CN102507993B - Burst signal generator with automatic initial phase calibration function - Google Patents

Abstract

The invention discloses a burst signal generator with an automatic initial phase calibration function. A signal measurement unit, which is composed of an average value measurement device and a peak-to-peak value measurement device, is additionally arranged on the base of the traditional burst signal generator. The signal measurement unit is used for firstly measuring a peak-to-peak value voltage UCPP and a direct-current bias voltage deltaUDC of a continuous carrier signal, and an average value UAVE of measured burst signals, and then calculating an initial phase theta2 of an output burst signal and setting a phase difference deltatheta between an initial phase theta1 and the initial phase theta2, and increasing and decreasing a phase control word according to the phase difference deltatheta. According to the invention, the signal measurement unit is placed in the burst signal generator and a measured result is fed back to a control unit to increase and decrease the phase control word and carry out corresponding calibration on the initial phase. The calibration process does not need manual intervention and has the advantage of rapid and accurate calibration compared with the traditional method.

Description

A kind of burst signal generator with automatic initial phase calibration function

Technical field

The invention belongs to waveform generation and field of measuring technique, more specifically say, relate to a kind of burst signal generator with automatic initial phase calibration function.

Background technology

In the technical field of electronic instrument, the application of burst signal is more and more extensive.For thering is the signal source of the function of bursting, how to guarantee the high-precision requirement of its initial phase of bursting, become that burst signal produces and fields of measurement in an important problem.

As shown in Figure 1, burst signal is actually a kind of modulation signal, is defined as after start pulse signal arrives, and exports the carrier waveform that one or several have characteristic frequency and phase place, before next start pulse signal arrives, output keeps constant direct current signal.Carrier wave can be the various common continuous waves such as sine wave, triangular wave, sawtooth wave.Fig. 1 is that initial phase is that 45 °, carrier wave are the sinusoidal wave waveform of bursting.Wherein, T is the duration of Constant Direct Current level, is the time interval of the upper pulse high level t1 finish time and the moment t2 of pulse high level arrival next time, the low level of corresponding start pulse signal; U _tDCvoltage for direct current signal.

Fast development along with digital technology, DDS technology is one of aborning a kind of common technology of burst signal, its ultimate principle is to calculate reset signal duration T according to the number of set carrier waveform, as Fig. 1 shows, the reset signal of controlling DDS phase accumulator in time T enables, periodically phase accumulator is carried out to clear operation, realize the generation of the waveform of bursting.The control of initial phase of bursting is to realize by changing the control word of phase place totalizer.In actual applications, because circuit elements device parameters is not mated and the impact of placement-and-routing, the high precision of burst signal initial phase cannot be guaranteed.Along with the application of burst signal is more and more extensive, the precision that how the to guarantee burst signal initial phase ever more important that also becomes.For the initial phase of calibration burst signal, traditional method is carried out software matching after often adopting specialized equipment to measure, but the method complex operation and consuming time.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, a kind of burst signal generator with automatic initial phase calibration function is provided, can carry out fast accurate automatic calibration to the burst signal initial phase of output.

For achieving the above object, the present invention has the burst signal generator of automatic initial phase calibration function, comprises the signal generation unit, the control module that phase accumulator, reset signal generator, phase place totalizer, RAM storer, DAC and analog channel, consist of;

The carrier frequency that control module is set according to user calculates corresponding frequency control word to phase accumulator, the burst signal initial phase θ that control module is set according to user ₁calculate corresponding phase control words to phase place totalizer;

Phase accumulator adds up to frequency control word, output accumulated value in phase place totalizer with phase control words phase adduction as address, reading carrier waveform data in RAM storer sends into DAC and carries out digital-to-analog conversion, generate simulating signal, simulating signal generates required carrier wave again after analog channel adjustment;

The burst frequency that control module is set according to user, reset signal generator is set, make its quenching pulse signal that produces corresponding burst frequency to phase accumulator, when quenching pulse signal is high level, enabling phase accumulator adds up, when quenching pulse signal is low level, phase accumulator stops adding up and keeps current output until quenching pulse signal starts the cumulative of next cycle while being high level;

It is characterized in that, also comprise a signal measurement unit being formed by measurement of average value device and peak-to-peak value measurement mechanism; In control module, also comprise peak-to-peak value voltage register, DC offset voltage register and mean value register;

