CN203502449U - Waveform synthesizer - Google Patents
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- CN203502449U CN203502449U CN201320664292.XU CN201320664292U CN203502449U CN 203502449 U CN203502449 U CN 203502449U CN 201320664292 U CN201320664292 U CN 201320664292U CN 203502449 U CN203502449 U CN 203502449U
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Abstract
The utility model provides a waveform synthesizer comprising the following structures: a waveform counter connected with a read-write controller and used for counting according to pulse signals; a waveform data memory connected with the read-write controller and used for storing preset waveform amplitude data and digital information; the read-write controller respectively connected with the waveform data memory and a digital analog converter, and used for extracting the amplitude data in sequence from the waveform data memory under the effect of the waveform counter and sending the extracted amplitude data in sequence to the digital analog converter; the digital analog converter connected with a filter amplifier and used for carrying out digital analog conversion for the amplitude data so as to obtain current signals; a current-to-voltage converter connected with the digital analog converter and used for converting the current signal into voltage signal. The waveform synthesizer can realize high accuracy analog, is precise, low in noise, stable in frequency, and outputs in high speed.
Description
Technical field
The utility model, about signal generation technique field, particularly about the synthetic technology of voltage and current signal, is a kind of waveform synthesizer concretely.
Background technology
Waveform generator is widely used in the fields such as electronic surveying, communication, radar, scientific experiment, is main signal source.To some degree, high-quality signal source is to realize the key of high performance index.In a lot of contemporary electronic systems, communication facilities or measuring system, all applied high performance signal generating source high-quality signal is provided.Therefore, high-quality signal generator has become requisite electronic system in modern society.
Traditional waveform generator, output frequency band limits waveform narrow, output is single, and output frequency is unstable.In actual applications, sometimes need the prompt change of output frequency of waveform generator, band limits is as far as possible wide, and wants to realize hyperchannel output, and this is very important to multi-channel system, and hyperchannel output is wanted synchronously, also will keep certain phase relation.
Traditional waveform generator is not considered the phase differential of the caused output signal of difference of unbalanced, the different chip chamber delay times of the external signal passage being produced by simulation process.
Patent document ZL200910056129.3 discloses a kind of diagnostic method of rotor interturn short-circuit, its simulation produces a current excitation source, thereby measure the resistance value of rotor winding, to measure revaluate and last measured value and original value, compare, draw whether existence and stability short trouble of generator amature AC impedance.But the resistance value described in the method, it is the current value divided by described current excitation source by magnitude of voltage, because the current excitation source accuracy that the method is developed is not high, so its impedance indicating value also exists larger error, cannot reach the object of accurate-metering rotor winding AC impedance.
Patent document ZL200610011680.2 discloses a kind of multichannel synchronous sinusoidal signal generator, and it is Multipexer sinusoidal signal simultaneously, and has adopted DDS technology for frequency stability.But the output of sort signal generator is only a signal source, and its current/voltage pushing portion does not relate to.Yet a lot of instruments in reality, such as handing over flow resistance tester, its current/voltage range is more special, therefore the output voltage of signal generator of this patent and the defect in the ability of output current have restricted its application, cannot cover the gamut of various surveying instruments such as ac impedance measurement instrument in industry.
Therefore, how to build a kind of waveform synthesizer, its can be applied to measuring system so that detect various surveying instruments especially ac impedance measurement instrument become this area technical barrier urgently to be resolved hurrily.
Utility model content
The utility model is for the above-mentioned technical matters existing in prior art, a kind of waveform synthesizer has been proposed, by default waveform is decomposed and is quantized, then in order the amplitude data of waveform is stored with numerical information, again according to the needs of initial phase, from prima facies site with the identical Wave data that takes out complete storage in turn, and be transformed into analog quantity through D/A circuit, it is the exportable waveform of wishing to get, this waveform synthesizer can be used as electronic system, the signal generating source of communication facilities or measuring system provides high-quality signal, for the pin-point accuracy testing of system provides condition and guarantee.
