CN104730300B - A kind of measuring device with alc circuit - Google Patents
A kind of measuring device with alc circuit Download PDFInfo
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- CN104730300B CN104730300B CN201310721663.8A CN201310721663A CN104730300B CN 104730300 B CN104730300 B CN 104730300B CN 201310721663 A CN201310721663 A CN 201310721663A CN 104730300 B CN104730300 B CN 104730300B
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Abstract
The invention discloses a kind of measuring devices with alc circuit, alc circuit includes: the input terminal of the input terminal connection alc circuit of variable attenuation unit, output end connects power distributing unit, output end of first output end of power distributing unit as alc circuit, the input terminal of second output terminal tie geophone, the input terminal of wave detector connection logafier, the first input end of logafier connection addition unit, second input terminal of addition unit connects reference voltage, the input terminal of output end connection integrator, the input terminal of integrator connection voltage conversion unit, the adjustable side of voltage conversion unit connection variable attenuation unit;Logafier, addition unit, integrator and voltage conversion unit are realized by a digit chip, and analog-digital converter is equipped between wave detector and logafier, and a digital analog converter is equipped between voltage conversion unit and variable attenuation unit.The temperature stability of alc circuit of the invention is good.
Description
Technical field
The present invention relates to measurements, the field of test technology, more particularly to a kind of measuring device with alc circuit.
Background technique
In measurement, testing field, radio-frequency signal source is a kind of measurement test equipment of frequency microwave worker's indispensability.It penetrates
Frequency source signal is a kind of emission of radio frequency signals device, it can export the continuous wave radiofrequency signal of the parameters such as various frequencies, amplitude,
Certainly various modulated signals, such as FM, AM, PM, IQ, Pulse modulated signal can also be exported.The width of radio-frequency signal source output signal
It spends accuracy and stability is one of important indicator of radio-frequency signal source, and these indexs are usually by alc circuit
(Automatic Level Control automatic level control circuit) is realized.
The Chinese patent application file that number of patent application is 201210539525.3 discloses a kind of radio-frequency signal source 100
Principle, in conjunction with reference attached drawing 1, radio-frequency signal source 100 mainly includes sequentially connected frequency synthesizer circuit 101, automatic electric-level
Control circuit 102, stepping attenuator circuit 103.
The main function of the frequency synthesizer circuit 101 is to generate certain frequency according to the various parameters of user setting
The radiofrequency signal of (fixed frequency or certain frequency range), frequency synthesizer circuit 101 have a variety of implementations, can be by
Phase-locked loop circuit directly constitutes, so point/frequency multiplication after can produce the radiofrequency signal of wider frequency range, with immediate data frequency
The development of rate synthetic technology, using DDS signal source (also referred to as direct digital synthesis technique source or DDFS, Direct Digital
Frequency Synthesis) combine the technology of phase-locked loop circuit more mature, such as the U.S. of Patent No. US8044725
Patent " Signal generator with directly-extractable DDS signal source " discloses this
The radio-frequency signal source that a kind of frequency synthesizer 101 of sample is constituted.
The main function of automatic level control circuit 102 is that the radiofrequency signal for generating frequency synthesizer circuit 101 is stablized
It in certain amplitude, is realized by analog circuit, the Chinese patent of number of patent application 201210530377.9,201210530239.0
Application documents disclose a kind of radio-frequency signal source with automatic level control circuit,.In conjunction with reference attached drawing 2, Fig. 2 shows
A kind of circuit theory of automatic level control circuit 102, including variable attenuator 201, radio frequency amplifier 203, coupler 204,
Resistance 202, wave detector 212, logafier 210, adder 209, capacitor 207, operational amplifier 208, logafier
211, adder 206, exponential amplifier 205.
The input terminal 2A of the variable attenuator 201 accesses the radiofrequency signal that the frequency synthesizer circuit 101 generates, and
Decay to the radiofrequency signal of access, control of the pad value by the input signal of adjustable side (being referred to as control terminal) 2C
The output end 2B of system, variable attenuator 201 exports the stabilization signal after overdamping.The variable attenuator 201 has a variety of
Implementation, such as the Chinese patent application file that number of patent application is 201210530622.6 disclose part of realization
Mode, variable attenuator 201 are usually to be made of PIN diode.
The signal that the radio frequency amplifier 203 exports the variable attenuator 201 amplifies, and is then output to described
Coupler 204.
Input signal is divided into two-way by coupler 204, and straight-through port 2F directly exports radiofrequency signal, and coupling port is then by portion
Point radiofrequency signal is introduced into the wave detector 212, and isolated port is then directly grounded by resistance 202.The effect of coupler 204 is
In the case where minimizing influences radiofrequency signal, the amplitude information of radiofrequency signal is got, coupler 204 can use power
Distributor etc. replaces.
The signal that wave detector 212 sends the coupling port of coupler 204 carries out detection, gets the amplitude letter of signal
Breath generates direct current (or collimation stream) voltage signal relevant to signal amplitude.
Amplitude (" dB " form) general exponent function relation of detecting circuit and the signal for inputing to wave detector 212, therefore make
With logafier 210 by the wave detector voltage and the linearly for inputing to wave detector 212.
The effect of adder 209 is that voltage signal that logafier 210 exports and a comparison voltage (are passed through port
2G is generated) it is compared, get error voltage.
Capacitor 207 and operational amplifier 208 constitute an integrator, the mistake that integrator can generate adder 209
Potential difference is integrated, and the signal after integral can be directly output to exponential amplifier 205, but due to also needing to realize AM tune
(amplitude modulation) function is made, therefore also needs that adder 206 is arranged, the signal after integrator integral is exported to the addition at this time
Device 206.
When AM being needed to modulate, user setting AM modulates relevant parameter, generates the output of AM modulated signal eventually by port 2H
To the logafier 211, the effect of logafier 211 is that AM modulated signal is converted to logarithmic form, after cooperation
The exponential amplifier 205 on side could correctly drive the variable attenuator 201.The signal difference that logafier 211 generates is defeated
Out to the adder 209 and adder 206, when AM frequency modulating signal is lower, in the signal that logafier 211 exports
To the normal work of adder 209, after rectified signal, reference signal and AM modulated signal are carried out add operation by adder 209
It generates error voltage and is sent into integrator, entire circuit can work normally at this time;When AM frequency modulating signal is higher, logarithm is put
Give the normal work of adder 206 in the signal that big device 211 exports, adder 206 is by integrator output signal and logarithmic amplification
The signal that device 211 exports makees add operation, and then common output is to the exponential amplifier 205.
The effect of exponential amplifier 205 is that the linear signal before after logafier is converted is reconverted into index
Then signal drives the variable attenuator 201, realizes the automatic lever regulation of entire circuit, until port 2F output
Signal stabilization is in a fixed amplitude.
