dds信號發(fā)生器外文資料翻譯

1、<p>　　Design of Digital Controlled Signal Generator Based on DDS and MCU</p><p>　　Yinjun Chena, Zehuai Yuan</p><p>　　Faculty of Electronic Information and Mechanical Electrical Engineering,

2、 Zhaoqing University,</p><p>　　Zhaoqing 526061, China</p><p>　　Keywords: DDS; MCU; Signal generator; Phase Accumulator; DAC</p><p>　　Abstract. Its advantage to use DDS chip is outpu

3、t signal frequency bigger, and precision higher, But users can't change the output signal waveforms. The MCU can produce the required arbitrary</p><p>　　waveforms, but its program execution of the order

4、limit the speed.So we use their Synergy to design the digital controlled signal generator. The System has the advantage of output good quality waveform, frequency of precision and stability ,and high frequency, empty, am

5、plitude and phase is to step into the need.</p><p>　　Introduction</p><p>　　The digitally synthesized sine waveform (Direct Digital Synthesis, DDS) is a well-known method and has been applied to

6、many embedded applications [1]. This technique can be used to create a positive digital sine waveform. Compared to other frequency composing method, Direct Digital Frequency Synthesis(DDS) has been the most popular trend

7、 in modern frequency synthetic technique for its excellent characteristics. The signal source that the DDS technology realizes can carry out accurate controlling</p><p>　　The commercial DDS chip can only exp

8、ort a sine wave for the data in the ROM form already has been solidified. If needing to come into being any wave form, it may come true by the way that FPGA adopts DDS IP core or hardware describe language etc, however,t

9、he cost of This way cost is high; on the other hand, any wave form can be achieved by making use of micro controller unit (MCU) to carry out figure frequency combining and DA converting. The experiment and applying testi

10、ng have shown that the n</p><p>　　DDS and wave form programming pattern</p><p>　　The core of DDS system is phase accumulator carriage, and it is composed of a ADR and one unit phase register. Wh

11、en any clock comes, the phase register increases by with the step length, phase register output and phase control word add together, and then the output is imported to sine inquiry form address.</p><p>　　The

12、 sine inquiring form includes the numeral extent information of one-period sine wave, each</p><p>　　address corresponds to the phase dot of 0~360 degrees of the sine wave. The mapping digital signal drives D

13、AC and outputs analog value. The output sine circle and frequency are</p><p>　　The phase register will return to the original state when the 2N/M fc clock is finished. Accordingly, the DDS system output a si

14、ne wave when the sine inquiring form finish a circle. The output sine circle and frequency is TO --output sine wave circle, unit: s; TC --external referenced clock circle, unit: s; M --accumulated step length of phase re

15、gister, constant; f out --output sine wave frequency, unit: Hz; f c --external referenced clock frequency, unit: Hz; N --phase accumulator digit, const</p><p>　　The relationship among the frequency control

16、word, and the output signal frequency and the</p><p>　　referenced clock frequency are:</p><p>　　Frequency control word is directly proportional to the output signal frequency. In order to descri

17、be clearly, the sine wave form is as one vector turns around phase circle, the phase circle matches along with a cycle sine wave. Every sampling pots in wave form corresponds to a phase dot of the phase circle.</p>

18、<p>　　To synthesis the required frequency signal, it needs to accomplish the following steps</p><p>　　1. Controlling every sampling increment of phase and accumulating them (frequency control word K),

19、 output 2 pi cumulated phase (using phase accumulator).</p><p>　　2. Converting 2 pi accumulating phase into the corresponding sine amplitude, use ROM to store the corresponding phase-extent form of sine func

20、tion in general.</p><p>　　3. Use DAC to change extent code into the signal simulating voltage.</p><p>　　4. The voltage signal that DAC exports is ladder wave form , the required simulation volta

21、ge out is achieved after LPF smoothing.</p><p>　　Numerical control DDS signal source system designs analysis</p><p>　　System uses the STM32 as control core and the AD9850 as generator. STM32 is

