CN106304304B - Rfid transmissions Poewr control method and device - Google Patents
Rfid transmissions Poewr control method and device Download PDFInfo
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- CN106304304B CN106304304B CN201610670220.4A CN201610670220A CN106304304B CN 106304304 B CN106304304 B CN 106304304B CN 201610670220 A CN201610670220 A CN 201610670220A CN 106304304 B CN106304304 B CN 106304304B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/18—TPC being performed according to specific parameters
- H04W52/22—TPC being performed according to specific parameters taking into account previous information or commands
- H04W52/226—TPC being performed according to specific parameters taking into account previous information or commands using past references to control power, e.g. look-up-table
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/18—TPC being performed according to specific parameters
- H04W52/24—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters
- H04W52/248—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters where transmission power control commands are generated based on a path parameter
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Abstract
The present invention provides a kind of rfid transmissions Poewr control method and device, and wherein method includes following circulation set-up procedure: the power of detection transmitting signal；Compare the difference between the power of transmitting signal and setting performance number；When the absolute value of the difference is less than given threshold, stop adjustment；When the difference is greater than zero, by adjusting the pad value for increasing adjustable attenuator and/or reduce the road the I modulated signal of quadrature modulator, the amplitude that the road Q modulated signal inputs；When the difference is less than zero, by adjusting the pad value for reducing adjustable attenuator and/or increase the road the I modulated signal of quadrature modulator, the amplitude that the road Q modulated signal inputs.The accuracy of the transmission power control of radio-frequency identification reader/writer can be improved in the present invention, easy to adjust to be easily achieved and free from the influence of the external environment.
Description
Technical field
The present invention relates to technical field of RFID more particularly to a kind of rfid transmissions Poewr control methods and dress
It sets.
Background technique
Mainly there are two key indexes for the factor of decision super high frequency radio frequency recognition read-write machine operating distance, are to receive spirit respectively
Sensitivity and transmission power.According to the propagation characteristic of electromagnetic wave free space, the field strength energy of the radio-frequency identification reader/writer area of coverage with
Its relationship exponentially declined to the distance of radio-frequency identification reader/writer, theoretically, operating distance is every to increase by 1 times, field strength energy
Decline 6dB.The size of radio-frequency identification reader/writer transmission power determines that it can trigger radio frequency recognizing electronic label backscattering
The operating distance of signal, when radio-frequency identification reader/writer operating distance is larger, influence of the transmission power to its operating distance is just special
Unobvious, often the transmission power error of 1dB can make operating distance phase difference rice.In order to enable radio-frequency identification reader/writer has
The consistency of batch, it is necessary to realize the accurate control of its transmission power.
In addition, the division frequency range of China's super high frequency radio frequency identification is 840-845MHz and 920-925MHz, the two frequency ranges
The frequency spectrum resource of surrounding is very crowded, and relevant departments the transmission power of radio-frequency identification reader/writer have also been made stringent regulation.For
Radio-frequency identification reader/writer is made to have optimal performance, maximum transmission power must be substantially equal to wanting for relevant regulations
It asks, it is therefore necessary to strictly and accurately control its maximum transmission power.
However, existing radio-frequency identification reader/writer mostly uses the mode of power coarse adjustment, the continuous stepping of power may be implemented,
But the accurate control that cannot achieve power, be mainly the following mode: 1. transmission powers are originally determined, and transmission power is a certain
Fixed value, can not configure transmission power, and this mode cannot achieve the flexible Application of radio-frequency identification reader/writer；2. passing through control function
The gain of rate amplifier, this mode are limited by the inconsistency of device in circuit, can only realize the adjustment of output power size,
It cannot achieve the accurate control of radio-frequency identification reader/writer.
Summary of the invention
The purpose of the present invention is to provide a kind of rfid transmissions Poewr control method and devices, solve the prior art
Transmission power control accuracy in middle radio-frequency identification reader/writer is not high, is easily affected by the surrounding environment.
