CN208209969U - A kind of GSM signal downlink Self-excitation Detection device - Google Patents
A kind of GSM signal downlink Self-excitation Detection device Download PDFInfo
- Publication number
- CN208209969U CN208209969U CN201820426813.0U CN201820426813U CN208209969U CN 208209969 U CN208209969 U CN 208209969U CN 201820426813 U CN201820426813 U CN 201820426813U CN 208209969 U CN208209969 U CN 208209969U
- Authority
- CN
- China
- Prior art keywords
- input terminal
- output end
- power
- connects
- frequency module
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Transceivers (AREA)
Abstract
The utility model discloses a kind of GSM signal downlink Self-excitation Detection devices, including downlink radio frequency module, power detector, central processing unit, power circuit and switch module；First output end of the downlink radio frequency module connects the input terminal of the power detector, the output end of the power detector connects the input terminal of the central processing unit, the output end of the central processing unit connects the first input end of the switch module, the power circuit connects the second input terminal of the switch module, first output end of the switch module connects the first input end of the downlink radio frequency module, the Self-excitation Detection of circuit can be carried out automatically, and it is reacted in time after self-excitation phenomena occurs, cut off circuit, it avoids communicating surrounding and itself circuit arrangement impacts.
Description
Technical field
The utility model relates to circuit detection field more particularly to a kind of GSM signal uplink Self-excitation Detection devices.
Background technique
With quickly propelling for urbanization process, the swift and violent development at full speed of present mobile communication, people are to mobile radio communication
The requirement of network quality and data transmission is higher and higher.In the occasions such as building low layer, market place builet below the ground, underground parking, shape
At the blind area and shadow region of mobile communication.In conference and exhibition center, the places such as large-scale stadium, due to crowded, telephone traffic
Height, will not only solve signal covering problem, also need to solve capacity problem.Therefore room can not be solved only by outdoor base station covering
Interior signal problem, it is necessary to which problems just can solve by indoor covering system.Signal expires lattice treasured as solving, and system chambers are interior to be believed
One of the mode of number covering, have many advantages, such as structure it is simple, it is cheap, quick for installation, be easy maintenance and be widely used, letter
Number full lattice treasured is signal coverage enhancement equipment, can support a mould or the multimode signal in 2G/3G/4G, effectively solves indoor weak covers
Lid problem is suitable for the scenes such as the underground space, bottom commerce, residential households, office, elevator, at low cost, deployment is fast, matter
The advantages such as the reliable, signal stabilization of amount.
Signal expires the input of lattice treasured, output is same frequency equipment, alms giver and retransmitting antenna isolation it is bad, will result in and be
System self-excitation, simplicity of explanation are exactly that the signal that the donor antenna that signal expires lattice treasured has received retransmitting antenna expires lattice treasured using signal
Amplification, is exported by retransmitting antenna, and such vicious circle, consequence is equipment damage, is with the phenomenon that mobile phone test, receives letter
It is number good, do not show phone.Former net is caused to seriously affect from goading into action if signal expires lattice treasured, the receiving for influencing neighbouring base station is sensitive
Degree, the coverage area of base station will greatly reduce.It, can be big by the destruction of interference since the work antenna that signal expires lattice treasured is higher
Area expands.
The self-excitation test that the prior art expires lattice treasured for signal is mainly conversed in project installation and commissioning with mobile phone test
Quality checks that mobile phone receives power, or tests frequency spectrum with frequency spectrograph, if in-site installation has self-excitation phenomena, field adjustable alms giver
The direction and isolation etc of antenna and retransmitting antenna.
During implementing the embodiment of the present invention, inventor's discovery: the prior art is only carried out in project installation and commissioning
Self-excitation Detection, but equipment have in actual use the uncertain factors such as some weather, artificial change antenna direction,
Occurring some failures inside isolation and equipment causes equipment self-excitation phenomena occur, and at this moment engineering staff cannot rush to existing in time
, it can affect to the communication of surrounding, will cause equipment damage if serious.
Utility model content
The purpose of the utility model embodiment is to provide a kind of GSM signal downlink Self-excitation Detection device, can carry out automatically
The Self-excitation Detection of circuit, and reacted in time after self-excitation phenomena occurs, circuit is cut off, avoids communicating surrounding and equipment of itself is made
At influence.