22、32-bit ARM-based micro controller with 128 K byte flash memory.</p><p>　　The two signal output of STM32 can be achieved by controlling AD9850 and DAC0832 output simultaneously. The system designs block diagr

23、am is shown in Fig. 1. One signal output can generate 30 MHz sine wave and rectangular wave by controlling AD9850, the other output generate any wave form with its frequency less than 10 KHz by numerical frequency mixtur

24、e of DAC0832.</p><p>　　Fig. 1 System designs block diagram</p><p>　　Hardware design</p><p>　　AD9850 module</p><p>　　AD9850 contains the DDS system and high-speed compar

25、ator. The AD9850 can realize the entire numerical frequency combining. The core of the programmable DDS is the phase accumulator, it is composed of a ADR and a N bit phase register, N is for 24 ~ 32.</p><p>

26、　　After connecting to the accurate clock source and writing the frequency phase control word,</p><p>　　AD9850 can generate the frequency-programmable and phase-programmable output of analog sine wave, which

27、can be used as the direct frequency signal source or be transferred into rectangular wave through high-speed comparator.</p><p>　　With the 125 MHz clock, 32-bit frequency control word can carry out the outpu

28、t frequency</p><p>　　resolution ratio of AD9850 with 0.0291 Hz[4].</p><p>　　DAC0832 module</p><p>　　The circuit exports the phase data sheet to DAC0832 from STM32 and gets correspon

29、ding wave form by DA converting. The step-by-step adjusting phase amounts can create arbitrary frequency, the PWM signal from the STM32 transfers into the corresponding voltage by low-pass filter, therefore, the referenc

30、ed voltage of DAC0832 is controlled, furthermore, the output wave form extent is tuned appropriately. The digital to analog conversion circuit is shown in Fig.2</p><p>　　Fig. 2 DAC circuit</p><p&g

31、t;　　PWM converting DA circuit</p><p>　　The low-pass filtered PWM signal from STM32 is then stable using the voltage follower, which will yield a stable output voltage; the voltage can be adjusted by tuning t

32、he PWM dutyfactor. The system output three PWM signals, which controls AD9850 output extent, dutyfactor and the output extent of DAC0832, respectively,. Fig. 3 shows the PWM controls DA transferring circuit.</p>&

33、lt;p>　　Fig. 3 PWM controlled DA converting circuit</p><p>　　Fig. 4 Export amplification and the wave filtering circuit. (a) amplification circuit; (b) filtering</p><p><b>　　circuit</

34、b></p><p>　　Amplification and wave filtering circuit</p><p>　　The amplification circuit will export amplified wave form and modify the factor of amplification. An excellent smooth output wave

35、form can be achieved by using the low-pass active power filtering. The amplification circuit and the filtering circuit is showed in Fig. 4.</p><p>　　Software design</p><p>　　And the system softw

36、are mainly include AD9850 driving module, DAC0832 driving module, the step-by-step automation module, PWM-converting-DA module and uC/GUI figure supporting</p><p>　　system implanted in procedure. The operati

37、on interface is full of humanization for the multi-window pattern is adopted. The design process of the system software is shown in Fig. 5.</p><p>　　Implanted uC/GUI</p><p>　　The numerical contr

38、ol signal source has used the uC/GUI software sufficiently to establish many windows and control buttons. By means of invoking the corresponding windows and control with the feedback information, the peripheral equipment

39、 operated under the control of the system.</p><p>　　The external equipment is mainly separated into two drivers, the drive being an AD9850 module and DAC0832 module drive, respectively. The two modules can b

40、e controlled by means of the outside interruption and timing interruption.</p><p>　　AD9850 Drive</p><p>　　AD9850 has 40 control words, among them, 32-bit is used for frequency control, 5-bit is

41、used for the phase control, 1-bit is used for the power source dormancy control, 2-bit is used to choose operation pattern.</p><p>　　Fig. 5 Systematic procedure flow chart</p><p>　　This 40 contr