In order to solve the above-mentioned technical problem, a kind of rfid transmissions Poewr control method of the invention, by adjusting just
The input of the road the I modulated signal, the road Q modulated signal of quadrature modulator and by adjusting adjustable attenuator control signal to realize day
The adjustment of the transmitting signal power of beta radiation, the method includes recycling set-up procedure as follows:
The power of detection transmitting signal；
Compare the difference between the power of transmitting signal and setting performance number；
When the absolute value of the difference is less than given threshold, stop adjustment；When the difference is greater than zero, by adjusting
Increase the pad value of adjustable attenuator and/or reduces the amplitude of the road the I modulated signal of quadrature modulator, the input of the road Q modulated signal；
When the difference is less than zero, by adjusting the pad value for reducing adjustable attenuator and/or the road the I modulation for increasing quadrature modulator
The amplitude that signal, the road Q modulated signal input；
When the absolute value of the difference is greater than predetermined value, the control signal of step by step modulating adjustable attenuator；In the difference
When the absolute value of value is less than predetermined value, the road the I modulated signal of quadrature modulator, the amplitude of the road Q modulated signal input are adjusted.
As the further improvement of the above-mentioned rfid transmissions Poewr control method of the present invention, the detection transmitting signal
Power is emitted signal all the way by coupling and is transferred to logarithmic detector realization.
As the further improvement of the above-mentioned rfid transmissions Poewr control method of the present invention, believed by coupling transmitting all the way
Number and be transferred to logarithmic detector signal power value obtained multiplied by specific penalty coefficient with determine transmitting signal power.
As the further improvement of the above-mentioned rfid transmissions Poewr control method of the present invention, in specific period internal trigger institute
It states circulation set-up procedure or initiates to trigger the circulation set-up procedure by backstage.
In order to solve the above-mentioned technical problem, a kind of rfid transmissions power control device of the invention, including follow as follows
Ring adjusts module:
Detection unit, for detecting the power of transmitting signal；
Comparing unit, for comparing the difference between the power of transmitting signal and setting performance number；
Adjustment unit when being less than given threshold for the absolute value in the difference, stops adjustment；It is greater than in the difference
When zero, by adjusting the pad value for increasing adjustable attenuator and/or reduce the road I modulated signal, the amplitude of the road Q modulated signal；?
When the difference is less than zero, by adjusting the pad value for reducing adjustable attenuator and/or increase the road I modulated signal, the road Q tune
The amplitude of signal processed；
The adjustment unit is specific further include: when the absolute value of the difference is greater than predetermined value, step by step modulating is adjustable to decline
Subtract the control signal of device；When the absolute value of the difference is less than predetermined value, the road I modulated signal, the Q of quadrature modulator are adjusted
The amplitude of road modulated signal input.
As the further improvement of the above-mentioned rfid transmissions power control device of the present invention, the detection transmitting signal
Power is emitted signal all the way by coupling and is transferred to logarithmic detector realization.
As the further improvement of the above-mentioned rfid transmissions power control device of the present invention, believed by coupling transmitting all the way
Number and be transferred to logarithmic detector signal power value obtained multiplied by specific penalty coefficient with determine transmitting signal power.
As the further improvement of the above-mentioned rfid transmissions power control device of the present invention, described device further includes triggering
Unit adjusts module for the circulation described in specific period internal trigger or initiates to trigger the circulation adjustment module by backstage.
Compared with prior art, the present invention judges whether transmission power is adjusted in place by way of loop detection, then benefit
Realize the accurate adjustment of power with the mode that adjustable attenuator coarse adjustment and quadrature modulator fine tuning combine, Adjustment precision is reachable ±
The output power batch consistency of 0.1dB, product are preferable.The transmission power control of radio-frequency identification reader/writer can be improved in the present invention
Accuracy, it is easy to adjust to be easily achieved and free from the influence of the external environment.
After the detailed description of embodiment of the present invention is read in conjunction with the figure, the other features and advantages of the invention will become more
Add clear.
Detailed description of the invention
In order to illustrate more clearly of embodiment of the present invention or the technical solution of the prior art, below will to embodiment or
Attached drawing needed to be used in the description of the prior art is briefly described, it is therefore apparent that the accompanying drawings in the following description is only this
The some embodiments recorded in invention, for those of ordinary skill in the art, in the premise not made the creative labor
Under, it is also possible to obtain other drawings based on these drawings.
Fig. 1 is radio frequency identification forward link schematic diagram in an embodiment of the present invention.
Fig. 2 is rfid transmissions Poewr control method flow chart in an embodiment of the present invention.
Fig. 3 is rfid transmissions power control device module map in an embodiment of the present invention.
Specific embodiment
Hereinafter, the present invention will be described in detail with reference to various embodiments shown in the accompanying drawings.But these embodiments are not
The limitation present invention, structure that those skilled in the art are made according to these embodiments, method or change functionally
It changes and is included within the scope of protection of the present invention.
