CN2764070Y - Radio short wave non-metal long distance transmission system from short wave receiving antenna to receiver - Google Patents
Radio short wave non-metal long distance transmission system from short wave receiving antenna to receiver Download PDFInfo
- Publication number
- CN2764070Y CN2764070Y CNU2005201122746U CN200520112274U CN2764070Y CN 2764070 Y CN2764070 Y CN 2764070Y CN U2005201122746 U CNU2005201122746 U CN U2005201122746U CN 200520112274 U CN200520112274 U CN 200520112274U CN 2764070 Y CN2764070 Y CN 2764070Y
- Authority
- CN
- China
- Prior art keywords
- circuit
- optical
- laser
- receiver
- signal
- 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 - Lifetime
Links
Images
Abstract
The utility model relates to a radio short wave non-metal long distance transmission system used from short wave receiving antennas to a receiver, which comprises a transmitting device, a receiving device and optical fibers connected between the transmitting device and the receiving device. The transmitting device is provided with an optical transmitter and a multipath analog signals multiplex circuit whose input terminal is connected with a plurality of antennas. The output terminal of the multipath analog signal multiplex circuit is connected with the optical transmitter. The optical transmitter comprises a laser modulator, a temperature detector, an automatic temperature control circuit, a full range direct predistortion circuit, a receiving device and a multipath analog signal demultiplexing circuit, wherein the laser modulator is connected with the output terminal of the multipath analog signals multiplex circuit, and is used for modulating output radio frequency signals into light signals; the temperature detector is positioned on the surface of the laser modulator to detect the temperature of the laser modulator; the automatic temperature control circuit controls a freezer to refrigerate the laser modulator according to the temperature detected by the temperature detector; the full range direct predistortion circuit is arranged before the laser modulator; the receiving device is provided with an optical receiver connected with an optical fiber circuit; the multipath analog signal demultiplexing circuit is connected with the output terminal of the optical receiver.
Description
Technical field
The utility model relates to a kind of wireless transmission transmission system, and particularly a kind of short-wave receiver antenna is to the nonmetal distance transmission system of radio shortwave of receiver.
Background technology
Short wave communication is historical radio communication means the most remote, it have equipment simple, set up characteristics such as quick, that communication distance is far away, mobility and survivability are strong, application along with Anti-Jamming Techniques such as self adaptation, frequency hoppings, short wave communication has been brought into play crucial effects in great military activities such as training for preparedness against war, military exercises, edge sealing control limit, anti-terrorism stability maintenance, rescue and relief work, it is one of main means of communication of army's strategy, campaign, tactical action commander, sometimes or even unique means of communication, be regarded as " trump card " of military communication.
As everyone knows, the short wave communication antenna is the important component part of Shortwave Communication System.In recent years, the short wave communication technical development is rapid, the performance of short-wave radio set improves constantly, and the organizational form of short wave communication is networking day by day, thus short-wave antenna has been proposed the new demand of broadband, omnirange, high-gain.But aerial network transmission manner development relatively lags behind, and my army can't form remote, networked transmission means still being modes such as traditional twin lead, cable with short-wave antenna to the transmission of transceiver at present.
It is the development trend of signal remote transmission that optical transport network replaces the electrical transmission network.Optical fiber has the advantage that cost is low, signal attenuation is little, reliability is high for cable, and therefore all kinds of remote transmission networks such as the cable television network of broadcasting and TV, the communication network of telecommunications etc. adopt the mode of Optical Fiber Transmission entirely.
Militarily, as the transmission medium of short-wave antenna, can avoid EMP/T Bomb that communication equipment is disturbed and destruction with optical fiber to transceiver.The pulse energy of the EMP/T Bomb mainly induction of the metal by antenna, cable is burnt the protective devices such as fuse, discharge tube of electric power system, communication equipment input, makes power supply and communication system work interruption.Be interference and the destruction that prevents electromagnetic pulse, can adopt safeguard procedures such as shielding, isolation, filtering, reduce the electromagnetic pulse component of sensing in the electronics system as far as possible according to different situations.Also can take multiple measure that EMP/T Bomb is carried out integrated protection, for example,, can adopt the strong electronic devices and components of anti-electromagnetic interference capability for the electronic equipment of some cores; Communication line adopts optical fiber to replace traditional cable or the like as far as possible.These safeguard procedures can reduce the destructive power of killing and wounding of EMP/T Bomb greatly.Therefore exploitation and development radio shortwave nonmetal (optical fiber) distance transmission system will be to improving army's shortwave fixed station communication quality and usefulness, and the flexibility of enhancing network organization, survivability etc. produce far-reaching influence.
