CN102480308A - Method for restraining carrier leak - Google Patents
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- CN102480308A CN102480308A CN2010105594474A CN201010559447A CN102480308A CN 102480308 A CN102480308 A CN 102480308A CN 2010105594474 A CN2010105594474 A CN 2010105594474A CN 201010559447 A CN201010559447 A CN 201010559447A CN 102480308 A CN102480308 A CN 102480308A
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Abstract
The invention discloses a system for restraining carrier leak. The system comprises a directional coupler, a quadrature demodulator and a reflected signal module, wherein the directional coupler is used for outputting a leaked radio-frequency carrier signal to the quadrature demodulator from an isolation port; the quadrature demodulator is used for demodulating in-phase and orthogonal signals from the leaked radio-frequency carrier signal, sending the in-phase and orthogonal signals to the reflected signal module, and utilizing a reflected signal reflected by the reflected signal module to restrain the leaked radio-frequency carrier signal; and the reflected signal module is used for carrying out filtration, phase rotation gain control and in-phase antiphase integration on the in-phase and orthogonal signals so as to obtain a control signal of the reflected signal, the control signal is utilized to control the reflected signal, and the reflected signal is sent to the quadrature demodulator. The invention also discloses a method for restraining carrier leak. The system and method provided by the invention can be used for simply and effectively restraining the leak of a forward radio-frequency carrier signal.
Description
Technical field
The present invention relates to carrier Control field in the ultra-high-frequency passive radio-frequency recognition system, be meant the system and method that a kind of suppressed carrier leaks especially.
Background technology
In the ultra-high-frequency passive radio-frequency recognition system, when label and reader communication, reader need send carrier wave always and provide tag-powered, and label sends to reader through backscatter modulation with information.Therefore when reader received the signal of label, the radio-frequency carrier that the reader forward direction sends can leak into the reverse receiving unit of reader.The signal strength signal intensity that the label backscattering is returned is compared very little with the carrier signal strength that forward direction sends, the intensity difference of reverse signal and forward signal can reach more than the 90dB in the actual system.Therefore, the hyperfrequency reader adopts directional coupler to realize the isolation of forward signal and reverse signal usually.
The directional coupler of four ports that the hyperfrequency reader uses is divided into input port, output port, coupling port and isolated port.When reader sent signal, the radiofrequency signal of power amplifier output was imported from input port, and output port outputs to antenna, and portion of energy outputs to coupling port, and few energy outputs to isolated port.When reader received signal, because the port reciprocity of directional coupler, label signal was imported from output port, and part is coupled to isolated port, outputs to reverse demodulator through isolated port.Thereby realize the isolation of forward signal and reverse signal.
In reader; Because antenna impedance is influenced by environment and production technology and can not mate fully; Antenna changes to the length of cable between the reader, and the inner device parameters of reader can be because variation of ambient temperature, and production batch is different and change; Directional coupler can only provide general 20 to 30dB isolation under the combined influence, and isolation effect is not ideal.
Further also have the part reader to adopt the directional coupler plus signal to close the method on road; Generate the signal that offsets with former leakage signal; Close the road but carry out signal through mixer, complex structure, to offset efficient low, and mixer can increase reverse signal and inserts loss.
Summary of the invention
In view of this, the system and method that main purpose of the present invention is to provide a kind of suppressed carrier to leak, leakage that can simple and effective inhibition forward direction radio-frequency carrier signal.
For achieving the above object, technical scheme of the present invention is achieved in that
The invention provides the system that a kind of suppressed carrier leaks, said system comprises: directional coupler, quadrature demodulator and reflected signal module, wherein,
Said directional coupler is used for the radio-frequency carrier signal that leaks is outputed to quadrature demodulator from isolated port;
Said quadrature demodulator is used for the radio-frequency carrier signal that leaks is demodulated homophase and orthogonal signalling, sends to the reflected signal module, utilizes the reflected signal of said reflected signal module reflected back to suppress the radio-frequency carrier signal of said leakage;
Said reflected signal module after being used for homophase and orthogonal signalling are carried out filtering, phase place rotation gain controlling, homophase anti-phase integration, obtains the control signal of reflected signal, utilizes control signal control reflected signal, and reflected signal is sent to quadrature demodulator.