It should be noted that in various embodiments, identical label or label may be used, but these not generations
Table structure or absolute connection relationship functionally.Also, " first ", " second ", " third " being previously mentioned in each embodiment
Not representative structure or absolute differentiation relationship functionally, these are merely for convenience of description.
As shown in Figure 1, radio frequency identification forward link schematic diagram in an embodiment of the present invention.Radio frequency identification forward link packet
Include Base Band Unit 10, quadrature modulator 20, adjustable attenuator 30, power amplifier unit 40, coupler 50, logarithmic detector 60, annular
Device 70, antenna element 80.Antenna element 80 be used for transceiving radio frequency signal, antenna element 80 from forward direction link definition standard not
It together, can not also include belonging to a module outside radio frequency identification forward link in radio frequency identification forward link.Specifically,
Antenna element 80 includes front network 81 and antenna 82, and front network 81 is used between antenna 82 and radio frequency identification forward link
Access is provided, antenna 82 introduces the radiofrequency signal of forward link by front network 81.Front network 81 may include for receiving
Send out the device of isolation, the device etc. including day line options.Antenna 82 is a kind of converter, it is the leading propagated on transmission line
Wave is transformed into the electromagnetic wave propagated in unbounded medium (usually free space), or carries out opposite transformation, and antenna 82 is
Device for direct transceiving radio frequency signal.Base Band Unit 10 is for controlling radiofrequency signal or Acquisition Circuit parameter, Base Band Unit
It may include control circuit inside 10, pass through the specified control signal of control circuit output.
Quadrature modulator 20 realizes that quadrature modulator 20 is connected using the framework directly modulated in the present embodiment
Base Band Unit 10 provides the road I modulated signal, the road Q modulated signal, quadrature modulator 20 from Base Band Unit 10 to quadrature modulator 20
Also receive local oscillation signal, it is preferable that quadrature modulator 20 connects internal phase-locked loop frequency integrator, passes through internal phaselocked loop
Frequency synthesizer provides local oscillation signal.Quadrature modulator 20 will receive the road I modulated signal and the road Q modulated signal is loaded onto carrier wave,
Orthogonal modulation is carried out to modulated signal according to local oscillation signal, quadrature modulator 20 is penetrated after passing through orthogonal modulation from output end output
Frequency signal needs the radiofrequency signal radiateing by antenna element 80.Because at a distance to radio frequency recognizing electronic label into
Row identification, so having certain requirement to the transmission power of radiofrequency signal, so also needing through other circuits to radiofrequency signal
It is handled.In the present embodiment, the road the I modulated signal, the road Q modulated signal of the offer of Base Band Unit 10 are as modulated signal package
Information containing data communication also includes the amplitude power of adjustable modulating wave.By adjusting the road I modulated signal, the road Q modulation letter
The fine tuning of modulating wave output power number may be implemented.
Adjustable attenuator 30 connects quadrature modulator 20 to receive the radiofrequency signal of the output of quadrature modulator 20, is also connected with base
The control signal that tape cell 10 is adjusted with receiving attenuation amount.Adjustable attenuator 30 is according to the control signal of Base Band Unit 10 to radio frequency
Signal carries out power adjustment.Preferably, adjustable attenuator 30 is digital adjustable attenuator, i.e., includes several segments in adjustable attenuator
Attenuation module, attenuation module have several switching circuits, pass through switch according to actually there is different pad values between attenuation module
Circuit closes the size that any combination in several attenuation modules is connected to realize differential declines amount, and switching circuit closes
It is executed by receiving control signal.Therefore, control signal is provided to realize to defeated to adjustable attenuator 30 by Base Band Unit 10
The adjustment of power out.Adjustable attenuator specifically can be 6 digit control adjustable step attenuators, the minimum control of adjustable attenuator
Not only up to 0.5dB, it can be achieved that the accurate step by step modulating of output power, radiofrequency signal can realize amplitude range through adjustable attenuator
The variation of about 31.5dB.
