CN206546580U - A kind of phase shift transfers net system of anti-blind spot - Google Patents
A kind of phase shift transfers net system of anti-blind spot Download PDFInfo
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- CN206546580U CN206546580U CN201720123469.3U CN201720123469U CN206546580U CN 206546580 U CN206546580 U CN 206546580U CN 201720123469 U CN201720123469 U CN 201720123469U CN 206546580 U CN206546580 U CN 206546580U
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Abstract
The utility model provides a kind of phase shift transfers net system of anti-blind spot, and system includes forward emitted unit, directional coupler, phase-shifting unit, the reverse demodulating unit being sequentially connected；Forward emitted unit is used to provide the forward signal launched to label；Directional coupler is used to take out preceding reverse signal, and the forward signal being coupled to for frequency mixer after phase-shifting unit by providing local oscillation signal, and the reverse signal feeding frequency mixer being coupled to is demodulated；Phase-shifting unit is used for the phase for switching two 90 ° of differences；Reverse demodulating unit is used to handle the reverse baseband signal of mixing output.The phase shift transfers net system and method for a kind of anti-blind spot described in the utility model have miniaturization, low-power consumption, low cost, and circuit is simple, debug the advantage such as easy, so as to reduce the blind spot of read write line, improves covering.
Description
Technical field
The utility model belongs to communication technical field, more particularly, to a kind of phase shift transfers net system of anti-blind spot.
Background technology
Current radio frequency identification (RFID) industry development is very fast, is all opened in multiple fields such as traffic, logistics, monitoring
Beginning is widely used.RFID system is made up of read write line, reading and writing device antenna and label.Read write line transmits signals to label, mark
Reflected signal, to reading and writing device antenna, forms a complete communication link to label again.Read write line is different according to usage scenario, substantially divides
For outdoor version read write line, desktop type read write line and hand-held read-write.Outdoor version read write line is primarily targeted for checking at a distance,
Reading and writing, thus it is higher to the performance requirement of read write line；Desktop type read write line is mainly responsible for the work such as the distribution and initialization of label,
Because main application scenarios are defined in desktop closely hair fastener, therefore to the less demanding of performance, but should have miniaturization, low cost
Advantage.Hand-held read-write is primarily targeted for that traffic police is hand-held to be used, and requires that read write line should have low-power consumption, miniaturization under the scene
The characteristics of.The signal that label is returned is demodulated by read write line, but because of the position relationship between label and reading and writing device antenna, typically
For blind spot can all occur.
Because read write line uses passive label, therefore label provides energy by read write line.Read write line sends the life for checking label
After order, continue as label and energy is provided, and wait tag backscatter signal.The energy that now label is provided using read write line enters
Row is powered and communicated by the way of backscattering read write line signal with read write line.Because label is adjusted by the way of scattering
System, then read write line should being demodulated using synchronous detection.Because label is different from the position of reading and writing device antenna and environment complexity etc.
Deng factors, there is certain phase difference in the back-scattered signal of label with the local oscillation signal of read write line itself.Ordinary circumstance
Blind spot can be overcome by the way of I/Q demodulation down.But often power consumption is larger (generally requiring 200-300mA) for I/Q demodulation chips,
Price is higher.Much room will be taken if oneself building, is not suitable for desktop type and hand-held read-write is compact and low-power consumption
Requirement.
Utility model content
In view of this, the utility model is directed to a kind of phase shift transfers net system of anti-blind spot, to reduce read write line
Blind spot, improve covering.
To reach above-mentioned purpose, what the technical solution of the utility model was realized in：
A kind of phase shift transfers net system of anti-blind spot, including be sequentially connected forward emitted unit, directional coupler, shifting
Facies unit, reverse demodulating unit；
The forward emitted unit is used to provide the forward signal launched to label；
The directional coupler is used to take out preceding reverse signal, and the forward signal being coupled to is by being mixed after phase-shifting unit
Frequency device provides local oscillation signal, and the reverse signal feeding frequency mixer being coupled to is demodulated；
The phase-shifting unit is used for the phase for switching two 90 ° of differences；
The reverse demodulating unit is used to handle the reverse baseband signal of mixing output.
