CN106932661A - A kind of measurement apparatus with AM modulation functions - Google Patents
A kind of measurement apparatus with AM modulation functions Download PDFInfo
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- CN106932661A CN106932661A CN201511002918.0A CN201511002918A CN106932661A CN 106932661 A CN106932661 A CN 106932661A CN 201511002918 A CN201511002918 A CN 201511002918A CN 106932661 A CN106932661 A CN 106932661A
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- G—PHYSICS
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The present invention provides a kind of measurement apparatus with AM modulation functions, including：The input of calibration module is the input of digit chip；When external modulation is carried out, the output end of calibration module is connected with the input of index of modulation module by modulating switching switch；When internal modulation is carried out, the output end of frequency synthesizer is connected with the input of index of modulation module by modulating switching switch；The input of base band biasing module is connected with the output end of index of modulation module, and the first output end of base band biasing module is connected with the input of combining module, and the second output end of base band biasing module is connected with the input of nonlinearity compensation module；The output end of nonlinearity compensation module is connected with outside AM attenuators.The present invention analyzes AM demands (internal modulation, external modulation and modulation depth etc.), with reference to attenuator actual performance and calibration requirements, it is proposed that AM realizes reference scheme in digit chip on the basis of digital AM schemes.
Description
Technical field
The present invention relates to signal testing, field of measuring technique, more particularly to a kind of measurement dress with AM modulation functions
Put.
Background technology
AM (Aplitude Modulation, amplitude modulation) is a kind of important means of wireless telecommunications, AWG
AM signals can be produced with the equipment such as radio-frequency signal source, is studied for communication system or tested.Closed using simulation part
AWG and most of radio-frequency signal sources into mode can be realized by the way of analog attenuator is controlled
AM.For radio-frequency signal source, the signal frequency that AWG is produced is typically relatively low, is mostly used for
The beforehand research or design of communication scheme, technology.The frequency modulating signal that radio-frequency signal source is produced is suitable with actually used scope,
Can be used for the research or test of practicality communication apparatus and device.Radio-frequency signal source Main Function is generation certain frequency model
The radiofrequency signal with amplitude range is enclosed, as the excitation or reference of device under test, the test measurement of electronic device is assisted.
Range accuracy and stability are one of important technology indexs of radio-frequency signal source, and it relies primarily on ALC (Automatic
Level Control, automatic level control circuit) ensure.When AM is opened, it is also desirable to the carrier signal (base of signal source
Plinth radiofrequency signal) amplitude is basically unchanged and keeps original stability.
Patent CN201310721663.8 describes a kind of radio-frequency signal source, and its theory diagram is as shown in figure 1, radio frequency
Signal source mainly includes frequency synthesizer 101, automatic level control circuit 102 and step attenuator 103.Frequency is closed
101 Main Functions of growing up to be a useful person are the radiofrequency signal for producing user's setpoint frequency, and automatic level control circuit 102 is believed radio frequency
Number range accuracy and stability be controlled, step attenuator 103 using than larger attenuation stepping to output
The amplitude of signal is further adjusted, the amplitude range that extensive radio frequency signal source can be exported.
In radio-frequency signal source, AM is realized in the part of automatic level control circuit 102, used as its expanded function.Patent
CN201310721663.8 describes a kind of common simulation ALC schemes and its AM is realized, as shown in Figure 2.
ALC parts are by adjustable radio frequency attenuator 201, build-out resistor 202, radio frequency amplifier 203, directional coupler
204th, exponential amplifier 205, adder 206, compare integrator (being made up of electric capacity 207 and amplifier 208),
Adder 209, logafier 210, logafier 211 and wave detector 212 are constituted.2A believes for input radio frequency
Number, 2F is output radiofrequency signal, and 2G is the reference signal of setting.If exporting the amplitude of radiofrequency signal 2F and setting
The amplitude that fixed reference signal 2G is represented is unequal, compares integrator (being made up of electric capacity 207 and amplifier 208)
Output can change, by exponential amplifier 205 amplification after as adjustable radio frequency attenuator 201 attenuation,
Until amplitude output signal reaches the value of setting.AM modulated signals (baseband signal, 2H) are by logafier
Respectively enterd after 211 in the adder 209 and adder 206 for comparing before and after integrator, control ALC realizes AM.
In ALC schemes are simulated, AM depends on ALC, higher to adjustable radio frequency attenuator requirement.
For the problem that simulation ALC schemes are present, patent CN201310721663.8 proposes a kind of digital ALC
Structure and corresponding AM implementations, as shown in Figure 3.
