spectrademoapp.vb

是“MATLAB混合编程与工程应用”一书的源码

' *******************************************************************************
'
' SpectraDemoApp.vb
'
' This file is an example application for the MATLAB Builder for .NET product.
'
' Copyright 2001-2005 The MathWorks, Inc.
'
' *******************************************************************************

Imports System

Imports MathWorks.MATLAB.NET.Utility
Imports MathWorks.MATLAB.NET.Arrays

Imports SpectraDemoComp


Namespace MathWorks.Demo.SpectraDemoApp

' <summary>
' This application computes and plots the power spectral density of an input signal. 
' </summary>
Class SpectraDemoApp

#Region " MAIN "

        ' <summary>
        ' The main entry point for the application.
        ' </summary>
        Shared Sub Main(ByVal args() As String)
            Try
                Const interval As Double = 0.01   ' The sampling interval
                Const numSamples As Integer = 1001   ' The number of samples

                ' Construct input data as sin(2*PI*15*t) + (sin(2*PI*40*t) plus a
                ' random signal.  Duration= 10; Sampling interval= 0.01
                Dim data As MWNumericArray = New MWNumericArray(MWArrayComplexity.Real, MWNumericType.Double, numSamples)

                Dim random As Random = New Random

                ' Initialize data 
                Dim t As Double
                Dim idx As Integer
                For idx = 1 To numSamples
                    t = (idx - 1) * interval
                    data(idx) = New MWNumericArray(Math.Sin(2.0 * Math.PI * 15.0 * t) + Math.Sin(2.0 * Math.PI * 40.0 * t) + random.NextDouble())
                Next idx

                ' Create a new signal analyzer object
                Dim signalAnalyzer As SignalAnalyzer = New SignalAnalyzer

                ' Compute the fft and power spectral density for the data array
                Dim argsOut() As MWArray = signalAnalyzer.computefft(3, data, MWArray.op_Implicit(interval))

                ' Print the first twenty elements of each result array
                Dim numElements As Integer = 20
                Dim resultArray As MWNumericArray = New MWNumericArray(MWArrayComplexity.Complex, MWNumericType.Double, numElements)

                For idx = 1 To numElements
                    resultArray(idx) = (CType(argsOut(0), MWNumericArray))(idx)
                Next idx

                Console.WriteLine("FFT:{0}{1}{2}", Chr(10), resultArray, Chr(10))

                For idx = 1 To numElements
                    resultArray(idx) = (CType(argsOut(1), MWNumericArray))(idx)
                Next idx

                Console.WriteLine("Frequency:{0}{1}{2}", Chr(10), resultArray, Chr(10))

                For idx = 1 To numElements
                    resultArray(idx) = (CType(argsOut(2), MWNumericArray))(idx)
                Next idx

                Console.WriteLine("Power Spectral Density:{0}{1}{2}", Chr(10), resultArray, Chr(10))

                ' Create a new plotter object
                Dim plotter As Plotter = New Plotter

                ' Plot the fft and power spectral density for the data array
                plotter.plotfft(argsOut(0), argsOut(1), argsOut(2))

                Console.ReadLine()  ' Wait for user to exit application

            Catch exception As Exception
                Console.WriteLine("Error: {0}", exception)

            End Try
        End Sub
#End Region

    End Class
End Namespace