42、ol words may arrive at AD9850 by concurrence way or serial way, in the concurrence way, 8 data highway generals can transfer the data to a register.</p><p>　　After repeating 5 times, the 40-bit data is loade

43、d into the frequency / phase data register (for refreshing DDS output frequency and phase) at the FQ-UD rising edge, meanwhile, the address pointer is reset to the first input register</p><p>　　Then the 8-bi

44、t data is loaded at the W-CLK rising edge, and the pointer is set to the next input register. After repeating 5 times of W-CLK rising edge, the W-CLK rising edge will work no longer until the reset signal comes or the ad

45、dress pointer is reset to the first input register by the FQ-UD rising edge.</p><p>　　The procedure operate AD9850 module through the bottom function, as</p><p>　　void ad9850(</p><p&g

46、t;　　double frequency, //frequency</p><p>　　unsigned char phase, //phase</p><p>　　unsigned char mode, //pattern</p><p>　　unsigned char power //source</p><p><b>　　)

47、</b></p><p>　　The DAC0832 driven module</p><p>　　In the design of the numerical control signal source, DAC0832 is defined as single buffered</p><p>　　pattern, when the 8 bit P

48、arallel data D0~D7 is input, the DA will transfer data in the CS.</p><p>　　The bottom function of void DA0832(u8 value)can invoke Out_To_DDS0832(double</p><p>　　Frequency,u8 type) function and c

49、ontrol the defined wave form and frequency.</p><p>　　This function is based on figure frequency composes principle, it transfers the input frequency into corresponding control word, and then combing phase st

50、ep-by-step expect, output wave form data sheet in memory.</p><p>　　The extent and dutyfactor can be tuned through invoking Adjust_Vpp() and Adjust Duty()</p><p>　　Step-by-step automation procedu

51、re</p><p>　　A step-by-step automation procedure brick is added to the design to define the frequency range, step-by-step rate , step-by-step amounts , ascending or lapse, cycling pattern.</p><p>

52、;　　The step-by-step automation function can be realized through invoking Auto Step(AutoStepStr*AS) and passing memory structure type to a function.</p><p>　　Test the experiment and data analysis</p>&

53、lt;p>　　The DDS numerical control signal source can import the various changeable control words by a touching screen, and then accurately control the signal frequency, dutyfactor, extent and phase. Figure 6 shows the c

54、orresponding experimental wave forms.</p><p>　　Fig. 6 The oscillograph exports experiment picture (a) 1 KHz wave form output; (b) 1 MHz wave</p><p>　　form output; (c) 20 MHz wave form output.<

55、;/p><p>　　With the oscillograph testing, it shows that the circuit work stably and rightly. The various parametric index exhibit fine numerical control effect.</p><p>　　a. Output frequency range: 1

56、Hz—30MHz，peak-to-peak value: 50mV～10V；dutyfactor:</p><p>　　10%~100%, difference≤1%。</p><p>　　b. Export the sine wave, sawtooth wave rectangular wave, triangle wave and arbitrarily wave</p>

57、<p><b>　　form.</b></p><p>　　c. Continuous Step-by-step adjustment of frequency, dutyfactor, extent and phase.</p><p>　　d. The operation of the touching screen includes supposi

58、tional keyboard, sliding strip and various suppositional control carry out entering operation, and the every parameters can be demonstrated visually.</p><p>　　e. Step-by-step automation, definition of: maxim

59、um value , minimum value , step-by-step rate , step-by-step amounts , ascending or lapse, cycling or not.</p><p>　　Numerical control reform advantage of signal source</p><p>　　The designed numer

60、ical control signal source is applied to the lathe reform experiment. The main targets of the numerical control system are the coordinate axis displacement (including displacement speed , direction , location etc.) , the

61、 control message originates from numerical control treating or moving control procedure mainly.</p><p>　　Therefore, systematic the most fundamental composition of the numerical control system should include

62、three parts: The input/output procedure device, numerical control equipment and the servo drives.</p><p>　　Conclusions</p><p>　　Making compound use of DDS and MCU controller, the system can expo