Power divider 802, wave detector 803 in digit chip 806, digital signal processing module 804, tunable radio frequency
Attenuator 801 constitutes relatively independent digital ALC loops, and the output data of digit chip 806 is by data processing list
The adjustable radio frequency attenuator 805 that separation is directly driven after unit 807 realizes AM.
In digital ALC schemes, AM does not depend on ALC, less demanding to adjustable radio frequency attenuator.But only
Composition and the connection of AM are described on hardware, realizations of the AM in digit chip there is no clear and definite scheme to be available for ginseng
Examine.
The content of the invention
The embodiment of the invention provides a kind of measurement apparatus with AM modulation functions, there is provided AM is in digital core
Reference scheme is realized in piece.Measurement apparatus include the digit chip for realizing AM modulation functions；
The digit chip includes calibration module, frequency synthesizer, modulation switching switch, index of modulation module, base
Band biasing module, combining module and nonlinearity compensation module；
The input of the calibration module is the input of digit chip；
When external modulation is carried out, by modulating switching switch by the output end of the calibration module and the index of modulation mould
The input connection of block；When internal modulation is carried out, by modulate switching switch by the output end of the frequency synthesizer with
The input connection of the index of modulation module；
The input of the base band biasing module is connected with the output end of the index of modulation module, and the base band biases mould
First output end of block is connected with the input of the combining module, the second output end of the base band biasing module and institute
State the input connection of nonlinearity compensation module；
The output end of the nonlinearity compensation module is connected with outside AM attenuators；
The calibration module is used to calibrate the signal of user input, obtains external modulation signal；
The frequency synthesizer is used to produce internal modulation signal；
The index of modulation module is used to change the modulation depth of external modulation signal or internal modulation signal；
The base band biasing module is used to change the skew of external modulation signal or internal modulation signal；
The combining module is used to be combined external modulation signal or internal modulation signal with ALC reference voltages；
The nonlinearity compensation module is used for external modulated signal or internal modulation signal carries out nonlinear compensation.
In one embodiment, the calibration module includes downsampling factor unit and sample-offset unit；
The input of the downsampling factor unit is the input of the calibration module, the output of the downsampling factor unit
End is connected with the input of the sample-offset unit, and the output end of the sample-offset unit is opened with the modulation switching
Connection connects；
Or, the input of the sample-offset unit is the input of the calibration module, the sample-offset unit
Output end is connected with the input of the downsampling factor unit, and the output end of the downsampling factor unit is cut with the modulation
Change switch connection.
In one embodiment, first adder is also included in the digit chip；
By modulate switching switch simultaneously by the output end of the output end of the calibration module and the frequency synthesizer with
First adder is connected；
Result and external modulation signal that internal modulation signal is multiplied by internal modulation coefficient are multiplied by by the first adder outer
The result of the index of modulation is added, and obtains Hybrid-modulated Signal.
In one embodiment, Postponement module is also included in the digit chip；
The input of the Postponement module is connected with the output end of base band biasing module, the first output of the Postponement module
End is connected with the input of the combining module, the second output end and the nonlinearity compensation module of the Postponement module
Input connection；
The Postponement module is used to adjust the phase of internal modulation signal or external modulation signal or Hybrid-modulated Signal.
In one embodiment, the digit chip includes normalizing module；
The input of the normalization module is connected with the first output end of the Postponement module, the normalization module
Output end is connected with the input of the combining module；
The normalization module is used for internal modulation signal or external modulation signal or Hybrid-modulated Signal and ALC reference electricity
Pressure is normalized.
In one embodiment, the normalization module is logafier, and the combining module is adder.
In one embodiment, the normalization module is divider, and the combining module is multiplier.
In one embodiment, the nonlinearity compensation module includes main wave table unit, frequency compensation table unit, first
Multiplier, second adder, temperature compensation unit and the 3rd adder；
The input of the main wave table unit is connected with the output end of the Postponement module, the frequency compensation table unit
Input is connected with the output end of the Postponement module；
The main wave table module is used for according to internal modulation signal or external modulation signal or Hybrid-modulated Signal in main wave table
Searched, obtained the first checking result；
The frequency compensation table unit is used for according to internal modulation signal or external modulation signal or Hybrid-modulated Signal in frequency
Searched in compensation table, obtain the second checking result；
First multiplier is used to be multiplied the second checking result with coefficient of frequency, obtains multiplied result；
The second adder is used to be added multiplied result with the first lookup result, obtains control voltage；
The temperature compensation unit is used to carry out temperature-compensating to control voltage, obtains temperature-compensated voltage；
3rd adder is used to be added temperature-compensated voltage with control voltage, obtains final control voltage.
