A kind of high-performance channel simulator automatically controls receiver and its checking deviceTechnical field
The present invention relates to communication technical field, specifically a kind of high-performance channel simulator automatically control receiver andIts checking device.
Background technology
Lifting with the mankind to communication requirement, and support of the country to the communications industry, wireless communication technology are obtainedQuickly development.Radio communication channel environment is complicated, there is the influence communications such as multipath fading, delay extension, Doppler's declineThe characteristic of quality.The wireless communications environment for becoming increasingly complex, difficulty is brought to high-quality wireless communication system is designed and developed.Logical, it is necessary to take into full account the unfavorable factor that wireless channel is present during letter system development.Channel simulator have to wireless channel compared withGood approximate simulation effect, true wireless channel environment is simulated using radio channel simulator, is substantially shorter base station and terminalThe overall development cycle, reduce substantial amounts of field testing.
In the system of channel simulator, three parts are mainly included：Emitter, receiver and main control unit.ReceiverReceive signal and be demodulated into baseband signal.Baseband signal by after a series of algorithm of channel simulations, then is passed by main control unitIt is defeated by emitter.Particular hardware structure and application scenarios are referring to Fig. 1.
During the use of channel simulator, it is typically necessary and reports to channel simulator, the signal power for receiving.ConnectReceipts machine changes the power distribution in receiver path so that channel simulation path is more reasonable, by this by corresponding calculatingMode reaches the optimum Working of channel simulator.
It can be seen that, general channel simulator has a process of preset value, receiver cannot automatic decision identification receive letterNumber size, the power distribution of adaptively changing communication link.
The content of the invention
The purpose of the present invention is to overcome the deficiencies in the prior art, there is provided a kind of without default received signal power, only needs rootIn having calibrated the prior typing main control unit of its optimum power value according to corresponding frequencies, will automatically be adjusted according to the signal magnitude for receivingSection path attenuation reaches the receiver of optimum Working.
To achieve the above object, design kind high-performance channel simulator automatically controls receiver, including main control unit, and it is specialLevy and be：
Also include radio frequency variable attenuation unit, broadband couple device unit, radio demodulating unit, detection unit, operational amplifierUnit, local oscillator unit, main control unit；
Described radio frequency variable attenuation unit, the broadband rf signal from base station or terminal for that will receive is carried outAfter power distribution, retransmit to broadband couple device unit；
Described broadband couple device unit, in the broadband rf signal that will receive >=80% energy is transferred to and penetratesFrequency demodulating unit, and remaining energy is exported to detection unit；
Described radio demodulating unit, for the signal received from broadband coupling unit is demodulated into analog signal I andAnalog signal Q is exported；
Described detection unit, corresponding detection is obtained for carrying out detection to the signal received from broadband coupling unitVoltage, and send to main control unit and compare and missed with the corresponding optimum power value corresponding voltage of record in main control unitPotential difference, the error voltage obtained from main control unit feedback is retransmited to amplifier unit；
Described amplifier unit, for the error voltage value obtained from detection unit, the then radio frequency described in drive controlVariable attenuation unit changes the attenuation of radio frequency variable attenuation unit, and then changes two output ports of broadband couple device unitPerformance number；
Described local oscillator unit, it is controlled for providing corresponding local oscillation signal to radio demodulating unit by main control unit；
Described main control unit, memory cell is provided with it, for storing the optimum power value corresponding to various frequencies, andControl detection unit and local oscillator unit.
The incoming frequency of the radio frequency variable attenuation unit is 0.4~6GHz, -60~+15dBm of input power dynamic.
