open circuit stub that on the sense path of low-frequency range, is provided with among Fig. 4 for another example; Because this kind impedance can be controlled the frequency of two or more transmission zeros arbitrarily; So produce the transmission zero of some d (Xd=2.40GHz, Yd=-48.84) and some e (Xe=5.40GHz, Ye=-41.23) on Fig. 5 medium and low frequency section curve 503, and can be, control the position of two or above transmission zero through the adjustment of this step impedance open circuit stub according to demand; In this example; Can be according to the position of the situation of High-frequency Interference adjustment point e, the wave band of the high frequency that will filter with decision institute also can be adjusted a d and put the distance between e.
Via analysis result shown in Figure 5; The present invention uses the self adaptation band to refuse the flexibility ratio that filter not only can promote filter; Because of the signal of height frequency range can't cause the interference to primary band; So the usefulness that can promote primary band, and the set step impedance open circuit stub that places the double frequency sensing circuit of tool transmission zero then can control the frequency of two or more transmission zeros arbitrarily, can prevent that unnecessary frequency is coupled; Refuse the unlatching opportunity that filter and low-frequency range band are refused filter so that can control the high band band more accurately; Wherein adjustable gain amplifier can provide and be adjusted to suitable gain simultaneously, and makes voltage ratio with a comparator, controls the running of radio frequency switch unit at last opportunity through the switch of each switch.
The filter step of utilizing above-mentioned filter to produce is as shown in Figure 6; Step begins, and this filter receives outside signal, refers in particular to the signal that alien frequencies cross-talk system is produced; Comprising plural at least frequency range (step S601); Carry out the effect of filtering frequency division afterwards through the two-band sensing cell, the filtering mode that wherein adopts the height frequency range to separate, and collocation step impedance open circuit stub produces effectively adjustable filter effect (step S603).
After the frequency division, the signal of high band will be through the detecting unit detection signal energy (step S605) of high band, and transfers voltage signal (step S607) to, and in like manner, the signal of low-frequency range is the detecting unit detected energy through low-frequency range then, and converts voltage into.
Then; The part of high band and low-frequency range all can let the user through external control, and produce controlling signal (step S611) a to adjustable gain amplifier and adjust gain amplification (step S609), mainly be can be according to the different disturbed condition of each system; Control through this control voltage; Be adjusted to suitable gain, then, use a comparing unit to carry out voltage signal and the comparison operation (step S613) of a reference voltage after the gain amplification; Result with comparison operation produces the signal (step S615) that the control switch opens and closes opportunity, and the enforcement aspect of each switch switch can be consulted embodiment shown in Figure 3.
The switch of each switch is controlled by the signal of input opportunity; And and then the accurate band of control height frequency range unlatching opportunity of refusing filter; Be with and refuse filter execution filtering; Promptly through judging that at that time interference strength launches the filtering method of high frequency or low frequency and avoid being with internal loss (step S617), at last again through antenna output signal (step S619).
As long as add modular two-band sensing cell provided by the present invention on the product of general application RF signal; Then can set the gain amplification effect of adjustable gain amplifier according to product needed; The switch of each switch in the control radio frequency switch unit after comparison operation; And then control respectively is with the unlatching opportunity of refusing filter; Via the purpose that control radio frequency switch unit reaches alien frequencies cross-talk coexistence of systems and effectively suppresses to disturb, most importantly can avoid in the band unnecessary interference in (in-bound) or the system.
In sum; The present invention one is used in the filter and the method for dual frequency band sensing circuit; It is characterized in that the user can be through outside setting (setting as carrying out through external computer system) the adjustable gain of decision; This customized result can let filter and the method that the embodiment of the invention provided be applicable to various products, and the unlikely user of letting (or client) needs to different purposes different design consideration is arranged.
The above is merely preferable possible embodiments of the present invention, and is non-so promptly limit to claim of the present invention, thus use such as specification of the present invention and accompanying drawing content institute for it equivalent structure change, all in like manner be contained in the scope of the present invention.