In one embodiment, the temperature compensation unit includes second level amplifier, temperature-compensating table unit and second
Multiplier；
The second level amplifier is used to for control voltage to carry out Linear Amplifer；
The temperature-compensating table unit is used to be searched in temperature compensation table according to the control voltage after Linear Amplifer, obtains
Temperature-compensating result；
Second multiplier is used to be multiplied temperature-compensating result with penalty coefficient, obtains temperature-compensated voltage.
In one embodiment, the nonlinear compensation unit also includes first order amplifier；
The input of the first order amplifier is the input of the nonlinear compensation unit, the first stage amplifier
Output end is connected with the input of the main wave table unit, for by internal modulation signal or external modulation signal or hybrid modulation
Signal carries out Linear Amplifer.
In embodiments of the present invention, on the basis of digital AM schemes, AM demands (internal modulation, investigation mission outside the city or town are analyzed
System and modulation depth etc.), with reference to attenuator actual performance and calibration requirements, it is proposed that realities of the AM in digit chip
Referring now to scheme.
Brief description of the drawings
Accompanying drawing described herein is used for providing a further understanding of the present invention, constitutes the part of the application, not
Constitute limitation of the invention.In the accompanying drawings：
Fig. 1 is a kind of radio-frequency signal source basic structure schematic diagram provided in an embodiment of the present invention；
Fig. 2 is a kind of simulation alc circuit block diagram provided in an embodiment of the present invention；
Fig. 3 is a kind of digital AM circuit block diagrams provided in an embodiment of the present invention；
Fig. 4 is a kind of measurement apparatus structure chart with AM modulation functions provided in an embodiment of the present invention；
Fig. 5 is a kind of nonlinearity compensation module structured flowchart provided in an embodiment of the present invention；
Fig. 6 is another measurement apparatus structure chart with AM modulation functions provided in an embodiment of the present invention.
Specific embodiment
To make the object, technical solutions and advantages of the present invention become more apparent, with reference to implementation method and accompanying drawing,
The present invention is described in further details.Here, exemplary embodiment of the invention and its illustrating for explaining this hair
It is bright but not as a limitation of the invention.
In existing digital ALC schemes, composition and the connection of AM are only described on hardware, AM is in numeral
Realization in chip there is no the clear and definite scheme can be for reference.The number that the present invention is proposed in patent CN201310721663.8
On the basis of word AM schemes, with reference to the actual demand and calibration of AM, the structure in digit chip is carried out in detail
Design, forms and a kind of can be used for actual digital AM schemes.
Fig. 4 is a kind of measurement apparatus structure chart with AM modulation functions provided in an embodiment of the present invention, such as Fig. 4
Shown, measurement apparatus include the digit chip for realizing AM modulation functions；
The digit chip includes calibration module, frequency synthesizer 403, modulation switching switch, index of modulation module
406th, base band biasing module 407, combining module and nonlinearity compensation module 411；
The input of the calibration module is the input of digit chip；
When external modulation is carried out, by modulating switching switch by the output end of the calibration module and the index of modulation mould
The input connection of block 406；When internal modulation is carried out, by modulating switching switch by the frequency synthesizer 403
Output end be connected with the input of the index of modulation module 406；
The input of the base band biasing module 407 is connected with the output end of the index of modulation module 406, the base
The first output end with biasing module 407 is connected with the input of the combining module, the base band biasing module 407
The second output end be connected with the input of the nonlinearity compensation module 411；
The output end of the nonlinearity compensation module 411 is connected with outside AM attenuators；
The calibration module is used to calibrate the signal of user input, obtains external modulation signal；
The frequency synthesizer 403 is used to produce internal modulation signal；
The index of modulation module 406 is used to change the modulation depth of external modulation signal or internal modulation signal；
The base band biasing module 407 is used to change the skew of external modulation signal or internal modulation signal；
The combining module is used to be combined external modulation signal or internal modulation signal with ALC reference voltages；
The nonlinearity compensation module 411 is used for external modulated signal or internal modulation signal carries out nonlinear compensation.