The effect of step attenuator circuit 103 is to consolidate frequency and amplitude that the automatic level control circuit 102 generates
Fixed Signal Regulation is the amplitude that user needs, and can mark the amplitude model that may be implemented in the index of general radio-frequency signal source 100
It encloses, such as generally may be implemented just stepping to be needed to decline at this time up to+20dBm or broader amplitude range from -130dBm or lower
Subtract device circuit 103 to adjust, step attenuator circuit 103 is the prior art, such as number of patent application is 201210539536.1
Chinese patent application file discloses a kind of implementation.
In addition, also need additional driving circuit to drive sometimes the variable attenuator 201, due to it is described can
Becoming attenuator 201 generally has a PIN diode composition, and when work needs certain current or voltage, and operating current is up to tens
Milliampere, therefore existing driving circuit is generally constant current driving or constant pressure driving.Constant current driving, as by variable attenuator 201
The attenuation of demand is converted to corresponding current, generates the constant current by a circuit and exports to variable attenuator 201
Adjustable side, and the voltage of variable attenuator 201 is determined by diode self character;Constant pressure driving is just by variable attenuator 201
The attenuation of demand is converted to corresponding voltage, generates constant voltage by a circuit and exports to the tune of variable attenuator 201
End is saved, and the electric current of variable attenuator 201 is determined by diode self character.
Since diode itself is easy to be influenced by temperature change, as circuit works, the temperature at this circuit becomes
When change, the diode voltage current relationship of variable attenuator 201 also changes: constant current is driven, what driving circuit generated
Electric current remains unchanged, and voltage changes;Constant pressure is driven, the voltage that driving circuit generates remains unchanged, and electric current changes.But it is opposite
For, the temperature stability of the variable attenuator 201 under constant current driving condition drives higher than constant pressure, because of the voltage electricity of diode
Flow relation approximate can use following function representation:
In above formula, IS, VTFor the constant varied with temperature;ISNumerical value is smaller, but varies with temperature larger (the about 1E-15 of range
~1E-6A).VTWith temperature line relationship (T is thermodynamic temperature), under room temperature (about 27 DEG C, 300K) about
26mV, variable quantity are relatively small.AC impedance (RAC) it is slope of the diode at operating point, to above formula differential:
As can be seen that when electric current immobilizes, AC impedance approximation and VTIt is linear;When voltage immobilizes
When, AC impedance and temperature are at complicated relationship, ISVariation will cause AC impedance that very big change occurs.
On the other hand, the attenuator bandwidth under constant current drive mode is lower than constant voltage drive pattern, the reason is as follows that: on the one hand,
The bandwidth of constant-current drive circuit itself limits the bandwidth of attenuator;On the other hand, the driving circuit of constant current mode uses mostly
The non-linear element of triode or diode etc is built, and is passed through the method for dynamic regulation triode or diode resistance and is realized electricity
Flow constant, and variable attenuator 201 itself is built using PIN diode, is had biggish non-linear.When the two is used in combination
When, the voltage at 201 both ends of variable attenuator will will appear serious nonlinear change, and attenuator bandwidth greatly reduces.
Therefore, there is certain limitation in constant-current drive circuit and constant voltage drive circuit, not be able to satisfy in measuring device
The demand of variable attenuator.
By to discussion above it can be seen that existing automatic level control circuit 102 using analog circuit realize, mould
In quasi- circuit, (wave detector 212 is generally with inspection other than variable attenuator 201, wave detector 212 are generally realized using diode
Wave diode is realized), logafier 210 and 211, exponential amplifier 205 etc. generally built using diode and triode and
At diode and triode are temperature-sensing element (device), and circuit characteristic can be varied with temperature and be changed, and are allowed for entire
The stability of automatic level control circuit 102 is insufficient, and the stability of automatic level control circuit 102 itself is only capable of reduction operation and puts
The influence of 208 subsequent circuit (mainly exponential amplifier 205) of big device, and can not be to wave detector 212, logafier 210
It is had an impact with 211 etc.;If temperature detection sensor is arranged, usually at wave detector 212 to detect using temperature-compensating
Then the temperature of circuit board at wave detector 212 carries out processing post-compensation to the temperature of detection, but can not reduce logarithm and put
The brings such as big device 210 and 211 influence.
Moreover, the automatic level control circuit 102 also needs to realize that AM modulates function in the radio-frequency signal source 100
Can, i.e., the port 2H in attached drawing 2 inputs AM modulated signal, and output gives adder 209 He after being converted by logafier 211
206, and then the variable attenuator 201 is driven to realize AM modulation.In the process, due to introducing logafier 211, meeting
So that AM modulation is distorted because additionally amplifying with temperature change.On the one hand, AM modulation is to ring to 201 major requirement of variable attenuator
Speed is answered, needs to extend the AM modulating frequency upper limit, and then major requirement is that amplitude is accurate to automatic level control circuit 102 itself
Degree to promote the amplitude accuracy of output signal, therefore realizes AM modulation and ALC using a variable attenuator 201 simultaneously
Circuit requires variable attenuator 201 while having very high accuracy and very short response time, and the model of adjustable damping amount
It encloses very wide.Moreover AM modulation and alc circuit finally drive the variable attenuator 201 using the same driving circuit, need
The variable attenuator 201, which will also keep and control signal within the scope of very wide attenuation, has good linear relationship, no
Then when the radiofrequency signal for driving the voltage of the variable attenuator 201 identical and being inputted from 201 input terminal of variable attenuator
When the power difference of (i.e. the carrier wave of corresponding A M modulation), modulated signal (have passed through the signal exported after AM modulation, namely at this time
The signal of 201 output end of variable attenuator output) it will change.The above variety of problems both increase AM modulation function and
The difficulty of alc circuit design together, so that entire circuit is difficult to realize.
It can be concluded that, following problem exists in the prior art by discussed above:
1, it is realized due to entire automatic level control circuit using analog circuit, temperature has very big shadow to entire circuit
It rings, is also difficult to eliminate the influence of temperature by the various means such as temperature-compensating, and then influence the amplitude of automatic level control circuit
Accuracy and stability;
2, since AM is modulated together with alc circuit design, so that the design of entire circuit is in the presence of greatly difficult;
3, all there is certain restrictions in the constant current driving of variable attenuator and constant voltage drive pattern, not be able to satisfy in measuring device
Variable attenuator demand.
Summary of the invention
In order to solve to realize due to entire automatic level control circuit using analog circuit present in background technique, in turn
The problem of influencing the amplitude accuracy and stability of automatic level control circuit, the present invention provides a kind of amplitude accuracy and surely
The measuring device with alc circuit spent calmly.