Claims (3)
1. a filter that is used in dual frequency band sensing circuit is characterized in that, comprising:
One two-band sensing cell; Receive the signal of alien frequencies cross-talk system through a connectivity port, and carry out frequency division, wherein this two-band sensing cell has a plurality of splicing ears; To connect the sensing circuit of many different frequency ranges; Comprise the sense path of a high band, the sense path of a low-frequency range and the sense path of a primary band, wherein the sense path of this high band is provided with an open circuit stub or step impedance open circuit stub at least, is used to filter out the signal than low frequency; The sense path of this low-frequency range is provided with step impedance open circuit stub, to control the frequency of two or more transmission zeros, is used to filter the signal of primary band and high band;
One or more frequency range detecting unit is coupled to this two-band sensing cell, comprises the detecting ability of high band and low-frequency range at least, detects the energy of the signal of this reception, converts voltage again into;
One or more adjustable gain amplifier; Be coupled to this frequency range detecting unit; Receive the voltage of this frequency range detecting unit conversion, and receive the effect of the gain amplification of outside this voltage of controlling signal adjustment, wherein this high band and this low-frequency range sense path all are provided with this adjustable gain amplifier;
One or more comparing unit couples this adjustable gain amplifier, and this comparing unit is introduced a reference voltage, carries out a comparison operation with this voltage after gain is amplified; And
One radio frequency switch unit; Be coupled to this comparing unit; Comprise a plurality of switchs, utilize to receive the open and close of these a plurality of switchs of signal control after this comparison operation, control the unlatching opportunity that the band of high-frequency signals and low-frequency signal in this radio frequency switch unit is refused filter in view of the above.
2. a filter that is used in dual frequency band sensing circuit is characterized in that, comprising:
One two-band sensing cell; Receive the signal of alien frequencies cross-talk system through a connectivity port; The signal that signal region is divided into high band, primary band and low-frequency range; Connect a high band sense path, a primary band sense path and a low-frequency range sense path through a plurality of splicing ears, wherein the sense path of this high band is provided with an open circuit stub or step impedance open circuit stub at least, is used to filter out the signal than low frequency; This low-frequency range sense path is provided with step impedance open circuit stub, to control the frequency of two or more transmission zeros, is used to filter the signal of primary band and high band;
One high band detecting unit is arranged on this high band sense path, is coupled to this two-band sensing cell through one of these a plurality of splicing ears, is used to detect the high band signal and converts voltage signal into;
One low-frequency range detecting unit is arranged on this low-frequency range sense path, is coupled to this two-band sensing cell through one of these a plurality of splicing ears, is used to detect the low-frequency range signal and converts voltage signal into;
One or more adjustable gain amplifier is coupled to this high band detecting unit and this low-frequency range detecting unit, is used to adjust the gain of this voltage signal;
One or more terminal is through the gain of this terminal by this adjustable gain amplifier of outside adjustment;
One or more comparing unit is coupled to this adjustable gain amplifier, carries out this through the voltage signal of gain amplification and the comparison operation of a reference voltage;
One radio frequency switch unit; Comprising being arranged, a plurality of switchs and one or more band refuse filter; These a plurality of switchs include a plurality of positive logic radio frequency switchs and negative logic radio frequency switch; Receive conducting that result after this comparison operation controls each switch and end, and then control the unlatching opportunity that this band is refused filter.
3. a filtering method that is used in dual frequency band sensing circuit is characterized in that, comprising:
Receive signal, this signal is the signal that an alien frequencies cross-talk system is produced, and comprises plural frequency range at least;
Carry out the filtering frequency division through a two-band sensing cell; Wherein this double frequency sensing cell is provided with an open circuit stub or step impedance open circuit stub at least; Be used to filter out signal, or use the frequency of two or more transmission zeros of control, be used to filter the signal of primary band and high band than low frequency;
Respectively by a high band detecting unit or a low-frequency range detecting unit detection signal energy;
Changing this energy is a voltage signal;
By the gain of this voltage signal of adjustable gain amplifier adjustment, this gain is controlled by an external control signal;