The technology relevant with the utility model is CN1127056A disclosed " method that cellular system and transmission cell phone are given the sub-district ", wherein, between a plurality of base station units and respective antenna unit, utilize optical fiber to communicate, a frame generator/multiplexer is supplied with in Microcell communication output, a digital modulation laser is supplied with in the output of frame generator/multiplexer, and the output of laser sends the far-end antenna element to by optical fiber.Far-end antenna element tap Microcell communication signal offers digital to analog converter then, and a power amplifier is supplied with in the output of digital to analog converter, and power amplifier is connected to main antenna.R F signal from mobile unit is received by main antenna and diversity antenna.Received signal is through filtering, digitlization, and multiplexing back returns to the base station by optical fiber, and the strongest signal is selected for use by the base station.
Above-mentioned " method that cellular system and transmission cell phone are given the sub-district " patented technology is unsuitable for the transmission of the how secondary short-wave antenna of army to transceiver, because what above-mentioned patented technology solved is the signal transmission issues of base station to antenna array, its frequency range is narrow, and do not consider effective transmission (base station is only selected peak signal for use), therefore can not to the transmission of transceiver, guarantee to transmit without distortion the multichannel RF signal that short-wave receiving antenna receives in the 2-30MHZ frequency range at the how secondary short-wave antenna of army to all signals.
To the transmission of transceiver, essential solve following technical problem at the how secondary short-wave antenna of army:
1) the transmitted frequency scope is 2-30MHz, the dynamic range multiple signals greater than 100dB without distortion;
2) because the environment that system uses is special, so require apparatus adaptability to be eager to excel, the temperature accommodation that promptly requires laser device is at-50 ℃ to+70 ℃;
Summary of the invention
The purpose of this utility model provides the radio shortwave nonmetal distance transmission system of a kind of short-wave receiver antenna to receiver.
Above-mentioned purpose of the present utility model is achieved in that the radio shortwave nonmetal distance transmission system of a kind of short-wave receiver antenna to receiver, it is characterized in that comprising:
Transmitter has multichannel analog signals multiplex circuit and optical sender that its input connects multiple antenna, and the output of described multichannel analog signals multiplex circuit connects optical sender, and described optical sender comprises:
A laser modulator connects the output of multichannel analog signals multiplex circuit and the radiofrequency signal of output is modulated into light signal,
One is positioned at the laser modulator surface detecting the Temperature Detector of its temperature,
The automatic temperature-adjusting control circuit that the temperature control refrigerator that detects according to Temperature Detector freezes to laser modulator;
The direct predistortion circuit of full frequency band that is arranged on before the laser modulator;
Receiving equipment has the optical receiver that connects fibre circuit, with the multichannel analog signals signal demultiplexing circuit that is connected the optical receiver output;
Article one, be arranged on the fibre circuit between described optical sender output and the optical receiver input.
Wherein, described multichannel analog signals multiplex circuit is a FDM circuit.
Wherein, described optical sender also comprises: connect the optical power detector that the laser modulator output detects its power output; And the luminous power automatic control circuit of controlling the laser modulator bias current according to the testing result of optical power detector.
Wherein, the direct predistortion circuit of described full frequency band comprises the second-order distortion generator and the third order distortion generator of cascade.
Wherein, described multichannel analog signals signal demultiplexing circuit is a frequency division demultiplexing circuit.
Wherein, described optical receiver comprises the variable attenuator that is arranged on pass receiver end.
The utlity model has following technique effect:
1) by the automatic temperature-adjusting control circuit to the laser modulator temperature controlling, make short-wave antenna of the present utility model to the nonmetal distance transmission system of radio shortwave of transceiver can be effectively worked-50 ℃ to+70 ℃ ambient temperatures;
2) by the direct predistortion circuit of full frequency band was set before laser, produce second-order distortion and even-order distortion product, with third order distortion and odd-order distortion product, directly laser is being modulated then, can balance out the distortion of laser greatly, be the multiple signals of 2-30MHz thereby can transmit dynamic range without distortion greater than 100dB, frequency range.
The utility model is elaborated with specific embodiment below in conjunction with accompanying drawing.