The power amplifier unit 40 of connection adjustable attenuator 30 is used to amplify the power of radiofrequency signal, it is preferable that power amplifier unit 40
Including driving amplifier 41 and power amplifier 43, power amplifier 43 connects driving amplifier 41 and amplifies as the second level, drives
Dynamic amplifier 41 inputs to power amplifier 43 after then amplifying signal, finally forms high-power output through power amplifier 43 and believes
Number launch eventually by coupler 50, antenna element 80 etc..Driving amplifier 41, i.e. driving stage amplifier, pass through itself
Gain, so that overall power can export enough power with driving power amplifier 43.Power amplifier 43 is final amplifier,
Provide the peak power output configured needed for radio-frequency identification reader/writer.In radio frequency identification forward link in present embodiment,
The linear circuit that high dynamic range is formed by adjustable attenuator 30 and driving amplifier 41, in addition, power amplifier 43 also fills
Divide and this design of Reducing Rating is utilized, it can be ensured that forward link has the sufficiently high linearity, prevents the radiofrequency signal of transmitting non-
Linear zone generates phenomena such as deformation or intermodulation.
In addition, radio-frequency identification reader/writer is typically all to be arranged outdoors, the variation of external environment is easy to influence radio frequency knowledge
The radiofrequency signal of forward link in other reader, and radio-frequency identification reader/writer, after starting up, internal temperature can also be sent out
Raw very big variation, often this variation for influencing will cause output power is very big.In a preferred embodiment, in order to eliminate
Temperature compensation attenuator 42, the decaying of temperature compensation attenuator 42 is arranged in this influence between driving amplifier 41 and power amplifier 43
Be worth it is in a linear relationship with temperature change, can under temperature variations effective correcting circuit entire gain.Specifically, work as temperature
When degree rises, the decaying of amplifying device gain reduction and temperature compensation attenuator also becomes smaller；Conversely, upon a drop in temperature, amplifying device
Gain increase and the decaying of temperature compensation attenuator also become larger therewith.Environment can be effectively reduced using the environmental characteristics of temperature compensation attenuator
Influence of the temperature to the output power of radio frequency identification forward link in radio-frequency identification reader/writer, so that output power is maintained at one
Relatively steady state.
Coupler 50 is mainly used for the radiofrequency signal that coupling emits all the way and is used as power detection.The input terminal of coupler 50 connects
Power amplifier unit 40 is connect, radiofrequency signal is radiate by the output end of coupler 50 by antenna element 80, the coupling of coupler 50
End connection logarithmic detector 60, logarithmic detector 60 obtain radiofrequency signal by coupling.In order to save cost, coupler 50 is preferred
Ground is strip line coupler, including two quarter-wave microstrip lines, the first quarter-wave being respectively parallel to each other
One end of microstrip line and the second quarter-wave microstrip line, the first quarter-wave microstrip line connects power amplifier as input terminal
The other end of unit 40, the first quarter-wave microstrip line connects antenna element 80 as output end, in more embodiment party
In formula, it is connected with circulator 70 between antenna element 80 and the other end of the first quarter-wave microstrip line, it below will be detailed
It states, i.e. radiofrequency signal is radiate by the other end of the first quarter-wave microstrip line by antenna element 80.Two or four point
One of wave microstrip line one end as coupled end connect logarithmic detector 60, to logarithmic detector 60 provide radiofrequency signal.It needs
It is noted that the embodiment of coupler 50 is not described as limiting with above-mentioned, however not excluded that can be used directional coupler etc. its
He replaces power coupling circuit.
Logarithmic detector 60, is the preferred embodiment of power detecting unit, and the radiofrequency signal that will be coupled into switchs to voltage
Parameter carries out magnitude demodulator to radiofrequency signal, the amplitude information of radiofrequency signal is linearly changed into voltage signal.Logarithm inspection
First output end of wave device 60 connects Base Band Unit 10, the first output end output first input end input of logarithmic detector 60
The voltage signal that radiofrequency signal is converted into obtains transmission power level, base by voltage signal to Base Band Unit 10, Base Band Unit 10
Tape cell 10 adjusts quadrature modulator 20 and adjustable attenuator 30 according to transmission power level, that is, passes through the control letter after output adjustment
Number give quadrature modulator 20 and adjustable attenuator 30.For example, transmission power level is not up to designated value, quadrature modulator 20 is just increased
Output power or reduce adjustable attenuator 30 decaying.
In the present embodiment, Base Band Unit 10 includes processor 11 and analog-digital converter 13(ADC, Analog-to-
Digital Converter), the input terminal of analog-digital converter 13 receives the voltage signal that logarithmic detector 60 exports, by interior
Portion's processing is converted into digital signal, provides it transmission power level from the output end of analog-digital converter 13 connection processor 11.Place
Manage device 11 by connection digital analog converter 12(DAC, Digital-to-Analog Converter) input terminal output control letter
Number, the output end of digital analog converter 12 connects quadrature modulator 20, the digital command that digital analog converter 12 generates processor 11
Be converted to modulated signal, i.e., digital analog converter 12 receive the digital signal of processor 11 and be converted into the corresponding road I modulated signal,
The road Q modulated signal.