63、rted the numerical control signal source as the consumer need, it has the merits such as good exporting wave form, frequency accuracy, reliable stability and high dutyfactor. Each parameter and be easily adjusted by touc

64、hing a screen, the experiments show that the various parametric indexes have fine numerical control effect.</p><p>　　Acknowledgements</p><p>　　This work was financially supported by the National

65、 Natural Science Foundation of China (No:</p><p>　　61006075) and Guided Projects on Integration of Production, Education and Research of Guangdong Province (No：2011B090400253).</p><p>　　Referenc

66、es</p><p>　　[1] Lygouras J. N., Tarchanidis K. N., Tsalides Ph. G., “Suspended Sediment and Dye Concentration Measurements Using a Digital Techniques”, Int. J. Electronics, 87, No.1, pp 107, (2000).</p>

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69、 and</p><p>　　Intelligent Measurement Systems, VIMS 2000, Annapolis, MD, USA, 29-30 April 2000, pp 115,</p><p><b>　　(2000).</b></p><p>　　[5] Koukourlis C. S., Voulgaris

70、N. C., “A Digital Method for Sinewave Generation.” Archiv fur</p><p>　　Electrotechnik, 72, pp 327, (1989).</p><p>　　[6] Koukourlis Chr. S, Trigonidis V. K., Sahalos J. N., “Differential Synchron

71、ous Demodulation for Small Signal Amplitude Estimation.”, IEEE Instrumentation and Measurement, 42, No. 5, pp 926, (1993).</p><p>　　基于DDS和單片機數(shù)字控制信號發(fā)生器的設(shè)計</p><p>　　關(guān)鍵詞: DDS; MCU;信號發(fā)生器;相位累加器;DAC&l

72、t;/p><p>　　摘要: 它的優(yōu)點，使用DDS芯片輸出信號的頻率更大，精度更高，但用戶不能改變輸出信號的波形。MCU可以產(chǎn)生所需的任意波形，但其程序執(zhí)行的順序限制速度。因此，我們利用它們之間的協(xié)同設(shè)計數(shù)字控制信號發(fā)生器。該系統(tǒng)的優(yōu)點是輸出質(zhì)量好的精度和穩(wěn)定性，波形，頻率和高頻率的，空的振幅和相位是步入需要。</p><p><b>　　介紹</b></p>

73、<p>　　數(shù)字合成的正弦波形（直接數(shù)字頻率合成器DDS）是一種公知的方法已被應(yīng)用到許多嵌入式應(yīng)用[1]。這種技術(shù)可以用來創(chuàng)建一個積極的數(shù)字正弦波形。其它頻率合成方法相比, 直接數(shù)字頻率合成器（DDS）一直以其優(yōu)良的特性在現(xiàn)代頻率合成技術(shù)中最流行的趨勢。DDS技術(shù)實現(xiàn)信號源，可以進行精確控制DDS的頻率，程度，相輸出波形的數(shù)值控制電路等,系統(tǒng)利用這種方法有許多優(yōu)點，如安定，可靠和準確度。</p><p&

74、gt;　　商業(yè)DDS芯片只能導(dǎo)出一個正弦波因為ROM表中的數(shù)據(jù)形式已經(jīng)被凝固。如果需要進入任何波形，它可能會真正的由FPGA采用DDS的IP核或硬件描述語言等方式來實現(xiàn)，然而, 這種方式成本費用高;另一方面，可以任意波形通過開展數(shù)字頻率結(jié)合使用的微控制器單元（MCU）和DA轉(zhuǎn)換實現(xiàn)。實驗和應(yīng)用測試表明，數(shù)控信號源所組成的STM32微控制器和DDS芯片可以很好地工作。</p><p>　　DDS和波形編程模式<