Description of drawings
Fig. 1 is the schematic diagram of short-wave antenna of the present utility model to the nonmetal distance transmission system of radio shortwave of transceiver;
Fig. 2 is the theory diagram of the multichannel analog signals multiplex circuit of transmitter among Fig. 1;
Fig. 3 is the theory diagram of the optical sender of transmitter among Fig. 1;
Fig. 4 is the theory diagram with optical sender of predistortion correction;
Fig. 5 is the theory diagram that predistortion correction adopts the full frequency band predistortion circuit;
Fig. 6 is the theory diagram of the optical receiver of the receiving equipment among Fig. 1;
Fig. 7 is the theory diagram with optical receiver of level adjustment of the present utility model;
Fig. 8 is the theory diagram of the multichannel analog signals demultiplexing circuit of receiving equipment among Fig. 1;
Fig. 9 is the schematic diagram of the nonmetal distance transmission system of another kind of radio shortwave of the present utility model.
Embodiment
At first referring to short-wave receiver antenna of the present utility model shown in Figure 1 schematic diagram to the nonmetal distance transmission system of radio shortwave of receiver.The nonmetal distance transmission system of radio shortwave of the present utility model comprises:
Receive the multiple antenna 1 of a plurality of short-wave radio signals respectively;
A laser modulator, the output that connects the multichannel analog signals multiplex circuit to be being modulated into light signal (referring to Fig. 3) to the described road signal that closes,
One is positioned at the Temperature Detector (referring to Fig. 3) of laser modulator surface to detect its temperature,
The automatic temperature-adjusting control circuit (referring to Fig. 3) that the temperature control refrigerator that detects according to Temperature Detector freezes to laser modulator;
The direct predistortion circuit of full frequency band (referring to Fig. 5) that is arranged on before the laser modulator;
Receiving equipment 5, has the optical receiver (referring to Fig. 6 and Fig. 7) that connects fibre circuit, with multichannel analog signals signal demultiplexing circuit (referring to Fig. 8), described optical receiver sends optical sender via fibre circuit light signal converts to and closes the road signal, and it is shunting sign that described multichannel analog signals demultiplexing circuit will close road signal demultiplexing;
The receiver 5 that a plurality of and described antenna 1 is corresponding is used for receiving respectively described shunting sign, wherein the short-wave radio frequency signal that receives corresponding to respective antenna of each shunting sign;
Article one, be arranged on the fibre circuit 3 between described optical sender and the optical receiver.
Referring to Fig. 1, the utility model is divided into transmitting apparatus 2 and receiving equipment 3 two parts, and is by (single core) optical fiber that the multichannel RF signal that how secondary short-wave receiving antenna receives in the 2-30MHZ frequency range is undistorted, and long Distance Transmission is to the destination.According to the real work situation, this system is by transmitting 5 secondary reception antenna Design of Signal simultaneously at present.Because the frequency range of five road signals (dynamic range of input signal is greater than 100dB) is 2-30MHz, direct mixed transport is so employing frequency division multiplexing mode is transmitted five road signals simultaneously.
The utility model uses multichannel analog signals multiplex circuit shown in Figure 2 to realize frequency division multiplexing.The multichannel analog signals multiplex circuit comprises many channels, the input of its every channel connects a width of cloth short-wave receiving antenna, every channel comprises: and the short-wave radio frequency signal bandpass filter (2～30MHZ), be used for the interference signal outside filtering 2～30MHZ short-wave signal; Frequency mixer is modulated to predetermined band with 2～30MHZ short-wave signal; Modulated filter is used for the signal outside the described predetermined band of filtering.
The multichannel analog signals multiplex circuit also comprises radio-frequency (RF) mixing, is used for the signal multiplexing Cheng Helu radiofrequency signal with the different predetermined band of each bar channel output.
In addition, the multichannel analog signals multiplex circuit also comprises pilot source, is used for adjusting automatically the gain of whole transmission system, just adjusts the gain of radiofrequency signal in every channel transmission automatically.
The multichannel analog signals multiplex circuit is in the front end of system, and noise factor, dynamic range, frequency accuracy, the channel isolation of whole system had very large influence.Can address these problems in the following ways for this reason.
1. adopt low noise integrated monolithic amplifier (not shown), the impedance matching network of modelled signal input amplifies prime and has best noise factor, guarantees that the system noise index is up to standard.
2. rationally arrange the circuit gain of circuit at different levels.
The sensitivity of system and non-linear index are conflicting, improve the sensitivity that circuit gain can improve system, but the nonlinear distortion of system can increase again.Because the terminal receiver of system has very high sensitivity, therefore, it is low slightly but reasonable that gain is arranged.
3. adopt dynamic greatly, high linear active frequency mixer, effectively suppress all kinds of distortions.
4. adopt the high stable constant-temperature crystal oscillator as local oscillation circuit, guarantee that the output signal frequency precision reaches 2Hz.