During specific implementation, the effect of the calibration module is the non-ideal characteristic calibration to sample circuit, i.e. user input
During signal (such as 1Vpp sinusoidal signals) that Hardware Description Manual is specified, signal and the internal modulated signal for producing after calibration
It is identical.Specifically, calibration module can include sample-offset unit 401 (subtracter) and downsampling factor unit 402
(multiplier)；
The input of the downsampling factor unit 402 is the input of the calibration module, the downsampling factor unit
402 output end is connected with the input of the sample-offset unit 402, the output end of the sample-offset unit with
The modulation switching switch connection；
Or, the input of the sample-offset unit 401 is the input of the calibration module, the sample-offset list
Unit 401 output end be connected with the input of the downsampling factor unit 402, the downsampling factor unit 402 it is defeated
Go out end to be connected with the modulation switching switch；
The sample-offset unit 401 and the downsampling factor unit 402 act as to since user input to number
Link error (mainly comprising system design error and devices in batches conformity error) between wordization sampling is finished is carried out
Calibration so that the signal amplitude after calibration is consistent with the standard signal amplitude of user input.Calibration is complete before equipment is dispatched from the factory
Into being typically only performed once.When user uses, the coefficient of this module is fixed.
The concrete structure of sample-offset unit 401 and the downsampling factor unit 402 can be adjusted according to physical circuit, also
Sample-offset unit 401 etc. can be cancelled.
During specific implementation, AM needs to realize modulating frequency and modulation depth adjustable function, it is necessary to realize internal modulation and outer
Modulation, equipment component may also have the modulating mode of " interior+outer ".Now, modulation switching switch can be changed into power
Re-computation handover module and first adder.
When internal modulation is carried out, internal modulation uses the signal that digit chip inside produces, and used as modulated signal, (base band is believed
Number), this modulated signal can be by DDS (Direct Digital Synthesizer, Direct Digital Synthesizer)
403 directly produce, and weight calculation handover module sets weight-interior (internal modulation coefficient) 405 for " 1 " simultaneously, weight
- outer (external modulation coefficient) 406 is " 0 ".
When external modulation is carried out, the modulated signal 4A provided using user, then calculating handover module setting weight-
Interior (internal modulation coefficient) 405 is " 0 ", and weight-outer (external modulation coefficient) 406 is " 1 ".
When hybrid modulation (" interior+outer " pattern) is carried out, weight calculation handover module sets weight-interior (interior simultaneously
The index of modulation) 405 and weight-outer (external modulation coefficient) 406 be " 0.5 "." interior+outer " pattern is by device interior
The modulated signal that the modulated signal of generation is provided with user is added by first adder again after being each multiplied by 0.5, is made
It is final modulated signal (Hybrid-modulated Signal baseband signal final in other words conj.or perhaps).
The form of above-mentioned described internal modulation signal and external modulation signal is y=sin (w0*t), and wherein w0 is modulation frequency
Rate.When hybrid modulation is carried out, inside sources and outside are both needed to produce the index of modulation of y=sin (w0*t), while setting
Weight-interior and weight-be outward " 0.5 ".
During specific implementation, during internal modulation, the internal baseband signal for producing is allowed to carry out subsequent arithmetic；During external modulation, allow outer
Portion is input into and the modulated signal after calibrating enters subsequent arithmetic；During hybrid modulation, allow internal modulation signal to be multiplied by 0.5 and add
External modulation signal enters subsequent arithmetic after being multiplied by 0.5.
Subsequent arithmetic includes being adjusted the depth of modulated signal and skew.Wherein, index of modulation module 406 is used for
Change the modulation depth of external modulation signal, internal modulation signal and Hybrid-modulated Signal, modulation depth 0~100% can adjust.
Base band biasing module 407 is used to change the skew of external modulation signal, internal modulation signal and Hybrid-modulated Signal, after being easy to
Continuous logical design.Signal after base band biasing can represent that wherein w0 is modulation using y=1+ma*sin (w0*t)
Frequency, ma is modulation depth.
During specific implementation, the digit chip can also include Postponement module (408,409) for adjust AM with
Phase error when ALC coordinates, the i.e. phase of internal modulation signal or external modulation signal or Hybrid-modulated Signal.According to
Actual conditions may have 1 or 2, or not have.
When there is one, the input of Postponement module is connected with the output end of base band biasing module 407, Postponement module
First output end is connected with the input of combining module, the second output end and the nonlinearity compensation module 411 of Postponement module
Input connection.
When there is two, the input of Postponement module 607 is connected with the first output end of base band biasing module 407, prolongs
The output end of slow module 607 is connected with the input of combining module；The input of Postponement module 609 biases mould with base band
The second output end connection of block 407, the output end of Postponement module 609 connects with the input of nonlinearity compensation module 411
Connect.