Wherein, said reflected signal module comprises:
Said reflected signal control submodule after being used for homophase and orthogonal signalling are carried out filtering, phase place rotation gain controlling, homophase anti-phase integration, obtains the control signal of reflected signal, and sends to phase shift and reflect submodule;
Said phase shift reflection submodule is used to utilize the reflected signal of control signal control directional coupler coupling port, and coupling port and the isolated port of reflected signal through directional coupler sent to quadrature demodulator.
Wherein, to carry out filtering specifically be LPF to said reflected signal module; Said phase place rotation gain controlling is through changing the anglec of rotation and the gain of signal, adjusting the phase place and the amplitude of homophase and orthogonal signalling; Obtain four tunnel control signals behind the homophase anti-phase integration, be respectively applied for the intensity of four tapping points of the said reflected signal of control on transmission line.
Wherein, the reflected signal in the said reflected signal module specifically is the radio-frequency carrier signal by the coupling port output of directional coupler, through the control of reflected signal module, the coupling port of reflected back directional coupler.
Wherein, the function of said reflected signal control submodule further realizes through analog-to-digital conversion submodule, digital reflection signals control submodule and digital-to-analogue conversion submodule that calculation function is identical.
Wherein, said digitized reflected signal control submodule also comprises: stop to control submodule, be used to judge homophase and the amplitude of orthogonal signalling after the leakage signal demodulation, and during less than threshold value, the generation of stop control signal.
The method that the present invention also provides a kind of suppressed carrier to leak, said method comprises:
The radio-frequency carrier signal that leaks is exported from isolated port;
Utilize quadrature demodulator that the radio-frequency carrier signal that leaks is demodulated homophase and orthogonal signalling;
After homophase and orthogonal signalling were carried out filtering, phase place rotation gain controlling, homophase anti-phase integration, controlled signal utilized control signal control reflected signal, suppresses the radio-frequency carrier signal of said leakage.
Wherein, the carrier signal that the generation of said control signal and inhibition are leaked specifically comprises:
Homophase and orthogonal signalling are carried out filtering; Excute phase rotation gain controlling; Homophase and orthogonal signalling to after the phase place rotation gain are carried out homophase anti-phase integration, obtain the control signal of the reflected signal of directional coupler coupling port; Utilize the reflected signal of control signal control coupling port; Utilize the reflected signal of coupling port to suppress said radio-frequency carrier signal.
Wherein, said filtering specifically is LPF; Said phase place rotation gain controlling is through changing the anglec of rotation and the gain of signal, adjusting the phase place and the amplitude of homophase and orthogonal signalling; Obtain four tunnel control signals behind the homophase anti-phase integration, be respectively applied for the intensity of four tapping points of reflected signal on transmission line of the said coupling port of control.
Wherein, said reflected signal specifically is the radio-frequency carrier signal by the coupling port output of directional coupler, through the control of reflected signal module, the coupling port of reflected back directional coupler.
The system and method that suppressed carrier provided by the present invention leaks is exported from isolated port through the radio-frequency carrier signal that leaks; Utilize quadrature demodulator that the radio-frequency carrier signal that leaks is demodulated homophase and orthogonal signalling; After homophase and orthogonal signalling were carried out filtering, phase place rotation gain controlling, homophase anti-phase integration, controlled signal utilized control signal control reflected signal, suppresses the radio-frequency carrier signal of said leakage.Owing to be to utilize reflected signal to offset leakage signal; Therefore the ratioing signal method of closing the road has simple in structure; Counteracting efficient is high; Do not increase the advantage that reverse signal inserts loss, can effectively suppress the leakage of forward direction radio-frequency carrier signal simultaneously, the sensitivity that has improved the ultra-high-frequency passive radio-frequency recognition system.
Description of drawings
The system configuration sketch map that Fig. 1 leaks for a kind of suppressed carrier of the present invention;
Fig. 2 is the structural representation of reflected signal control submodule of the present invention;
Fig. 3 is the structural representation of phase shift reflection submodule of the present invention;
Fig. 4 is the structural representation of the reflected signal control submodule of digital processing;
The method flow sketch map that Fig. 5 leaks for a kind of suppressed carrier of the present invention;
Fig. 6 is the sketch map of reverse signal isolation before not adopting when of the present invention;
Fig. 7 for adopting when of the present invention before the sketch map of reverse signal isolation.