In a preferred embodiment, circulator 70, circulator 70 are additionally provided between coupler 50 and antenna element 80
First end 71 connect the output end of coupler 50, the second end 72 of circulator 70 connects antenna element 80, the of circulator 70
Three ends 73 connect the second input terminal of logarithmic detector 60, and in the present embodiment, logarithmic detector 60 is dual input logarithm
Wave detector.The effect of circulator 70 is not breakdown under 80 no-load condition of antenna element to can protect power amplifier, in addition
The echo-signal that antenna 82 can also be extracted is used for the detection of antenna condition.Preferably, the third end 73 of circulator 70 with it is right
It is provided with coupler 91 between several wave detectors 60, for preventing logarithmic detector 60 by the reflected high energy excessively of antenna element 80
Amount damage.Specifically, the third end 73 of the input terminal connection circulator 70 of coupler 91, the output end of coupler 91 is connected with negative
92 are carried, the second input terminal of the coupled end connection logarithmic detector 60 of coupler 91.Coupler 91 specifically can be microstrip line,
The third end 73 of one end connection circulator 70 of microstrip line, the other end connection load 92 of microstrip line, parallel connection is set on the microstrip line
It is equipped with the second input terminal of coupling resistance connection logarithmic detector 60.It should be noted that the embodiment of coupler 91 is not
It is described as limiting with above-mentioned, however not excluded that other power couplings such as embodiment of directional coupler or above-mentioned parallel microstrip line can be used
Close circuitry instead.
Because of three port direction characteristics of circulator 70 itself, when the first end 71 of circulator 70 is input terminal, the
Two ends 72 are output end, and third end 73 is isolation end, first end of the signal that the output end of coupler 50 exports from circulator 70
71 flow to the second end 72 of circulator 70, are transmitted further to antenna element 80, without being received by logarithmic detector 60.Work as annular
When the second end 72 of device 70 is input terminal, the third end 73 of circulator 70 is output end, and the first end 71 of circulator 70 is isolation
End, therefore the echo-signal of antenna 82 flows to the third end 73 of circulator 70 by the second end 72 of circulator 70, will not transmit
To power amplifier 43, reflected signal will not be caused to burn out power amplifier 43 because of zero load.Circulator 70 is set
The reflection that can reduce high-power signal under no-load condition is set, effectively avoids what be may cause under power amplifier mismatch Conditions from hitting
Phenomenon is worn, so that the safety of circuit and reliability greatly promote.
In the corresponding circuit of embodiment as described above, modulated by adjusting the road the I modulated signal of quadrature modulator, the road Q
The input of signal and the adjustment that the transmitting signal power of aerial radiation is realized by adjusting the control signal of adjustable attenuator, but
The circuit that rfid transmissions Poewr control method of the invention is implemented is not limited with the embodiment of foregoing circuit meaning.
When radio-frequency identification reader/writer is started to work, the road I modulated signal, the road Q modulated signal are initialized, initial setting up is required for reaching
The reference configuration for emitting signal power, because of the difference according to external environment, it is impossible to can directly reach ideal power, simultaneously
With the variation of external environment, the power for emitting signal will also be able to maintain stabilization.
As shown in Fig. 2, rfid transmissions Poewr control method in an embodiment of the present invention.Rfid transmissions power
Control method includes following circulation set-up procedure:
Step S1, the power of detection transmitting signal.The power of transmitting signal refers to that radio-frequency identification reader/writer passes through antenna spoke
It is mapped to external RF signal power.In actual application, the power for emitting signal is too low, just influences whether the model of covering
It encloses, possible longer-distance radio frequency recognizing electronic label would not be identified to, and power is too big to influence whether other equipment again, be disobeyed
The anti-regulation of communication standard.Therefore, it is necessary to first detect the power of transmitting signal, it is preferable that referring in above embodiment
Circuit, signal is emitted by coupler coupling all the way and is transferred to logarithmic detector, by logarithmic detector to transmitting signal
Amplitude information be linearly changed into voltage signal, then processor obtains specific power by analog-digital converter.Such as Fig. 1 institute
Show, the position of coupler is different, and coupler 50 is caused to arrive the trend of logarithmic detector 60 to the trend and coupler 50 of antenna 82
It is also difference, therefore it is also different to decay, but the decaying of coupler 50 to antenna 82 is linear, coupler 50 to logarithmic detector
The decaying of device 60 is also linear, so the performance number of the performance number and antenna actual transmission obtained by logarithmic detector 60 has
Some linear is obtained by coupling to emit signal all the way and be transferred to logarithmic detector in a preferred embodiment
Signal power value multiplied by specific penalty coefficient with determine transmitting signal power.Above-mentioned specific penalty coefficient is one
Fixed value because circuit be it is determining, linear relationship is not by the variation of environment, so penalty coefficient is pre-determined one solid
Definite value can store in the memory unit, call directly when determining the power of transmitting signal.
