A kind of frequency agility signal frequency response compensation method based on electrically controlled attenuator
Technical field
The invention belongs to technical field of measurement and test, particularly relate to a kind of frequency agility signal frequency response based on electrically controlled attenuator and compensate
Method.
Background technology
In technical field of measurement and test, power controls typically to have two kinds of methods: auto level control (Auto Level
Control, i.e. ALC) and direct Power Control.Auto level control is a kind of close-loop power control mode, and general employing is born instead
Feedback loop, automatically adjusts to signal power within the specific limits, is allowed to remain one with preset reference power level
Cause, thus ensure the accurate, stable of signal power.Direct Power Control is then a kind of open Loop Power control mode, typically adopts
The power of output signal is directly changed with modulated amplifier or electrically controlled attenuator etc..During the Circuit responce of close-loop power controlling method
Between general in microsecond to millimeter magnitude;And open Loop Power control mode, according to the difference of employing circuit, the response time is in several nanoseconds
To several millimeters.The advantage of close-loop power control mode is that the power accuracy of output signal is high, typically within 1.0dB,
In the case of variation of ambient temperature is little, within the power accuracy index of field calibration is up to 0.3dB.But due to fixed ampllitude loop
Existence, the power of close-loop power control mode is generally difficult to accomplish below musec order switching time.And open Loop Power control
Under mode, owing to not having the response time of controlling of amplitude circuit, its response time is generally solely dependent upon the sound of power control device
Between Ying Shi.
In the case of output signal power index request switching time is the highest, in order to i.e. can guarantee that the quick of output signal
Switching, the power accuracy of output signal when can guarantee that again closed loop, generally use modulated amplifier to realize the power control of signal
System.
Owing to open Loop Power control mode does not has power detection, application condition and integration link, therefore its full range such as to follow
Section, the especially frequency response uniformity under wide-band microwave millimeter wave frequency band is poor, is generally required for being calibrated and compensated for.Existing
Open loop compensating for frequency response theory diagram based on modulated amplifier is as shown in Figure 1.The preset data of power reference and compensating for frequency response
After controlling data summation, be converted to the control voltage of modulated amplifier through DAC-circuit, control the multiplication factor of modulated amplifier,
Thus regulate the power of output signal, it is achieved the frequency response uniformity regulation under full frequency band different frequency.
But existing open-loop power control method based on modulated amplifier, it is slow that shortcoming is in response to speed, due to modulation
The reasons such as the sampling time of device, the time of integration, the response time generally in 500 nanoseconds to 2 musec order, the compensating for frequency response of its correspondence
Time also at musec order, such response speed, it is clear that be unable to reach 10 nanosecond orders frequency agility signal occur control
Requirement.
And frequency agility signal source is the signal generating Instrument that radar, communication and electronic warfare field are conventional, its output signal
Frequency and power are typically smaller than hundred nanosecond orders switching time.The state switching of complete machine hundred nanosecond order to be realized, its plate level shape
State switching generally to complete on ten nanosecond orders.In the shortest time, the auto level control in classical signal source is (i.e.
ALC) speed of loop is the farthest not by far up to the mark, it is therefore necessary to use open loop preset mode to realize in frequency agility signal source
Power controls.
Summary of the invention
For reaching above-mentioned purpose, the present invention provides a kind of frequency agility signal frequency response compensation method based on electrically controlled attenuator,
The method considers the control factor such as data transmission period, digital-to-analogue conversion time, makes the compensating for frequency response all-pass road of circuit respond
Time ensure that at 10 nanosecond orders, can meet state requirement switching time of signal generating apparatus complete machine hundred nanosecond order.