During specific implementation, to modulation of the AM in ALC rings, baseband signal (internal modulation signal or external modulation signal
Or Hybrid-modulated Signal) into needing to be changed according to the pattern of ALC before ALC.Therefore, the digital core
Also include normalization module in piece, the input for normalizing module is connected with the first output end of the Postponement module, institute
The output end for stating normalization module is connected with the input of the combining module.
If ALC is referenced as logarithmic mode (reference voltage unit in db form is represented), normalization module is right
Number amplifiers, after internal modulation signal or external modulation signal or Hybrid-modulated Signal are carried out into logarithmic amplification, then with ALC
Reference voltage 6C is added, i.e. combining module is adder, the result of addition as ALC loops final ginseng
Examine voltage.If ALC is referenced as linear model (reference voltage is with volt --- the unit of V-arrangement formula is represented), normalizing
Changing module needs to bias 608 numerical value divided by base band, then with ALC with reference to being multiplied, i.e., combining module is multiplier,
The result of multiplication as ALC loops final reference voltage.In linear ALC, if modulated signal has been with " 1 "
Centered on, normalization module can be cancelled.
Because general digit chip is to the design of integer and processes slightly simpler than decimal, it is contemplated that modulated signal is multiplied by
One larger multiplying power, then normalize or be converted directly into final output last.
During specific implementation, in modeling scheme, the nonlinear compensation of attenuator is carried out according to the output signal of dB forms.
And the measurement of AM distortions is carried out based on volt (V).When modulation depth is close to 100%, modulation is deep
The change of degree 1% can correspond to the change of dB form very littles in AM positive peaks, and can then be corresponded at negative peak very big
Change.The nonlinear compensation of dB forms practicality for AM is not high, AM easy distortions at positive peak.
In digital AM schemes, compensation scheme of the AM characteristics designs for AM applications, i.e. nonlinear compensation can be directed to
Module 411.
Fig. 5 is a kind of nonlinearity compensation module structured flowchart provided in an embodiment of the present invention, as shown in figure 5, non-linear
Compensating module 411 include main wave table unit 502, frequency compensation table unit 503, the first multiplier, second adder,
Temperature compensation unit and the 3rd adder；
The input of the main wave table unit 502 is connected with the output end of the Postponement module, the frequency compensation list
The input of unit 503 is connected with the output end of the Postponement module；
The main wave table unit 502 is used for according to internal modulation signal or external modulation signal or Hybrid-modulated Signal in main ripple
Searched in table, obtained the first checking result；
The frequency compensation table unit 503 is used to be existed according to internal modulation signal or external modulation signal or Hybrid-modulated Signal
Searched in frequency compensation table, obtain the second checking result；
First multiplier is used to be multiplied the second checking result with coefficient of frequency, obtains multiplied result；
The second adder is used to be added multiplied result with the first lookup result, obtains control voltage；
The temperature compensation unit is used to carry out temperature-compensating to control voltage, obtains temperature-compensated voltage；
3rd adder is used to be added temperature-compensated voltage with control voltage, obtains final control voltage.
During specific implementation, nonlinearity compensation module 411 can also include first order amplifier 501, first order amplifier
Input be the nonlinear compensation unit input, the output end of the first stage amplifier and the main wave table list
The input connection of unit, it act as the range signal 5A of input being converted to wave table input (address of tabling look-up), is
Linear amplifier.If the range signal of input has been able to table look-at, then first order amplifier 501 can also
No.
The operation principle of nonlinearity compensation module is：
Input voltage 5A tables look-up by respectively enteing main wave table and frequency compensation table after first order linear amplifier 501
Obtain corresponding output.Frequency compensation table checking result is multiplied with coefficient of frequency, then is added with main wave table checking result,
Obtain without the attenuator control voltage 5C of temperature-compensating.Not compensated control voltage 5C can enter temperature-compensating
Module obtains corresponding temperature compensation value, and final control voltage 5B is obtained being added with not compensated voltage 5C.
During specific implementation, temperature compensation unit is by second level amplifier 505, temperature-compensating wave table unit 506 and second
Multiplier is constituted.Second level amplifier 505 act as control voltage 5C to be compensated being converted to temperature-compensating wave table
Input (address of tabling look-up), will obtain an initial offset voltage after tabling look-up, this voltage can be by multiplier and temperature
Degree coefficient 507 is multiplied, and can just obtain final temperature-compensated voltage.