Embodiment
Below in conjunction with accompanying drawing and specific embodiment technical scheme of the present invention further is discussed in more detail.
The system configuration sketch map that Fig. 1 leaks for a kind of suppressed carrier of the present invention, as shown in Figure 1, said system comprises: directional coupler 11, quadrature demodulator 12 and reflected signal module 13, wherein,
Said directional coupler 11 is used for the radio-frequency carrier signal that leaks is outputed to quadrature demodulator 12 from isolated port;
Concrete, the power amplifier module 14 in the said ultra-high-frequency passive radio-frequency recognition system, output forward direction radio-frequency carrier signal outputs to antenna 15 from output port then through the input port of directional coupler 11.Under the acting in conjunction of the isolation of the standing wave of antenna 15 and directional coupler 11, a part of radio-frequency carrier signal leaks into the isolated port of directional coupler 11, and exports from isolated port.In the present invention, power amplifier module 14, directional coupler 11 and antenna 15 do not need special qualification, can adopt general power amplifying device, directional coupler and antenna commonly used to get final product.
Said quadrature demodulator 12 is used for the radio-frequency carrier signal that leaks is demodulated homophase and orthogonal signalling, sends to reflected signal module 13, utilizes the reflected signal of said reflected signal module 13 reflected backs to suppress the radio-frequency carrier signal of said leakage;
Concrete, the said quadrature demodulator 12 that utilizes demodulates homophase and orthogonal signalling (I signal and Q signal), is respectively:
I＝r
1*cos(θ
1)；Q＝r
1*sin(θ
1)
Wherein, r
1Be the intensity of the radio-frequency carrier signal of said leakage; θ
1Be the radio-frequency carrier signal of leakage and the phase difference of local oscillation signal, because the standing wave of antenna is the main source of reverse leakage, θ
1Mainly receive the influence of the feeder line length of antenna 15.Wherein, when said local oscillation signal is to use quadrature demodulator 12, a baseband signal of importing for demodulation.
Said reflected signal outputs to quadrature demodulator 12 by the coupling port of reflected signal module 13 reflection process directional couplers 11 from isolated port; Because control signal has been carried out phase place rotation gain; Therefore the phase place of the reflected signal of controlled signal control and former leakage radio-frequency carrier signal is opposite; Control signal makes the amplitude of reflected signal increase under the effect of homophase anti-phase integration in addition; Realized the cancelling out each other of former leakage radio-frequency carrier signal, reached and suppressed the purpose that radio-frequency carrier leaks.
Said reflected signal module 13; After being used for homophase and orthogonal signalling are carried out filtering, phase place rotation gain controlling, homophase anti-phase integration; Obtain the control signal of reflected signal; Utilize the reflected signal of control signal control directional coupler 11 coupling port, reflected signal is sent to quadrature demodulator 12 through directional coupler 11.
Concrete, homophase and orthogonal signalling are adopted low-pass filtering treatment, purpose is to filter out HF noise signal.Homophase after the filtering and orthogonal signalling are carried out phase place rotation gain controlling, are through changing the anglec of rotation and the gain of signal, adjusting the phase place and the amplitude of homophase and orthogonal signalling, then through obtaining I behind the homophase anti-phase integration
+, I
-, Q
+, Q
-Signal is used to control four reflected signals on the tapping point.Wherein, Said reflected signal is meant: when directional coupler 11 forward directions send radio-frequency carrier signal; The part radio-frequency carrier signal of the coupling port output signaling module 13 control back reflections that are reflected return the coupling port of directional coupler 11; The reflected signal of the coupling port of input directional coupler 11 arrives quadrature demodulator 12 through directional coupler 11.
Further, said reflected signal module 13 comprises: reflected signal control submodule 131 and phase shift reflection submodule 132, wherein,
Said reflected signal control submodule 131 after being used for homophase and orthogonal signalling are carried out filtering, phase place rotation gain controlling, homophase anti-phase integration, obtains the control signal of reflected signal, and sends to phase shift and reflect submodule 132;
Concrete, Fig. 2 is for the structural representation of reflected signal control submodule of the present invention, and is as shown in Figure 2, and in the said reflected signal control submodule 131, I signal and Q signal are exported through after the filtering of low pass filter 201 respectively earlier.The I signal of output is imported first multiplier 202, second multiplier 203, multiplies each other with phase place adjustment coefficient A*cos (θ), A*sin (θ) respectively; Q signal is imported the 3rd multiplier 204, the 4th multiplier 205, multiplies each other with phase place adjustment coefficient A*cos (θ), A*sin (θ) respectively.Obtain four tunnel results after multiplying each other respectively: A*I*cos (θ), A*I*sin (θ), A*Q*cos (θ), A*Q*sin (θ).