The frequency agility signal frequency response compensation method based on electrically controlled attenuator of the present invention, comprising:
Step 1, calibrates according to corresponding frequency and power in signal source complete machine full frequency band, full power range, builds
The frequency agility signal frequency response calibration array of vertical two dimension;
Step 2, upon power-up, is stored in the frequency agility of described two dimension by calibration data according to the index of described frequency and power
In the respective storage areas of signal frequency response calibration array;
Step 3, when the frequency of frequency agility signal or power change, utilizes master controller according to frequency to be switched to
Rate and power, calibrate in the memory block of array from the frequency agility signal frequency response of described two dimension and take out corresponding calibration data;
Step 4, calculates current corresponding compensating for frequency response data according to the calibration data taken out in step 3, and is led to
Cross digital-to-analogue conversion to send in electrically controlled attenuator, described frequency agility signal is carried out the compensating for frequency response of frequency, power points;
Further, described step 1 includes:
Step 11, calculates, according to preset power flatness data, the compensating for frequency response numerical value that ongoing frequency is corresponding with power points,
This value is as initial calibration value;Then arranging signal source is continuous wave mode, and the input parameter of juxtaposition power reference DAC is current
Power P 0 to be calibrated;
Step 12, in a continuous wave mode, starts calibration, and calibration will be when calibrating success or reaching maximum calibration number of times
Terminate, when calibrating successfully, calibration value is stored in frequency agility signal frequency response calibration array, when calibration reaches maximum calibration number of times
Time, select the frequency response calibration value calibration value as this point of a closest current power P 0 to be calibrated, and this value is stored in agile
Frequently signal frequency response calibration array;Wherein, calibration successfully concretely comprises the following steps:
Step 121, by real output Pi under external power meter acquisition continuous wave state wherein, 1≤i < senior colonel
Quasi-number of times, then calculates the absolute value Pcal=fabs of the difference of described real output Pi and current power P to be calibrated 0
(Pi-P0);
Step 122, compares Pcal and the size of limits of error ErrPowLimit that calibration is specified, if Pcal less than or etc.
In ErrPowLimit, then calibrate successfully, current calibration value is stored in calibration array;
Step 13, for signal source complete machine, frequency step and power stepping according to setting carry out full rate section total power
Section calibration;
Further, described step 4 includes:
Step 41, finds calibrated 2 points in the frequency agility signal frequency response of described signal source complete machine calibrates array
CalP1 and CalP2, and the frequency of CalP1 is less than or equal to Freq, the power frequency less than or equal to Power, CalP2 is more than
Freq, power are more than Power;Wherein, ongoing frequency is Freq, is abbreviated as F, and current power is Power, is abbreviated as P;
Step 42, finds two other CalP3, CalP4, and point at calibrated according to CalP1 and CalP2 2
CalP3, CalP4 meet: the frequency that the frequency of CalP3 is F1, power is P2, CalP4 is F2, power is P1;And CalP1,
The frequency agility signal frequency response calibration value of CalP2, CalP3, CalP4 is respectively D1, D2, D3, D4;
Step 43, is calculated some CalP13, CalP24 according to tetra-calibration points of CalP1, CalP2, CalP3, CalP4,
Wherein CalP13 meets: CalP13 and CalP1, CalP3 2 have same frequency, and the power of CalP13 is current power
Power, calibration value D13 be the power P 1 and P2 according to CalP4, CalP3 2 and current power Power calculated,
Computing formula is:
D13=D1+ (D3-D1) * ((Power-P1)/(P2-P1)),
Wherein CalP24 meets: CalP24 and CalP2, CalP4 2 have same frequency, and the power of CalP24 is current
Power P ower, calibration value D24 is the power P 2 and P1 according to CalP3, CalP4 2 and current power Power is calculated
, computing formula is:
D24=D2+ (D4-D2) * ((Power-P2)/(P1-P2));
Step 44, according to calibration point CalP13, CalP24 of ongoing frequency Freq and acquisition, according to formula D=
((D24-D13)/(F2-F1))*Freq+D13-((D24-D13)/(F2-F1))*F1
Being calculated ongoing frequency calibration value, this current frequency calibration value is current corresponding compensating for frequency response data.
The beneficial effects of the present invention is:
The present invention follows that the compensating for frequency response data of pointwise calibration and side frequency and power points are close and continually varying
Thought, by internal electrically controlled attenuator and drive circuit thereof, can make frequency agility signal while frequency agility, can realize height
The accurate agile of power of precision.