To achieve the above object, the utility model embodiment provides a kind of GSM signal downlink Self-excitation Detection device, including
Downlink radio frequency module, power detector, central processing unit, power circuit and switch module；
The downlink radio frequency module have first input end and the first output end, the power detector have input terminal and
Output end, the central processing unit have input terminal and output end, and the switch module has first input end, the second input terminal
And first output end；
First output end of the downlink radio frequency module connects the input terminal of the power detector, the power detector
Output end connect the input terminal of the central processing unit, the output end of the central processing unit connects the of the switch module
One input terminal, the power circuit connect the second input terminal of the switch module, and the first output end of the switch module connects
Connect the first input end of the downlink radio frequency module.
It as an improvement of the above scheme, further include the first sound table duplexer；
The downlink radio frequency module also has the second input terminal；
The output end of the first sound table duplexer connects the second input terminal of the downlink radio frequency module.
It as an improvement of the above scheme, further include rising tone table duplexer；
The downlink radio frequency module also has second output terminal；
The second output terminal of the downlink radio frequency module connects the input terminal of the rising tone table duplexer.
It as an improvement of the above scheme, further include upstream radio-frequency module；
The upstream radio-frequency module has first input end, the second input terminal and output end；
The switch module also has second output terminal；
The output end of the rising tone table duplexer connects the first input end of the upstream radio-frequency module, the switching molding
The second output terminal of block connects the second input terminal of the upstream radio-frequency circuit, and the output end of the upstream radio-frequency circuit connects institute
State the input terminal of the first sound table duplexer.
As an improvement of the above scheme, the downlink radio frequency module includes the first low-noise amplifier, the filtering of the first sound table
Device and the first RF power amplification pipe；
First low-noise amplifier has first input end, the second input terminal and output end, the first sound table filter
Wave device has input terminal and output end, and the first RF power amplification pipe has input terminal, the first output end and second output terminal；
The first input end of first low-noise amplifier connects the first input end of the downlink radio frequency module, described
Second input terminal of the first low-noise amplifier connects the second input terminal of the downlink radio frequency module, and first low noise is put
The output end of big device connects the input terminal of first SAW filter, the output end of first SAW filter and described the
The input terminal of one RF power amplification pipe connects, and the first output end of the first RF power amplification pipe connects the downlink radio frequency module
First output end, the second output terminal of the first RF power amplification pipe connect the second output terminal of the downlink radio frequency module.
As an improvement of the above scheme, the upstream radio-frequency module includes the second low-noise amplifier, the filtering of rising tone table
Device and the second RF power amplification pipe；
Second low-noise amplifier has first input end, the second input terminal and output end, the rising tone table filter
Wave device has input terminal and output end, and the second RF power amplification pipe has input terminal and output end；
The first input end of second low-noise amplifier connects the first input end of the upstream radio-frequency module, described
Second input terminal of the second low-noise amplifier connects the second input terminal of the upstream radio-frequency circuit, and second low noise is put
The output end of big device connects the input terminal of second SAW filter, the output end of second SAW filter and described the
The input terminal of two RF power amplification pipes connects, and the output end of the second RF power amplification pipe connects the output of the upstream radio-frequency circuit
End.
As an improvement of the above scheme, the switch module is power MOS field effect transistor.
As an improvement of the above scheme, the power circuit includes switching power circuit, voltage-stabilized power supply circuit, stabilized current supply
Any one in circuit, power power-supply circuit, inverter power circuit, DC-DC power source circuit and protection power source circuit.
Compared with prior art, a kind of GSM signal downlink Self-excitation Detection device provided by the embodiment of the utility model, passes through
The power detector detects the downlink signal in the downlink radio frequency module, and the downlink signal is sent to the centre
Device is managed, to carry out judging whether to generate downlink self-excitation phenomena by the central processing unit, if generating downlink self-excitation phenomena, in
The switch module that central processor control is connect with the power circuit disconnects, to stop the power circuit to entire GSM
The power supply of signal downlink Self-excitation Detection device, the self-excitation link of timely pass hull closure avoid impacting surrounding communication, simultaneously
It is also beneficial to the equipment for protecting itself circuit, extends the service life of equipment, saves equipment cost and human cost.
Detailed description of the invention
Fig. 1 is a kind of structural schematic diagram of GSM signal downlink Self-excitation Detection device in the utility model embodiment.
Fig. 2 is the structural schematic diagram of downlink radio frequency module as shown in Figure 1.
Fig. 3 is the structural schematic diagram of upstream radio-frequency module as shown in Figure 1.