75、;/p><p>　　DDS系統(tǒng)的核心是相位累加器的框架，它是由一個ADR和一單位相位寄存器組成的。當(dāng)任何時鐘到來時，相位寄存器增加步長，相寄存器的輸出與相位控制字相加，然后輸出導(dǎo)入到正弦查詢形成地址。</p><p>　　正弦查詢表格包含一個周期正弦波，每個數(shù)字幅度信息地址對應(yīng)于0?360度的正弦波的相位點。測繪數(shù)字信號驅(qū)動DAC并模擬輸出值。輸出正弦波周期和頻率是:</p>&

76、lt;p>　　相位寄存器將返回到原來的狀態(tài)時，2N/ M fc時鐘完成。因此，DDS系統(tǒng)輸出一個正弦波的正弦查詢表時，完成一個周期。輸出正弦波的周期和頻率為TO - 輸出正弦波周期，單位：秒; TC - 外部參考時鐘周期，單位：秒; M - 相位寄存器累計步長，恒定f輸出 - 輸出正弦波頻率，單位：赫茲; fc - 外部參考時鐘頻率，單位為赫茲; N - 相位累加器的位數(shù)，不變。頻率控制字和輸出信號的頻率與參考時鐘頻率之間的關(guān)系是

77、：</p><p>　　頻率控制字與輸出信號的頻率成正比。為了描述清楚，正弦波的形式是一個向量轉(zhuǎn)換的相位周期，相位周期與正弦波的一個周期相匹配。在波形里的每個采樣點對應(yīng)一個相位點的相位周期。</p><p>　　合成所需的頻率信號，它需要完成以下步驟：</p><p>　　1.控制每個采樣相位增量和積累（頻率控制字K），輸出2 pi累計相位（使用相位累加器）。<

78、;/p><p>　　2.轉(zhuǎn)換成相應(yīng)的正弦振幅2 pi積累階段，使用ROM來存儲相應(yīng)的相位幅度的一般正弦函數(shù)形式。</p><p>　　3.采用DAC代碼轉(zhuǎn)換成模擬信號電壓變化幅度。</p><p>　　4.電壓信號，DAC出口是階梯波的形式，實現(xiàn)所需的模擬電壓輸出低通濾波器平滑后的電壓。</p><p>　　數(shù)控DDS信號源系統(tǒng)設(shè)計分析</

79、p><p>　　系統(tǒng)使用STM32作為控制核心和AD9850作為發(fā)生器。STM32是基于ARM的32位微控制器與128 K字節(jié)的閃存。</p><p>　　STM32的兩個信號輸出，可以實現(xiàn)同時通過控制AD9850的和DAC0832輸出。該系統(tǒng)的設(shè)計的框圖如圖1所示。一個信號輸出通過控制AD9850，可產(chǎn)生30 MHz正弦波和矩形波，其他輸出的任意波形及其頻率低于10千赫是通過頻率數(shù)值混合器D

80、AC0832產(chǎn)生的。</p><p><b>　　圖1 系統(tǒng)設(shè)計框圖</b></p><p><b>　　硬件設(shè)計</b></p><p><b>　　AD9850的模塊</b></p><p>　　AD9850包含DDS系統(tǒng)和高速比較器。 AD9850可以實現(xiàn)對整個數(shù)字頻率相

81、結(jié)合?？删幊痰腄DS的核心是相位累加器，它是由ADR和一個N位相位寄存器組成，N為24?32。</p><p>　　連接到精確的時鐘源和寫入頻率相位控制字后，AD9850的可以產(chǎn)生可編程頻率和相位可編程的模擬正弦波輸出波，這可以用來作為直接的高頻信號源，或者通過高速比較器被轉(zhuǎn)移到矩形波。</p><p>　　通過125 MHz時鐘，32位頻率控制字可以把AD9850的輸出頻率分辨率展開到0