The present invention, based on external perimysium reference power meter, obtains the compensating for frequency response number in full frequency band, the quasi-power bracket of whole school successively
According to, it is deposited in nonvolatile memory, compensating for frequency response data are applied on electrically controlled attenuator by digital to analog converter, logical
Cross the Rapid Variable Design of electrically controlled attenuator 10 nanosecond order, thus realize the fast amplitude change of frequency agility signal.
The present invention can realize recurring of frequency agility signal.By calculating, compensating for frequency response data are pre-deposited frequency response
In compensation memory, when frequency agility signal recurs, can be by the control of agile bus, it is achieved the victory of 10 nanosecond orders
Become attenuator and control the consecutive variations of voltage.
The compensation of the present invention reaches the agile attenuator of nanosecond based on the response time, and the adjustment time of compensating for frequency response is up to 10
Nanosecond order, therefore can realize frequency or the power agile of 10 nanosecond orders, improves the power accuracy of frequency agility signal.
Accompanying drawing explanation
Fig. 1 is the compensating for frequency response theory diagram based on modulated amplifier of the present invention;
Fig. 2 is the compensating for frequency response theory diagram based on electrically controlled attenuator of the present invention.
Detailed description of the invention
The frequency agility signal frequency response compensation method based on electrically controlled attenuator of the present invention, comprising:
Step 1, calibrates according to corresponding frequency and power in signal source complete machine full frequency band, full power range, builds
The frequency agility signal frequency response calibration array of vertical two dimension;
Step 2, upon power-up, is stored in the frequency agility of described two dimension by calibration data according to the index of described frequency and power
In the respective storage areas of signal frequency response calibration array;
Step 3, when the frequency of frequency agility signal or power change, utilizes master controller according to frequency to be switched to
Rate, calibrates in the memory block of array from the frequency agility signal frequency response of described two dimension and takes out corresponding calibration data;
Step 4, calculates current corresponding compensating for frequency response data according to described calibration data, and is passed through digital-to-analogue conversion
Send in electrically controlled attenuator, described frequency agility signal is carried out the compensating for frequency response of frequency, power points.
Further, described step 1 includes:
Step 11, calculates, according to preset power flatness data, the compensating for frequency response numerical value D that ongoing frequency is corresponding with power points,
This value is as initial calibration figure;Then arranging signal source is continuous wave state, and juxtaposition power reference DAC is current merit to be calibrated
Rate P0;
Step 12, in a continuous wave mode, starts calibration, and calibration will be when calibrating success or reaching maximum calibration number of times
Terminate, when calibrating successfully, calibration value D is stored in frequency agility frequency response calibration array, when calibration reaches maximum calibration number of times, choosing
The frequency response calibration value of one closest preset power output is as the calibration value of this point, and this value is stored in frequency agility frequency response calibration
Array;
Step 13, for signal source complete machine, according to frequency step and power stepping carry out full rate section total power section school
Accurate.
In frequency agility signal testing field, it is desirable to the frequency of signal or power switching time are below musec order.?
Radar, electronic countermeasure and technical field of measurement and test, frequency and the power of frequency agility signal typically to reach to receive hundred switching time
Second-time.The shortest compensating for frequency response switching time, use close-loop power control mode the most impossible.Therefore,
In agile signal testing field, typically use the compensating for frequency response circuit shown in Fig. 2.Power reference in figure controls data and frequency response
Compensate the control through high-speed DAC after control data are sued for peace, power reference and compensating for frequency response are converted to the control of electrically controlled attenuator
Voltage processed, by the Rapid Variable Design of the attenuation of electrically controlled attenuator, it is achieved below hundred nanosecond orders of input signal frequency response
Compensate and regulation, thus ensure the power accuracy of output signal.
Calibration algorithm:
Before calibration starts, set the frequency step in complete machine calibration process and power stepping, it is intended that specific error merit
Rate limits of error ErrPowLimit, and according to the frequency range of complete machine and power bracket, determines array big depositing calibration data
Little.