＝A*r
1*cos(θ)*cos(θ
1)+A*r
1*sin(θ)*sin(θ
1)＝A*r
1*cos(θ
1-θ)；
＝A*r
1*sin(θ
1)*cos(θ)-A*r
1*cos(θ
1)*sin(θ)＝A*r
1*sin(θ
1-θ)。
Wherein, I ', Q ' are respectively homophase and the orthogonal signalling after the phase place rotation gains.In addition, phase theta and amplitude gain A need adjust setting, carry out when the total system debugging will be in the end carried out in concrete setting; Set low amplitude gain A earlier, adjustment θ is when selecting signal cancellation; The phase theta that value is minimum is adjusted gain A then, makes the time of counteracting the shortest.
In the practical application, input A*cos (θ) and A*sin (θ) signal are accomplished computing, can realize through adjustable potentiometer, in digital processing, can directly import the numerical value of A*cos (θ) and A*sin (θ).Multiplier, adder and subtracter all can adopt operation amplifier circuit to realize, in digital processing, can utilize addition, subtraction and the multiplying of software or digital circuit to realize.Inverting integrator remakes the anti-phase integration after can adopting typical computing amplification anti-phase integrating circuit, homophase integrating circuit with signal inversion.Noninverting integrator realizes that by accumulator Y=Y+X inverting integrator is realized by accumulator Y=Y-X in digital processing realizes.
I ' the signal of adder 206 output outputs to first noninverting integrator 208, first inverting integrator 209.Q ' the signal of subtracter 207 output outputs to second noninverting integrator 210, second inverting integrator 211.The result of noninverting integrator and input signal homophase add up, and the result of inverting integrator and input signal anti-phase add up.First noninverting integrator, 208 output results are I
+=A*r
1* ∫ cos (θ
1-θ); First inverting integrator, 209 output results are I
-=-1*A*r
1* ∫ cos (θ
1-θ); Second noninverting integrator, 210 output results are Q
+=A*r
1* ∫ sin (θ
1-θ); Second inverting integrator, 211 output results are Q
-=-1*A*r
1* ∫ sin (θ
1-θ); I
+, I
-, Q
+, Q
-Signal is used to control the reflected signal strength of phase shift reflection submodule 132.
Further; Because reflected signal will pass through directional coupler 11 and arrive quadrature demodulator 12; The phase shifts of reflected signal need not be considered the influence of the feeder line length of antenna 15 in this process, but the cabling from directional coupler 11 isolated ports to quadrature demodulator 12 all can bring reflected signal a fixing phase shifts θ on directional coupler 11 and the veneer
2, better suppressing said radio-frequency carrier signal in order to make reflected signal, preferred scheme is control signal I
+, I
-, Q
+, Q
-All with θ
2Take into account, concrete, the phase place of preferred θ is θ=θ
2-180 o'clock, the phase place of the increment of reflected signal was (θ
1-θ
2+ 180), the θ of process directional coupler and cabling
2Phase shift after, be (θ to the phase place of quadrature demodulator
1+ 180) with former leakage signal θ
1Phase phasic difference 180 degree, the reflected signal that generates like this is opposite with former leakage signal phase place when arriving quadrature demodulator 12.Because phase shift theta
2Irrelevant with the feeder line length of antenna 15, so phase place adjustment coefficient θ does not receive the influence of feeder line length, have excellent adaptability.
Said phase shift reflection submodule 132 is used to utilize the reflected signal of control signal control directional coupler 11 coupling port, and coupling port and the isolated port of reflected signal through directional coupler 11 sent to quadrature demodulator 12.