User, set carrier frequency, burst signal initial phase θ ₁, after burst frequency, the quenching pulse signal that control module is controlled reset signal generator output is high level always, and burst signal generator output continuous carrier signal, connects peak-to-peak value measurement mechanism and mean value measurement mechanism successively, the continuous carrier signal of measuring output, obtains peak-to-peak value voltage U _cPP, DC offset voltage _Δu _dC, and be stored in respectively in peak-to-peak value voltage register, DC offset voltage register;

After measuring continuous carrier signal, it is f that control module is controlled reset signal generator output burst frequency ₂quenching pulse signal and send into phase accumulator, the burst signal that burst signal generator output is set; Connect measurement of average value device, measure the mean value U of burst signal _aVE, and be stored in mean value register.

In control module, by following formula, calculate the initial phase θ of output burst signal ₂:

${\mathrm{\θ}}_2=\arcsin \left(\frac{U_{\mathrm{AVE}}-U_{\mathrm{DC}}^{\mathrm{\Δ}}}{U_{\mathrm{CPP}}/2}\right)---\left(1\right)$

Then, calculate and set initial phase θ ₁with measurement initial phase θ ₂phase difference θ=θ ₁-θ ₂, if just, phase control words is being carried out the increase of phase difference θ corresponding amount, negative if, phase control words is carried out to phase differential | Δ θ | the minimizing of corresponding amount, the burst signal of the initial phase that output is accurately controlled.

Goal of the invention of the present invention is achieved in that

The present invention has the burst signal generator of automatic initial phase calibration function, at existing burst signal generator, on the basis of signal generation unit, control module, increased a signal measurement unit being formed by measurement of average value device and peak-to-peak value measurement mechanism.First signal measurement unit measures the peak-to-peak value voltage U of continuous carrier signal _cPP, DC offset voltage _Δu _dCand the mean value U that measures burst signal _aVE, then calculate the initial phase θ that exports burst signal ₂, θ ₂be the burst signal prima facies place value of measurement, according to setting initial phase θ ₁with measurement initial phase θ ₂calculate both phase difference θ, and according to phase difference θ, phase control words is carried out the increase of corresponding amount or reduced, the initial phase of the burst signal of output has just obtained calibration like this.In the present invention, signal measurement unit is built in burst signal generator, with original module composition feedback control loop, measurement feedback is returned to control module and phase control words is increased or reduced, and initial phase is calibrated accordingly.This calibration process, without manual intervention, is compared classic method, has the advantage of quick accurate calibration.

Accompanying drawing explanation

Fig. 1 is burst signal and as an oscillogram of the start pulse signal of modulation signal;

Fig. 2 is the theory diagram that the present invention has burst signal generator one embodiment of automatic initial phase calibration function;

Fig. 3 is actual phase oscillogram corresponding to phase value that burst signal carrier wave is measured while being sinusoidal carrier;

Fig. 4 is burst signal carrier wave calibrating principle oscillogram of the present invention while being sinusoidal carrier.

Embodiment

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described, so that those skilled in the art understands the present invention better.Requiring particular attention is that, in the following description, when perhaps the detailed description of known function and design can desalinate main contents of the present invention, these are described in here and will be left in the basket.

Fig. 2 is the theory diagram that the present invention has burst signal generator one embodiment of automatic initial phase calibration function.

In the present embodiment, as shown in Figure 2, the burst signal generator that the present invention has an automatic initial phase calibration function comprises signal generation unit 1, the control module 2 being comprised of phase accumulator, reset signal generator, phase place totalizer, RAM storer, DAC and analog channel and the signal measurement unit 3 being comprised of measurement of average value device and peak-to-peak value measurement mechanism.Frequency control word and phase control words that frequency control word register in signal generation unit 1 and phase control word register provide for storage control unit 2.

The carrier frequency f that control module 2 is set according to user ₁calculate corresponding frequency control word and deposit in frequency control word register, then offer phase accumulator; The burst signal initial phase θ that control module 2 is set according to user ₁calculate corresponding phase control words and deposit in phase control word register, then offer phase place totalizer.

Phase accumulator adds up to frequency control word, output accumulated value in phase place totalizer with phase control words phase adduction as address, reading carrier waveform data in RAM storer sends into DAC and carries out digital-to-analog conversion, generate simulating signal, simulating signal generates required carrier wave again after analog channel adjustment.