I, at ongoing frequency and power (freq, pow) point, according to preset power flatness data (power flatness data
It is that signal source guaranteed output when agile decays to 0 exports normal compensating for frequency response data), calculate ongoing frequency and power points pair
The compensating for frequency response numerical value D answered, the initial calibration figure that this value is calibrated as this point;
Ii, to arrange signal source be continuous wave mode, and juxtaposition power reference DAC is that current preset power output is (the most to be calibrated
Power) P0;
Iii, obtained after currently practical power output Pi by external power meter, calculate real output Pi now and
The absolute value Pcal=fabs (Pi-P0) of the difference of preset power output P0;
Iv, compare the size of limits of error ErrPowLimit of Pcal and calibration, if Pcal is less than or equal to
ErrPowLimit, it is believed that this point is calibrated successfully after circulation has calibrated i time, is stored in calibration array by current calibration value D
In, terminate the calibration of ongoing frequency power points;
V, otherwise, when Pcal is more than ErrPowLimit and 1≤i < maximum calibration number of times, if Pi is more than P0, then will
Current alignment numerical value D deducts correction value StepPowCal;If Pi is less than P0, then by current alignment numerical value D plus correction value
StepPowCal, then sends into the new calibration value D obtained after calculating in agile adjustable attenuation DAC.Again obtain now
Power output Pi, forwards iii to.
Note: the above step for one point (freq, pow) of calibration, for signal source complete machine, in corresponding power bracket
In (example :-10dBm-30dBm) frequency range (example: 100MHz-20GHz), according to certain power stepping (example: 5dBm) and frequency
Rate stepping (example: 200MHz) carries out the calibration of full rate section total power section.
Backoff algorithm:
Ongoing frequency is Freq, and current power is Power, and ongoing frequency and power at calibrated band limits and
In power bracket.
Calibrated frequency and power is found to be respectively less than or equal to and greatly in the array of complete machine frequency agility frequency response calibration
In 2 CalP1 and CalP2 of Freq and Power, make the frequency of CalP1 (F1, P1) and power less than or equal to Freq and
Power, makes the frequency of CalP2 (F2, P2) and power be more than or equal to Freq and Power;
Two other CalP3, CalP4, their frequency and merit is found at calibrated according to CalP1 and CalP2 2
Rate is respectively (F1, P2) and (F2, P1);
The agile frequency response calibration value of corresponding CalP1, CalP2, CalP3, CalP4 point is D1, D2, D3, D4;
According to four calibration points being currently found, be calculated other CalP13, CalP24 at 2, wherein CalP13 and
CalP1, CalP3 2 have same frequency, and power is power P ower that current complete machine is to be exported, and calibration value D13 is basis
Power P 1 and P3 that CalP1, CalP3 are 2 and current power Power calculated D13=D1+ (D3-D1) *
((Power-P1)/(P2-P1)), same principle D24=D2+ (D4-D2) * ((Power-P2)/(P1-P2));
Ongoing frequency is Freq, and frequency and calibration value that CalP13, CalP24 are 2 are (F1, D13), (F2, D24), with
D13 and D24 same principle is calculated ongoing frequency calibration value D=((D24-D13)/(F2-F1)) * Freq+D13-((D24-
D13)/(F2-F1))*F1。
In the range of complete machine full frequency band, full preset power, take to disclosure satisfy that between frequency and the power of frequency response index request
Every, set up a two-dimentional frequency agility signal frequency response calibration array to store calibration data.During start, by above-mentioned data according to frequency
Rate and power index are stored in corresponding memory block;When the frequency of frequency agility signal or preset power change, main control
Device, according to the frequency that will switch to, takes out corresponding compensating for frequency response data from compensating for frequency response data storage area, calculates and works as
The compensating for frequency response data of front correspondence, send into electrically controlled attenuator and drive in DAC, thus realize ongoing frequency, the frequency response of power points
Compensate, it is ensured that the frequency response index of frequency agility signal.
Certainly, the present invention also can have other various embodiments, in the case of without departing substantially from present invention spirit and essence thereof, ripe
Know those skilled in the art to work as and can make various corresponding change and deformation according to the present invention, but these change accordingly and become
Shape all should belong to the protection domain of appended claims of the invention.