Imports BasicDSP
Public Class dsp1ex1

    Dim iwv As New Signal
    Dim owv As New Signal

    Private Sub OpenAudioFileToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OpenAudioFileToolStripMenuItem.Click
        ' ask for a file
        If OpenFileDialog.ShowDialog() = Windows.Forms.DialogResult.OK Then
            ' try and load the audio
            If iwv.LoadWaveFile(OpenFileDialog.FileName) Then
                ' filter the audio
                owv = New Signal(iwv.Count, iwv.Rate)
                Dim ltis As LTISystemChain = Filter.ButterworthLowPass(1000 / iwv.Rate, 4)
                For i As Integer = iwv.First To iwv.Last
                    owv(i) = ltis(iwv(i))
                Next
            Else
                ' failed to load audio
                MsgBox("Failed to load audio from " & OpenFileDialog.FileName)
            End If
        End If
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        ' replay input
        iwv.Replay()
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        ' replay output
        owv.Replay()
    End Sub
End Class