Further, PLL, low-noise amplifier, modulator, the power that the forward emitted unit includes being sequentially connected are put
Big device.
Further, the phase-shifting unit includes the microstrip line and two RF switches that two-route wire length differs λ/4.
Relative to prior art, a kind of phase shift transfers net system of anti-blind spot described in the utility model has following excellent
Gesture：
(1) a kind of phase shift transfers net system of anti-blind spot described in the utility model have miniaturization, low-power consumption, it is low into
This, circuit is simple, debug the advantage such as easy, so as to reduce the blind spot of read write line, improves covering；
(2) the single frequency mixer demodulation of phase-shifting unit collocation described in the utility model, can be substantially reduced PCB surface product, reduce into
This, reduces volume；
(3) phase-shifting unit described in the utility model welds diverse location using fan-shaped resistance pose pattern by selecting
Resistance, realizes the purpose of easily debugging line length.
Brief description of the drawings
Constitute a part of accompanying drawing of the present utility model to be used for providing further understanding to of the present utility model, this practicality is new
The schematic description and description of type is used to explain the utility model, does not constitute to improper restriction of the present utility model.
In accompanying drawing：
Fig. 1 is the structural representation of the phase difference described in the utility model embodiment；
Fig. 2 is a kind of structural representation of the phase shift transfers net system of anti-blind spot described in the utility model embodiment；
Fig. 3 is the structural representation of the phase-shifting unit described in the utility model embodiment；
Fig. 4 is that the resistance described in the utility model embodiment puts schematic diagram.
Embodiment
It should be noted that in the case where not conflicting, the feature in embodiment and embodiment in the utility model can
To be mutually combined.
In description of the present utility model, it is to be understood that term " " center ", " longitudinal direction ", " transverse direction ", " on ", " under ",
The orientation or position relationship of the instruction such as "front", "rear", "left", "right", " vertical ", " level ", " top ", " bottom ", " interior ", " outer " are
Based on orientation shown in the drawings or position relationship, it is for only for ease of description the utility model and simplifies description, rather than indicate
Or imply that the device or element of meaning must have specific orientation, with specific azimuth configuration and operation, therefore be not understood that
For to limitation of the present utility model.In addition, term " first ", " second " etc. are only used for describing purpose, and it is not intended that indicating
Or imply relative importance or the implicit quantity for indicating indicated technical characteristic.Thus, " first ", " second " are defined
Deng feature can express or implicitly include one or more this feature.In description of the present utility model, unless
It is otherwise noted, " multiple " are meant that two or more.
, it is necessary to which explanation, unless otherwise clearly defined and limited, term " are pacified in description of the present utility model
Dress ", " connected ", " connection " should be interpreted broadly, for example, it may be fixedly connected or be detachably connected, or integratedly
Connection；Can be mechanical connection or electrical connection；Can be joined directly together, can also be indirectly connected to by intermediary,
It can be the connection of two element internals.For the ordinary skill in the art, on being understood by concrete condition
State concrete meaning of the term in the utility model.
Describe the utility model in detail below with reference to the accompanying drawings and in conjunction with the embodiments.
The utility model is overcomes blind spot, using following technical scheme：
Herein using AM come the scattering of approximate analysis label.Assuming that returning to the signal of read write line after label modulation by orientation
The leakage signal of coupler and forward direction is superimposed to be obtained：
Vrev=Vm*(ma*cosΩt)*cos ωct+Vm*cos(ωct+θ)
Wherein θ is the carrier wave and the phase difference of directional coupler leakage signal that label is returned.
Local oscillation signal is：
Vlo=cos (ωct+φ)
Wherein φ is the phase difference of the local oscillation signal of the carrier wave that label is returned and frequency mixer.
Into frequency mixer demodulation after and filter out high frequency and direct current, obtain:
Wherein cos Ω t are the data that label returns to read write line.
As can be seen here, the amplitude of the signal after demodulation is returned with label carrier wave and the phase difference of the local oscillation signal of frequency mixer
φ is directly proportional.