Step S2, compare the difference between the power of transmitting signal and setting performance number, setting performance number is actual needs
The power reached can provide a pre-determined maximum value according to communication standard.The transmitting signal that step S1 is detected
Power is compared with setting performance number, if bigger than normal, illustrated that power is excessively high and has been violated defining for communication standard, if partially
It is small, illustrate that the radiofrequency signal coverage area of aerial radiation becomes smaller.
Step S3, when the absolute value of the difference is less than given threshold, stop adjustment；Determine have according to the size of difference
The adjustment mode of body.Specifically, when the absolute value of the difference is less than given threshold, stop adjustment；It is greater than in the difference
When zero, by adjusting the pad value for increasing adjustable attenuator and/or reduce the road the I modulated signal of quadrature modulator, the road Q modulation letter
Number input amplitude；When the difference is less than zero, by adjusting the pad value for reducing adjustable attenuator and/or increase positive intermodulation
The road I modulated signal, the amplitude of the road Q modulated signal input of device processed.
When the absolute value of the difference is less than given threshold, illustrate that the power for emitting signal has been adjusted to position, at this time
It can stop adjusting, not need recycling and have adjusted.Due to the limitation of circuit itself, the power for emitting signal be there may come a time when
It will not be entirely capable of being adjusted to setting performance number, can be in one acceptable marginal range of setting up and down of setting performance number, this
The boundary of a marginal range is exactly above-mentioned given threshold, when transmitting signal power be in this marginal range, that is, approach
When setting performance number, the difference can also be determined as and be approximately equal to zero.
When the difference is greater than zero, illustrates that the power for emitting signal is greater than setting performance number, transmitting should be turned down at this time
The power of signal by adjusting the pad value for increasing adjustable attenuator and/or reduces quadrature modulator in the present embodiment
The road I modulated signal, the amplitude of the road Q modulated signal input, by taking digital adjustable attenuator as an example, stepping can be passed through by increasing pad value
Increase control signal, increases the complete attenuation value of the attenuation module of conducting.It is to illustrate to emit signal less than zero in the difference
Power is less than setting performance number, and emitting the space that the power of signal is also turned up in the present embodiment can by adjusting reducing
The pad value of controlled attenuator and/or the amplitude for increasing the road the I modulated signal of quadrature modulator, the input of the road Q modulated signal.
In a preferred embodiment, the mode and original of the power of quadrature modulator and adjustable attenuator adjustment transmitting signal
Manage it is all different, the output power of adjustable attenuator can be adjusted on a large scale, general adjusting range up to 31.5dB, and
It is easy to adjust, it is suitble to coarse adjustment.And the adjustment more refined may be implemented in quadrature modulator.It is greater than in the absolute value of the difference
When predetermined value, predetermined value can be the minimum precision of adjustable attenuator, each attainable minimum power adjustment of step by step modulating institute
Difference, the control signal of step by step modulating adjustable attenuator, as described above, if it is greater than zero, stepping increase pad value, if it is less than
Zero, stepping reduces pad value.It is to modulate by adjusting the road I modulated signal, the road Q less than predetermined value in the absolute value of the difference
The amplitude of signal input adjusts the output power of quadrature modulator.
Because there is also the variation of environment when transmission power has been adjusted to after position, transmission power weight can be made in this way
Kainogenesis variation, therefore can initiate to trigger by triggering above-mentioned circulation set-up procedure or backstage again in specific period
Above-mentioned circulation set-up procedure, makes transmission power be again introduced into the adjusting stage, and transmission power is made to be adjusted to properly stable position again
It sets.
As shown in figure 3, rfid transmissions power control device in an embodiment of the present invention.Rfid transmissions power
Control device includes that following circulation adjusts module: detection unit E1, comparing unit E2, adjustment unit E3.