The present invention provides a kind of measuring device with alc circuit, and the alc circuit includes variable attenuation unit, power
Allocation unit, wave detector, logafier, addition unit, integrator, voltage conversion unit,
The input, output end that the input terminal of the variable attenuation unit connects the alc circuit connects the power point
Input terminal with unit,
First output end of the power distributing unit connects institute as the output end of the alc circuit, second output terminal
The input terminal of wave detector is stated,
The output end of the wave detector connects the input terminal of the logafier,
The output end of the logafier connects the first input end of the addition unit,
One reference voltage of the second input terminal connection, the output end of the addition unit connect the input of the integrator
End,
The output end of the integrator connects the input terminal of the voltage conversion unit,
The output end of the voltage conversion unit connects the adjustable side of the variable attenuation unit;
The logafier, addition unit, integrator and voltage conversion unit realized by a digit chip,
An analog-to-digital conversion is additionally provided between the output end of the wave detector and the input terminal of the logafier
Device is additionally provided with a digital-to-analogue between the output end of the voltage conversion unit and the adjustable side of the variable attenuation unit and turns
Parallel operation.
In measuring device of the invention, logafier, addition unit, integrator, the voltage in the alc circuit are turned
It changes unit to be all disposed in the same digit chip, the signal after the detector is adopted by the analog-digital converter
Sample obtains corresponding digital detection signal, and then the logafier can carry out at logarithmic amplification digital rectified signal
Reason, is then passed to the addition unit, the signal that the addition unit exports the logafier and the reference signal
It is compared, gives the error voltage after comparison to the integrator and integrate, and give the signal after integral to the electricity
Converting unit is pressed to realize voltage conversion, the digital voltage that then digital analog converter converts the voltage into unit output is converted to pair
The analog voltage answered gives the variable attenuation unit, to change the pad value of the variable attenuation unit, finally believes radio frequency
Number stablize in certain amplitude, since the logafier, addition unit, integrator, voltage conversion unit are all in number
Digital circuit is used in word chip, allowing for these circuits will not be affected by temperature substantially, and then further decrease
Influence of the temperature to entire alc circuit improves the accuracy and stability of variable attenuator in lc circuit.
Illustrate as an example, in the measuring device of the present invention with alc circuit, the digit chip is used
Programmable logic chip is realized.
Illustrate as an example, in the measuring device of the present invention with alc circuit, the programmable logic core
Piece uses FPGA type programmable logic chip.
Illustrate as an example, in the measuring device of the present invention with alc circuit, in the digit chip
In, the first linear amplifier, the first Linear Amplifer are also connected in series between the logafier and the addition unit
The signal that device can generate logafier carries out Linear Amplifer, to match requirement of the subsequent conditioning circuit to signal.
Illustrate as an example, in the measuring device of the present invention with alc circuit, in the digit chip
In, a holding circuit is connected in series between the integrator and the voltage conversion unit, the holding circuit includes
One first switch unit, first register, a state controller, an adder, the first switch unit connect
The output end of the integrator and the input terminal of first register are connect, the output end connection of first register is described to be added
The first input end of musical instruments used in a Buddhist or Taoist mass, the second input terminal of the adder connect a preset voltage, and the output end of the adder connects
Connect the input terminal of the voltage conversion unit;The control signal that the switch unit generates the state controller is quick
Sense makes the separated of the output end of the integrator and the input terminal of the register.
Illustrate as an example, in the measuring device of the present invention with alc circuit, in the digit chip
In, it further include the second linear amplifier, second switch unit, third switch unit, the second switch unit will for selection
The input terminal of one of the logafier and second linear amplifier is connect with the output end of the analog-digital converter, institute
State third switch unit, for select by the output end of one of the logafier and second linear amplifier with it is described
The input terminal of first linear amplifier connects.
Illustrate as an example, in the measuring device of the present invention with alc circuit, in the digit chip
In, it further include the second register, subtracter, second register, for storing one group of calibration value, the subtracter is used for
After the signal that the analog-digital converter exports is done subtraction with the calibration value, operation result is exported and is put to the logarithm
Big device.
Illustrate as an example, in the measuring device of the present invention with alc circuit, in the power distribution list
An attenuator is also connected in series between the first and described wave detector.
Illustrate as an example, in the measuring device of the present invention with alc circuit, in the wave detector and institute
It states and is also connected in series with another logafier between analog-digital converter.
In order to solve to set entire circuit together with alc circuit design due to AM modulation present in background technique
Difficult problem is counted, the present invention provides a kind of radio-frequency signal sources with amplitude modulation and automatic level control function.
Radio-frequency signal source of the present invention with amplitude modulation and automatic level control function, including variable attenuation list
Member, power distributing unit, wave detector, data processing unit, modulated signal generate unit,
The modulated signal generates unit, for generating am signals all the way,
The variable attenuation unit, for believing under the driving for the driving signal that the data processing unit exports input
Number decay, generate deamplification,
The power distributing unit, for the deamplification to be divided into two-way: wherein directly output, another way are defeated all the way
Out to wave detector,
The wave detector obtains rectified signal for the signal progress detection processing to input,
The data processing unit is believed for generating the driving according to the am signals and the rectified signal
Number,
The variable attenuation unit includes the first variable attenuator and the second variable attenuator being connected in series,
The data processing unit includes the first data processing unit and the second data processing unit,
First data processing unit drives first variable attenuator for generating according to the rectified signal
First driving signal,
Second data processing unit drives second variable attenuation for generating according to the am signals
Second driving signal of device.
In radio-frequency signal source of the present invention with amplitude modulation and automatic level control function, the AM is modulated
It is provided separately with the variable attenuator in automatic level control circuit, one of variable attenuator is used to realize that AM is modulated, separately
One variable attenuator is used to realize auto level control, and when needing to carry out AM modulation, the modulated signal generates unit and produces
Raw amplitude modulates (i.e. AM modulation) signal, and second data processing unit just drives correspondence according to the am signals
Variable attenuator, to realize AM modulation function, when needing automatic level control circuit to work, the wave detector is to power point
Detection is carried out with the signal that unit is exported to wave detector, rectified signal is obtained and exports to the first data processing unit, described first
Data processing unit normally drives corresponding variable attenuator according to rectified signal, to realize auto level control, due to
Amplitude modulation and auto level control are provided separately, the demand that all components take into account the two, therefore circuit are not needed
It is easy to accomplish.
Illustrate as an example, the radiofrequency signal of the present invention with amplitude modulation and automatic level control function
In source, first data processing unit and the second data processing unit are made of a digit chip;In the number
An analog-digital converter is also connected between chip and the wave detector, the analog-digital converter is used to turn the rectified signal
It is changed to the first data processing unit that digital signal is sent in the digit chip;First driving signal passes through one the
One digital analog converter drives first variable attenuator;Second driving signal by second digital analog converter come
Drive second variable attenuator.
Illustrate as an example, the radiofrequency signal of the present invention with amplitude modulation and automatic level control function
In source, the digit chip is FPGA type programmable logic chip.
Illustrate as an example, the radiofrequency signal of the present invention with amplitude modulation and automatic level control function
In source, a radio frequency amplifier is also connected in series between first variable attenuator and the second variable attenuator.