82、.0291赫茲[4]。</p><p><b>　　DAC0832模塊</b></p><p>　　電路是通過DA從STM32向DAC0832輸出相位數(shù)據(jù)表并得到相應(yīng)的波形。一步一步的調(diào)節(jié)相量，可以創(chuàng)建任意的頻率，PWM信號通過低通濾波器從STM32傳輸?shù)较鄳?yīng)的電壓，因此，DAC0832的參考電壓是被控制的，而且，輸出的波形幅度調(diào)節(jié)適當(dāng)。數(shù)字到模擬轉(zhuǎn)換電路，如圖2所示

83、:</p><p><b>　　圖2 DAC電路</b></p><p><b>　　PWM轉(zhuǎn)換DA電路</b></p><p>　　低通濾波器的PWM信號從STM32到穩(wěn)定使用電壓跟隨器，然后穩(wěn)定將產(chǎn)生一個穩(wěn)定的輸出電壓，通過調(diào)整PWM占空比可調(diào)節(jié)電壓。該系統(tǒng)輸出的3個PWM信號，它分別控制AD9850的輸出范圍，占空

84、比和輸出DAC0832的范圍。圖3顯示出的PWM控制DA傳輸電路。</p><p><b>　　放大和濾波電路</b></p><p>　　放大電路將輸出放大波形和修改放大的因素。一個很好的平滑的輸出波形，可以通過使用低通有源功率濾波實現(xiàn)。放大電路和濾波電路在圖4中顯示。</p><p>　　圖3 PWM控制DA轉(zhuǎn)換電路</p>

85、<p>　　圖4 導(dǎo)出放大和濾波電路:（a）放大電路（b）濾波電路</p><p><b>　　軟件設(shè)計</b></p><p>　　系統(tǒng)軟件主要包括AD9850的驅(qū)動模塊，DAC0832驅(qū)動模塊，一步一步的自動化模塊，PWM轉(zhuǎn)換DA模塊和uC/ GUI圖片支持的系統(tǒng)中植入程序。由于采用多窗口的圖案使得操作界面充滿人性化。系統(tǒng)軟件的設(shè)計過程如圖5所示。&l

86、t;/p><p><b>　　圖5系統(tǒng)程序流程圖</b></p><p>　　植入的uC/ GUI</p><p>　　數(shù)控信號源已足夠多的使用的uC / GUI軟件建立許多窗口和控制按鈕。通過調(diào)用相應(yīng)的窗口和控制反饋信息，外圍設(shè)備在系統(tǒng)的控制下操作。</p><p>　　外部設(shè)備主要分為兩個驅(qū)動器，驅(qū)動器AD9850的模塊

87、和DAC0832模塊驅(qū)動。這兩個模塊可以通過外側(cè)中斷和定時中斷被控制。</p><p>　　AD9850的驅(qū)動器</p><p>　　AD9850具有40個控制字，其中，32位用于頻率控制，5位用于的相位控制，1位用于電源休眠控制，2位用于選擇運作模式。</p><p>　　這40個控制字可在允許的方式或串行方式到達AD9850，在允許的方式下，8位數(shù)據(jù)一般可高速將

88、數(shù)據(jù)傳送到寄存器。</p><p>　　重復(fù)5次后，在40位的數(shù)據(jù)被加載到頻率/相位數(shù)據(jù)寄存器（用于刷新的DDS輸出頻率和相位），同時，上面的FQ-UD上升沿地址指針復(fù)位到第一個輸入寄存器。</p><p>　　然后8位數(shù)據(jù)被加載在W-CLK上升沿，將指針設(shè)置到下一個輸入注冊。W-CLK上升沿重復(fù)5次后，在W-CLK上升沿將不再工作，直到復(fù)位信號或地址指針復(fù)位到第一個輸入寄存器的FQ-UD

89、上升沿。</p><p>　　程序操作AD9850模塊通過底部的功能，作為：</p><p>　　void ad9850(</p><p>　　double frequency, //frequency</p><p>　　unsigned char phase, //phase</p><p>　　unsigned

90、char mode, //pattern</p><p>　　unsigned char power //source</p><p><b>　　)</b></p><p>　　DAC0832驅(qū)動模塊</p><p>　　在設(shè)計中的數(shù)字控制信號源，DAC0832被定義為單緩沖的模式，當(dāng)8位并行數(shù)據(jù)D0?D7被輸入，DA