The purpose of this utility model is, a kind of waveform synthesizer is provided, and described waveform synthesizer specifically comprises: waveform counter, is connected with read-write controller, for counting according to pulse signal; Waveform data memory, is connected with described read-write controller, for storing amplitude data and the numerical information of the waveform presetting; Described read-write controller, be connected with described waveform data memory, digital to analog converter respectively, for extract successively described amplitude data from described waveform data memory under the effect of described waveform counter, and the amplitude data of extraction is sent to described digital to analog converter successively; Described digital to analog converter, for described amplitude data is carried out to digital-to-analog conversion, obtains current signal; Current-to-voltage converter, is connected with described digital to analog converter, for described current signal is transformed to voltage signal.
Preferably, described waveform synthesizer also comprises: filter amplifier, be connected with described digital to analog converter, described current-to-voltage converter respectively, for described current signal is carried out to filter and amplification, and the current signal after filter and amplification is sent to described current-to-voltage converter.
Preferably, described waveform synthesizer also comprises: waveform decomposes and quantifying unit, is connected with described waveform data memory, for the waveform presetting being decomposed and quantizing, obtains amplitude data and numerical information.
The beneficial effects of the utility model are, a kind of waveform synthesizer proposing, by default waveform is decomposed and is quantized, then in order the amplitude data of waveform is stored with numerical information, again with identical taking out in turn and be transformed into analog quantity through D/A circuit, the i.e. exportable waveform of wishing to get.By digital waveform synthesize technology, realize the pin-point accuracy simulation of waveform synthesizer, the beneficial effect with precision, low noise, frequency stabilization, high speed output, and the signal generating source that this waveform synthesizer can be used as electronic system, communication facilities or measuring system provides high-quality signal, for the pin-point accuracy testing of system provides condition and guarantee.
For above and other object of the present utility model, feature and advantage can be become apparent, preferred embodiment cited below particularly, and coordinate appended graphicly, be described in detail below.
Accompanying drawing explanation
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only embodiment more of the present utility model, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.
The structural representation of the embodiment one of a kind of waveform synthesizer that Fig. 1 provides for the utility model embodiment;
The structural representation of the embodiment two of a kind of waveform synthesizer that Fig. 2 provides for the utility model embodiment;
The structural representation of the embodiment three of a kind of waveform synthesizer that Fig. 3 provides for the utility model embodiment;
Fig. 4 is the circuit theory diagrams of digital to analog converter in the waveform synthesizer of the utility model embodiment;
Fig. 5 is the sinusoidal wave waveform schematic diagram presetting in the utility model embodiment.
Embodiment
Below in conjunction with the accompanying drawing in the utility model embodiment, the technical scheme in the utility model embodiment is clearly and completely described, obviously, described embodiment is only the utility model part embodiment, rather than whole embodiment.Embodiment based in the utility model, those of ordinary skills are not making the every other embodiment obtaining under creative work prerequisite, all belong to the scope of the utility model protection.
The basic thought of digital waveform synthesizer of the present utility model is: first the sinusoidal signal waveform (waveform presetting) that will obtain decomposed and quantized, then in order the amplitude data of waveform being stored in storer with numerical information.During work, then with the identical amplitude information that takes out in turn, through digital to analog converter, be transformed into analog quantity, the waveform that output is wished to get.
The structural representation of the embodiment one of a kind of waveform synthesizer that Fig. 1 provides for the utility model embodiment, as shown in Figure 1, in embodiment one, waveform synthesizer specifically comprises:
Described read-write controller 300, be connected with described waveform data memory, digital to analog converter respectively, for extract successively described amplitude data from described waveform data memory under the effect of described waveform counter, and the amplitude data of extraction is sent to described digital to analog converter successively.