Illustrate as an example, the radiofrequency signal of the present invention with amplitude modulation and automatic level control function
In source, first variable attenuator is connected in series between second variable attenuator and the power distributing unit.
Illustrate as an example, the radiofrequency signal of the present invention with amplitude modulation and automatic level control function
In source, in the digit chip, first data processing unit includes: logafier, addition unit, integrator, electricity
Converting unit is pressed, the input terminal of the logafier connects the output end of the analog-digital converter, the logafier
Input terminal connects the first input end of the addition unit, the second input terminal of the addition unit connect a reference voltage,
Output end connects the input terminal of the integrator, and the output end of the integrator connects the input terminal of the voltage conversion unit,
The output end of the voltage conversion unit connects the input terminal of first digital analog converter.
Illustrate as an example, the radiofrequency signal of the present invention with amplitude modulation and automatic level control function
In source, in the digit chip, a holding electricity is connected in series between the integrator and the voltage conversion unit
Road, the holding circuit include a first switch unit, first register, a state controller, an adder,
The first switch unit connects the output end of the integrator and the input terminal of first register, first register
Output end connect the first input end of the adder, the second input terminal of the adder connects a preset voltage, institute
The output end for stating adder connects the input terminal of the voltage conversion unit;The switch unit generates the state controller
A control signal it is sensitive, make the separated of the output end of the integrator and the input terminal of the register.
Illustrate as an example, the radiofrequency signal of the present invention with amplitude modulation and automatic level control function
In source, in the digit chip, it is linear that first is also connected in series between the logafier and the addition unit
Amplifier.
Illustrate as an example, the radiofrequency signal of the present invention with amplitude modulation and automatic level control function
In source, an attenuator is also connected in series between the power distributing unit and the wave detector.
Illustrate as an example, the radiofrequency signal of the present invention with amplitude modulation and automatic level control function
In source, the modulated signal is generated unit and is constituted using dsp chip.
All there is limitation to solve constant current driving and the constant voltage drive pattern of variable attenuator present in background technique,
And then the problem of not being able to satisfy the variable attenuator demand in measuring device, the present invention provides a kind of driving effects preferably to survey
Measure device.
Measuring device of the present invention with variable attenuation unit, including variable attenuation unit, data processing unit,
The variable attenuation unit, under the driving for the driving signal that the data processing unit exports to defeated
Enter signal to decay, generate deamplification,
The data processing unit, for generating the driving signal,
Further include a driving signal processing unit, the driving signal processing unit include operational amplifier, resistance, can
Line pad is adjusted,
The adjustable side of the variable attenuation unit be separately connected the resistance first end and the operational amplifier it is same
To input terminal,
The second end of the resistance is separately connected the output end and the adjustable line pad of the operational amplifier
Output end,
The input terminal of the adjustable line pad connects the output end of the data processing unit,
The reverse input end of the operational amplifier connects the adjustment end of the adjustable line pad.
In measuring device of the present invention, it is made up of and drives setting operational amplifier, resistance and adjustable line pad
Dynamic signal processing unit, at work, adjustable line pad, which has, stablizes adjustable attenuation ratio, they and described can be changed are declined
Subtract unit and collectively form one group of electric bridge, the pad value by adjusting variable attenuator realize adjust the variable attenuation unit etc.
Imitate resistance and then realize the purpose of Attenuation adjustable so that the equivalent resistance of the variable attenuation unit only with it is described adjustable linear
The attenuation ratio of attenuator is related with the resistance value of the resistance, finally makes the linear decrement (institute of the variable attenuation unit
The output voltage of variable attenuation unit is stated than input voltage, multiplied by 100%) with the adjustable line pad pad value at line
Sexual intercourse has a preferable stability characteristic (quality) so that the equivalent resistance of the variable attenuation unit is constant, higher bandwidth, preferably
The linearity, can satisfy the demand of measuring device.
Illustrate as an example, in the measuring device of the present invention with variable attenuation unit, the adjustable line
Property attenuator using R-2R multiplying-type digital analog converter realize.
Illustrate as an example, further includes one in the measuring device of the present invention with variable attenuation unit
Configuration unit, for configuring the code value of the R-2R multiplying-type digital analog converter according to the driving signal.
Illustrate as an example, in the measuring device of the present invention with variable attenuation unit, at the data
Reason unit and the configuration unit are made of a FPGA type programmable logic chip.
Illustrate as an example, in the measuring device of the present invention with variable attenuation unit, the adjustable line
Property attenuator using digital regulation resistance realize.
Detailed description of the invention
Fig. 1 is the circuit diagram of radio-frequency signal source 100 of the invention;
Fig. 2 is the circuit diagram of automatic level control circuit 102 of the invention;
Fig. 3 is the circuit diagram of alc circuit 300 of the invention;
Fig. 4 is the another circuit diagram of alc circuit 300 of the invention;
Fig. 5 is the another circuit diagram of alc circuit 300 of the invention;
Fig. 6 is the another circuit diagram of alc circuit 300 of the invention;
Fig. 7 is the another circuit diagram of alc circuit 300 of the invention;
Fig. 8 is the another circuit diagram of radio-frequency signal source 100 of the invention;
Fig. 9 is the circuit diagram of measuring device 900 of the invention;
Figure 10 is a voltage relationship schematic diagram of measuring device 900 of the invention;
Figure 11 is the attenuation relation schematic diagram of measuring device 900 of the invention.
Specific embodiment
In order to make the foregoing objectives, features and advantages of the present invention clearer and more comprehensible, with reference to the accompanying drawing and specific real
Applying mode, the present invention is described in further detail.
In conjunction with reference attached drawing 3 and attached drawing 4, one kind of alc circuit of the invention (automatic level control circuit) 300 is shown
Specific embodiment, the alc circuit 300 include variable attenuation unit 301, power distributing unit 302, wave detector 303, digital core
Piece 304, analog-digital converter 305, digital analog converter 306, wherein the input terminal 3A of the variable attenuator 301 is the ALC electricity
The input terminal on road 300, the output end of the variable attenuator 301 then connects the input terminal of the power distributing unit 302, described
First output end 3B of power distributing unit 302 is as described in the output end of the alc circuit 300, second output terminal 3C connection
The input terminal of wave detector 303, the output end of the wave detector 303 connect the input terminal of the analog-digital converter 305, the modulus
The output end of converter 305 connects the input terminal 3D of the digit chip 304, the output end 3E connection of the digit chip 304
The input terminal of the digital analog converter 306, the output end of the digital analog converter 306 connect the variable attenuation unit 301
Adjustable side.
It wherein include logafier 401, addition unit 402, integrator 403, voltage turn in the digit chip 304
Unit 404 is changed, wherein the input terminal of the logafier 401 is connected to input terminal 3D, the output end of the digit chip 304
It is connected to the first input end of the addition unit 402, the second input terminal of the addition unit 402 connects a reference voltage
V1, output end are connected to the input terminal of the integrator 403, and the output end of the integrator 403 is connected to the voltage conversion
The input terminal of unit 404, the output end of the voltage conversion unit 404 are connected to the output end 3E of the digit chip 304.