The burst frequency f that control module 2 is set according to user ₂reset signal generator is set, make its quenching pulse signal that produces corresponding burst frequency to phase accumulator, when quenching pulse signal is high level, enabling phase accumulator adds up, when quenching pulse signal is low level, phase accumulator stops adding up and keeps current output until quenching pulse signal starts the cumulative of next cycle while being high level.Just to export burst frequency be f to burst signal generator like this ₂, carrier frequency is f ₁burst signal.This is the ultimate principle of the burst signal generator of prior art based on DDS.

The present invention, on the basis of existing burst signal generator, has increased a signal measurement unit being comprised of measurement of average value device and peak-to-peak value measurement mechanism on the basis of signal generation unit, control module.In control module, increased have peak-to-peak value voltage register, DC offset voltage register and mean voltage register, for storing the peak-to-peak value voltage U of continuous carrier signal _cPP, DC offset voltage _Δu _dCand the mean value U that measures burst signal _aVE.

Calibration and the course of work are as follows:

User, set carrier frequency f ₁burst signal initial phase θ ₁, burst frequency f ₂after, the quenching pulse signal that control module 2 is controlled reset signal generator output is high level always, burst signal generator output frequency is f ₁continuous carrier signal, connect successively peak-to-peak value measurement mechanism and mean value measurement mechanism, measure the continuous carrier signal of output, obtain peak-to-peak value voltage U _cPP, DC offset voltage _Δu _dC, and be stored in respectively in peak-to-peak value voltage register, DC offset voltage register;

After measuring continuous carrier signal, it is f that control module 2 is controlled reset signal generator output burst frequency ₂quenching pulse signal and send into phase accumulator, the burst signal that burst signal generator output is set; Connect measurement of average value device, measure the mean value U of burst signal _aVE, and be stored in mean voltage register;

In control module 2, by following formula, calculate the initial phase θ of output burst signal ₂:

${\mathrm{\θ}}_2=\arcsin \left(\frac{U_{\mathrm{AVE}}-U_{\mathrm{DC}}^{\mathrm{\Δ}}}{U_{\mathrm{CPP}}/2}\right)---\left(1\right)$

Then, calculate and set initial phase θ ₁with measurement initial phase θ ₂phase difference θ=θ ₁-θ ₂, if just, phase control words is being carried out the increase of phase difference θ corresponding amount, negative if, phase control words is carried out to phase differential | Δ θ | the minimizing of corresponding amount, output is the burst signal of the initial phase of control accurately, has realized the quick accurate calibration of initial phase.

In the present embodiment, carrier wave is sinusoidal wave, and the cycle is that the sinusoidal carrier of 2 π be take x=pi/2 as even symmetry, as shown in Figure 3, and initial phase θ ₂while being 30 ° and 150 °, correspondence identical sine function, now should do concrete judgement by the setting value of initial phase.If initial phase setting value is θ ₁(θ ₁90 ° of >), time, measured value is θ ₂(θ ₂90 ° of <), actual measured value should be 180 °-θ ₂; If θ ₁90 ° of <, actual measured value should be θ ₂.

Fig. 4 is burst signal carrier wave calibrating principle oscillogram of the present invention while being sinusoidal carrier.

The measuring principle of DC level is that the mean value of signal is measured.Following discussion is with DC-offset correction voltage _Δu _dCbasis on carry out.Definition phase value θ ₃: θ ₃for according to user's setting value θ ₁and the actual phase value producing, phase value θ ₂to θ ₃measured value.As shown in Figure 4, U _tDCinitial phase θ for the sinusoidal carrier burst signal of burst signal generator output ₃corresponding amplitude, U _aVEfor the mean value of the burst signal measured, U _cPPpeak-to-peak value voltage for carrier signal.In Fig. 4, definition S1, S2, S3, S4, S5, S6 are respectively the initial phase θ of sinusoidal carrier burst signal ₃time represented each dash area area.

In Fig. 4, the initial phase θ of sinusoidal carrier burst signal ₃for:

${\mathrm{\&theta;}}_3=\arcsin \left(\frac{U_{\mathrm{TDC}}}{U_{\mathrm{CPP}}/2}\right)---\left(2\right)$

The initial phase θ of sinusoidal carrier burst signal ₃corresponding DC level is U _tDC, the area in corresponding diagram 4 is:

