t=(1:100)';
s=sin(2*pi*t/10);
plot(t,s)
s=sin(2*pi*t/20);
plot(t,s)
figure(2)
plot(abs(fftshift(fft(s))))
plot(abs(fftshift(fft(s+1))))
plot(-49:50, abs(fftshift(fft(s+1))))
plot(-50:49, abs(fftshift(fft(s+1))))
plot(-50:49, abs(fftshift(fft(s))))
plot(abs(fft(s)))
edit fftshift
plot(-50:49, abs(fftshift(fft(s))))
semilogy(-50:49, abs(fftshift(fft(s))))
s2=sin(2*pi*t/19);
figure(1)
plot(t,s2)
plot(t,s2,t,s)
figure(2)
hold on
semilogy(-50:49, abs(fftshift(fft(s2))))
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    'ALimMode'
    'AmbientLightColor'
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    'CameraPositionMode'
    'CameraTarget'
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    'XMinorTick'
    'XScale'
    'XTick'
    'XTickLabel'
    'XTickLabelMode'
    'XTickMode'
    'YAxisLocation'
    'YColor'
    'YDir'
    'YGrid'
    'YLabel'
    'YLim'
    'YLimMode'
    'YMinorGrid'
    'YMinorTick'
    'YScale'
    'YTick'
    'YTickLabel'
    'YTickLabelMode'
    'YTickMode'
    'ZColor'
    'ZDir'
    'ZGrid'
    'ZLabel'
    'ZLim'
    'ZLimMode'
    'ZMinorGrid'
    'ZMinorTick'
    'ZScale'
    'ZTick'
    'ZTickLabel'
    'ZTickLabelMode'
    'ZTickMode'
desiredPropNames = 
    'ALim'
    'ALimMode'
    'AmbientLightColor'
    'BeingDeleted'
    'Box'
    'BusyAction'
    'CLim'
    'CLimMode'
    'CameraPosition'
    'CameraPositionMode'
    'CameraTarget'
    'CameraTargetMode'
    'CameraUpVector'
    'CameraUpVectorMode'
    'CameraViewAngle'
    'CameraViewAngleMode'
    'Children'
    'Clipping'
    'Color'
    'ColorOrder'
    'DataAspectRatio'
    'DataAspectRatioMode'
    'DrawMode'
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    'FontName'
    'FontSize'
    'FontUnits'
    'FontWeight'
    'GridLineStyle'
    'HandleVisibility'
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    'Layer'
    'LineStyleOrder'
    'LineWidth'
    'MinorGridLineStyle'
    'NextPlot'
    'Parent'
    'PlotBoxAspectRatio'
    'PlotBoxAspectRatioMode'
    'Position'
    'Projection'
    'SelectionHighlight'
    'Tag'
    'TickDir'
    'TickDirMode'
    'TickLength'
    'Title'
    'Type'
    'UIContextMenu'
    'Units'
    'View'
    'Visible'
    'XAxisLocation'
    'XColor'
    'XDir'
    'XGrid'
    'XLabel'
    'XLim'
    'XLimMode'
    'XMinorGrid'
    'XMinorTick'
    'XScale'
    'XTick'
    'XTickLabel'
    'XTickLabelMode'
    'XTickMode'
    'YAxisLocation'
    'YColor'
    'YDir'
    'YGrid'
    'YLabel'
    'YLim'
    'YLimMode'
    'YMinorGrid'
    'YMinorTick'
    'YScale'
    'YTick'
    'YTickLabel'
    'YTickLabelMode'
    'YTickMode'
    'ZColor'
    'ZDir'
    'ZGrid'
    'ZLabel'
    'ZLim'
    'ZLimMode'
    'ZMinorGrid'
    'ZMinorTick'
    'ZScale'
    'ZTick'
    'ZTickLabel'
    'ZTickLabelMode'
    'ZTickMode'
semilogy(-50:49, abs(fftshift(fft(s2))))
desiredPropNames = 
    'ALim'
    'ALimMode'
    'AmbientLightColor'
    'BeingDeleted'
    'Box'
    'BusyAction'
    'ButtonDownFcn'
    'CameraPosition'
    'CameraPositionMode'
    'CameraTarget'
    'CameraTargetMode'
    'CameraUpVector'
    'CameraUpVectorMode'
    'CameraViewAngle'