5. in five channels, adopt five modular power sources to be the power supply of this passage respectively.
6. use independently signal processing channel of five of metal box encapsulation, make each interchannel have high-isolation.
Theory diagram referring to the optical sender of transmitter shown in Figure 3.Optical sender mainly comprises a laser modulator, is used for the described road signal that closes is modulated into light signal.
Because in laser transmitter, the performance quality of laser modulation device has determined the performance quality of ray machine, and because fiber optic transmission system will transmit 2～30MHZ broadband rf signal, in this frequency range, aerial received signal amplitude difference very big (up to tens dB), therefore high especially to the linearity requirement of laser, the utility model has adopted following technical measures for this reason:
Select at first that background noise is extremely low for use, dynamic range is wanted the laser device of big (being better than 65dB);
Secondly, be provided with Temperature Detector and an automatic temperature-adjusting control circuit of a detection laser modulator temperature, make temperature control refrigerator that the automatic temperature-adjusting control circuit detects according to Temperature Detector refrigerating capacity to laser modulator, thus guarantee laser modulator can be in-50 ℃ to+70 ℃ temperature ranges operate as normal;
The 3rd, before laser modulator, be provided with a predistortion correction device (referring to Fig. 4), offset the distortion of laser by producing multistage distortion and odd even rank distortion product.Thereby transmitting dynamic range without distortion is the multiple signals of 2-30MHz greater than 100dB, frequency range.
Realize that predistortion correction can have multiple mode, wherein a kind of mode is the light feedforward compensation, this light feedforward compensation mode utilizes photo-detector that the signal S (not distortion) that the signal (S+m) of the band distortion of laser transmission detects and sends without laser is subtracted each other the error signal m that obtains distortion, represent this error signal back-modulation of laser distorted characteristic to arrive the identical laser of another characteristic again, obtain a light beam of representing distorted characteristic and with the addition of main path signal light beam, from the main road light beam, balance out distorted portion, to reach the purpose that improves main road light beam linearity.The shortcoming of light feedforward compensation is the cost height.
Another kind of mode is traditional signal of telecommunication pre-distortion compensated, in this pre-distortion compensated mode, the main main channel that partly enters of radiofrequency signal RF, fraction enters subaisle through splitter, the signal of subaisle is divided into two-way through distributor, one the tunnel produces second-order distortion and even-order distortion product, and another road produces third order distortion and odd-order distortion product.The nonlinear distortion that each subaisle produces should be identical with laser unintentional nonlinearity distortion amplitude, and phase place is opposite, reach best compensation effect by the amplitude of distortion product and the adjustment of time delay, the two-way distorted signal main road that is added to, again laser is modulated with main path signal addition, with the distortion of compensate for laser unintentional nonlinearity through time delay.
Predistortion correction device of the present utility model is arranged on the direct predistortion circuit of full frequency band (Fig. 5) before the laser modulator.The direct predistortion circuit of this full frequency band is made of the second-order distortion generator and the third order distortion generator of cascade.Main path signal directly enters the second-order distortion generator, produce second-order distortion and even-order distortion product, enter the third order distortion generator again, produce third order distortion and odd-order distortion product, directly laser is modulated then, here the even-order product of Chan Shenging is identical with odd-order product amplitude with the even-order of the intrinsic generation of laser with the odd-order product, phase place is opposite, balances out the distortion of laser greatly, makes optical sender reach a very high index.
The direct pre-distortion compensated of full frequency band of the present utility model also is signal of telecommunication pre-distortion compensated in essence, but compare with traditional signal of telecommunication pre-distortion compensated, do not need signal is carried out special time delay, do not need to carry out the phase place adjustment yet, can not produce the problem of temperature drift, the benefit that also has a maximum simultaneously is exactly that the non-linear distortion products that produces of sort circuit is adjusted by simple, can compensate the laser of a plurality of producers of multiple model, brought very big convenience for tissue production, can drop to the production cost of equipment minimum.
Because the utility model has adopted the direct pre-distortion compensated of full frequency band, make laser can reach good linear index, that is: CSO (combination secondary), CTB (making up three times) and C/N (carrier-to-noise ratio) index, it is stable etc. to avoid generation because of self nonlinearity product to influence system works.
Whole system work is adopted and is exceeded the pattern that height advances, that is: the high-power output of optical sender, and the high luminous power of optical receiver (4-8dBm) input reduces the influence of optical link to system performance index to greatest extent to reach.
Be elaborated below in conjunction with Fig. 3.