If the two phase difference is 0 °, cos0 °=1, read write line demodulation obtains maximum amplitude, as phase difference increases
To 90 ° (cos90 °=0), the reverse signal that demodulation is obtained is less and less, until there is vanishing, blind spot occurs.If now
Using λ/4 (quarter-wave) transmission line, phase shift is carried out to local oscillator, you can so that script phase difference, which is 90 °, becomes 180 °, shape
Into maximum.
To sum up, such as Fig. 1, if phase difference drops into shadow region, you can phase-shifting unit is selected into quarter-wave
Transmission line so that phase difference leaves shadow region.Two phases, which mutually switch, can be achieved to demodulate obtained baseband signal all the time
It is more thanThe demodulated signal of (being approximately equal to 0.707) again.
Whole system is divided into forward emitted unit, directional coupler, phase-shifting unit, reverse demodulating unit.Block diagram such as Fig. 2：
Forward emitted unit：By PLL, low-noise amplifier, modulator, the composition such as power amplifier.Mainly responsible offer
The forward signal launched to label (transmission checks order or sends single-tone provides energy for label).
Directional coupler：Preceding reverse signal is taken out using directional coupler, (read write line is sent the forward signal being coupled to
Signal) by providing local oscillation signal after phase-shifting unit for frequency mixer, the reverse signal (signal that label is returned) being coupled to is sent
Enter frequency mixer to be demodulated.
Phase-shifting unit：The microstrip line and two RF switches that phase-shifting unit differs λ/4 by two-route wire length are constituted, such as Fig. 3.Root
The line length of the quarter-wave microstrip line of respective frequencies is calculated according to the dielectric constant using pcb board material, but is actually made
The change due to dielectric constant or the compatibility of frequency range in, it may be necessary to finely tune and used in the length of microstrip line, the utility model
Fan-shaped resistance pose pattern, the resistance of diverse location is welded by selecting, and realizes the purpose of easily debugging line length, such as Fig. 4.Finally may be used
The phase of two 90 ° of differences of switching reaches the purpose for reducing blind spot.
Reverse demodulating unit：Reverse baseband signal to mixing output is amplified filtering etc., last collection analysis.
Receive that user sends checks after (reading and writing) instruction, provides stabilized carrier by forward emitted unit first, leads to
Ovennodulation device is modulated to base band commands signal, up-conversion to 920-925MHz.
Send after dependent instruction, continued to provide tone signal, power is provided for label.Now label receives read write line
After the forward signal sent, responded according to the coded system and speed of agreement, by the side for scattering read write line forward signal
Formula is modulated to signal.
Read write line single-tone is provided while etc. the data that return of label to be demodulated.Lead code is carried out according to agreement regulation
Matching.If successfully decoded, client is reported, completion is once interacted.
If read write line decoding failure, will control the switch of two single-pole double throws in phase-shifting unit, switches another phase, from
And 90 ° of local oscillator phase shift is re-started again and checks (reading and writing) and attempts and (repeat progress above-mentioned steps), solve the problems, such as blind spot.
The utility model is mainly used in hand-held read-write and desktop type read write line, in actual use label position
(several milliseconds) will not change before and after phase shift with aerial position, must once be more than in phase shift twice(it is approximately equal to
0.707) maximum again.So as to overcome blind spot problem.
The utility model can be realized：
Low-power consumption：The alternative device of I/Q modulators is limited, and to ensure that inside is mixed wanting to the power of local oscillator
Ask, generally all integrated internal radio frequency amplifier is amplified to local oscillator, and power consumption is not suitable for using battery generally in 200mA or so
Hand-held read-write.And read write line radio-frequency power itself is higher, local oscillation power, can be directly using passive mixed without individually amplifying
Frequency device.The frequency mixer used in the utility model belongs to passive frequency mixer, will not consume dc power.
Low cost, easily debugging：The Material Cost of frequency mixer is more much smaller than i/q demodulator, and without power supply, substantially reduces
BOM costs.In practical application, using fan-shaped resistance pose pattern, the resistance of diverse location is welded by selecting, is realized by such as Fig. 4
Easily debug the purpose of line length.