In specific works, input signal is entered by the input terminal 3A of alc circuit 300, by variable attenuation unit 301
It is exported after being decayed, using the first output end 3B of the power distributing unit 302, power distributing unit 302 will at this time
Sub-fraction signal is exported by its second output terminal 3C to the wave detector 303, and the signal of 303 pairs of wave detector inputs is examined
Wave obtains direct current (or collimation stream) signal, and the direct current signal that then analog-digital converter 305 obtains wave detector 303 samples,
It obtains corresponding digital signal and is sent to the input terminal 3D of the digit chip 304, logarithm is put in the digit chip 304
The digital signal is carried out logarithmic amplification first by big device 401, is then passed to the addition unit 402, and addition unit 402 is by logarithm
The signal and the reference voltage V1 that the conveying of amplifier 401 comes do addition or subtraction, and (doing add operation is because if institute
The symbol for the signal that reference voltage V1 comes with the logafier 401 conveying is stated on the contrary, needing just be obtained with add operation
Error voltage between them, because if the reference voltage V1 and the logafier 401 convey when doing subtraction
The symbol of the signal come is identical, it is necessary to do subtraction just and can obtain the error voltage between them), the error amount that then will be obtained
It gives the integrator 403 and does integral operation, the result after integral operation is converted to correspondence by the voltage conversion unit 404
Digital drive voltage after, give digital analog converter 306 by the output end 3E of digit chip 304, digital analog converter 306 will connect
The digital signal received drives the variable attenuation unit 301 to decay after being converted to analog voltage, so that the alc circuit
300 tend towards stability.
Since the logafier 401, addition unit 402, integrator 403, voltage conversion unit 404 are all a piece of
Realized inside digit chip 304 so that they be affected by temperature it is very small or hardly influenced by ambient temperature, therefore entire
It only needs to carry out temperature-compensating to other component bring temperature changes (mainly 303 bring of wave detector) in alc circuit,
Constant-temperature circuit is set to protect to the temperature-compensating of wave detector 303 can there are many implementations, such as around wave detector 303
It demonstrate,proves surrounding temperature to keep constant, or temperature-compensating can also be carried out in the digit chip 304, it can be individually in institute
It states and a temperature compensation module is set in digit chip 304, certain reference voltage values of adjusting digit chip 304 can also be passed through
Temperature-compensating is realized, therefore the temperature-compensating of entire alc circuit 300 is relatively easy, so that the amplitude of alc circuit 300 is accurate
Degree and stability effectively improve.
As explanation, the alc circuit 300 in measuring device have many application fields, such as can be applied to as
In the automatic level control circuit of radio-frequency signal source 100, the local oscillation circuit such as spectrum analyzer, calibration source electricity also can be applied to
In road or tracking source circuit.
As explanation, the variable attenuation unit 301 can be made of a variable attenuator, at this time if also needing reality
When the other functions such as existing amplitude modulation, am signals can be subjected to such as the identical processing of automatic level control circuit 102
Method is sent to the signal for carrying out obtaining with detection again after logarithmic amplification in digit chip 304 and carries out add operation, then altogether
With driving variable attenuator;The variable attenuation unit 301 can also be in series by two variable attenuators, if necessary to real
When the other functions such as existing amplitude modulation, differential declines function can be realized respectively.
As explanation, the power distributing unit 302 can be by the various existing sides such as directional coupler, power distributing circuit
Formula is realized.
Illustrate as an example, can also be arranged between the variable attenuation unit 301 and power distributing unit 302
Such as other circuits of radio frequency amplifier.
Illustrate as an example, the digit chip 304 realizes that FPGA type can using FPGA type programmable logic chip
Programmed logic resources of chip is more, low in energy consumption, is suitable for circuit design.
As a kind of deformation, the digit chip 304 can also be realized using CPLD type programmable logic chip, can be with
Realized using dsp chip, etc..
Illustrate as an example, in conjunction with reference attached drawing 5, in the digit chip 304, in the logafier 401
405, registers 406 of a subtracter are also set up before, are stored with one group of calibration value in the register 406, it is described to subtract
First output end of musical instruments used in a Buddhist or Taoist mass connects the input terminal 3D of the digit chip 304, the second input terminal connects the register 406, defeated
Outlet connects the logafier 401.When work, it can measure to obtain one group of calibration value first, this group of calibration value can be
The radiofrequency signal being input in variable attenuation unit 301 is very small or one group of data that measurement obtains when without radiofrequency signal, in reality
Border is in application, subtract the calibration data by the digital signal that port 3D is inputted for analog-digital converter 305 first, to reduce
Alc circuit 300 bring error itself.
Attached drawing 5 is referred to for example, combining as another, can also be arranged in parallel with the logafier 401
One linear amplifier 407, and there are two switch units 408 and 409 for setting, the switch unit 408 and 409 can be two
Select a switch, the output end of the subtracter 405 and described to amplifier 401, Linear Amplifer is arranged in the switch unit 408
Between the input terminal of device 407 (if without the subtracter 405, just setting port 3D and it is described to amplifier 401,
Between the input terminal of linear amplifier 407), switch unit 409 be arranged in it is described to amplifier 401, linear amplifier 407 it is defeated
Between outlet and the input terminal of the addition unit 402.The switch unit 408 can choose the letter for exporting subtracter 405
Number logafier 401 or linear amplifier 407 are given, and the switch unit 409 can choose the logarithmic amplification
One in device 401 or linear amplifier 407 outputs signal to the addition unit 402.Setting is because of ALC sometimes in this way
The signal amplitude that circuit 300 exports is had already been through pair with the voltage that " volt (V) " is the proportional variation of unit or rectified signal
Number amplification can pass through the linear amplifier by the signal that 3D conveying in port comes at this time without carrying out logarithmic amplification
407 amplify processing.
As a kind of deformation, the linear amplifier 407 is also possible to through path, without amplifying.
Attached drawing 5 is referred to for example, combining as another, in the switch unit 409 (if without switch unit
409, then being exactly logafier 401) and the addition unit 402 between be additionally provided with a linear amplifier 410, linearly
The signal that logafier 401 or linear amplifier 407 are sent can be carried out Linear Amplifer by amplifier 410 again, with matching
The circuits such as subsequent integration device 403.
As another for example, continuing with reference attached drawing 5, in the integrator 403 and voltage conversion unit 404
Between be additionally provided with a holding circuit 411, in conjunction with reference attached drawing 6, the holding circuit 411 includes switch 415, register
412, state controller 414, adder 413, one end of the switch 415 connect output end, the other end of the integrator 403
The input terminal of the register 412 is connected, the control terminal of switch 415 connects the state controller 414, the register 412
Output end connect the input terminal of the adder 413, the other end of the adder 413 connects a preset value voltage module
416, the preset voltage module 416 can produce a preset voltage, and the output end of the adder 413 connects the voltage
The input terminal of converting unit 404.