Concrete; Fig. 3 is for the structural representation of phase shift reflection submodule of the present invention, and is as shown in Figure 3, in the said phase shift reflection submodule 132; The first steerable retroreflective unit 301, the second steerable retroreflective unit 302, the 3rd steerable retroreflective unit 303 and the 4th steerable retroreflective unit 304 are respectively by Q
-, I
-, Q
+, I
+Control the reflected signal strength of four reflection nodes.Four nodes are four tapping points on the transmission line, adopt PIN (intrinsic diode) pipe can change the impedance of four nodes with the variable resistor mode.When control voltage is 0 or less than 0 the time, the bias current of PIN pipe is 0, variable-resistance impedance is far longer than 50 Europe, and this moment, the PIN tubing was similar to a little electric capacity, reflected very little.When control voltage greater than 0 the time, control voltage is big more, the bias current of PIN pipe is big more, the impedance of reflection node is more little, reflected signal strength is big more.Through this principle, realized the amplitude control of coupling port reflected signal.Termination load 305 is the terminating resistor in 50 Europe.
First phase-shifting unit 306, second phase-shifting unit 307 and the 3rd phase-shifting unit 308 have realized that 45 degree phase shifts of control reflected signal handle, and reflected signal is sent to the coupling port of directional coupler 11.Under the effect of first phase-shifting unit 306, the input signal phase place of the second steerable retroreflective unit 302 is than the first steerable retroreflective unit, 301 input signals time-delay, 45 degree.Therefore the second steerable retroreflective unit 302 signal that reflexes to the coupling port of directional coupler 11 is spent than the reflected signal time-delay 90 of the first steerable retroreflective unit 301.In like manner the reflected signal of the 3rd steerable retroreflective unit 303 is than the second steerable retroreflective unit, 302 time-delays, 90 degree; The reflected signal of the 4th steerable retroreflective unit 304 is than the 3rd steerable retroreflective unit 303 time-delays 90 degree.
For example: the reflected signal of establishing the first steerable retroreflective unit 301 is Γ
1* cos (ψ t-270), then the reflected signal of the second steerable retroreflective unit 302 is Γ
2* cos (ψ t-180), the reflected signal of the 3rd steerable retroreflective unit 303 is Γ
3* cos (ψ t-90), the reflected signal of the 4th steerable retroreflective unit 304 is Γ
4* cos (ψ t).Γ＝(Z
L-Z
0)/(Z
L+Z
0)。Z
0Being transmission line impedance, here is 50 Europe, Z
LBe load impedance Z
L=Z
L/ Z
PINZ wherein
PINBe the PIN tube impedance.Γ
1, Γ
2, Γ
3, Γ
4The Q that exports by the reflected signal control module respectively
-, I
-, Q
+, I
+Control is when control voltage reflected signal smaller or equal to 0 time is 0, when control voltage reflected signal greater than 0 time is the dull increasing function of control voltage.Reflected signal in the coupling port of directional coupler 11 is (Γ
4-Γ
2) * cos (ψ t)+(Γ
3-Γ
1) * sin (ψ t).
Further; The function of said reflected signal control submodule 131 can also realize through digital processing, and Fig. 4 is the structural representation of the reflected signal control submodule of digital processing; As shown in Figure 4; Said submodule comprises: analog-to-digital conversion submodule 401, digital reflection signals are controlled submodule 402, digital-to-analogue conversion submodule 403 and are stopped to control submodule 404, wherein
Analog-to-digital conversion submodule 401 is converted into digital signal with signal, and input digit reflected signal control submodule 402 is handled, and accomplishes the back and adopts digital-to-analogue conversion submodule 403 to carry out digital-to-analogue conversion to export.Wherein, the function that digital reflection signals control submodule 402 is realized can be controlled the computing that submodule 131 carries out with reference to reflected signal, uses the corresponding digital computing module and realizes.The response of limit for length's unit impulse (FIR) or cascade integrator comb (CIC) filter in digital processing, can have been adopted for low pass filter 201.
The said effect that stops to control submodule 404 is an amplitude of judging leakage signal demodulated I, Q signal, works as I
2+ Q
2During less than threshold value, stop in the digital reflection signals control submodule 402, the integration of four integrators, perhaps the numerical value with I, Q signal directly is changed to 0.The generation of stop control signal reduces the influence of the reflected signal of automatic bucking circuit control to reverse signal.Said threshold value can be set according to the leakage power value of target, and for example: the leakage power of target be-20dBm, and then when system debug, by the test signal of the RF signal input end mouth input-20dBm of quadrature demodulator 11, detection is calculating I also
2+ Q
2Value, with this value as the threshold value that stops to control submodule 404.