Detection unit E1 is used to detect the power of transmitting signal.Preferably, the power of detection transmitting signal passes through coupling one
Road transmitting signal is simultaneously transferred to logarithmic detector realization.Because coupled signal and the transmission power that antenna exports are in a linear relationship,
By couple all the way emit signal and be transferred to logarithmic detector signal power value obtained multiplied by specific penalty coefficient with
Determine the power of transmitting signal.
Comparing unit E2 is used to compare the difference between the power of transmitting signal and setting performance number, and setting performance number is real
Border needs power to be achieved, can provide a pre-determined maximum value according to communication standard.
Adjustment unit E3 is used to stop adjustment when the absolute value of the difference is less than given threshold.Given threshold refers to
Transmitting signal sets the error of performance number or more by adjusting can achieve, what the determination of value can be previously set.Institute
When stating difference greater than zero, by adjusting the pad value for increasing adjustable attenuator and/or reduce the road I modulated signal, the modulation of the road Q
The amplitude of signal；When the difference is less than zero, by adjusting the pad value for reducing adjustable attenuator and/or increase the road I
The amplitude of modulated signal, the road Q modulated signal.In a preferred embodiment, adjustment unit E3 is specific further include: in the difference
Absolute value be greater than predetermined value when, the control signal of step by step modulating adjustable attenuator；It is less than in the absolute value of the difference predetermined
When value, the road the I modulated signal of quadrature modulator, the amplitude of the road Q modulated signal input are adjusted.Predetermined value is also in advance can be true
It sets, can be the minimum precision of adjustable attenuator.
In order to guarantee to remain in the case where environmental change transmission power under a reasonable index, radio frequency identification
Emission power control device further includes trigger unit, for adjusting module in the above-mentioned circulation of specific period internal trigger or passing through backstage
It initiates to trigger above-mentioned circulation adjustment module.Specific embodiment is referred to the specific reality of rfid transmissions Poewr control method
Apply mode.
In conjunction with method and technology scheme disclosed in the present application, hardware can be embodied directly in, by the soft of control unit execution
Part module or both combination, i.e. one or more steps and/or one or more steps combination, both can correspond to computer journey
Each software module of sequence process can also correspond to each hardware module, such as ASIC(Application Specific
Integrated Circuit, specific integrated circuit), FPGA(Field-Programmable Gate Array, scene can compile
Journey gate array) or other programmable logic device, discrete gate or transistor logic, discrete hardware components or it is any suitable
Work as combination.For convenience of description, it is divided into various modules when description above-mentioned apparatus with function to describe respectively, certainly, is implementing this
The function of each module can be realized in the same or multiple software and or hardware when application.
As seen through the above description of the embodiments, those skilled in the art can be understood that the application can
It realizes by means of software and necessary general hardware platform.Based on this understanding, the technical solution essence of the application
On in other words the part that contributes to existing technology can be embodied in the form of software products.The software is by microcontroller list
Member executes, and depends on required configuration, may include any kind of one or more micro-control units, including but not limited to
Micro-control unit, microcontroller, DSP(Digital Signal Processor, Digital Signals unit) or its any group
It closes.The software is stored in memory, for example, volatile memory (such as random-access memory etc.), nonvolatile memory
(for example, read-only memory, flash memory etc.) or any combination thereof.
In conclusion the present invention judges whether transmission power is adjusted in place by way of loop detection, recycle adjustable
The mode that the coarse adjustment of attenuator and the fine tuning of quadrature modulator combine realizes the accurate adjustment of power, Adjustment precision is reachable ±
The output power batch consistency of 0.1dB, product are preferable.The transmission power control of radio-frequency identification reader/writer can be improved in the present invention
Accuracy, it is easy to adjust to be easily achieved and free from the influence of the external environment.
It should be appreciated that although this specification is described in terms of embodiments, but not each embodiment only includes one
A independent technical solution, this description of the specification is merely for the sake of clarity, and those skilled in the art should will say
As a whole, the technical solution in each embodiment may also be suitably combined to form those skilled in the art can for bright book
With the other embodiments of understanding.
The series of detailed descriptions listed above only for feasible embodiment of the invention specifically
Protection scope bright, that they are not intended to limit the invention, it is all without departing from equivalent implementations made by technical spirit of the present invention
Or change should all be included in the protection scope of the present invention.