The state that alc circuit 300 may be implemented in the holding circuit 411 is kept.In normal work, state controller
The 414 control switches 415 are closed, and the signal that integral generates constantly is sent to the register 412 by integrator 403, is deposited
412 real-time update of device, after the signal and the preset voltage that adder 413 exports the register 412 carry out add operation
Driving voltage is obtained, and is sent to the voltage conversion unit and is converted;When needing alc circuit 300 to be in hold mode
(i.e. alc circuit 300 is only maintained at the same state according to certain attenuation at this time, without feedback regulation variable attenuation
Unit 301), state controller 414 controls the switch 415 and disconnects, and register 412 does not update at this time, the number in register 412
According to being data finally sent before switch 415 disconnects, hereafter register 412 continues the data being constantly sent to adder
413, adder 413 is then forwarded to the progress voltage conversion of voltage conversion unit 404 after the data and preset voltage are done addition, this
When voltage be a fixed value, then drive the variable attenuation unit 301 according to the same decaying by digital analog converter 306
Value keeps decaying, if analog circuit realizes the function, since analogue integrator is sent to the number of adder or exponential amplifier
According to very short a period of time can only be kept, it is difficult to so that alc circuit 300 is always held at certain state.The preset voltage
It is linearly related with the amplitude output signal of alc circuit 300, the signal that analog-digital converter 305 generates can be converted to described pre-
Voltage is set, directly can also directly be configured by digit chip 304.
Illustrate as an example, in conjunction with reference attached drawing 7, in the digit chip 304, the integrator 403 is general
It is to be realized by accumulator 417, linear amplifier 418 is generally additionally provided with before the accumulator 417 addition unit 402 is defeated
Error voltage out amplifies, and is then sent to accumulator 417 and carries out accumulation calculating, accumulated result is integrator 403
Output signal.
Illustrate as an example, the logafier 401 generally uses dual slope logarithmic amplifier, dual slope logarithmic
Amplifier can be indicated with following formula:
Y=K* (ln (x)+ln (x+A))+B
Wherein, x is input, and y is output, and K, A, B are constant.
And the effect of the voltage conversion unit 404 is the voltage and variable attenuation that will input to voltage conversion unit 404
It is linearized between the attenuation of unit 301, corresponds to the logafier 401, voltage conversion unit can be put using index
Big device is realized, can also be directly realized by by the way of wave table value.Assuming that the control voltage of variable attenuation unit 301 declines with it
Relationship between decrement uses following function representation: yATT=f (x), then input and the output voltage of voltage conversion unit 404
Between functional relation and yATTInverse function f-1(x) linear, it can accurately realize the wave table of voltage conversion unit 404
Configuration.
Illustrate as an example, one can also be arranged between the power distributing unit 302 and the wave detector 303
A attenuator, the attenuator can further adjust the RF signal power into wave detector 303, and wave detector can also be isolated
303 with power distributing unit 302, what is both reduced interferes with each other.
Illustrate as an example, is also connected in series with one between the wave detector 303 and the analog-digital converter 305
A logafier, logafier is arranged here can further expand the radiofrequency signal that can be locked of alc circuit 300
Amplitude range, reduce requirement to analog-digital converter 305, but will affect temperature stability.
A kind of measuring device with alc circuit is present embodiments provided, by by the logarithmic amplification in the alc circuit
Device, addition unit, integrator, voltage conversion unit etc. are arranged in the same digit chip, to replace analog circuit, and then make
The component that is influenced by temperature change in entire alc circuit be reduced to only wave detector etc. a few, and wave detector can
To realize compensation by the method for temperature-compensating, so that entire alc circuit is affected by temperature reduction, alc circuit is enhanced
Stability and accuracy.
As other embodiment, when the alc circuit 300 is applied in radio-frequency signal source 100, the radiofrequency signal
Source 100 also needs to realize that AM modulates (amplitude modulation function), and in conjunction with reference attached drawing 8, attached drawing 8 shows a kind of radio-frequency signal source
100 new circuit theory, the automatic level control circuit 102 of the radio-frequency signal source 100 include 801 He of variable attenuator
805, power distributing unit 802, wave detector 803, data processing unit 804 and 807, modulated signal generate unit 806.
Wherein, the variable attenuator 805, variable attenuator 801 and power distributing unit 802 are sequentially connected in series in institute
It states between the input port 8A of automatic level control circuit 102 and output port 8B, the variable attenuator 801, power distribution
Unit 802, wave detector 803 and data processing unit 804 together constitute alc circuit, which can be using such as ALC electricity
The implementation on road 300, to realize auto level control, since the various realizations of alc circuit 300 have been discussed in detail in front
Mode, details are not described herein again.
And the variable attenuator 805 is used for then for realizing amplitude modulation wherein the modulated signal generates unit 806
Am signals are generated, can be used to implement the functions such as internal modulation, external modulation or inside and outside hybrid modulation, therefore there are a variety of realities
Existing scheme.For example, the modulated signal generation unit 806 can be and be realized by dsp chip, amplitude is arranged by keyboard in user
Correlation function and parameter are modulated, is then parsed the information of user setting by dsp chip, and be sent to data processing unit
807, the data processing unit 807 directly converts the function of user setting and parameter to the drive of driving variable attenuator 805
Dynamic signal.
As a kind of deformation, the modulated signal, which generates unit 806, can also be that host computer etc. is realized, user utilizes upper
Parameter is opened and be arranged to amplitude modulation function by position machine, and data processing unit 807 converts the function of user setting and parameter to
Drive the driving signal of variable attenuator 805.
As another deformation, the modulated signal generates unit 806 and is also possible to by generating modulation according to user setting
The analog circuit and voltage transformation module of signal collectively form, and generate the analog circuit of modulated signal according to the information of user setting
Corresponding analog signal is generated, variable attenuator is then controlled after voltage transformation module reconvert, realizes amplitude modulation.
As another deformation, the modulated signal, which generates unit 806, can also receive external modulation signal, then utilize
Analog-digital converter samples to obtain corresponding digital modulation signals, then recycles such as FPGA type programmable logic chip to number
Modulated signal is handled, and using variable attenuator is driven after digital-to-analogue conversion, realizes amplitude modulation.
In the present embodiment, the data processing unit 807 and data processing unit 804 can be compiled using the same FPGA type
Journey logic chip realizes that 804 two sides of data processing unit are additionally provided with analog-digital converter and digital analog converter at this time certainly,
The output end of the data processing unit 807 is additionally provided with digital analog converter, and such scheme can economize on resources, and FPGA type
Programmable logic chip has the function of that resource abundant comes two kinds of Parallel Implementation.