Described radio frequency variable attenuation unit includes some radio frequency variable attenuators and some radio frequency amplifiers of series connection；
Described broadband couple device unit uses wide-band coupler；The radio frequency that the input connection of wide-band coupler is described is variableThe output end of attenuation units；
Described radio demodulating unit includes a RF demodulator, and distinguishes with two output ends of RF demodulatorThe low pass filter of series connection a, input of RF demodulator connects an output end of the wide-band coupler；
Described local oscillator unit uses local oscillator；The output end of local oscillator connects the another of the RF demodulatorOne input；The input of local oscillator connects an output end of main control unit；
Described detection unit includes an addition for making the diode of wave detector and being connected with the negative electrode of diodeDevice；The anode of described diode connects another output end of the broadband couple device unit；One signal of the adderEnd is bi-directionally connected with a signal end of main control unit；
Described amplifier unit includes operational amplifier, electric capacity, and the inverting input of described operational amplifier divides two-way,Inverting input connects one end of electric capacity all the way, and another road of inverting input connects the output end of the adder；Operation amplifierThe in-phase input end ground connection of device；The output end of operational amplifier point two-way, the connection electric capacity all the way of the output end of operational amplifierThe other end, each potentiometer that another road of the output end of operational amplifier connects in radio frequency variable attenuation unit respectively is remainingExit.
When radio frequency variable attenuation unit receives signal, and successively through broadband couple device unit and detection unit treatment feeding masterAfter control unit, main control unit records its performance number in the memory unit, and according to formula：Optimum power value=Pi-n × decay work(Rate value+m × Po, calculates decay power value, wherein, n is by the radio frequency variable attenuator connected in radio frequency variable attenuation unitQuantity, by the quantity of radio frequency amplifier connected in radio frequency variable attenuation unit, Pi is the input work of broadband couple device unit to mRate, Po is the amplifying power of radio frequency amplifier.
Radio demodulating unit in the receiver is replaced with into frequency spectrograph, and removes the local oscillator list in the receiverUnit, the input signal checked in radio demodulating unit with frequency spectrograph, input signal in described radio demodulating unit=wideOutput signal with coupling unit.
The present invention compared with prior art, without prior default receiving power, can automatically adjust the level of path, it is ensured that connectReceipts machine stabilization in optimal working condition, the features such as with bandwidth, big dynamic, automation, using very easy, essence height,With splendid marketing.
Brief description of the drawings
Fig. 1 is structural representation of the radio channel simulator under working environment.
Fig. 2 is that principle of the invention connects block diagram.
Fig. 3 is circuit connection block diagram of the present invention in embodiment.
Fig. 4 is circuit connection block diagram of the present invention in embodiment.
Fig. 5 connects block diagram to verify the principle of effect of the present invention in the embodiment of the present invention using frequency spectrograph.
Specific embodiment
The present invention is further described in conjunction with accompanying drawing.
Embodiment 1
Referring to Fig. 2, a kind of high-performance channel simulator of the invention automatically controls receiver, including main control unit, and it is specialLevy and be：
Also include radio frequency variable attenuation unit, broadband couple device unit, radio demodulating unit, detection unit, operational amplifierUnit, local oscillator unit, main control unit；
Described radio frequency variable attenuation unit, the broadband rf signal from base station or terminal for that will receive is carried outAfter power distribution, retransmit to broadband couple device unit；Referring to Fig. 3, the radio frequency variable attenuation unit described in this example includes threeRadio frequency variable attenuator and three radio frequency amplifiers, the radio frequency amplifier that each radio frequency variable attenuator is connected described in are formedOne attenuation units, connects again between three attenuation units.