The core of optical sender is the DFB laser module, also has power supply, laser bias circuit, power control circuit in addition, and optical detection circuit is used for luminous power and detects the photodetector of controlling with automated power.Optical sender is stablized Output optical power by automatic temperature-adjusting control (ATC), auto light power control (APC) circuit; Signal input back adopts the broadband to amplify, and the five tunnel conversion of signals of logical then light modulation techniques after with frequency division multiplexing are light signal.
The luminous power automatic control circuit:
Because semiconductor laser is very sensitive to variation of temperature, obtain stable light output, automatic control circuit will be arranged.The aging mainly several below aspects of bringing to laser of instability of variation of temperature and device:
1. the threshold current of laser varies with temperature and is rendered as the index law variation, and increases with the aging of device, thereby the luminous power of output is changed a lot.
2. with the rising of temperature and wearing out of device, the electro-optical efficiency of laser reduces, and also causes Output optical power to change.
3. along with the rising of temperature, the peak of the emission wavelength of laser is shifted to long wave.
The effect of control circuit is exactly to eliminate the influence to Output optical power of variations in temperature and device aging, the luminous power of stable output.Because the threshold current of laser and photoelectric conversion efficiency all can change with the aging of temperature and device, therefore, accurately control the Output optical power of laser, should consider from two aspects:
1. control the bias current of laser, make its variation of following the tracks of threshold values automatically, make laser always be biased in best operating state;
2. control the amplitude of the modulated current of laser, make it follow the variation of photoelectric conversion efficiency automatically and change.
The photoelectric conversion efficiency of laser is not very sensitive with variation of temperature under normal conditions.Under situation about reducing cost, simplified control circuit adopts the average optical output power of direct detection laser to control inclined to one side value electric current, thereby keeps the stable of Output optical power.
Automatic temperature-adjusting control (ATC) circuit:
The automatic temperature-adjusting control circuit is made up of frigistor, temperature-sensitive element and control section (not shown).The junction temperature of temperature-sensitive element monitoring laser is compared with the fiducial temperature of setting, and amplifies the control circuit of rear drive refrigerator, changes refrigerating capacity, thereby guarantees that laser works is under stationary temperature.
In order to improve refrigerating efficiency and control precision, refrigeration modes in normal employing of temperature control of laser.Just refrigerator and thermistor are encapsulated in the laser shell, thermistor direct detection junction temperature, refrigerator directly contacts with the PN junction of laser.This mode can be controlled the laser junction temperature in ± 0.5 ℃ scope, thereby makes laser that more constant Output optical power and emission wavelength be arranged.But temperature control mode can not be controlled the influence that produces owing to laser ageing.The control precision of temperature-control circuit not only depends on the design of peripheral circuit, and is subjected to the influence of the encapsulation technology of laser.The temperature, refrigerator that thermistor can reflect the interface and PN junction contact the control precision that all directly has influence on temperature-control circuit such as whether good.
For making the laser steady operation, ATC is necessary, generally the temperature of LD chip is controlled at 25 ℃, and the light emitting power and the nonlinear distortion of laser depend on bias current.Because semiconductor laser is very sensitive to variations in temperature, therefore must be by the output of automated power control unit stable laser, the automated power control unit is the variation that makes its automatic tracking threshold values by the bias current of control laser, makes laser always be biased in best operating state; Control the amplitude of the modulated current of laser simultaneously, make it follow photoelectric conversion efficiency automatically and change.
Fig. 4 schematically shows the theory diagram that the optical sender of predistortion correction circuit is set of the present utility model.When reality is implemented, the parts of carrying out system controlled by computer and condition monitoring and telecommunication can also be set in optical sender.
Fig. 6 shows the optical receiver basic structure of receiving equipment 1 of the present utility model.The core of optical receiver is the PIN pipe, also has power supply, power control circuit, the amplification treatment circuit of optical detection circuit, RF signal etc. in addition.Optical receiver is converted to the signal of telecommunication by the PIN pipe with light signal; Optical receiver has the received optical power deixis; The gain of amplifying circuit should be suitable, and the distortion of the signal of telecommunication that assurance receives is as far as possible little, also needs certain amplitude and be convenient to the multichannel analog signals demultiplexing circuit of back level to Signal Processing; Variable attenuator is used to adjust output level.
Fig. 7 is the concept map of optical receiver of the present utility model, and as can be seen from the figure form substantially by upstream photoelectric tube, low noise amplifier and impedance matching box for optical receiver.Can be provided with temperature-compensation circuit in addition, change by the output level that variations in temperature causes with automatic compensation.