As a kind of deformation, the data processing unit 807 can be real using individual FPGA type programmable logic chip
It is existing, or realized using dsp chip or ARM chip etc..
As a kind of deformation, the position of the variable attenuator 805 and 801 be can be interchanged.
As a kind of deformation, it is also provided with radio frequency amplifier between the variable attenuator 805 and 801, to reduce
The signal-to-noise ratio degradation problem of the radiofrequency signal due to caused by the attenuator series connection of biggish attenuation.
Variable attenuator 801, power distributing unit 802,803 sum number of wave detector as a kind of deformation, in the present embodiment
Alc circuit is together constituted according to processing unit 804, the alc circuit can not also use the implementation such as alc circuit 300,
And use as it is attached Fig. 2 shows simulation alc circuit scheme, equally by amplitude modulation and auto level control separately design, make
The design for obtaining entire circuit is also relatively easy, but simulates alc circuit and equally exist the problem of being easily affected by temperature, and effect is not so good as
It is more preferable using the scheme of digit chip.
The radio-frequency signal source that the present embodiment is discussed is provided separately by modulating amplitude with two kinds of functions of auto level control,
Different variable attenuators is controlled respectively, is reduced radio-frequency signal source and is realized amplitude modulation function and automatic level control function
Difficulty.
Since variable attenuator generally also needs driving circuit to drive, as other embodiment, with reference to the accompanying drawing 9
To be discussed further a kind of measuring device 900 with variable attenuation unit, including variable attenuation unit 901, operational amplifier
902, adjustable line pad 903, resistance 904, data processing unit 905, wherein operational amplifier 902, adjustable linear attenuation
Device 903 and resistance 904 together constitute driving signal processing unit.
The variable attenuation unit 901 can be the variable attenuator of realization amplitude modulation, or realize automatic electric-level control
Variable attenuator of system, etc..The variable attenuation unit 901 is used for the drive exported in the data processing unit 905
Decay under the driving of dynamic signal to the signal of input terminal 9A input, generates deamplification and exported by output end 9B, driven
Signal is inputted by port 9C.
The am signals that the data processing unit 905 can be the modulation of realization amplitude generate unit, are used for basis
The setting of user generates corresponding am signals;The circuit for either realizing auto level control is used for basis from output
The voltage that port 9B detection obtains generates corresponding feedback control signal, etc..
The adjustable side 9C of the variable attenuation unit 901 is separately connected the first end of the resistance 904 and the operation is put
The noninverting input of big device 902, the second end of the resistance 904 are separately connected output end and the institute of the operational amplifier 902
The output end 9F of adjustable line pad 903 is stated, the input terminal of the adjustable line pad 903 connects the data processing list
The output end of member 905, the reverse input end of the operational amplifier 902 connect the adjustment end of the adjustable line pad 903
9E.In addition, power end 9D one power supply of connection of the operational amplifier 902, ground terminal ground connection.
When specific works, adjustable line pad 903, resistance 904 and variable attenuation unit 901 together constitute an electricity
Bridge.If the output end voltage of operational amplifier 902 is the electricity at the output end 9F of Vo namely the adjustable line pad 903
Pressure is Vo;The voltage of the adjustment end 9E of adjustable line pad 903 is Vr, the common end of resistance 904 and variable attenuation unit 901
The voltage of (adjustable sides of i.e. variable attenuation units 901) is Vd.
The relationship of the voltage Vr of the voltage Vo and its adjustment end 9E of the output end 9F of so adjustable line pad 903 are for example attached
Curve Vr1 and Vr2 in Figure 10, are two straight lines from origin 0, and the slope difference of curve Vr1 and Vr2 represents adjustable
The different intrinsic standoff ratios of line pad 903.And the input electricity of bleeder circuit composed by resistance 904 and variable attenuation unit 901
The relationship such as the curve Vd1 in attached drawing 10, curve Vd1 of the voltage Vd of pressure Vo and its adjustable side 9C is the logarithm for crossing origin 0
The intersection point of curve, curve Vr1, Vr2 and curve Vd1 are the operating point that entire circuit works normally.
It, can work after last entire circuit stability when adjustable line pad 903 work is in the state of curve Vr1
In S1 point, the noninverting input of operational amplifier 902 and the voltage of reverse input end are equal at this time, i.e. Vd=Vr=Vd1, operation
The output end voltage Vo=Vo1 of amplifier 902.Similarly, when the state for changing the adjustable line pad 903, make its work
In the state of curve Vr2, operating point, which can respond, is moved to point S2, at this time the noninverting input of operational amplifier 902 and reversed
Input terminal voltage is equal, i.e. Vd=Vr=Vd2, the output end voltage Vo=Vo2 of operational amplifier 902.
If the attenuation ratio of the adjustable line pad 903 is a, it may be assumed that
The resistance value of resistance 904 is R0, the equivalent resistance of variable attenuation unit 901 is Rd, then available:
According to the discussion of front, Vr=Vd after entire circuit stability is further obtained:
Therefore, it can be seen that when entire circuit the operation is stable, the equivalent resistance Rd of the variable attenuation unit 901 be with
The relevant value of attenuation ratio of adjustable line pad 903, can by adjust the attenuation ratio of adjustable line pad 903 come
It adjusts, and then realizes the purpose of 901 differential declines amount of variable attenuation unit.
Illustrate as an example, the adjustable line pad 903 is realized using R-2R multiplying-type digital analog converter, R-
2R multiplying-type digital analog converter is a kind of adjustable line pad (band of bandwidth index mode converter realization multiplication of broader bandwidth
Width is not the bandwidth of itself) so that the bandwidth of entire circuit is also wider, the R-2R multiplying-type digital analog converter passes through
Its code value of configuration of described dispensing unit, may be implemented different attenuation ratios, and the reference input of R-2R multiplying-type digital analog converter is (corresponding
The output end 9F of adjustable line pad 903) voltage be Vo, the output end (adjustable side of corresponding adjustable line pad 903
Voltage 9E) be Vr, if the number of significant digit of R-2R multiplying-type digital analog converter is L, the value range of code value D, D for [0,
2L- 1), then:
And then it is available:
After entire circuit stability, the equivalent resistance of the variable attenuation unit 901 are as follows:
I.e. due to resistance R0Fixed, the number of significant digit L of R-2R multiplying-type digital analog converter is fixed, is changed by configuration unit
The corresponding equivalent resistance for changing the variable attenuation unit 901 can be realized in its code value D.
Compare the driving circuit of the present embodiment and the difference of constant current driving and constant pressure driving, in conjunction with reference attached drawing 11, attached drawing
11 show the difference of three kinds of drivings, and wherein abscissa is the code value D of R-2R multiplying-type digital analog converter, and ordinate is variable declines
Subtracting the linear decrement ATT_lin of unit 901, (calculation method is voltage and the input of the output end 9B of variable attenuation unit 901
The ratio of the voltage of 9A is held, multiplied by 100%), unit %, value range is [0,100].Wherein curve X1 is constant pressure relationship
Curve, curve X2 are the circuit curves of the present embodiment, and curve X3 is constant current relation curve, it can be clearly seen that the song of the present embodiment
Line is closer to linear relationship, is easy to accurately adjust.
