1、附录二：英文原文 The Analysis and Design ofWaveform Generator Xue lian ,Wang Fan ,Zheng Jin-fa Engineering and CommerceCollege, South-CentralUniversity for Nationalities, WuhanHubei 430065 Abstract: In this paper, the sinusoidal waves in different frequency were synthesized into square wave according to the
2、 method of Fourier series. Firstly, the needed sinusoidal waves were achieved through the square wave generation circuit, the frequency division circuit and the filter circuit； then, after the sinusoidal waves phase position were shifted and synthesized, the square wave was generated. This circuit i
3、n this method was more cheaper than other circuits (eg: DDS). Keywords: Waveform Generator；SinusoidalWave；Filter；Phase PositionShift 1 waveform synthesis system overview This is designed to simulate the process of signal synthesis. For a square wave signal by Fourier series spread knowable, it can d
4、ecompose the amplitude of the more specific for unlimited odd harmonics, so in turn as long as infinite multiple odd harmonic component, the amplitude and the harmonic proportion in a particular superposition, also will certainly get a square wave signal. This paper is the simulated the base wave an
5、d three harmonic harmonic component synthesis process of square wave signal. Theoretically speaking, the harmonic components, synthetic waveform will more close to the standard square bobo shape. This system begin with a square wave oscillator to generate a frequency of 60KHz pulse signal, again int
6、o separate frequency device 10KHz to get a frequency for handling of square wave signal and a frequency of square wave signal for 30KHz, then respectively through the filter processing for the sine signal and 30KHz 10KHz to close-spaced 10KHz sine wave as base wave component, 30KHz sine wave as thre
7、e times, through modulation circuit harmonics of adjust them respectively in fengfeng value, can satisfy 2V 6V and Fourier series spread coefficient ratio； Put the sine signals into 10KHz to phase shifter phase adjuster, and after 30KHz sinusoidal signal together into addition circuit synthesis, nam
8、ely complete signal stack. It can be inferred that the output signal is adder an approximate square-wave signal, and frequency for probably 10KHz. System unit circuit as shown in figure 1 below. Figure 1 system structure diagram 2 the hardware circuit design 2.1 square wave generating circuit design
9、 方波发生电路 分频 电路 滤波 电路 10Khz调幅 30KHz 调幅 移相 电路 加法 电路 According to the above analysis, the 60kHz should be produced for pulse frequency. Square wave can use digital circuit generation, also can use analog circuits produce. As digital circuits produce waveform amplitude, needs to be smaller using simulate
10、d circuit to amplify； And compared with mixed-signal circuit pure analog circuits to complex, therefore, in this the paper only with analog circuits to generate square wave. The basic principle is: through the voltage comparator produce high level； Through the feedback loop and delay link to the ele
11、ctric frequency periodically height variations. Principle chart as figure2shows, diagram hysteretic comparator output voltage, threshold voltage； Oscillation period for. Through calculating formula by cycle that change, C, R1 ifss can be obtained with R2 ratio required pulse frequency. But this seve
12、ral variables in actual circuit will be some constraints, in choosing device parameters through actual adjustment should be determined. Select devices, it is suggested that resistance, so that circuit using metal film resistors the heat generated by the noise is small； Choose op-amp should consider
13、when its passband, passband more hours, it is difficult to achieve square-wave requirements, so we chose the frequency performance was good OPA820 op-amp. Front generated for square cant use, this latter stage, still need to pass the follow-up processing, should first except negative voltage isolati
14、on, here with a diode, so after diode for the voltage after subtracting tube voltage half before diode pressure drop. Thus square wave amplitude will more small, in order to achieve the minimum separate frequency circuit requirements, should be the voltage waveforms were pressurization. In proportio
15、n with pressor circuit USES amplifier, get the voltage amplitude moderate. Then after the voltage level for use, but in order to reduce load after each level circuit, the influence of wavelet produce circuit with load ability raise circuit, finally take a shot extremely follow device. To this, squar
16、e wave generator can be expected to reach, could plug in the latter stage circuit. Figure 2 square wave generating circuit principle diagram 2.2. Points frequency circuit design This points to the former stage frequency circuits are produced, into a square 60KHz 390v for 1/2, frequency respectively.
17、 30KHz And the square wave signal 10KHz. This treatment can easily think of using digital counter solve. The counter is commonly used sequential circuits to pulse, it not only can count, can also used for the points frequency, timing, produce beats pulse, etc. This paper use of its points frequency
18、characteristics, a N disables counter can will it input clock signal, points for occupies emptiescompared frequency for 1 / N, frequency for input signal 1 / N output the clock signal. So in order to get the 30KHz square wave signal, the 60KHz U1O P A 8 4 2 I D32 476R11kR21kR31k R410kK e y = A50%R5220C21 0 n FD1 1 N 4 7 2 8 AD2 1 N 4 7 2 8 AD31 N 4 0 0 74053216 Uo