The method flow sketch map that Fig. 5 leaks for a kind of suppressed carrier of the present invention, as shown in Figure 5, said method specifically may further comprise the steps:
When step 501, directional coupler were exported the forward direction radio-frequency carrier signal from output port, the radio-frequency carrier signal of leakage was exported from isolated port;
Concrete, the power amplifier module in the said ultra-high-frequency passive radio-frequency recognition system, output forward direction radio-frequency carrier signal outputs to antenna from output port then through the input port of directional coupler.Under the acting in conjunction of the isolation of the standing wave of antenna and directional coupler, a part of radio-frequency carrier signal leaks into the isolated port of directional coupler, and exports from isolated port.In the present invention, power amplifier module, directional coupler and antenna do not need special qualification, can adopt general power amplifying device, directional coupler and antenna commonly used to get final product.
Step 502 utilizes quadrature demodulator that the radio-frequency carrier signal that leaks is demodulated homophase and orthogonal signalling;
Concrete, saidly utilize quadrature demodulator to demodulate homophase and orthogonal signalling are respectively:
I＝r
1*cos(θ
1)；Q＝r
1*sin(θ
1)
Wherein, r
1Be the intensity of the radio-frequency carrier signal of said leakage; θ
1Be the radio-frequency carrier signal of leakage and the phase difference of local oscillation signal.Wherein, when said local oscillation signal is to use quadrature demodulator, a baseband signal of importing for demodulation.
Concrete, homophase and orthogonal signalling are adopted low-pass filtering treatment, purpose is to filter out HF noise signal.Homophase after the filtering and orthogonal signalling are carried out phase place rotation gain controlling, are through changing the anglec of rotation and the gain of signal, adjusting the phase place and the amplitude of homophase and orthogonal signalling, then through obtaining I behind the homophase anti-phase integration
+, I
-, Q
+, Q
-Signal is used to control four reflected signals on the tapping point.Wherein, said reflected signal is meant: be reflected back toward coupling port, and when the directional coupler forward direction sends radio-frequency carrier signal, the part radio-frequency carrier signal of coupling port output.Said I
+, I
-, Q
+, Q
-Signal is controlled the intensity of four tapping points of said reflected signal on transmission line respectively.Reflected signal outputs to quadrature demodulator through the coupling port of directional coupler from isolated port; Because control signal has been carried out phase place rotation gain; Therefore the phase place of the reflected signal of controlled signal control and former leakage radio-frequency carrier signal is opposite; Control signal makes the amplitude of reflected signal increase under the effect of homophase anti-phase integration in addition, has realized the cancelling out each other of former leakage radio-frequency carrier signal reached and suppressed the purpose that radio-frequency carrier leaks.
Further, step 503 also comprises:
Step 503a carries out filtering to homophase and orthogonal signalling;
Concrete, said filtering can be adopted the active low-pass filter that is made up of operational amplifier, or the passive low ventilating filter of resistance capacitance (RC) network and inductance capacitance (LC) network composition.The selection of parameter of low pass filter will be taken into account two contradictions; The one, for the amplitude and the phase information of the carrier signal of leaking; Homophase that quadrature demodulator demodulates and orthogonal signalling are direct current signals, require the passband of low pass filter and stop-band frequency low as far as possible, the interference of filtering noise as far as possible; The 2nd, during actual the use, require the fast convergence rate of automatic bucking circuit, time-delay can increase under the low situation of the passband of filter and stop-band frequency, can influence convergence rate.Among the embodiment, passband-3dB cut-off frequency is chosen as 10KHz, stopband cut-off frequency 25KHz, stopband attenuation-30dB.