During specific implementation, AM attenuators nonlinearity compensation module is used to that input will to be represented with volt (V) formal unit
Signal is converted to the actual control voltage of attenuator, it is necessary to be compensated to the frequency error and temperature error of attenuator.
Its input 5A can represent that export 5B is attenuator in corresponding frequency and temperature using y=A* (1+sinw0t)
Under control voltage.Attenuator error is weighed according to the form of volt (V), on the basis of a fixed voltage value,
When magnitude of voltage and a reference value of the demand time error that differs greatly are larger.This nonlinearity compensation module is by main wave table to one
Non-linear under frequency carries out good compensation, control electricity of the reuse frequency compensating module to different frequency under specified temp
Pressure is compensated, and the result after frequency compensation is finished just enters temperature compensation module, carries out temperature-compensating.Not by temperature
Degree compensating module is set with frequency compensation modular concurrent, and increased that a part of voltage also has temperature when reason is frequency compensation
Degree error, it is also desirable to carry out temperature-compensating.
Frequency compensated basic settings be different frequency under attenuation-control voltage profiles uniform change.I.e., such as
Fruit attenuator attenuation-control voltage curve under frequency freq1 can represent that (y is decay using function y=f1 (x)
Amount, x is control voltage) curve under frequency freq2 can be represented using y=f2 (x), then function is at other
Curve under frequency can represent that kf is frequency compensation system undetermined using function y=*f1 (x)+kf* (f2 (x)-f1 (x))
Number, changes with frequency.When frequency compensation is carried out, it is necessary to first to attenuator in two frequencies (freq1, freq2)
Lower scanning attenuation-control voltage relation, with the curve under a frequency (reference frequency, freq1) for main wave table (502)
Content, the curve under another frequency (reference frequency, freq2) is (identical to decline with the curve error under previous frequency
Control voltage under decrement is poor) it is frequency compensation wave table (503) content.Coefficient of frequency (504) under different frequency
Obtained by calibration.
The basic settings of temperature-compensating is similar to frequency compensation, that is, control voltage is uniform with temperature under setting identical attenuation
Change, but the speed that varies with temperature of control voltage and attenuation and frequency dependence.Use function y=y0
+ m (freq) * (T-T0) * g (y0) is compensated to the temperature characterisitic of attenuator, and temperature coefficient (504) includes m (freq)
With the product of (T-T0).Wherein, it is the control voltage (y0) of not compensated (fiducial temperature, T0) to be input into, output
It is the control voltage under Current Temperatures (T) and frequency (freq)；M (freq) is frequency factor, is become with frequency
Change；G (y0) is attenuation compensating factor, related to control voltage (attenuation)., it is necessary to first during temperature-compensating
Attenuation-control voltage the curve of attenuator under measurement different temperatures.Then calculate main wave table frequency (reference frequency,
Freq1 attenuation-control voltage curve temperature error under), and normalize to 1 degree Celsius, obtain basal temperature error.
Then, the abscissa (attenuation) of basal temperature error is transformed to the control voltage under fiducial temperature (T0).Most
Afterwards, control voltage-basal temperature error curve is linearized to abscissa (control voltage), obtains temperature error ripple
Table.The calculating of frequency factor can be to the corresponding basal temperature error of the identical attenuation of different frequency (or control voltage)
Proportionality coefficient is calculated, it is also possible to which the mode measurement of temperature in use experiment is obtained.
The present invention also proposes a kind of digital AM Solution Embodiments, as shown in fig. 6, in nonlinearity compensation module 610
After increased scratchpad register 611.
Operation principle is：
User input signal 6A after sample-offset unit 601 and downsampling factor unit 602 are calibrated, as modulation
The input all the way of switching switch 604, the modulated signal that inside sources 603 are produced is input into as another road.Modulation switching is opened
604 switchings for realizing inside/outside modulation are closed, index of modulation module 605 realizes that modulation depth changes, base band biasing module
606 skews for realizing modulated signal.The ALC of linear model need to the baseband signal after Postponement module 607 divided by
It is multiplied with reference to DAC with ALC after base band biasing 608.The ALC of logarithmic mode is needed to after Postponement module 607
Baseband signal carries out logarithmic amplification, then is added with reference to DAC with ALC after appropriate linear multiplying power is amplified.Base band
Biasing module 606 adjust after baseband signal (internal modulation signal or external modulation signal or Hybrid-modulated Signal), it is necessary to
It is used to control outside AM attenuators by output signal 6B after Postponement module 609 and nonlinearity compensation module 610.