    'CameraViewAngleMode'
    'Children'
    'CLim'
    'CLimMode'
    'Clipping'
    'Color'
    'ColorOrder'
    'CreateFcn'
    'CurrentPoint'
    'DataAspectRatio'
    'DataAspectRatioMode'
    'DeleteFcn'
    'DrawMode'
    'FontAngle'
    'FontName'
    'FontSize'
    'FontUnits'
    'FontWeight'
    'GridLineStyle'
    'HandleVisibility'
    'HitTest'
    'Interruptible'
    'Layer'
    'LineStyleOrder'
    'LineWidth'
    'MinorGridLineStyle'
    'NextPlot'
    'Parent'
    'PlotBoxAspectRatio'
    'PlotBoxAspectRatioMode'
    'Position'
    'Projection'
    'Selected'
    'SelectionHighlight'
    'Tag'
    'TickDir'
    'TickDirMode'
    'TickLength'
    'Title'
    'Type'
    'UIContextMenu'
    'Units'
    'UserData'
    'View'
    'Visible'
    'XAxisLocation'
    'XColor'
    'XDir'
    'XGrid'
    'XLabel'
    'XLim'
    'XLimMode'
    'XMinorGrid'
    'XMinorTick'
    'XScale'
    'XTick'
    'XTickLabel'
    'XTickLabelMode'
    'XTickMode'
    'YAxisLocation'
    'YColor'
    'YDir'
    'YGrid'
    'YLabel'
    'YLim'
    'YLimMode'
    'YMinorGrid'
    'YMinorTick'
    'YScale'
    'YTick'
    'YTickLabel'
    'YTickLabelMode'
    'YTickMode'
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    'ZDir'
    'ZGrid'
    'ZLabel'
    'ZLim'
    'ZLimMode'
    'ZMinorGrid'
    'ZMinorTick'
    'ZScale'
    'ZTick'
    'ZTickLabel'
    'ZTickLabelMode'
    'ZTickMode'
desiredPropNames = 
    'ALim'
    'ALimMode'
    'AmbientLightColor'
    'BeingDeleted'
    'Box'
    'BusyAction'
    'CLim'
    'CLimMode'
    'CameraPosition'
    'CameraPositionMode'
    'CameraTarget'
    'CameraTargetMode'
    'CameraUpVector'
    'CameraUpVectorMode'
    'CameraViewAngle'
    'CameraViewAngleMode'
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    'Clipping'
    'Color'
    'ColorOrder'
    'DataAspectRatio'
    'DataAspectRatioMode'
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    'FontName'
    'FontSize'
    'FontUnits'
    'FontWeight'
    'GridLineStyle'
    'HandleVisibility'
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    'Layer'
    'LineStyleOrder'
    'LineWidth'
    'MinorGridLineStyle'
    'NextPlot'
    'Parent'
    'PlotBoxAspectRatio'
    'PlotBoxAspectRatioMode'
    'Position'
    'Projection'
    'SelectionHighlight'
    'Tag'
    'TickDir'
    'TickDirMode'
    'TickLength'
    'Title'
    'Type'
    'UIContextMenu'
    'Units'
    'View'
    'Visible'
    'XAxisLocation'
    'XColor'
    'XDir'
    'XGrid'
    'XLabel'
    'XLim'
    'XLimMode'
    'XMinorGrid'
    'XMinorTick'
    'XScale'
    'XTick'
    'XTickLabel'
    'XTickLabelMode'
    'XTickMode'
    'YAxisLocation'
    'YColor'
    'YDir'
    'YGrid'
    'YLabel'
    'YLim'
    'YLimMode'
    'YMinorGrid'
    'YMinorTick'
    'YScale'
    'YTick'
    'YTickLabel'
    'YTickLabelMode'
    'YTickMode'
    'ZColor'
    'ZDir'
    'ZGrid'
    'ZLabel'
    'ZLim'
    'ZLimMode'
    'ZMinorGrid'
    'ZMinorTick'
    'ZScale'
    'ZTick'
    'ZTickLabel'
    'ZTickLabelMode'
    'ZTickMode'
figure(3)
plot([t;t],[s2;s2])
plot([s2;s2])
figure; plot(t,triangle(2*pi*t))
??? Undefined function or variable 'triangle'.