Step 503b, excute phase rotation gain controlling;
Concrete, carry out filtered homophase and orthogonal signalling and multiply by A*cos (θ) and A*sin (θ) respectively, be specially:
①A*I*cos(θ)、②A*I*sin(θ)、③A*Q*cos(θ)、④A*Q*sin(θ)。
Then, get 1. and 4. addition obtain: I '=A*I*cos (θ)+A*Q*sin (θ); Get 2. and 3. to subtract each other and obtain: Q '=A*Q*cos (θ)-A*I*sin (θ),
Because I=r
1* cos (θ
1); Q=r
1* sin (θ
1), therefore,
I’＝A*r
1*cos(θ)*cos(θ
1)+A*r
1*sin(θ)*sin(θ
1)＝A*r
1*cos(θ
1-θ)；
Q’＝A*r
1*sin(θ
1)*cos(θ)-A*r
1*cos(θ
1)*sin(θ)＝A*r
1*sin(θ
1-θ)。
Wherein, I ', Q ' are respectively homophase and the orthogonal signalling after the phase place rotation gains.In addition, phase theta and amplitude gain A need adjust setting, carry out when the total system debugging will be in the end carried out in concrete setting; Set low amplitude gain A earlier, adjustment θ is when selecting signal cancellation; The phase theta that offset result is minimum is adjusted gain A then, makes the time of counteracting the shortest.
Step 503c carries out homophase anti-phase integration to homophase and orthogonal signalling after the phase place rotation gain, obtains the control signal of the reflected signal of directional coupler coupling port;
Concrete, I ' is carried out obtaining I with phase integral
+=A*r
1* ∫ cos (θ
1-θ); I ' is carried out the anti-phase integration obtain I
-=-1*A*r
1* ∫ cos (θ
1-θ); Q ' is carried out obtaining Q with phase integral
+=A*r
1* ∫ sin (θ
1-θ); Q ' is carried out the anti-phase integration obtain Q
-=-1*A*r
1* ∫ sin (θ
1-θ), said I
+, I
-, Q
+, Q
-Signal is respectively applied for the intensity of four tapping points of reflected signal on transmission line of the said coupling port of control.
Step 503d utilizes control signal to control the reflected signal of coupling port;
Concrete, the reflected signal of said coupling port has four tapping points on transmission line, promptly aforesaid four tapping points, and four tapping points differ the phase difference of 90 degree respectively, with assurance the complete cycle of reflected signal are controlled.Four tapping points can adopt the variable resistor mode of PIN pipe realization to control respectively, specifically are through changing the impedance of four tapping points, realizing the amplitude of reflected signal is controlled.When the voltage of control signal is 0 or less than 0 the time, the bias current of PIN pipe is 0, variable-resistance impedance is far longer than 50 Europe, and this moment, the PIN tubing was similar to a little electric capacity, reflected very little.When the voltage of control signal greater than 0 the time, control voltage is big more, the bias current of PIN pipe is big more, the impedance of reflection tapping point is more little, reflected signal strength is big more.Through this principle, realized the amplitude control of coupling port reflected signal.
Step 503e utilizes the reflected signal of coupling port to suppress said radio-frequency carrier signal.
Concrete; The reflected signal of the coupling port of input directional coupler; Arrive quadrature demodulator through directional coupler; The phase shifts of reflected signal need not be considered the influence of the feeder line length of antenna in this process, but directional coupler, and the cabling from the directional coupler isolated port to quadrature demodulator all can bring reflected signal a fixing phase shifts θ on the veneer
2, better suppressing said radio-frequency carrier signal in order to make reflected signal, preferred scheme is control signal I
+, I
-, Q
+, Q
-All with θ
2Take into account, concrete, the phase place of preferred θ is θ=θ
2-180 o'clock, the phase place of the increment of reflected signal was (θ at this moment
1-θ
2+ 180), the θ of process directional coupler and cabling
2Phase shift after, be (θ to the phase place of quadrature demodulator
1+ 180) with former leakage signal θ
1Phase phasic difference 180 degree, the reflected signal that generates like this is opposite with former leakage signal phase place when arriving quadrature demodulator 12.Because phase shift theta
2Irrelevant with the feeder line length of antenna 15, so phase place adjustment coefficient θ does not receive the influence of feeder line length, have excellent adaptability.
Fig. 6 is for the sketch map of reverse signal isolation before not adopting when of the present invention, and is as shown in Figure 6, only utilizes the isolation of directional coupler self to preceding reverse signal, and when the 840MHz frequency, the isolation of forward direction and reverse signal is about-28dB.Fig. 7 for adopting when of the present invention before the sketch map of reverse signal isolation, as shown in Figure 7, adopt the method for quiescent carrier leakage of the present invention after, the isolation of forward direction and reverse signal is optimized to-55dB.This shows the isolation of reverse link signal before adopting the present invention to significantly improve.