Specific embodiment
The following will be combined with the drawings in the embodiments of the present invention, carries out the technical scheme in the embodiment of the utility model
Clearly and completely describe, it is clear that the described embodiments are only a part of the embodiments of the utility model, rather than whole
Embodiment.Based on the embodiments of the present invention, those of ordinary skill in the art are without creative efforts
Every other embodiment obtained, fall within the protection scope of the utility model.
It is that a kind of structure of GSM signal downlink Self-excitation Detection device 10 provided by the embodiment of the utility model is shown referring to Fig. 1
It is intended to.
The GSM signal downlink Self-excitation Detection device 10, including downlink radio frequency module 11, power detector 12, centre
Manage device 13, power circuit 14 and switch module 15；The downlink radio frequency module 11 has first input end and the first output end, institute
Power detector 12 is stated with input terminal and output end, the central processing unit 13 has input terminal and output end, the switch
Module 15 has first input end, the second input terminal and the first output end.
First output end of the downlink radio frequency module 11 connects the input terminal of the power detector 12, the power inspection
The output end for surveying device 12 connects the input terminal of the central processing unit 13, opens described in the output end connection of the central processing unit 13
The first input end of module 15 is closed, the power circuit 14 connects the second input terminal of the switch module 15, the switching molding
First output end of block 15 connects the first input end of the downlink radio frequency module 11.
The power detector 12 is to receive radio-frequency input signals, exports voltage corresponding with input radio frequency signal power
Component.
The central processing unit 13 (CPU) is one piece of ultra-large integrated circuit, mainly include arithmetic unit (ALU,
Arithmetic and Logic Unit) and the big component of controller (CU, Control Unit) two.In addition, further including several
Register and cache memory and the bus for realizing the data contacted between them, control and state.
Specifically, 1 frame of the downlink signal of GSM Base Transmitter contains 8 time slots, each slot length 577us, wherein having
30.525us protection interval is not comprising signal, and at this time the power level of sampling protection interval is the bottom with equipment in device
As making an uproar.When self-excitation situation occurs in equipment in device, the protection interval of 30.525us has been also filled with continuous self-excitation signal,
Whether the power detection using the protection interval in the time slot of GSM downlink signal occurs self-excitation phenomena come equipment in decision circuitry.
Power detector 12 described in GSM downlink signal is exported after being handled by the downlink radio frequency module 11 couples downlink radio frequency
GSM downlink signal, is extracted the signal of sub-fraction by the GSM downlink signal exported after the processing of module 11 from trunk channel
It is handled, corresponding with GSM downlink signal voltage analog signal is exported in described by the power detector 12
On central processor 13, the central processing unit 13 receives the voltage analog signal, samples to the voltage analog signal,
Sampling interval is T (μ s of T < 30.525), then sampling time 4.615ms is obtained in the power of GSM downlink signal of sampling
The minimum power is compared, the default function by minimum power, i.e. the protection interval power of time slot with predetermined power threshold value
Rate threshold value is that time slot signal power shows in the GSM signal downlink Self-excitation Detection device 10 if the difference of the two is greater than 0
There are self-excitation phenomena, the central processing unit 13 controls the switch module 15 and disconnects, so as to connect with the switch module 15
The power circuit 14 stop power supply to the GSM signal downlink Self-excitation Detection device 10, avoid communicating surrounding and cause
It influences, or even damage equipment of itself.
Preferably, the switch module 15 is power MOS field effect transistor (Power MOSFET), the power MOS
Field effect transistor is the device made of three kinds of metal, oxide (SiO2 or SiN) and semiconductor materials, so-called power
MOSFET (Power MOSFET) refers to that it can export biggish operating current (several peaces to dozens of Ann), for power output stage
Device, power MOS field effect transistor are mainly used for linear or Switching Power Supply.
Preferably, the power circuit 14 refers to the circuit design for being supplied to the power unit of electrical equipment power supply,
The circuit form and feature used, existing AC power source also have DC power supply.The power circuit 14 can for switching power circuit,
Voltage-stabilized power supply circuit, stabilized current supply circuit, power power-supply circuit, inverter power circuit, DC-DC power source circuit and protection power source electricity
Any one in road.
Further, the GSM signal uplink Self-excitation Detection device further includes the first sound table duplexer 16, rising tone table
Duplexer 17 and upstream radio-frequency module 18；The downlink radio frequency module 11 also has the second input terminal and second output terminal, described
Upstream radio-frequency module 18 has first input end, the second input terminal and output end, and the switch module 15 also has the second output
End.