Fig. 8 shows the theory diagram of multichannel analog signals demultiplexing circuit, this multichannel analog signals demultiplexing circuit is corresponding with the multi-channel analog multiplex circuit of transmitter 2, what carry out is the processing opposite with it, therefore omits specifying its structure and operation principle.
This multichannel analog signals demultiplexing circuit includes the high-isolation distributor circuit, adopts dynamic greatly, high linear active frequency mixer, effectively suppresses all kinds of distortions.Local oscillation circuit is selected Zhong Zhen for use, guarantees that output signal has very high frequency stability.
Multichannel analog signals demultiplexing circuit is in the end of system, and frequency accuracy, the channel isolation of whole system also had bigger influence.Therefore adopt following method to address these problems.
1. adopt dynamic greatly, high linear active frequency mixer, effectively suppress all kinds of distortions.
2. adopt the high stable constant-temperature crystal oscillator as local oscillation circuit, guarantee that the output signal frequency precision reaches 2Hz.
3. in five signal processing channels, adopt five modular power sources to be the power supply of this passage respectively.
4. use independently signal processing channel of five of metal box encapsulation, make between each channel to have high-isolation.
Fig. 9 shows the schematic diagram of the nonmetal distance transmission system of another kind of radio shortwave of the present utility model.
Because the special instructions for use and the service condition of system, the sensitivity of signal is required very high (less than 1 μ V), consider just have only and handle again after adopting the small signal amplifier that uses the ultra-low noise coefficient earlier signal to be amplified by normal.From principle is feasible, but finds that when system design is calculated bigger problem is arranged.
At first, be noise factor problem (the optical fiber link noise is not done narration here), noise factor is meant the degree that signal degenerates through carrier-to-noise ratio behind the amplifier, that is: noise factor=input signal carrier-to-noise ratio/output signal carrier-to-noise ratio.If one does not have the carrier signal of noise to amplify through amplifier, at this moment carrier-to-noise ratio (C/N)=incoming signal level-noise factor-Noise Background, wherein, Noise Background is the desirable thermal noise power under corresponding noise bandwidth, unit is dBmV or dB μ V, incoming signal level unit also should be consistent, and the conversion relation between dBmV of unit and the dB μ V of unit is: 0dBmV=60dB μ V.The factor that influences carrier-to-noise ratio is a lot, and it is in different size.The composition of native system overall noise factor: Nf
*Be noise factor, system's overall noise factor (this overall noise factor is the noise factor of the active device in the system equipment) is by (Nf2, Nf3, Nf4, Nf5, Nf6) 6 parts compositions such as the Nf1 of broadband ultra-low noise amplifier.
Analog signal is every all will to add up through an amplifier noise, if N identical amplifier cascade arranged, then total carrier-to-noise ratio (C/N) 0 is: (C/N) 0=(C/N) I-lgN.The present ultra-low noise coefficient amplifier that adopts usual manner (need not freeze) to make, noise factor can be accomplished about 1.5dB, but its cost is very high, and manufacture difficulty is also big.
Secondly, be dynamic range problem, the use of ultra-low noise coefficient amplifier not only can bring certain noise to system, also inevitably can reduce the input dynamic range of signal, and this is that characteristic by ultra-low noise coefficient amplifier is determined.Ultra-low noise coefficient amplifier is under the prerequisite of protecting positive noise objective, and the electric current of its work is all very little, is beneficial to the thermal noise of suppression device.But because the electric current of work is very little, simultaneously just make dynamically being restricted of input signal, generally speaking, the maximum input level of ultra-low noise coefficient amplifier can not surpass 70dB yet, and too high signal will make the amplifier overload even burn.
The 3rd, be opposing outside impact of strong electromagnetic (ELECTROMAGNETIC BOMB etc.) problem, the use of ultra-low noise coefficient amplifier is subjected to the dynamic constraints of input signal, too high signal will make the amplifier overload even burns.Therefore, its reliability is particularly worrying when being subjected to outside impact of strong electromagnetic.
In view of the appearance of these problems, for the use that reaches system and the needs of high reliability.The utility model proposes a brand-new system schema shown in Figure 9.