figure; plot(t,tri(2*pi*t))
??? Undefined function or variable 'tri'.

help triangle

triangle.m not found.

tri=[0:49,48:1]
tri =
  Columns 1 through 18 
     0     1     2     3     4     5     6     7     8     9    10    11    12    13    14    15    16    17
  Columns 19 through 36 
    18    19    20    21    22    23    24    25    26    27    28    29    30    31    32    33    34    35
  Columns 37 through 50 
    36    37    38    39    40    41    42    43    44    45    46    47    48    49
tri=[0:49,48:-1:0]
tri =
  Columns 1 through 18 
     0     1     2     3     4     5     6     7     8     9    10    11    12    13    14    15    16    17
  Columns 19 through 36 
    18    19    20    21    22    23    24    25    26    27    28    29    30    31    32    33    34    35
  Columns 37 through 54 
    36    37    38    39    40    41    42    43    44    45    46    47    48    49    48    47    46    45
  Columns 55 through 72 
    44    43    42    41    40    39    38    37    36    35    34    33    32    31    30    29    28    27
  Columns 73 through 90 
    26    25    24    23    22    21    20    19    18    17    16    15    14    13    12    11    10     9
  Columns 91 through 99 
     8     7     6     5     4     3     2     1     0
tri=[0:50,49:-1:1]
tri =
  Columns 1 through 18 
     0     1     2     3     4     5     6     7     8     9    10    11    12    13    14    15    16    17
  Columns 19 through 36 
    18    19    20    21    22    23    24    25    26    27    28    29    30    31    32    33    34    35
  Columns 37 through 54 
    36    37    38    39    40    41    42    43    44    45    46    47    48    49    50    49    48    47
  Columns 55 through 72 
    46    45    44    43    42    41    40    39    38    37    36    35    34    33    32    31    30    29
  Columns 73 through 90 
    28    27    26    25    24    23    22    21    20    19    18    17    16    15    14    13    12    11
  Columns 91 through 100 
    10     9     8     7     6     5     4     3     2     1
tri=[0:50,49:-1:1]/50
tri =
  Columns 1 through 11 
         0    0.0200    0.0400    0.0600    0.0800    0.1000    0.1200    0.1400    0.1600    0.1800    0.2000
  Columns 12 through 22 
    0.2200    0.2400    0.2600    0.2800    0.3000    0.3200    0.3400    0.3600    0.3800    0.4000    0.4200
  Columns 23 through 33 
    0.4400    0.4600    0.4800    0.5000    0.5200    0.5400    0.5600    0.5800    0.6000    0.6200    0.6400
  Columns 34 through 44 
    0.6600    0.6800    0.7000    0.7200    0.7400    0.7600    0.7800    0.8000    0.8200    0.8400    0.8600
  Columns 45 through 55 
    0.8800    0.9000    0.9200    0.9400    0.9600    0.9800    1.0000    0.9800    0.9600    0.9400    0.9200
  Columns 56 through 66 
    0.9000    0.8800    0.8600    0.8400    0.8200    0.8000    0.7800    0.7600    0.7400    0.7200    0.7000
  Columns 67 through 77 
    0.6800    0.6600    0.6400    0.6200    0.6000    0.5800    0.5600    0.5400    0.5200    0.5000    0.4800
  Columns 78 through 88 
    0.4600    0.4400    0.4200    0.4000    0.3800    0.3600    0.3400    0.3200    0.3000    0.2800    0.2600
  Columns 89 through 99 
    0.2400    0.2200    0.2000    0.1800    0.1600    0.1400    0.1200    0.1000    0.0800    0.0600    0.0400
  Column 100 
    0.0200
figure(2)
hold on
plot(-50:49, abs(fftshift(fft(tri.*s2))))
??? Error using ==> .*
Matrix dimensions must agree.

plot(-50:49, abs(fftshift(fft(tri'.*s2))))
desiredPropNames = 
    'BeingDeleted'
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    'CallbackObject'
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    'Diary'
    'DiaryFile'
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    'Selected'
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    'Units'
    'UserData'
    'Visible'
desiredPropNames = 
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    'Language'
    'More'
    'Parent'
    'ScreenDepth'
    'ScreenSize'
    'SelectionHighlight'
    'Tag'
    'Type'
    'UIContextMenu'
    'Units'
    'Visible'
diary