The output end of the first sound table duplexer 16 connects the second input terminal of the downlink radio frequency module 11, under described
The second output terminal of row radio-frequency module 11 connects the input terminal of the rising tone table duplexer 17, the rising tone table duplexer 17
Output end connect the first input end of the upstream radio-frequency module 18, described in the second output terminal connection of the switch module 15
Second input terminal of upstream radio-frequency circuit, the output end of the upstream radio-frequency circuit connect the defeated of the first sound table duplexer 16
Enter end.
Sound table duplexer is alien frequencies two-way radios, and the key fitment of trunk desk, effect is will to emit and receive signal phase
Isolation guarantees to receive and emit and can work normally simultaneously, it is made of the bandstop filter of two groups of different frequencies, avoids this
Machine transmitting signal is transferred to receiver, and general duplexer is made of six stop-band filters, and each resonance is in transmitting and receives frequency；
Receiving end filter resonance prevents transmission power from sealing in receiver in tranmitting frequency, and transmitting terminal filter resonance is in reception frequency
Rate.
Specifically, the GSM downlink signal of GSM Base Transmitter enters the first sound table duplexer 16 by the port BS, so
The downlink radio frequency module 11 is entered by the first sound table duplexer 16 afterwards, by the radio frequency of the downlink radio frequency module 11
Enter rising tone table duplexer 17 after the operations such as signal amplification, frequency-selecting, then enters mobile phone terminal, the function by the port MS
Rate detector 12 couples the GSM downlink signal in the downlink radio frequency module 11, carries out handling it to the GSM downlink signal
Afterwards, the 12 output voltage analog signal of power detector inputs the central processing unit 13 (CPU), and the power circuit 14 passes through
The power MOS field effect transistor is crossed to power to the downlink radio frequency module 11 and the upstream radio-frequency module 18, it is described in
Central processor 13 (CPU) control power MOS field effect transistor opens or closes；The GSM uplink signal warp of mobile phone terminal transmitting
The port MS is crossed into the rising tone table duplexer 17, the upstream radio-frequency is then entered by the rising tone table duplexer 17
It is double to enter the first sound table after the operations such as radiofrequency signal amplification, frequency-selecting by the upstream radio-frequency module 18 for module 18
Then work device 16 enters base station by the port BS.
It should be noted that the uplink signal frequency range of mobile GSM900 includes 885-909Mhz, downlink signal frequency range includes
930-954Mh。
Further, referring to Fig. 2, the downlink radio frequency module 11 includes the first low-noise amplifier 111, the first sound
Table filter 112 and the first RF power amplification pipe 113；First low-noise amplifier 111 has first input end, the second input
End and output end, first SAW filter 112 have input terminal and output end, and the first RF power amplification pipe 113 has
Input terminal, the first output end and second output terminal.
The first input end of first low-noise amplifier 111 connects the first input of the downlink radio frequency module 11
End, the second input terminal of first low-noise amplifier 111 connects the second input terminal of the downlink radio frequency module 11, described
The output end of first low-noise amplifier 111 connects the input terminal of first SAW filter 112, the first sound table filtering
The output end of device 112 is connect with the input terminal of the first RF power amplification pipe 113, and the first of the first RF power amplification pipe 113
Output end connects the first output end of the downlink radio frequency module 11, and the second output terminal of the first RF power amplification pipe 113 connects
Connect the second output terminal of the downlink radio frequency module 11.
Further, referring to Fig. 3, the upstream radio-frequency module 18 includes the second low-noise amplifier 181, the rising tone
Table filter 182 and the second RF power amplification pipe 183；Second low-noise amplifier 181 has first input end, the second input
End and output end, second SAW filter 182 have input terminal and output end, and the second RF power amplification pipe 183 has
Input terminal and output end.
The first input end of second low-noise amplifier 181 connects the first input of the upstream radio-frequency module 18
End, the second input terminal of second low-noise amplifier 181 connect the second input terminal of the upstream radio-frequency circuit, and described the
The output end of two low-noise amplifiers 181 connects the input terminal of second SAW filter 182, second SAW filter
182 output end is connect with the input terminal of the second RF power amplification pipe 183, the output end of the second RF power amplification pipe 183
Connect the output end of the upstream radio-frequency circuit.
The very low amplifier of low-noise amplifier, that is, noise coefficient, before high frequency or intermediate frequency as all kinds of radio receivers
Set amplifier, and the amplifying circuit of highly sensitive electron detection equipment.