Described broadband couple device unit, in the broadband rf signal that will receive >=80% energy is transferred to and penetratesFrequency demodulating unit, and remaining energy is exported to detection unit；Broadband couple device unit described in this example uses wide-band coupler；The output end of last radio frequency amplifier in radio frequency variable attenuation unit described in the input connection of wide-band coupler；
Described radio demodulating unit, for the signal received from broadband coupling unit is demodulated into analog signal I andAnalog signal Q is exported；Radio demodulating unit described in this example includes a RF demodulator, and with RF demodulator twoThe low pass filter that individual output end is connected respectively, of the input connection wide-band coupler of RF demodulator is defeatedGo out end；
Described local oscillator unit, it is controlled for providing corresponding local oscillation signal to radio demodulating unit by main control unit；Local oscillator unit described in this example uses local oscillator；The output end of local oscillator connects the another of the RF demodulatorIndividual input；The input of local oscillator connects an output end of main control unit；
Described detection unit, corresponding detection is obtained for carrying out detection to the signal received from broadband coupling unitVoltage, and send to main control unit and compare and missed with the corresponding optimum power value corresponding voltage of record in main control unitPotential difference, the error voltage obtained from main control unit feedback is retransmited to amplifier unit；Detection unit described in this example includesOne diode for making wave detector and the adder connected with the negative electrode of diode；The anode connection institute of described diodeState another output end of broadband couple device unit；One signal end of the adder is two-way with a signal end of main control unitConnection；
Described amplifier unit, for the error voltage value obtained from detection unit, the then radio frequency described in drive controlVariable attenuation unit changes the attenuation of radio frequency variable attenuation unit, and then changes two output ports of broadband couple device unitPerformance number；Amplifier unit described in this example includes operational amplifier, electric capacity, the inverting input of described operational amplifierTwo-way, inverting input is divided to connect one end of electric capacity all the way, another road of inverting input connects the output end of the adder；FortuneCalculate the in-phase input end ground connection of amplifier；The output end of operational amplifier point two-way, the output end of operational amplifier connects all the wayThe other end of electric capacity is connect, another road of the output end of operational amplifier connects each current potential in radio frequency variable attenuation unit respectivelyThe remaining exit of device；
Described main control unit, memory cell is provided with it, for storing the optimum power value corresponding to various frequencies, andControl detection unit and local oscillator unit.
In this example, the incoming frequency 0.4~6GHz of scope of channel simulator receiver, input power dynamic -60~+15dBm。
Designed and developed the stage in the present invention, the corresponding optimum power value of good each frequency is calibrated first.Now with 1GHz receiversAs a example by during optimum Working, the input power of its correspondence radio demodulating unit is 0dBm, and 0dBm is converted into corresponding controlWord is stored in main control unit.Because frequency is smaller on influence of the invention, therefore by taking frequency as an example：
In radio frequency variable attenuation unit, the scope of the adjustable attenuation of each radio frequency variable attenuator is 0~30dB, thenThe gain that each radio frequency amplifier is fixed is 20dB；
When receiver receives signal, main control unit note performance number is Pi ∈ [- 60 ,+15], and radio frequency is variable in this example declinesSubtract the fixation that unit employs the radio frequency amplifier employed in 3 radio frequency variable attenuators and 3 radio frequency amplifiers, and this exampleGain be 20dB, therefore according to formula：Optimum power value=Pi-3 × decay power value+3 × 20, can calculate decay powerValue ∈ [0 ,+25], decay power value can meet design requirement in the range of 0~30dB.
When receiver receives -60dBm input signals, detection unit can automatically adjust optimum power value and detecting circuit itBetween error, the error pass through after amplifier element integral adjust variable attenuator attenuation, until broadband couple device unit exportTo radio demodulating unit power stability to 0dBm optimum power values；
When receiver receives+15dBm input signals, same detection unit can compare error voltage, most receiver at lastStabilization is in optimum Working.
Equally, change other input signal powers, change other frequencies, inventive receiver can automatically adjust performance number,Until receiver stabilization is in optimum Working.
Embodiment 2
This example is substantially the same manner as Example 1, and simply described radio frequency variable attenuation unit is slightly adjusted, referring to Fig. 4, this exampleIt is middle to use three radio frequency variable attenuators and 4 radio frequency amplifiers, first radio frequency variable attenuator to be sequentially connected in series second and penetrateFrequency variable attenuator, first radio frequency amplifier, the second radio frequency amplifier, the 3rd radio frequency variable attenuator, the 4th radio frequencyAmplifier, the 5th radio frequency amplifier.