Miniaturization：Demodulated using single channel frequency mixer, it will cause blind spot problem not solve.And use the I/ oneself built
Q demodulators can take very large area again.Using the single frequency mixer demodulation of phase shifter element of the present utility model collocation, it can be substantially reduced
PCB surface is accumulated, and reduces cost, reduces volume.
P1dB compression points are high：Frequency mixer is widely used, and alternative material is very more, and P1dB compression points are high.Due to reading
Write that device relative power is larger, the echo of antenna and inner link will be reflexed on demodulator, held using common i/q demodulator
I/q demodulator will be caused to compress by high-power input, nonlinearity product increases, so as to influence the demodulation of read write line.
Preferred embodiment of the present utility model is the foregoing is only, it is all at this not to limit the utility model
Within the spirit and principle of utility model, any modification, equivalent substitution and improvements made etc. should be included in the utility model
Protection domain within.
Claims (3)
1. a kind of phase shift transfers net system of anti-blind spot, it is characterised in that：Including be sequentially connected forward emitted unit, orientation
Coupler, phase-shifting unit, reverse demodulating unit, in addition to label；
The forward emitted unit is used to provide the forward signal launched to label；
The directional coupler is used to take out preceding reverse signal, and the forward signal being coupled to is by being frequency mixer after phase-shifting unit
Local oscillation signal is provided, the reverse signal feeding frequency mixer being coupled to is demodulated；
The phase-shifting unit is used for the phase for switching two 90 ° of differences；
The reverse demodulating unit is used to handle the reverse baseband signal of mixing output.
2. a kind of phase shift transfers net system of anti-blind spot according to claim 1, it is characterised in that：The forward emitted
Unit includes PLL, low-noise amplifier, modulator, the power amplifier being sequentially connected.
3. a kind of phase shift transfers net system of anti-blind spot according to claim 1, it is characterised in that：The phase-shifting unit
The microstrip line and two RF switches of λ/4 are differed including two-route wire length.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201720123469.3U CN206546580U (en) | 2017-02-10 | 2017-02-10 | A kind of phase shift transfers net system of anti-blind spot |
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| CN201720123469.3U CN206546580U (en) | 2017-02-10 | 2017-02-10 | A kind of phase shift transfers net system of anti-blind spot |
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| CN206546580U true CN206546580U (en) | 2017-10-10 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106650543A (en) * | 2017-02-10 | 2017-05-10 | 天津中兴智联科技有限公司 | Blind spot-resistant phase-shift transmission network system and method |
-
2017
- 2017-02-10 CN CN201720123469.3U patent/CN206546580U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106650543A (en) * | 2017-02-10 | 2017-05-10 | 天津中兴智联科技有限公司 | Blind spot-resistant phase-shift transmission network system and method |
| CN106650543B (en) * | 2017-02-10 | 2023-09-19 | 高新兴智联科技股份有限公司 | Anti-blind-spot phase-shift transmission network system and method |
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| GR01 | Patent grant | ||
| CP03 | Change of name, title or address |
Address after: 300000 Room 401, building 12, east area, airport business park, No. 80, Huanhe North Road, Tianjin Free Trade Zone (Airport Economic Zone), Binhai New Area, Tianjin Patentee after: Gaoxing Zhilian Technology Co.,Ltd. Address before: 300308, Zhongxing Industrial base, 2 East seven, Airport Economic Zone, Tianjin Binhai New Area Patentee before: ZTE INTELLIGENT IOT TECHNOLOGY Co.,Ltd. |
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| CP03 | Change of name, title or address | ||
| CP01 | Change in the name or title of a patent holder |
Address after: Room 401, building 12, East Airport Business Park, 80 Huanhe North Road, Tianjin pilot free trade zone (Airport Economic Zone), Binhai New Area, Tianjin Patentee after: Zte Intelligent Iot Technology Co.,Ltd. Address before: Room 401, building 12, East Airport Business Park, 80 Huanhe North Road, Tianjin pilot free trade zone (Airport Economic Zone), Binhai New Area, Tianjin Patentee before: Gaoxing Zhilian Technology Co.,Ltd. |
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| CP01 | Change in the name or title of a patent holder |