Described digital to analog converter 400, for described amplitude data is carried out to digital-to-analog conversion, obtains current signal.The circuit theory diagrams of digital to analog converter as shown in Figure 5, as shown in Figure 5, N1 is accurate reference voltage, N2 is accurate low noise operational amplifier, N3 is current-output type digital to analog converter, and N4 is accurate low noise operational amplifier, and C1, C5, C7 are 1 μ F shunt capacitances, C2, C3, C6, C8 are 0.1 μ F shunt capacitances, and C4 is 2.2pF building-out capacitor.
In concrete embodiment, digital to analog converter is available is the AD5547 chip that U.S. analog semiconductor ANALOG company produces.Circuit adopts electric current output DAC AD5547, accurate reference voltage ADR01 and operational amplifier A D8512 to realize accurate, bipolarity data-switching.It has precision, low noise, high speed output voltage capability, is applicable to very much the application such as process control, ATE (automatic test equipment) and digital calibration.
Current-output type DAC is binary channels, precision, 16, multiplication, low-power consumption, electric current output, parallel input digital to analog converter, adopts 2.7V to 5.5V single power supply, and the multiplication reference voltage of four-quadrant output is ± 15V.Built-in four-quadrant resistance is conducive to resistors match and temperature is followed the tracks of, and makes many quadrants apply required number of elements and be down to minimum.
Current-to-voltage converter 500, is connected with described digital to analog converter, for described current signal is transformed to voltage signal f
o.Current-to-voltage converter is I/V conversion, is N in Fig. 4
4, model adopts AD8512, is to convert the current signal of input to meet certain relation voltage signal, and the voltage after conversion is equivalent to a constant pressure source that output is adjustable, and its output voltage should be able to keep stable and can not change with the variation of load.
In specific embodiment of the utility model, in current-to-voltage converter (I-V) level, used operational amplifier.The bias current of operational amplifier and offset voltage are the major criterion of selecting precision current output DAC, so this circuit adopts the AD8512 operational amplifier with Low-offset voltage (B level device representative value is 80 μ V) and bias current (representative value is 25pA).C9 is building-out capacitor.The C9 capacitance of this application is 2.2pF, through optimizing the outside output capacitance that can compensate DAC.Therefore this circuit adopts the AD8512 operational amplifier with Low-offset voltage and bias current.
The input offset voltage of operational amplifier will be multiplied by the variable noise gain (owing to there being the relevant output impedance of code of DAC) of circuit.Due to the input voltage imbalance of amplifier, the noise gain variation between two consecutive number character codes can make output voltage produce step change.Exporting change required between this output voltage variation and two codes is superimposed, causes differential linearity error; If this error is enough large, may cause DAC non-monotonic.Generally speaking, keep monotonicity when along each code stepping, input offset voltage must only be equivalent to the fraction for LSB.For ADR01 and AD5547, LSB size is:
The input bias current of operational amplifier also can produce imbalance on Voltage-output, and its reason is the biased electrical feedback resistance RFB that flows through that fails to be convened for lack of a quorum.With regard to AD8512, its input bias current representative value is only 25pA, only produces the error of 0.25 μ V during the RFB resistance of flowing through (being generally 10k Ω).
AD5547DAC framework adopts the design of electric current guiding R-2R ladder shaped resistance, requires to use outside reference voltage source and amplifier, to be converted to output voltage.The output voltage V of AD5547
oUTcan calculate by following formula:
The decimal equivalent that wherein D is input code; For 16 DAC, D=0 to 65535.
Also, waveform synthesizer of the present utility model has stored amplitude data and numerical information in waveform data memory in advance.At pulse signal f
iunder effect, waveform counter is sent into digital to analog converter from the taking-up of waveform data memory appropriate address successively from 0-35999 counting and by amplitude data successively.In digital to analog converter, the numerical information of amplitude is become to corresponding analog quantity (current signal), then through current-to-voltage converter, current signal is become to ambipolar voltage signal.Because waveform has been counted and has been reached 36000 points, very level and smooth, can be without additional low-pass filter again.This circuit is used high precision, high stability, 10V accurate reference voltage ADR01.The temperature coefficient of reference voltage source and long term drift performance are the major consideration that requires high precision transformation applications.The signal generating source that the waveform synthesizer that the utility model provides can be used as electronic system, communication facilities or measuring system provides high-quality signal, for the pin-point accuracy testing of system provides condition and guarantee, especially such as being applied to measuring system, can Measurement accuracy ac impedance measurement instrument etc. instrument.