The effect of scratchpad register 611 is：When test pattern is enabled, the value control of scratchpad register 611 is directly used
Attenuator performance is tested in attenuator processed, help.
The effect that the present invention is obtained is：
When not carrying out frequency-temperature compensation to attenuator, if AM carrier frequencies change, the AM after demodulation
Positive and negative peak deviation is up to more than 10%.After using the frequency of logarithmic mode, compensation schemes, to AM distortions
Calibrated, positive and negative peak error can be within 3% under different carrier frequencies.But peak error is varied with temperature acutely,
Modulation depth is set as 90%, and about 5 degrees Celsius of temperature change, positive peak occurs about 7% or so change.Using this
Invention compensation scheme, -5~55 degrees Celsius, 100% debugging depth, positive and negative peak error variable quantity is less than about 5%.
Obviously, those skilled in the art should be understood that each module or each step of the above-mentioned embodiment of the present invention can be with
Realized with general computing device, they can be concentrated on single computing device, or be distributed in multiple calculating
On the network that device is constituted, alternatively, they can be realized with the executable program code of computing device, so that,
Can be stored in being performed by computing device in storage device, and in some cases, can be being different from
Order herein performs shown or described step, or they are fabricated to each integrated circuit modules respectively, or
Multiple modules or step in them are fabricated to single integrated circuit module to realize by person.So, the embodiment of the present invention
Any specific hardware and software is not restricted to combine.
The preferred embodiments of the present invention are the foregoing is only, is not intended to limit the invention, for the skill of this area
For art personnel, the embodiment of the present invention can have various modifications and variations.It is all within the spirit and principles in the present invention,
Any modification, equivalent substitution and improvements made etc., should be included within the scope of the present invention.
Claims (10)
1. a kind of measurement apparatus with AM modulation functions, it is characterised in that measurement apparatus are included for realizing AM
The digit chip of modulation function；
The digit chip includes calibration module, frequency synthesizer, modulation switching switch, index of modulation module, base
Band biasing module, combining module and nonlinearity compensation module；
The input of the calibration module is the input of digit chip；
When external modulation is carried out, by modulating switching switch by the output end of the calibration module and the index of modulation mould
The input connection of block；When internal modulation is carried out, by modulate switching switch by the output end of the frequency synthesizer with
The input connection of the index of modulation module；
The input of the base band biasing module is connected with the output end of the index of modulation module, and the base band biases mould
First output end of block is connected with the input of the combining module, the second output end of the base band biasing module and institute
State the input connection of nonlinearity compensation module；
The output end of the nonlinearity compensation module is connected with outside AM attenuators；
The calibration module is used to calibrate the signal of user input, obtains external modulation signal；
The frequency synthesizer is used to produce internal modulation signal；
The index of modulation module is used to change the modulation depth of external modulation signal or internal modulation signal；
The base band biasing module is used to change the skew of external modulation signal or internal modulation signal；
The combining module is used to be combined external modulation signal or internal modulation signal with ALC reference voltages；
The nonlinearity compensation module is used for external modulated signal or internal modulation signal carries out nonlinear compensation.
2. there are the measurement apparatus of AM modulation functions as claimed in claim 1, it is characterised in that the calibration
Module includes downsampling factor unit and sample-offset unit；
The input of the downsampling factor unit is the input of the calibration module, the output of the downsampling factor unit
End is connected with the input of the sample-offset unit, and the output end of the sample-offset unit is opened with the modulation switching
Connection connects；
Or, the input of the sample-offset unit is the input of the calibration module, the sample-offset unit
Output end is connected with the input of the downsampling factor unit, and the output end of the downsampling factor unit is cut with the modulation
Change switch connection.
3. there are the measurement apparatus of AM modulation functions as claimed in claim 1, it is characterised in that the numeral
Also include first adder in chip；
By modulate switching switch simultaneously by the output end of the output end of the calibration module and the frequency synthesizer with
First adder is connected；
Result and external modulation signal that internal modulation signal is multiplied by internal modulation coefficient are multiplied by by the first adder outer
The result of the index of modulation is added, and obtains Hybrid-modulated Signal.
4. there are the measurement apparatus of AM modulation functions as claimed in claim 3, it is characterised in that the numeral
Also include Postponement module in chip；
The input of the Postponement module is connected with the output end of base band biasing module, the first output of the Postponement module
End is connected with the input of the combining module, the second output end and the nonlinearity compensation module of the Postponement module
Input connection；
The Postponement module is used to adjust the phase of internal modulation signal or external modulation signal or Hybrid-modulated Signal.