Use a comparing unit to carry out this comparison operation through gain an adjusted voltage signal and a reference voltage;
Produce the signal that a plurality of switchs of control open and close opportunity;
Control the unlatching opportunity that one or more height frequency range band is refused filter;
Carry out filtering; And
Output signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2007101678248A CN101420238B (en) | 2007-10-26 | 2007-10-26 | Filtering device and method used for dual frequency band sensing circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2007101678248A CN101420238B (en) | 2007-10-26 | 2007-10-26 | Filtering device and method used for dual frequency band sensing circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101420238A CN101420238A (en) | 2009-04-29 |
| CN101420238B true CN101420238B (en) | 2012-07-25 |
Family
ID=40630873
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2007101678248A Expired - Fee Related CN101420238B (en) | 2007-10-26 | 2007-10-26 | Filtering device and method used for dual frequency band sensing circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101420238B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106033972B (en) * | 2015-03-16 | 2019-05-31 | 联想(北京)有限公司 | A kind of electronic equipment |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1162377A (en) * | 1994-09-30 | 1997-10-15 | 夸尔柯姆股份有限公司 | Multiple band radio |
| EP1696579A1 (en) * | 2003-12-11 | 2006-08-30 | Hitachi Metals, Ltd. | Multi-band high-frequency circuit, multi-band high-frequency circuit part, and multi-band communication device using the same |
| CN1988247A (en) * | 2005-12-22 | 2007-06-27 | 佛山市顺德区顺达电脑厂有限公司 | Edge coupling coplanar wave guide bandpass filter |
| CN101043228A (en) * | 2007-02-01 | 2007-09-26 | 宇龙计算机通信科技(深圳)有限公司 | Multi-mode mobile communication terminal and RF receiving and transmitting circuit, method |
-
2007
- 2007-10-26 CN CN2007101678248A patent/CN101420238B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1162377A (en) * | 1994-09-30 | 1997-10-15 | 夸尔柯姆股份有限公司 | Multiple band radio |
| EP1696579A1 (en) * | 2003-12-11 | 2006-08-30 | Hitachi Metals, Ltd. | Multi-band high-frequency circuit, multi-band high-frequency circuit part, and multi-band communication device using the same |
| CN1988247A (en) * | 2005-12-22 | 2007-06-27 | 佛山市顺德区顺达电脑厂有限公司 | Edge coupling coplanar wave guide bandpass filter |
| CN101043228A (en) * | 2007-02-01 | 2007-09-26 | 宇龙计算机通信科技(深圳)有限公司 | Multi-mode mobile communication terminal and RF receiving and transmitting circuit, method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101420238A (en) | 2009-04-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101005289B (en) | Apparatus for automatically matching frequency of antenna in wireless terminal and method of using the same | |
| CN104852749B (en) | Radio circuit and terminal device | |
| US8874061B2 (en) | Filtering apparatus and method for dual-band sensing circuit | |
| CN105577259B (en) | Diversity receiver front end system with variable gain amplifier | |
| CN110011721B (en) | Power amplifier equipment and power amplifier system in satellite communication system | |
| CN106330247B (en) | A kind of power amplification circuit and power amplification box | |
| CN105610453A (en) | High-gain narrowband radio frequency receiver | |
| CN108322237B (en) | Interference suppression system and method | |
| CN109167608A (en) | A kind of miniaturization S-Ku wave band Ultra-Wideband RF Receiver | |
| CN109150227A (en) | A kind of multimode radio-frequency front end circuit and its control method | |
| CN107257245A (en) | Anti-interference Transmit-Receive Unit, R-T unit and anti-interference attenuation processing method | |
| CN107017917B (en) | A kind of power amplifier method and apparatus of tri- frequency automatic identification of TD-LTE | |
| CN217282884U (en) | Multi-mode multi-frequency power amplifier, radio frequency system and communication equipment | |
| JP2012257030A (en) | Signal switching device | |
| CN215818097U (en) | Radio frequency power amplifying circuit, transmitting module, communication equipment and communication system | |
| CN101710836B (en) | Frequency sweep device and frequency sweep method | |
| CN101420238B (en) | Filtering device and method used for dual frequency band sensing circuit | |
| KR20060082444A (en) | Apparatus and method of eliminating noise for transmitter and receiver of wireless | |
| CN102904537A (en) | Weak wireless signal amplifier of time division duplex system and control method | |
| US7505743B2 (en) | Dual band transmitter having filtering coupler | |
| CN115567070B (en) | Front end assembly capable of self-adapting to instantaneous dynamic expansion | |
| EP1891734B1 (en) | Method and arrangement for improved feeder sharing in a telecommunication system | |
| CN109104214B (en) | Signal processing device, electronic equipment and signal processing method | |
| CN111294086A (en) | Gain control method of communication system and communication system | |
| JPH08503594A (en) | Method and system for controlling operation of high frequency power amplifier |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| 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: 20120725 Termination date: 20151026 |
|
| EXPY | Termination of patent right or utility model |