Of course for some damages of big signal to receiving circuit are prevented, first radio frequency variable attenuator position is constant,Radio frequency variable attenuator and the adjustable change place of radio frequency amplifier below, namely first radio frequency variable attenuator are sequentially connected in seriesOne radio frequency amplifier, the second radio frequency amplifier, second radio frequency variable attenuator, the 4th radio frequency amplifier, the 5th penetrateAudio amplifier, the 3rd radio frequency variable attenuator.
In this example, increase an amplifier, the incoming frequency 0.4~6GHz of scope of channel simulator receiver, input work- 60~+15dBm of rate dynamic.
In the stage of designing and developing, the corresponding optimum power value of good each frequency is calibrated first.Now by taking 2GHz frequencies as an example, its is rightAnswer the input power of radio demodulating unit for 0dBm, 0dBm is converted into corresponding control word and is stored in main control unit.Due to frequencyRate is smaller on influence of the invention, therefore by taking a frequency as an example：
In radio frequency variable attenuation unit, the scope of the adjustable attenuation of each radio frequency variable attenuator is 0~`0dB, thenThe gain that each radio frequency amplifier is fixed is 15dB；
When receiver receives signal, main control unit note performance number is Pi ∈ [- 60 ,+15], according to formula：Optimal work(Rate value=Pi-3 × decay power value+4 × 15, can calculate decay power value ∈ [0 ,+25], and decay power value is in 0~30dBIn the range of, design requirement can be met.
When receiver receives -60dBm input signals, detection unit can automatically adjust optimum power value and detecting circuit itBetween error, the error pass through after amplifier element integral adjust variable attenuator attenuation, until broadband couple device unit exportTo radio demodulating unit power stability to 0dBm optimum power values；
When receiver receives+15dBm input signals, same detection unit can compare error voltage, most receiver at lastStabilization is in optimum Working.
Embodiment 3
Referring to Fig. 5, in order to prove effect of the invention, the circuit to present invention design is verified below, specific wayIt is as follows：
The corresponding optimum power value of channel simulator receiver optimum state has been calibrated first.With 1GHz optimum power valuesAs a example by 0dBm.The signal received with signal source analog channel simulator receiver, radio demodulating unit is checked with frequency spectrographInput signal, namely broadband couple device unit output signal；The delivery outlet connecting channel simulator receiver of signal source is input intoMouthful, the delivery outlet connection frequency spectrograph input port of the broadband couple device unit of channel simulator receiver, and remove detection unit.
The output frequency in setting signal source is 1GHz again, and power is -60dBm, and modulation bandwidth is 20MHz.Frequency spectrograph is setCentre frequency be 1GHz, with a width of 50MHz, it can be seen that signal spectrum now, frequency spectrograph measurement now the bandwidth of signal andPower, can measure with a width of 20MHz, and power output is 0dBm；
The input power for changing signal source is+15dBm, and other settings are constant, check the signal band that this time-frequency spectrometer is measuredWide and power, it is still 20MHz to measure bandwidth, and channel power is still 0dBm.
Other settings of signal source are constant, and the power output for changing signal source is the arbitrary value in -60dBm~+15dBm, is looked intoThe data that this time-frequency spectrometer is measured are seen, the channel power that discovery measures signal is almost unchanged.
The output frequency of signal source is changed, above step is repeated, it is possible to find arbitrarily change output in -60dBm~+15dBmPower, the signal power that frequency spectrograph is measured can be stablized in optimum power value always under this frequency.
The signal automatic stabilisation that above-mentioned experiment proof receiver of the invention will can be received is in an optimal power.
Apply the present invention to channel simulator receiver, it is obvious that without reporting to channel simulator input signal powerSize, receiver can auto-adjusting circuit, it is ensured that channel simulator is operated in optimum state, very easy to use, regulation and control effectIt is really splendid, have very much practicality.