$S_{\mathrm{ture}}=|\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA0000099977730000022.png"\; state="\{\{state\}\}">S</figure-callout>}1+\mathrm{<figure-callout\; id="4"\; label="S"\; filenames="HDA0000099977730000022.png"\; state="\{\{state\}\}">S</figure-callout>}4+\mathrm{<figure-callout\; id="5"\; label="S"\; filenames="HDA0000099977730000022.png"\; state="\{\{state\}\}">S</figure-callout>}5+\mathrm{<figure-callout\; id="6"\; label="S"\; filenames="HDA0000099977730000022.png"\; state="\{\{state\}\}">S</figure-callout>}6|=U_{\mathrm{TDC}}\&times;\frac{1}{f_2}---\left(3\right)$

Obtain

$U_{\mathrm{TDC}}=\frac{{\mathrm{<figure-callout\; id="1"\; label="S\; ture"\; filenames="HDA0000099977730000022.png"\; state="\{\{state\}\}">S</figure-callout>}}_{\mathrm{ture}}}{1/f_2}---\left(4\right)$

The mean value U of the burst signal of measuring _aVEwith U _tDCbetween had certain error, in Fig. 4, the algebraic sum of actual measurement part area can be expressed as:

$S_{\mathrm{measure}}=|\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA0000099977730000022.png"\; state="\{\{state\}\}">S</figure-callout>}1+S2-\mathrm{<figure-callout\; id="3"\; label="S"\; filenames="HDA0000099977730000012.png,HDA0000099977730000022.png"\; state="\{\{state\}\}">S</figure-callout>}3+\mathrm{<figure-callout\; id="5"\; label="S"\; filenames="HDA0000099977730000022.png"\; state="\{\{state\}\}">S</figure-callout>}5+\mathrm{<figure-callout\; id="6"\; label="S"\; filenames="HDA0000099977730000022.png"\; state="\{\{state\}\}">S</figure-callout>}6|=U_{\mathrm{AVE}}\&times;\frac{1}{f_2}---\left(5\right)$

Obtain

$U_{\mathrm{AVE}}=\frac{S_{\mathrm{measure}}}{1/f_2}---\left(6\right)$

The measured value θ of the initial phase of sinusoidal carrier burst signal ₂for:

${\mathrm{\&theta;}}_2=\arcsin \left(\frac{U_{\mathrm{AVE}}}{U_{\mathrm{CPP}}/2}\right)$

By formula (4) and formula (6), obtain U _aVEwith U _tDCerror be:

$\mathrm{\&Delta;V}=\frac{S_{\mathrm{ture}}-S_{\mathrm{measure}}}{1/{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="HDA0000099977730000022.png"\; state="\{\{state\}\}">f</figure-callout>}}_2}=\frac{|\mathrm{<figure-callout\; id="4"\; label="S"\; filenames="HDA0000099977730000022.png"\; state="\{\{state\}\}">S</figure-callout>}4+(S3-S2)|}{1/f_2}---\left(8\right)$

Try to achieve

$\mathrm{\&Delta;V}=U_{\mathrm{TDC}}\&times;\frac{f_2}{f_1}---\left(9\right)$

Thus can be in the hope of the mean value U of sinusoidal carrier burst signal _aVEthe error delta producing is

$\mathrm{\&delta;}=\frac{\mathrm{\&Delta;V}}{U_{\mathrm{TDC}}}=\frac{f_2}{f_1}---\left(10\right)$

So the error that use the present invention measures burst signal initial phase is mainly by f ₂/ f ₁introduce.When bursting waveform initial phase one regularly, f ₂/ f ₁value less, precision is higher; Otherwise, lower.

Example

Because the present invention is higher to the accuracy requirement of voltage measurement, so in specific implementation process, use high-precision voltage measuring apparatus in signal measurement unit.The measuring accuracy of signal measurement unit is 6 half in this example.Meanwhile, because the present invention is self-operated measuring unit, so in the concrete process of implementing, all measuring processes are for automatically completing.Take sinusoidal carrier burst signal as example, introduce the course of work as follows:

1. a frequency of signal generation unit generation is the continuous sine wave signal that 100kHz, amplitude are 1V after setting completed, connects successively measurement of average value device and peak-to-peak value measurement mechanism, records measurement result U _cPPwith _Δu _dC, measurement result is inserted in table 1.

2. burst signal generator produces burst signal: initial phase is 0, and burst frequency is 100Hz, and carrier wave is sinusoidal wave, and carrier amplitude is that 1V, frequency are 100kHz.Measure its mean value level U _tDC, the result of measurement is inserted in table 1.

3. calculate the measured value θ of initial phase ₂with phase deviation Δ θ, insert in table 1.