The structural representation of the embodiment two of a kind of waveform synthesizer that Fig. 2 provides for the utility model embodiment, as shown in Figure 2, in embodiment two, waveform synthesizer also comprises:
The structural representation of the embodiment three of a kind of waveform synthesizer that Fig. 3 provides for the utility model embodiment, as shown in Figure 3, in embodiment three, waveform synthesizer also comprises:
Waveform decomposes and quantifying unit 700, is connected with described waveform data memory 200, for the waveform presetting being decomposed and quantizing, obtains amplitude data and numerical information.The waveform presetting of herein mentioning is trial voltage, the current signal needing when test macro is wanted testing tool such as ac impedance measurement instrument.Before test, can determine according to the instrument that will test.
First presetting sinusoidal signal waveform, decompose and quantize, then in order the amplitude of waveform being stored in storer with numerical information.According to the adjusting fineness of phase place, select counting of decomposition, phase adjusted fineness is higher, and counting of should decomposing is just more, and desired data amount is just larger.Suppose that the sinusoidal wave waveform schematic diagram that presets as shown in Figure 5, in one-period, be divided into 16 sections, a complete sine wave is comprised of 16 points, every point-to-point transmission is separated by with 360 °/16=22.5 °, between amplitude peak-to-peak value, be divided into into ± 100 grades, the quantification gradation of 16 points is marked in figure.Obviously, make waveform true to nature, counting of decomposing in one-period is The more the better with the quantification progression of amplitude.But counting of decomposing is more, produces the required data volume of complete sine wave just larger.Generally to select counting of decomposition according to the adjusting fineness of phase place.When phase adjusted fineness is 1 °, desirable 360 points, when regulating fineness to be 0.1 °, desirable 3600 points.Phase adjusted fineness is higher, and counting of should decomposing is just more, and desired data amount is just larger.According to our designing requirement, phase adjusted fineness is 0.01 °, so one-period is got 36000 points.
The progression of amplitude quantizing is more, and in the future required D/A figure place is just more.For example, while being quantified as 256 grades, need 8 D/A (2
8=256),, while being quantified as 2048 grades, need 12 D/A.When D/A figure place is few, cost is low, but output waveform is unsmooth, contains higher hamonic wave, need to be with in addition filtering of low-pass filter, and low-pass filter can produce additional phase shift.Therefore, desirable 65536 grades, thus need be with 16 D/A when waveform is synthetic, and employing offset binary bipolar code represents sinusoidal wave positive-negative polarity.The null value that is about to analog quantity moves on to corresponding with the 8000H of digital quantity, and when Sin0 °=0, quantized value is 8000H.Sinusoidal wave positive half cycle represents with 8000H～FFFFH, and Sin90 °=1 o'clock, quantized value was FFFFH; Sinusoidal wave negative half period represents with 0000H～8000H, and sin270 °=-1 o'clock, quantized value was 0000H.Store so sinusoidal wave information, required memory capacity is 36000 * 16 * 2, needs to have 144000 byte units.
It is the waveform synthesizer that the utility model provides, in wave memorizer, stored after Wave data, under pulse signal fi effect, waveform counter is sent into digital to analog converter from the taking-up of wave memorizer appropriate address successively from 0-35999 counting and by amplitude data successively.In digital to analog converter, the numerical information of amplitude is become to corresponding analog quantity, i.e. current signal, then through operational amplifier, current signal is become to ambipolar voltage signal.Due to waveform nearly 36000 points of counting, sinusoidal waveform is very level and smooth, so without extra additional low-pass filter.Digital to analog converter is selected the parallel input of electric current output 16 figure place weighted-voltage D/A converters.Circuit adopts electric current output DAC chip, accurate reference voltage ADR01 and operational amplifier A D8512 to realize accurate, bipolarity data-switching.