The above is merely preferred embodiment of the present invention, is not to be used to limit protection scope of the present invention, all any modifications of within spirit of the present invention and principle, being done, is equal to replacement and improvement etc., all should be included within protection scope of the present invention.
Claims (4)
1. the suppressed carrier method of leaking is characterized in that said method comprises:
The radio-frequency carrier signal that leaks is exported from isolated port;
Utilize quadrature demodulator that the radio-frequency carrier signal that leaks is demodulated homophase and orthogonal signalling;
After homophase and orthogonal signalling were carried out filtering, phase place rotation gain controlling, homophase anti-phase integration, controlled signal utilized control signal control reflected signal, suppresses the radio-frequency carrier signal of said leakage.
2. method according to claim 1 is characterized in that, the carrier signal that the generation of said control signal and inhibition are leaked specifically comprises:
Homophase and orthogonal signalling are carried out filtering; Excute phase rotation gain controlling; Homophase and orthogonal signalling to after the phase place rotation gain are carried out homophase anti-phase integration, obtain the control signal of the reflected signal of directional coupler coupling port; Utilize the reflected signal of control signal control coupling port; Utilize the reflected signal of coupling port to suppress said radio-frequency carrier signal.
3. method according to claim 1 and 2 is characterized in that, said filtering specifically is LPF; Said phase place rotation gain controlling is through changing the anglec of rotation and the gain of signal, adjusting the phase place and the amplitude of homophase and orthogonal signalling; Obtain four tunnel control signals behind the homophase anti-phase integration, be respectively applied for the intensity of four tapping points of reflected signal on transmission line of the said coupling port of control.
4. method according to claim 1 and 2 is characterized in that, said reflected signal specifically is the radio-frequency carrier signal by the coupling port output of directional coupler, through the control of reflected signal module, the coupling port of reflected back directional coupler.
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| CN2010105594474A CN102480308A (en) | 2010-11-23 | 2010-11-23 | Method for restraining carrier leak |
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| CN2010105594474A CN102480308A (en) | 2010-11-23 | 2010-11-23 | Method for restraining carrier leak |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102902939A (en) * | 2012-09-29 | 2013-01-30 | 中国物品编码中心 | Carrier cancellation device |
| CN103595431A (en) * | 2012-08-13 | 2014-02-19 | 晨星软件研发(深圳)有限公司 | A transceiver applicable to radio frequency identification and a noise elimination method |
| CN106100690A (en) * | 2016-08-03 | 2016-11-09 | 江苏本能科技有限公司 | Radio frequency offsets signal generation apparatus |
| CN109120290A (en) * | 2018-08-03 | 2019-01-01 | 武汉万集信息技术有限公司 | RFID reception circuit and storage medium, electronic device |
| CN114650201A (en) * | 2022-03-14 | 2022-06-21 | 深圳市国芯物联科技有限公司 | UHF RFID carrier suppression method |
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2010
- 2010-11-23 CN CN2010105594474A patent/CN102480308A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103595431A (en) * | 2012-08-13 | 2014-02-19 | 晨星软件研发(深圳)有限公司 | A transceiver applicable to radio frequency identification and a noise elimination method |
| CN103595431B (en) * | 2012-08-13 | 2015-09-02 | 晨星软件研发(深圳)有限公司 | Can be used for transceiver and the noise cancellation method of radio frequency identification |
| CN102902939A (en) * | 2012-09-29 | 2013-01-30 | 中国物品编码中心 | Carrier cancellation device |
| CN102902939B (en) * | 2012-09-29 | 2015-07-22 | 中国物品编码中心 | Carrier cancellation device |
| CN106100690A (en) * | 2016-08-03 | 2016-11-09 | 江苏本能科技有限公司 | Radio frequency offsets signal generation apparatus |
| CN106100690B (en) * | 2016-08-03 | 2018-06-05 | 江苏本能科技有限公司 | Radio frequency offsets signal generation apparatus |
| CN109120290A (en) * | 2018-08-03 | 2019-01-01 | 武汉万集信息技术有限公司 | RFID reception circuit and storage medium, electronic device |
| CN114650201A (en) * | 2022-03-14 | 2022-06-21 | 深圳市国芯物联科技有限公司 | UHF RFID carrier suppression method |
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Application publication date: 20120530 |