Table 1 for initial phase be 0 o'clock measurement data.

Table 1

Table 2 for the sinusoidal carrier burst signal waveform of bursting be 100Hz, the initial phase calibration value of bursting under the condition that carrier signal is 100KHz.

Table 2

The experimental test data of sinusoidal carrier burst signal initial phase testing and calibration provide in table 2.Above-mentioned measurement data is analyzed, can be shown that the method can carry out accurate calibration to burst signal initial phase effectively.Simultaneously, when the carrier waveform of burst signal is that triangular wave, sawtooth wave etc. can be described with formula, and in cycle (within the scope of 0-2 π as sawtooth wave etc.), semiperiod (within the scope of 0-π as triangular wave etc.) or the 1/4 cycle scope such as (within the scope of 0-pi/2 as sinusoidal wave), wave-shape amplitude is strictly monotone increase (or strictly monotone minimizing), all can adopt this invention to carry out accurate calibration to burst signal initial phase.

Visible result of the present invention is accurate, can to the initial phase of burst signal, calibrate quickly and accurately.

Although above the illustrative embodiment of the present invention is described; so that the technician of this technology neck understands the present invention; but should be clear; the invention is not restricted to the scope of embodiment; to those skilled in the art; as long as various variations appended claim limit and definite the spirit and scope of the present invention in, these variations are apparent, all utilize innovation and creation that the present invention conceives all at the row of protection.

Claims (2)

1. a burst signal generator with automatic initial phase calibration function, comprises the signal generation unit, the control module that phase accumulator, reset signal generator, phase place totalizer, RAM storer, DAC and analog channel, consist of;

The carrier frequency that control module is set according to user calculates corresponding frequency control word to phase accumulator, the setting initial phase θ of the burst signal that control module is set according to user ₁calculate corresponding phase control words to phase place totalizer;

Phase accumulator adds up to frequency control word, output accumulated value in phase place totalizer with phase control words phase adduction as address, reading carrier waveform data in RAM storer sends into DAC and carries out digital-to-analog conversion, generate simulating signal, simulating signal generates required carrier wave again after analog channel adjustment;

The burst frequency that control module is set according to user, reset signal generator is set, make its quenching pulse signal that produces corresponding burst frequency to phase accumulator, when quenching pulse signal is high level, enabling phase accumulator adds up, when quenching pulse signal is low level, phase accumulator stops adding up and keeps current output until quenching pulse signal starts the cumulative of next cycle while being high level;

It is characterized in that, also comprise a signal measurement unit being formed by measurement of average value device and peak-to-peak value measurement mechanism; In control module, also include peak-to-peak value voltage register, DC offset voltage register and mean voltage register;

User, set the setting initial phase θ of carrier frequency, burst signal ₁, after burst frequency, the quenching pulse signal that control module is controlled reset signal generator output is high level always, and burst signal generator output continuous carrier signal, connects peak-to-peak value measurement mechanism and mean value measurement mechanism successively, the continuous carrier signal of measuring output, obtains peak-to-peak value voltage U _cPP, DC offset voltage _Δu _dC, and be stored in respectively in peak-to-peak value voltage register, DC offset voltage register;

After measuring continuous carrier signal, it is f that control module is controlled reset signal generator output burst frequency ₂quenching pulse signal and send into phase accumulator, the burst signal that burst signal generator output is set; Connect measurement of average value device, measure the mean value U of burst signal _aVE, and be stored in mean voltage register;

In control module, by following formula, calculate the measurement initial phase θ of output burst signal ₂:

${\mathrm{\&theta;}}_2=\arcsin \left(\frac{U_{\mathrm{AVE}}-U_{\mathrm{DC}}^{\mathrm{\&Delta;}}}{U_{\mathrm{CPP}}/2}\right)---\left(1\right)$

Then, calculate and set initial phase θ ₁with measurement initial phase θ ₂phase difference θ=θ ₁-θ ₂, if just, phase control words is being carried out the increase of phase difference θ corresponding amount, negative if, phase control words is carried out to phase differential | Δ θ | the minimizing of corresponding amount, the burst signal of the initial phase that output is accurately controlled.

2. the burst signal generator with automatic initial phase calibration function according to claim 1, is characterized in that, described carrier wave is sinusoidal wave, sets initial phase θ ₁in the time of >90 °, measure initial phase θ ₂be modified to 180 °-θ of actual measured value ₂.

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