虚拟仪器实验指导二.doc

实验二1 任务编写一个函数发生器，要求 :能够通过用户界面选择产生正弦波、三角波、锯齿波、方波等函数波形用曲线图控件绘制用户选择的波形。2 实验步骤步骤1：根据要实现的功能，设计如图2-1所示的用户界面，其具体控件属性设置如表2-1所示。图2-1 最终用户界面表2-1 主要控件的基本属性列表控件类型Constant Name 属性设置面板PanelPANEL命令按钮Command ButtonQUITBUTTONCallback FunctionQuitCallbackLable_Quit曲线图控件GraphGRAPH1ControlModeIndicatorData ModeRetainLable波形显示下拉列表控件RingWAVEFORMCallback FunctionWaveFormChooseCBLabel波形选择Label/ValuePairsLabel无Value0Label正弦波Value1Label三角波Value2Label锯齿波Value3Label方波Value4步骤2：生成代码框架。选择CodeGenerateAll Code, 生成代码框架，接着添加自定义函数show_wave 进行显示。 /*下拉列表控件“波形选择”对应的回调函数*/int CVICALLBACK WaveFormChooseCB (int panel, int control, int event,void *callbackData, int eventData1, int eventData2) switch (event)case EVENT_COMMIT: show_wave();break;return 0;然后，在函数show_wave内添加如下代码。void show_wave(void) int POINTS=200; int waveForm;/*波形选择变量*/double ample=5.0;/*幅度*/double phase=0.0,waveDataPOINTS;/*相位和波形数据变量*/double sampleRate=10000.0,freq=100.0;/*采样率和频率变量*/GetCtrlVal (panelHandle, PANEL_WAVEFORM, &waveForm);switch (waveForm)case 0: /*无波形*/ DeleteGraphPlot(panelHandle,PANEL_GRAPH1,-1,VAL_IMMEDIATE_DRAW);/*清除所画曲线*/break;case 1:/*正弦波*/SineWave (POINTS, ample, freq/sampleRate, &phase, waveData);break;case 2:/*三角波*/TriangleWave (POINTS, ample, freq/sampleRate, &phase, waveData);break;case 3:/*锯齿波*/SawtoothWave (POINTS, ample, freq/sampleRate, &phase, waveData);break;case 4:/*方波*/SquareWave (POINTS, ample, freq/sampleRate, &phase, 50.0, waveData);break;if(waveForm)/*先判断是否选择了波形*/ DeleteGraphPlot (panelHandle, PANEL_GRAPH1, -1, VAL_IMMEDIATE_DRAW); PlotWaveform (panelHandle, PANEL_GRAPH1, waveData, POINTS, VAL_DOUBLE, 1.0, 0.0, 0.0, 1.0/sampleRate, VAL_THIN_LINE, VAL_EMPTY_SQUARE, VAL_SOLID, 1, VAL_RED);/*画出波形*/ 代码中的函数意义及调用方法如下（1） 函数DeleteGraphPlot 清除所画曲线，调用路径为：LibraryUer Interface LibraryControls/Graphs/Strip Charts.Graphs and Stirp ChartsDelete Graph Plot其参数设置见图2-2。（2） 函数SineWave，TriangleWave，SawtoothWave，SquareWave分别为正弦波，三角波，锯齿波和方波生成函数。它们都在Library Advanced Analysis Library Signal Generation 目录下获得，其参数设置如图2-32-6所示。（3） 函数PlotWaveform，画曲线图函数，调用路径为：LibraryUer Interface LibraryControls/Graphs/Strip Charts.Graphs and Stirp ChartsPlotWaveform，其参数设置见图2-7。图2-2 DeleteGraphPlot函数面板图2-3 正弦波生成函数面板图2-4 三角波生成函数面板图2-5 锯齿波生成函数面板图2-6 方波生成函数面板图2-7 PlotWaveform函数面板步骤3：运行程序。选择RunDebug ex1_dbg.exe。选做：任务：波形的频率幅度可调；用曲线图控件绘制波形频谱。步骤1：根据功能需要，我们添加一曲线图控件和两数值控件，其具体设置如表2-2所示。表2-2 添加控件的基本属性列表控件类型Constant Name 属性设置曲线图控件GraphGRAPH2ControlModeIndicatorData ModeRetainLable频谱显示数值控件NumericAMPLECallback FunctionChangeAmpleCBLable幅度FREQCallback FunctionChangeFreqCBLable频率最终界面如图2-8 所示。图2-8 最终用户界面完成用户界面后，编写回调函数ChangeAmpleCB和ChangeFreqCB，注意把其事件改为EVENT_VAL_CHANGED，其代码如下。/*数值控件AMPLE对应的回调函数*/int CVICALLBACK ChangeAmpleCB (int panel, int control, int event,void *callbackData, int eventData1, int eventData2)switch (event)case EVENT_VAL_CHANGED:/*事件不是EVENT_COMMIT*/ show_wave();break;return 0;/*数值控件FREQ对应的回调函数*/int CVICALLBACK ChangeFreqCB (int panel, int control, int event,void *callbackData, int eventData1, int eventData2)switch (event)case EVENT_VAL_CHANGED: show_wave(); break;return 0;然后还需要对show_wave函数作如下改动：void show_wave(void) int waveForm;double ample;double phase=0.0,waveDataPOINTS,filterDataPOINTS,specDataPOINTS;double sampleRate=10000.0,freq;double cutoff_freq=3000.0;/*设置截止频率*/GetCtrlVal (panelHandle, PANEL_WAVEFORM, &waveForm);GetCtrlVal (panelHandle, PANEL_AMPLE, &le);/*获得幅度值*/GetCtrlVal (panelHandle, PANEL_FREQ, &freq);/*获得频率值*/switch (waveForm)case 0: DeleteGraphPlot(panelHandle,PANEL_GRAPH1,-1,VAL_IMMEDIATE_DRAW);break;case 1:SineWave (POINTS, ample, freq/sampleRate, &phase, waveData);break;case 2:TriangleWave (POINTS, ample, freq/sampleRate, &phase, waveData);break;case 3:SawtoothWave (POINTS, ample, freq/sampleRate, &phase, waveData);break;case 4:SquareWave (POINTS, ample, freq/sampleRate, &phase, 50.0, waveData);break;if(waveForm) DeleteGraphPlot (panelHandle, PANEL_GRAPH1, -1, VAL_IMMEDIATE_DRAW); PlotWaveform (panelHandle, PANEL_GRAPH1, waveData, POINTS, VAL_DOUBLE, 1.0, 0.0, 0.0,1.0/sampleRate, VAL_THIN_LINE, VAL_EMPTY_SQUARE, VAL_SOLID, 1, VAL_RED); Bw_LPF (waveData, POINTS, sampleRate, cutoff_freq, 5, filterData);/*低通滤波*/ Copy1D (filterData, POINTS, specData);/*复制数据*/ Spectrum (specData, POINTS);/*进行功率谱分析*/ DeleteGraphPlot (panelHandle, PANEL_GRAPH2, -1, VAL_IMMEDIATE_DRAW); PlotWaveform (panelHandle, PANEL_GRAPH2, specData, POINTS, VAL_DOUBLE, 1.0, 0.0, 0.0,sampleRate/POINTS, VAL_THIN_LINE, VAL_EMPTY_SQUARE, VAL_SOLID, 1, VAL_RED);/*画出信号的功率谱*/ 上面代码中的函数意义及调用方法如下（1） 函数Bw_LPF 巴特沃兹低通滤波器函数，其调用路径为：Library Advanced Analysis LibrarySignal ProcessingIIR Digital FiltersOne-step Filters FunctionsLowpass Butterworth,其参数设置见图2-8。（2） 函数Copy1D 数组拷贝函数，其调用路径为：Library Advanced Analysis LibraryArray Operations1D Operations,其参数设置见图2-9。（3） 函数Spectrum 功率谱函数，其调用路径为：Library Advanced Analysis LibrarySignal ProcessingFrequency DomainPower Spectrum,其参数设置见图2-10。图2-8Bw_LPF函数面板图2-9 Copy1D函数面板图2-10 Spectrum函数面板最后，保存并运行程序如下：#include #include #include #include test.hstatic int panelHandle;int main (int argc, char *argv)if (InitCVIRTE (0, argv, 0) = 0)return -1;/* out of memory */if (panelHandle = LoadPanel (0, test.uir, PANEL) 0)return -1;DisplayPanel (panelHandle);RunUserInterface ();DiscardPanel (panelHandle);return 0;int CVICALLBACK QuitCallback (int panel, int control, int event,void *callbackData, int eventData1, int eventData2)switch (event)case EVENT_COMMIT:QuitUserInterface (0);break;return 0;void show_wave(void) int POINTS=200;int waveForm;double ample;double phase=0.0,waveDataPOINTS,filterDataPOINTS,specDataPOINTS;double sampleRate=10000.0,freq;double cutoff_freq=3000.0;/*设置截止频率*/GetCtrlVal (panelHandle, PANEL_WAVEFORM, &waveForm);GetCtrlVal (panelHandle, PANEL_AMPLE, &le);/*获得幅度值*/GetCtrlVal (panelHandle, PANEL_FREQ, &freq);/*获得频率值*/switch (waveForm)case 0: DeleteGraphPlot(panelHandle,PANEL_GRAPH1,-1,VAL_IMMEDIATE_DRAW); DeleteGraphPlot(panelHandle,PANEL_GRAPH2,-1,VAL_IMMEDIATE_DRAW); break;case 1:SineWave (POINTS, ample, freq/sampleRate, &phase, waveData);break;case 2:TriangleWave (POINTS, ample, freq/sampleRate, &phase, waveData);break;case 3:SawtoothWave (POINTS, ample, freq/sampleRate, &phase, waveData);break;case 4:SquareWave (POINTS, ample, freq/sampleRate, &phase, 50.0, waveData);break;if(waveForm) DeleteGraphPlot (panelHandle, PANEL_GRAPH1, -1, VAL_IMMEDIATE_DRAW); PlotWaveform (panelHandle, PANEL_GRAPH1, waveData, POINTS, VAL_DOUBLE, 1.0, 0.0, 0.0,1.0/sampleRate, VAL_THIN_LINE, VAL_EMPTY_SQUARE, VAL_SOLID, 1, VAL_RED); Bw_LPF (waveData, POINTS, sampleRate, cutoff_freq, 5, filterData);/*低通滤波*/ Copy1D (filterData, POINTS, specData);/*复制数据*/ Spectrum (specData, POINTS);/*进行功率谱分析*/ DeleteGraphPlot (panelHandle, PANEL_GRAPH2