5. there are the measurement apparatus of AM modulation functions as claimed in claim 4, it is characterised in that the numeral
Chip includes normalizing module；
The input of the normalization module is connected with the first output end of the Postponement module, the normalization module
Output end is connected with the input of the combining module；
The normalization module is used for internal modulation signal or external modulation signal or Hybrid-modulated Signal and ALC reference electricity
Pressure is normalized.
6. there are the measurement apparatus of AM modulation functions as claimed in claim 5, it is characterised in that the normalizing
Change module is logafier, and the combining module is adder.
7. there are the measurement apparatus of AM modulation functions as claimed in claim 5, it is characterised in that the normalizing
Change module is divider, and the combining module is multiplier.
8. there are the measurement apparatus of AM modulation functions as claimed in claim 3, it is characterised in that the non-thread
Property compensating module include main wave table unit, frequency compensation table unit, the first multiplier, second adder, temperature-compensating
Unit and the 3rd adder；
The input of the main wave table unit is connected with the output end of the Postponement module, the frequency compensation table unit
Input is connected with the output end of the Postponement module；
The main wave table unit is used for according to internal modulation signal or external modulation signal or Hybrid-modulated Signal in main wave table
Searched, obtained the first checking result；
The frequency compensation table unit is used for according to internal modulation signal or external modulation signal or Hybrid-modulated Signal in frequency
Searched in compensation table, obtain the second checking result；
First multiplier is used to be multiplied the second checking result with coefficient of frequency, obtains multiplied result；
The second adder is used to be added multiplied result with the first lookup result, obtains control voltage；
The temperature compensation unit is used to carry out temperature-compensating to control voltage, obtains temperature-compensated voltage；
3rd adder is used to be added temperature-compensated voltage with control voltage, obtains final control voltage.
9. there are the measurement apparatus of AM modulation functions as claimed in claim 8, it is characterised in that the temperature
Compensating unit includes second level amplifier, temperature-compensating table unit and the second multiplier；
The second level amplifier is used to for control voltage to carry out Linear Amplifer；
The temperature-compensating table unit is used to be searched in temperature compensation table according to the control voltage after Linear Amplifer, obtains
Temperature-compensating result；
Second multiplier is used to be multiplied temperature-compensating result with penalty coefficient, obtains temperature-compensated voltage.
10. there are the measurement apparatus of AM modulation functions as claimed in claim 8, it is characterised in that the non-thread
Property compensating unit also include first order amplifier；
The input of the first order amplifier is the input of the nonlinear compensation unit, the first stage amplifier
Output end is connected with the input of the main wave table unit, for by internal modulation signal or external modulation signal or hybrid modulation
Signal carries out Linear Amplifer.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114531331A (en) * | 2022-02-07 | 2022-05-24 | 北京奕斯伟计算技术有限公司 | IQ signal calibration method and device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1926770A (en) * | 2004-03-01 | 2007-03-07 | 松下电器产业株式会社 | Transmitter apparatus and wireless communication apparatus |
| CN103873408A (en) * | 2012-12-10 | 2014-06-18 | 北京普源精电科技有限公司 | Radio frequency signal source with modulation function |
| CN104730300A (en) * | 2013-12-24 | 2015-06-24 | 苏州普源精电科技有限公司 | Measuring device with ALC |
| CN104734656A (en) * | 2013-12-24 | 2015-06-24 | 苏州普源精电科技有限公司 | Radio frequency signal source with amplitude modulation and automatic level control functions |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1926770A (en) * | 2004-03-01 | 2007-03-07 | 松下电器产业株式会社 | Transmitter apparatus and wireless communication apparatus |
| CN103873408A (en) * | 2012-12-10 | 2014-06-18 | 北京普源精电科技有限公司 | Radio frequency signal source with modulation function |
| CN104730300A (en) * | 2013-12-24 | 2015-06-24 | 苏州普源精电科技有限公司 | Measuring device with ALC |
| CN104734656A (en) * | 2013-12-24 | 2015-06-24 | 苏州普源精电科技有限公司 | Radio frequency signal source with amplitude modulation and automatic level control functions |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114531331A (en) * | 2022-02-07 | 2022-05-24 | 北京奕斯伟计算技术有限公司 | IQ signal calibration method and device |
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