As a kind of deformation, the adjustable line pad 903 can also be using digital regulation resistance or simulation potentiometer etc.
It realizes, the purpose of the present embodiment also may be implemented.But R-2R multiplying-type digital analog converter more easily configure, adjust it is more quasi-
Really, accuracy is higher, in the measuring device especially suitable for generating driving variable attenuation unit using digit chip.
Illustrate as an example, the data processing unit 905 and configuration unit in the present embodiment can be by a FPGA
Type programmable logic chip is realized, such as the driving circuit in the present embodiment is applied to as that can use in alc circuit 300
The a piece of FPGA type programmable logic chip realizes numerous functions.
As a kind of deformation, data processing unit 905 and configuration unit in the present embodiment can be by individual digital cores
Piece is realized, such as dsp chip, ARM chip, can also be by realizing there is a variety of realizations with a piece of such as dsp chip, ARM chip
Mode.
The driving circuit for present embodiments providing a kind of variable attenuator, by the way that adjustable line pad is arranged, operation is put
Big device and resistance constitute electric bridge, and resistance determines when due to electric bridge stabilizing, so that the equivalent resistance of variable attenuator is relatively stable;By
Be affected by temperature in adjustable line pad, resistance etc. it is relatively small so that entire driving circuit is affected by temperature relatively small, temperature
Stability is relatively high;And there is the preferable linearity, it can satisfy the demand of variable attenuator in measuring device.
The above specific embodiment is to illustrate the invention and not to limit the present invention, this field general technology people
Make any creation for not having creativeness according to above-mentioned design philosophy, is regarded as within the protection scope of this patent.
Claims (8)
1. a kind of measuring device with alc circuit, the alc circuit includes variable attenuation unit, power distributing unit, detection
Device, logafier, addition unit, integrator, voltage conversion unit,
The input, output end that the input terminal of the variable attenuation unit connects the alc circuit connects the power distribution list
The input terminal of member,
First output end of the power distributing unit connects the inspection as the output end of the alc circuit, second output terminal
The input terminal of wave device,
The output end of the wave detector connects the input terminal of the logafier,
The output end of the logafier connects the first input end of the addition unit,
One reference voltage of the second input terminal connection, the output end of the addition unit connect the input terminal of the integrator,
The output end of the integrator connects the input terminal of the voltage conversion unit,
The output end of the voltage conversion unit connects the adjustable side of the variable attenuation unit;
It is characterized by:
The logafier, addition unit, integrator and voltage conversion unit realized by a digit chip,
An analog-digital converter is additionally provided between the output end of the wave detector and the input terminal of the logafier,
A digital analog converter is additionally provided between the output end of the voltage conversion unit and the adjustable side of the variable attenuation unit;
In the digit chip, a holding electricity is connected in series between the integrator and the voltage conversion unit
Road,
The holding circuit includes a first switch unit, first register, a state controller, an addition
Device, the first switch unit connect the output end of the integrator and the input terminal of first register, and described first posts
The output end of storage connects the first input end of the adder, and the second input terminal of the adder connects a preset electricity
Pressure, the output end of the adder connect the input terminal of the voltage conversion unit;
The control signal that the first switch unit generates the state controller is sensitive, makes the output of the integrator
End is separated with the input terminal of the register.
2. a kind of measuring device with alc circuit according to claim 1, it is characterised in that:
The digit chip is realized using programmable logic chip.
3. a kind of measuring device with alc circuit according to claim 2, it is characterised in that:
The programmable logic chip uses FPGA type programmable logic chip.
4. a kind of measuring device with alc circuit according to claim 1,2 or 3, it is characterised in that:
In the digit chip, first is also connected in series between the logafier and the addition unit and is linearly put
Big device.
5. a kind of measuring device with alc circuit according to claim 4, it is characterised in that:
It further include the second linear amplifier, second switch unit, third switch unit in the digit chip,
The second switch unit, for selecting the input terminal of one of the logafier and second linear amplifier
It is connect with the output end of the analog-digital converter,
The third switch unit, for selecting the output end of one of the logafier and second linear amplifier
It is connect with the input terminal of first linear amplifier.
6. a kind of measuring device with alc circuit according to claim 1,2 or 3, it is characterised in that:
It further include the second register, subtracter in the digit chip,
Second register, for storing one group of calibration value,
The subtracter, after signal and the calibration value for exporting the analog-digital converter do subtraction, by operation
As a result it exports to the logafier.
7. a kind of measuring device with alc circuit according to claim 1,2 or 3, it is characterised in that:
An attenuator is also connected in series between the power distributing unit and the wave detector.
8. a kind of measuring device with alc circuit according to claim 5, it is characterised in that:
Another logafier is also connected in series between the wave detector and the analog-digital converter.
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CN106932661B (en) * | 2015-12-29 | 2020-10-27 | 普源精电科技股份有限公司 | Measuring device with AM modulation function |
CN109039294B (en) * | 2018-08-08 | 2022-02-18 | 义乌工商职业技术学院 | Automatic correcting circuit for computer signal |
CN109379090A (en) * | 2018-12-25 | 2019-02-22 | 成都前锋电子仪器有限责任公司 | Pre- fixed amplitude circuit for radio frequency synthetic source |
CN110441599B (en) * | 2019-07-15 | 2021-05-28 | 深圳市鼎阳科技股份有限公司 | Detection method and device for frequency spectrograph and readable storage medium |
CN111181601B (en) * | 2019-11-22 | 2021-06-29 | 北京麦克斯韦科技有限公司 | Control system of quick response automatic level control loop |
CN115420940B (en) * | 2022-11-04 | 2023-03-03 | 山东恒美电子科技有限公司 | Direct current signal detecting system of multipurpose |
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US8331486B1 (en) * | 2009-12-18 | 2012-12-11 | Maxim Integrated Products, Inc. | Transmitter circuit with integrated power control |
CN102136826B (en) * | 2010-12-09 | 2013-02-27 | 东莞理工学院 | ACL control and temperature compensation method and device |
CN201904765U (en) * | 2010-12-24 | 2011-07-20 | 北京北广科技股份有限公司 | Analog-to-digital double loop control ALC circuit |
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Address after: Suzhou City, Jiangsu province 215163 Suzhou New District kolding Road No. 8 Patentee after: Puyuan Jingdian Technology Co., Ltd Address before: Suzhou City, Jiangsu province 215163 Suzhou New District kolding Road No. 8 Patentee before: SUZHOU RIGOL PRECISION ELECTRIC TECHNOLOGIES Co.,Ltd. |