Claims (8)
1. a kind of rfid transmissions Poewr control method, which is characterized in that modulate letter by adjusting the road I of quadrature modulator
Number, the input of the road Q modulated signal and the transmitting signal function that aerial radiation is realized by adjusting the control signal of adjustable attenuator
The adjustment of rate, the method includes recycling set-up procedure as follows:
The power of detection transmitting signal；
Compare the difference between the power of transmitting signal and setting performance number；
When the absolute value of the difference is less than given threshold, stop adjustment；When the difference is greater than zero, by adjusting increase
The pad value of adjustable attenuator and/or the amplitude for reducing the road the I modulated signal of quadrature modulator, the input of the road Q modulated signal；Institute
When stating difference less than zero, letter is modulated by adjusting the pad value for reducing adjustable attenuator and/or the road I for increasing quadrature modulator
Number, the road Q modulated signal input amplitude；
When the absolute value of the difference is greater than predetermined value, the control signal of step by step modulating adjustable attenuator；In the difference
When absolute value is less than predetermined value, the road the I modulated signal of quadrature modulator, the amplitude of the road Q modulated signal input are adjusted.
2. rfid transmissions Poewr control method according to claim 1, which is characterized in that the detection emits signal
Power by coupling all the way emit signal and be transferred to logarithmic detector realization.
3. rfid transmissions Poewr control method according to claim 2, which is characterized in that emitted all the way by coupling
Signal is simultaneously transferred to the function that logarithmic detector signal power value obtained determines transmitting signal multiplied by specific penalty coefficient
Rate.
4. rfid transmissions Poewr control method according to claim 1, which is characterized in that in specific period internal trigger
The circulation set-up procedure is initiated to trigger the circulation set-up procedure by backstage.
5. a kind of rfid transmissions power control device, which is characterized in that including recycling adjustment module as follows:
Detection unit, for detecting the power of transmitting signal；
Comparing unit, for comparing the difference between the power of transmitting signal and setting performance number；
Adjustment unit when being less than given threshold for the absolute value in the difference, stops adjustment；It is greater than zero in the difference
When, by adjusting the pad value for increasing adjustable attenuator and/or reduce the road I modulated signal, the amplitude of the road Q modulated signal；Institute
When stating difference less than zero, by adjusting the pad value for reducing adjustable attenuator and/or increase the road I modulated signal, the modulation of the road Q
The amplitude of signal；
The adjustment unit is specific further include: when the absolute value of the difference is greater than predetermined value, step by step modulating adjustable attenuator
Control signal；When the absolute value of the difference is less than predetermined value, the road I modulated signal, the road the Q tune of quadrature modulator are adjusted
The amplitude of signal input processed.
6. rfid transmissions power control device according to claim 5, which is characterized in that the detection emits signal
Power by coupling all the way emit signal and be transferred to logarithmic detector realization.
7. rfid transmissions power control device according to claim 6, which is characterized in that emitted all the way by coupling
Signal is simultaneously transferred to the function that logarithmic detector signal power value obtained determines transmitting signal multiplied by specific penalty coefficient
Rate.
8. rfid transmissions power control device according to claim 5, which is characterized in that described device further includes touching
Bill member adjusts module for the circulation described in specific period internal trigger or initiates to trigger the circulation adjustment mould by backstage
Block.
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| CN201610670220.4A CN106304304B (en) | 2016-08-16 | 2016-08-16 | Rfid transmissions Poewr control method and device |
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| CN201610670220.4A CN106304304B (en) | 2016-08-16 | 2016-08-16 | Rfid transmissions Poewr control method and device |
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| CN108513692A (en) * | 2017-04-21 | 2018-09-07 | 深圳市大疆创新科技有限公司 | A kind of rf control system and control method |
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| CN110505174B (en) * | 2019-08-22 | 2024-07-19 | 北京聚利科技有限公司 | Modulation depth adjusting device and road side unit |
| CN113300794B (en) * | 2021-05-20 | 2022-07-22 | 重庆会凌电子新技术有限公司 | Control method of frequency spectrum sensor |
| CN114141005B (en) * | 2021-12-03 | 2023-05-12 | 维沃移动通信有限公司 | Power control method and device, control circuit and electronic equipment |
| CN113867238B (en) * | 2021-12-06 | 2022-02-11 | 成都威频科技有限公司 | Agile ALC system with amplitude and pulse modulation functions and control method thereof |
| CN115085826B (en) * | 2022-07-20 | 2024-02-09 | 深圳市兆驰数码科技股份有限公司 | Transmitting power detection circuit, method and wireless communication device |
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