In optical fiber remote transmission system shown in Figure 9 (only having shown light path part), optical sender comprises wide band radio-frequency information source filter and laser modulator; Optical receiver comprises optical-electrical converter and wide band radio-frequency information source output translator, can learn thus on the RF radio-frequency channel of system's optical sender and optical receiver, saved two ultra-low noise coefficient amplifiers, will make the noise objective of system improve 3dB (ultra-low noise coefficient amplifier Nf presses 1.5dB and considers) at least in theory.The dynamic range of input signal also owing to there is not the influence of ultra-low noise coefficient amplifier, improves, only the dynamic effects of Stimulated Light device greatly.Do not use ultra-low noise coefficient amplifier, also just make the influence that is subjected to outside impact of strong electromagnetic obtain reducing greatly, improved the ability that system resists outside impact of strong electromagnetic greatly, reliability is improved greatly.But owing to saved ultra-low noise coefficient amplifier, can the gain of system will be subjected to certain influence, also meet the requirements of problem with regard to the modulation sensitivity that has brought laser.The utility model addresses this problem by following two technical measures.
1) select to satisfy the following Laser Devices that require:
At first, the laser works frequency band is wide, background noise is extremely low, dynamic range big (being better than 65dB);
Secondly, laser environment adaptitude is strong, just the temperature accommodation of laser device wide (50 ℃ to+70 ℃);
Once more, laser must have very high modulation sensitivity and good linear index, that is: CSO (combination secondary), CTB (make up three times) and C/N (carrier-to-noise ratio) index, avoid self nonlinearity product generation and influence system works and stablize etc.
2) light signal of optical sender output high-power, optical receiver receives the light signal of high luminous power.Owing in optical sender, do not adopt the RF amplifier, therefore the transmission gain of system (when receiver luminous power-2dB imports) will reduce about 10-15dB, for the transmission gain that do not make system low excessively, do not increase amplifier again and reduce system noise factor dynamically and under the prerequisite of reliability, the utility model has adopted the mode that changes the optical receiver received optical power to compensate owing to do not adopt the reduction of the transmission gain that amplifier brings, promptly exceed the pattern that height advances, the output of optical sender high power, the receiver input optical power is greater than+2dB, the 6dB gain that the system that remedies reduces.Adopt this scheme through experiment, every technical indicator of system all reaches designing requirement, by the actual needs that use full up foot use.
Radio shortwave of the present utility model nonmetal (optical fiber) distance transmission system has solved long-term puzzlement army preferably, the signal that the short-wave receiver antenna receives is difficult for problems such as remote biography, poor signal quality, particularly change the networking model of traditional short wave communication, strengthened the flexibility of network organization and the ability of survivability aspect.
Need to prove that although above explanation is to describe of the present utility modelly via transmitter 2, light circuit 3, receiving equipment 4 a to transmission direction of receiver 5 with short-wave antenna 1, the utility model is not limited to such one-way transmission.The utility model also can be with opposite transmission direction transmitting radio frequency signal, just in the transmitter 2 of Fig. 1, be provided with and the identical receiving system of receiving equipment 4 structures, and in the receiving equipment 4 of Fig. 1, be provided with and the identical emitter of transmitter 2 structures, thereby the bi-directional RF signal of realizing transceiver and aerial array 1 transmits.
Claims (6)
1. a short-wave receiver antenna is characterized in that comprising to the nonmetal distance transmission system of radio shortwave of receiver:
Transmitter has multichannel analog signals multiplex circuit and optical sender that its input connects multiple antenna, and the output of described multichannel analog signals multiplex circuit connects optical sender, and described optical sender comprises:
A laser modulator, the output that connects the multichannel analog signals multiplex circuit to be being modulated into light signal to the radiofrequency signal of being exported,
One is positioned at the laser modulator surface detecting the Temperature Detector of its temperature,
A temperature that detects according to Temperature Detector, the control refrigerator is to the automatic temperature-adjusting control circuit of laser modulator refrigeration;
The direct predistortion circuit of full frequency band that is arranged on before the laser modulator;
Receiving equipment has the optical receiver that connects fibre circuit, with the multichannel analog signals demultiplexing circuit that is connected the optical receiver output;
Article one, be arranged on the fibre circuit between described optical sender output and the optical receiver input.
2. the nonmetal distance transmission system of radio shortwave according to claim 1 is characterized in that described multichannel analog signals multiplex circuit is a FDM circuit.
3. the nonmetal distance transmission system of radio shortwave according to claim 1 is characterized in that described optical sender also comprises:
Connect the optical power detector that the laser modulator output detects its power output; And
Control the luminous power automatic control circuit of laser modulator bias current according to the testing result of optical power detector.
4. the nonmetal distance transmission system of radio shortwave according to claim 1 is characterized in that, the direct predistortion circuit of described full frequency band comprises the second-order distortion generator and the third order distortion generator of cascade.
5. the nonmetal distance transmission system of radio shortwave according to claim 1 is characterized in that, described multichannel analog signals signal demultiplexing circuit is a frequency division demultiplexing circuit.