Accurate reference voltage ADR01, the temperature coefficient of reference voltage source and long term drift performance are the major consideration that requires high precision transformation applications, have high precision, high stability feature.ADR01 is 400 in Fig. 1 waveform generation module, and for digital to analog converter provides the 10.0V reference voltage of high precision, this device also provides TRIM pin, for precision, adjusts output voltage.
In sum, a kind of waveform synthesizer the utility model proposes, by default waveform is decomposed and is quantized, then in order the amplitude data of waveform is stored with numerical information, again with identical taking out in turn and be transformed into analog quantity through D/A circuit, the i.e. exportable waveform of wishing to get.By digital waveform synthesize technology, realize the pin-point accuracy simulation of waveform synthesizer, the beneficial effect with precision, low noise, frequency stabilization, high speed output, and the signal generating source that this waveform synthesizer can be used as electronic system, communication facilities or measuring system provides high-quality signal, for the pin-point accuracy testing of system provides condition and guarantee.
One of ordinary skill in the art will appreciate that all or part of flow process realizing in above-described embodiment system, can come the hardware that instruction is relevant to complete by computer program, described program can be stored in general computer read/write memory medium, this program, when carrying out, can comprise as the flow process of the embodiment of above-mentioned each system.Wherein, described storage medium can be magnetic disc, CD, read-only store-memory body (Read-Only Memory, ROM) or random store-memory body (Random AccessMemory, RAM) etc.
In the utility model, applied specific embodiment principle of the present utility model and embodiment are set forth, the explanation of above embodiment is just for helping to understand of the present utility model and core concept; , for one of ordinary skill in the art, according to thought of the present utility model, all will change in specific embodiments and applications, in sum, this description should not be construed as restriction of the present utility model meanwhile.
Claims (3)
1. a waveform synthesizer, is characterized in that, described waveform synthesizer specifically comprises:
Waveform counter, is connected with read-write controller, for counting according to pulse signal;
Waveform data memory, is connected with described read-write controller, for storing amplitude data and the numerical information of the waveform presetting;
Described read-write controller, be connected with described waveform data memory, digital to analog converter respectively, for extract successively described amplitude data from described waveform data memory under the effect of described waveform counter, and the amplitude data of extraction is sent to described digital to analog converter successively;
Described digital to analog converter, for described amplitude data is carried out to digital-to-analog conversion, obtains current signal;
Current-to-voltage converter, is connected with described digital to analog converter, for described current signal is transformed to voltage signal.
2. waveform synthesizer according to claim 1, is characterized in that, described waveform synthesizer also comprises:
Filter amplifier, is connected with described digital to analog converter, described current-to-voltage converter respectively, for described current signal is carried out to filter and amplification, and the current signal after filter and amplification is sent to described current-to-voltage converter.
3. waveform synthesizer according to claim 1, is characterized in that, described waveform synthesizer also comprises:
Waveform decomposes and quantifying unit, is connected with described waveform data memory, for the waveform presetting being decomposed and quantizing, obtains amplitude data and numerical information.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103529256A (en) * | 2013-10-25 | 2014-01-22 | 国家电网公司 | Waveform synthesis device |
| CN104198779A (en) * | 2014-08-13 | 2014-12-10 | 武汉精测电子技术股份有限公司 | Probe short-circuit signal detection device and signal generating method thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103529256A (en) * | 2013-10-25 | 2014-01-22 | 国家电网公司 | Waveform synthesis device |
| CN104198779A (en) * | 2014-08-13 | 2014-12-10 | 武汉精测电子技术股份有限公司 | Probe short-circuit signal detection device and signal generating method thereof |
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