91、將在CS中傳輸數(shù)據(jù)。</p><p>　　空的DA0832（U8值）的底層函數(shù)可以調(diào)用Out_To_DDS0832（雙頻率，U8型）的功能和控制定義的波形和頻率。</p><p>　　此功能是基于數(shù)字頻率合成原則，它把輸入頻率傳送到相應(yīng)的控制字，然后一步一步結(jié)合相位預(yù)計，在記憶體中輸出波形數(shù)據(jù)表。</p><p>　　通過的調(diào)用Adjust_Vpp（）的程度和占空因

92、數(shù)可調(diào)諧和調(diào)整印花稅（）</p><p>　　一步一步的自動化程序</p><p>　　一步一步的自動化程序磚被添加到設(shè)計來定義的頻率范圍內(nèi)，一步一步的速度，一步一步的計算，遞增或失效，循環(huán)模式。一步一步的自動化功能，可實現(xiàn)通過調(diào)用自動步驟（AutoStepStr*AS）和通過存儲器結(jié)構(gòu)類型的一個函數(shù)來實現(xiàn)。</p><p><b>　　測試實驗和數(shù)據(jù)分析

93、</b></p><p>　　DDS數(shù)字控制信號源能夠通過觸摸屏導(dǎo)入各種多變的控制字，然后準確地控制信號的頻率，占空比，范圍和相位。圖6給出了相應(yīng)的實驗波形。</p><p>　　圖6示波器出口實驗圖片（a）1千赫茲的輸出波形（b）1兆赫茲的輸出波形（c）20兆赫茲的輸出波形</p><p>　　用示波器測試，表明該電路工作穩(wěn)定，正確。各參數(shù)指標表現(xiàn)出精

94、細的數(shù)值控制效果。</p><p>　　一、輸出頻率范圍：1Hz-30MHz的的峰 - 峰值值：50mV的~~10V;占空比：10％?100％，差異≤1％。</p><p>　　二、輸出正弦波，方波，鋸齒波，三角波和任意波形式。</p><p>　　三、連續(xù)步驟一步調(diào)整頻率，占空比，幅度和相位。</p><p>　　四、觸摸屏的操作包括虛擬鍵

95、盤，滑條和各種虛擬控制進行輸入操作，每一個參數(shù)都可以 直觀演示。</p><p>　　五、一步一步的自動化，定義：最高值，最低值，一步一步的速度， 一步一步的計算，按升序或下降，循環(huán)或不循環(huán)。</p><p>　　數(shù)控改革信號源的優(yōu)勢</p><p>　　設(shè)計的數(shù)值的控制信號源被施加到車床改革實驗。主要數(shù)控系統(tǒng)的目標是協(xié)調(diào)坐標軸的位移（包括位移，

96、速度，方向，位置等），該控制消息來源于數(shù)控操作或運動控制程序。</p><p>　　因此，系統(tǒng)的數(shù)值控制系統(tǒng)的組合物，最根本的包括三個部分：輸入/輸出的程序的移動設(shè)備，數(shù)控設(shè)備和伺服驅(qū)動器。</p><p><b>　　結(jié)論</b></p><p>　　使DDS和MCU控制器組合使用，系統(tǒng)可以導(dǎo)出的數(shù)值控制消費者的需要的信號源，它具有的優(yōu)點，如

97、良好的輸出的波形，頻率準確，可靠的穩(wěn)定性和高占空比。每個參數(shù)，并通過觸摸屏幕很容易地調(diào)整，實驗表明，各種參數(shù)指標具有優(yōu)良的數(shù)控效果。</p><p><b>　　致謝</b></p><p>　　這項工作是由國家自然科學(xué)基金會，中國（無財政支持：61006075）和指導(dǎo)目整合生產(chǎn)，教育及研究廣東?。ň幪枺?011B090400253）。</p><

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