6. the nonmetal distance transmission system of radio shortwave according to claim 1 is characterized in that, described optical receiver comprises the variable attenuator that is arranged on pass receiver end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2005201122746U CN2764070Y (en) | 2005-07-04 | 2005-07-04 | Radio short wave non-metal long distance transmission system from short wave receiving antenna to receiver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2005201122746U CN2764070Y (en) | 2005-07-04 | 2005-07-04 | Radio short wave non-metal long distance transmission system from short wave receiving antenna to receiver |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2764070Y true CN2764070Y (en) | 2006-03-08 |
Family
ID=36141607
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2005201122746U Expired - Lifetime CN2764070Y (en) | 2005-07-04 | 2005-07-04 | Radio short wave non-metal long distance transmission system from short wave receiving antenna to receiver |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2764070Y (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101577557B (en) * | 2008-05-07 | 2013-08-14 | 朱军 | Short-wave nonmetal remote transmitting system |
| CN105425213A (en) * | 2015-11-02 | 2016-03-23 | 北京无线电测量研究所 | Method and system for meteorological radar long distance radio frequency transmission |
| CN109375697A (en) * | 2018-12-24 | 2019-02-22 | 中国电子科技集团公司第五十八研究所 | A kind of temperature drift correcting and adjusting circuit for second order curvature standard of compensation source |
-
2005
- 2005-07-04 CN CNU2005201122746U patent/CN2764070Y/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101577557B (en) * | 2008-05-07 | 2013-08-14 | 朱军 | Short-wave nonmetal remote transmitting system |
| CN105425213A (en) * | 2015-11-02 | 2016-03-23 | 北京无线电测量研究所 | Method and system for meteorological radar long distance radio frequency transmission |
| CN109375697A (en) * | 2018-12-24 | 2019-02-22 | 中国电子科技集团公司第五十八研究所 | A kind of temperature drift correcting and adjusting circuit for second order curvature standard of compensation source |
| CN109375697B (en) * | 2018-12-24 | 2023-10-20 | 中国电子科技集团公司第五十八研究所 | Temperature drift trimming circuit |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP1443687B1 (en) | Improved VCSEL analog optical link | |
| US9537519B2 (en) | Systems and methods for performing power amplifier bias calibration | |
| Hirata et al. | 5.8-km 10-Gbps data transmission over a 120-GHz-band wireless link | |
| US20040001719A1 (en) | Optical transmission system of radio signal over optical fiber link | |
| CN106850068B (en) | Utilize the double parallel horse in parallel method that once modulator and balanced detector improve microwave photon link dynamic range | |
| CN1240230C (en) | Radio communication base station system including optical advanced base station | |
| CN101296041B (en) | Optical fiber transmission repeater and largely dynamic optical receiving-transmitting module | |
| James et al. | Nonlinearity and noise effects in multi-level signal millimeter-wave over fiber transmission using single and dual wavelength modulation | |
| EP2846602A1 (en) | Mobile communication terminal | |
| CN101043274A (en) | Modulator-free optical millimeter wave generating method and full-duplex optical fiber wireless communication system | |
| Cossu et al. | Long distance indoor high speed visible light communication system based on RGB LEDs | |
| CN2764070Y (en) | Radio short wave non-metal long distance transmission system from short wave receiving antenna to receiver | |
| US20080159749A1 (en) | Optical communication system and optical transmitting apparatus for the same | |
| CN201039190Y (en) | Optical fiber transmission repeater and its highly dynamic optical receiving and transmission module | |
| CN109861717B (en) | Wireless communication signal processing system and method based on FPGA | |
| WO2021056846A1 (en) | Rof communication remote machine and rof system | |
| Williams | Signal processing subsystems for RF photonics | |
| WO2022065905A1 (en) | Method and receiver for receiving optical signal in optical wireless communication system | |
| Kanta et al. | SOI-ring based analog phase processing for chromatic dispersion compensation in A-IFoF Fronthaul | |
| CN108521299B (en) | Optical fiber wireless fusion communication system for multi-scene application and signal processing method | |
| Wake et al. | Design and performance of radio over fibre links for next generation wireless systems using distributed antennas | |
| Zhang et al. | LED nonlinearity impact on frequency modulation signals over visible light communication systems | |
| JPH11122190A (en) | Optical transmitter | |
| Kim | RoF-based mobile fronthaul network implemented by using directly modulated laser | |
| CN2631124Y (en) | Wide-dynamic-range predistortion circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Expiration termination date: 20150704 Granted publication date: 20060308 |
|
| EXPY | Termination of patent right or utility model |