SAW filter (SAW) is the piezoelectric property using piezoelectric material, utilizes input and output transducer
(Transducer) input signal of electric wave is converted into mechanical energy, after treatment, then converts mechanical energy into the signal of electricity,
To reach the unnecessary signal of filtering and noise, promote the target of reception quality, be widely used in various wireless telecommunication systems,
LC resonance circuit is substituted on television set, recorder and GPS receiver, is used for interstage coupling and filtering.It is main
Want function that noise is to filter, it is simpler than traditional LC filter installation, volume is smaller.
RF power amplification pipe is also known as power amplifier (power amplifier), refers under the conditions of given distortion rate, can produce
Maximum power output is given birth to drive the amplifier of a certain load, radio-frequency power amplifier (RF PA) is various wireless transmitters
Important component, in order to obtain sufficiently large radio frequency power output, it is necessary to use radio-frequency power amplifier, radio-frequency power amplification
The key technical indexes of device is output power and efficiency, and in addition to this, the harmonic component in output should also be small as far as possible, with
It avoids generating interference to other channels.
A kind of GSM signal downlink Self-excitation Detection device 10 provided by the embodiment of the utility model, passes through the power detection
Device 12 detects the downlink signal in the downlink radio frequency module 11, and the downlink signal is sent to the central processing unit 13,
To carry out judging whether to generate downlink self-excitation phenomena by the central processing unit 13, if generating downlink self-excitation phenomena, center
Processor 13 controls the disconnection of the switch module 15 connecting with the power circuit 14, to stop the power circuit 14 to whole
The power supply of a GSM signal downlink Self-excitation Detection device 10, the self-excitation link of timely pass hull closure avoid communicating surrounding and cause shadow
It rings, while being also beneficial to the equipment for protecting itself circuit, extend the service life of equipment, save equipment cost and human cost.
The above is preferred embodiments of the present invention, it is noted that for the ordinary skill of the art
For personnel, without departing from the principle of this utility model, several improvements and modifications can also be made, these are improved and profit
Decorations are also considered as the protection scope of the utility model.
Claims (8)
1. a kind of GSM signal downlink Self-excitation Detection device, which is characterized in that including downlink radio frequency module, power detector, center
Processor, power circuit and switch module；
The downlink radio frequency module has first input end and the first output end, and the power detector has input terminal and output
End, the central processing unit have input terminal and output end, and the switch module has first input end, the second input terminal and the
One output end；
First output end of the downlink radio frequency module connects the input terminal of the power detector, the power detector it is defeated
Outlet connects the input terminal of the central processing unit, and it is first defeated to connect the switch module for the output end of the central processing unit
Enter end, the power circuit connects the second input terminal of the switch module, and the first output end of the switch module connects institute
State the first input end of downlink radio frequency module.
2. GSM signal downlink Self-excitation Detection device according to claim 1, which is characterized in that further include that the first sound table is double
Work device；
The downlink radio frequency module also has the second input terminal；
The output end of the first sound table duplexer connects the second input terminal of the downlink radio frequency module.
3. GSM signal downlink Self-excitation Detection device according to claim 2, which is characterized in that further include that rising tone table is double
Work device；
The downlink radio frequency module also has second output terminal；
The second output terminal of the downlink radio frequency module connects the input terminal of the rising tone table duplexer.
4. GSM signal downlink Self-excitation Detection device according to claim 3, which is characterized in that further include upstream radio-frequency mould
Block；
The upstream radio-frequency module has first input end, the second input terminal and output end；
The switch module also has second output terminal；
The output end of the rising tone table duplexer connects the first input end of the upstream radio-frequency module, the switch module
Second output terminal connects the second input terminal of the upstream radio-frequency circuit, the output end connection of the upstream radio-frequency circuit described the
The input terminal of one sound table duplexer.
5. GSM signal downlink Self-excitation Detection device according to claim 3, which is characterized in that the downlink radio frequency module
Including the first low-noise amplifier, the first SAW filter and the first RF power amplification pipe；
First low-noise amplifier has first input end, the second input terminal and output end, first SAW filter
With input terminal and output end, the first RF power amplification pipe has input terminal, the first output end and second output terminal；
The first input end of first low-noise amplifier connects the first input end of the downlink radio frequency module, and described first
Second input terminal of low-noise amplifier connects the second input terminal of the downlink radio frequency module, first low-noise amplifier
Output end connect the input terminal of first SAW filter, the output end of first SAW filter is penetrated with described first
The input terminal of frequency power tube connects, and the first output end of the first RF power amplification pipe connects the first of the downlink radio frequency module
Output end, the second output terminal of the first RF power amplification pipe connect the second output terminal of the downlink radio frequency module.
6. GSM signal downlink Self-excitation Detection device according to claim 4, which is characterized in that the upstream radio-frequency module
Including the second low-noise amplifier, the second SAW filter and the second RF power amplification pipe；
Second low-noise amplifier has first input end, the second input terminal and output end, second SAW filter
With input terminal and output end, the second RF power amplification pipe has input terminal and output end；
The first input end of second low-noise amplifier connects the first input end of the upstream radio-frequency module, and described second
Second input terminal of low-noise amplifier connects the second input terminal of the upstream radio-frequency circuit, second low-noise amplifier
Output end connect the input terminal of second SAW filter, the output end of second SAW filter is penetrated with described second
The input terminal of frequency power tube connects, and the output end of the second RF power amplification pipe connects the output end of the upstream radio-frequency circuit.
7. according to claim 1 to GSM signal downlink Self-excitation Detection device described in 6 any one, which is characterized in that described to open
Pass module is power MOS field effect transistor.
8. GSM signal downlink Self-excitation Detection device according to claim 7, which is characterized in that the power circuit includes
Switching power circuit, voltage-stabilized power supply circuit, stabilized current supply circuit, power power-supply circuit, inverter power circuit, DC-DC power source electricity
Any one in road and protection power source circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820426813.0U CN208209969U (en) | 2018-03-27 | 2018-03-27 | A kind of GSM signal downlink Self-excitation Detection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820426813.0U CN208209969U (en) | 2018-03-27 | 2018-03-27 | A kind of GSM signal downlink Self-excitation Detection device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN208209969U true CN208209969U (en) | 2018-12-07 |
Family
ID=64528827
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201820426813.0U Expired - Fee Related CN208209969U (en) | 2018-03-27 | 2018-03-27 | A kind of GSM signal downlink Self-excitation Detection device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN208209969U (en) |
-
2018
- 2018-03-27 CN CN201820426813.0U patent/CN208209969U/en not_active Expired - Fee Related
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101615958B (en) | Method for detecting isolation between antennas for digital radio repeater system | |
| CN101938306B (en) | Inhibition method of uplink base noise of GSM (Global System for Mobile Communication) digital optical fiber repeater station | |
| CN201298847Y (en) | Frequency-selection and frequency conversion repeater device | |
| CN208094557U (en) | A kind of GSM signal uplinks Self-excitation Detection device | |
| CN208209969U (en) | A kind of GSM signal downlink Self-excitation Detection device | |
| CN101594710B (en) | Automatic shut-off method for uplink of TD repeater | |
| CN202269021U (en) | Multi-system access platform for airport communication | |
| CN201947265U (en) | Wireless signal security device for an Internet of things remote meter reading system | |
| CN208094556U (en) | A kind of TDD-LTE signal downlinks Self-excitation Detection device | |
| CN208209968U (en) | A kind of TD-SCDMA signal downlink Self-excitation Detection device | |
| CN203942528U (en) | A kind of wireless coverage strengthens equipment | |
| CN102036257A (en) | Digital frequency shift companding system | |
| CN201957247U (en) | Automatic switching WLAN (wireless local area network) bidirectional amplifier device | |
| CN101132216A (en) | Microwave repeater station and communication method based on SCDMA microwave repeater station | |
| CN103619028A (en) | RFID based TD-LTE signal-double flow indoor distribution monitoring system and method | |
| CN207442846U (en) | Telecommunications bimodulus indoor coverage equipment | |
| CN108494505A (en) | A kind of TD-SCDMA signal downlinks Self-excitation Detection method and system | |
| CN108494502A (en) | A kind of TD-SCDMA signal downlinks Self-excitation Detection method and system | |
| CN108599875A (en) | A kind of TDD-LTE signal downlinks Self-excitation Detection method and system | |
| CN201499316U (en) | Radio-frequency signal indoor repeating device | |
| CN108494503A (en) | A kind of TDD-LTE signal downlinks Self-excitation Detection method and system | |
| CN100349389C (en) | Communication signal bidirection amplifier | |
| CN108521308A (en) | A kind of GSM signal downlinks Self-excitation Detection method and system | |
| CN108494504A (en) | A kind of GSM signal uplinks Self-excitation Detection method and system | |
| CN208489850U (en) | A kind of communication device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20181207 Termination date: 20200327 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |