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IntroductionSignal Representation > Waveform and Sonagram Manipulations > Zoom and Browse
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Zooming In and Out the Representations

Sommaire
  1. Temporal Zoom
  2. Amplitude or Frequency Zoom
  3. Zooming In or Out a Region/Full Scale
  4. Temporal Location
  5. Temporal Selection
  6. Instantaneous Spectrum
  7. Examples
  8. Frequency Zoom
  9. Zooming In or Out a Region

The signal representations – sonogram, waveform and instantaneous spectrum – can be studied in time, frequency and amplitude domains. Most manipulations described in this section are common to the three representations. The representations can be browsed and zoomed in or out.

Additionnaly to "manual" operations, the Windows menu gives access to most operations described in this section. Besides, a single procedure can apply to different parameters : zooming in a frequency or amplitude zone is done the same way, for instance.

Temporal Zoom

Zooming Around the Cursor Position or Pointer Position

To zoom around the cursor position, use the Window/Zoom Time In-Out or the corresponding Cmd + = or - shortcut.

To zoom around the pointer position

  • Click somewhere on one of the temporal scale and scroll the mouse up or down to zoom in or out.

  • Click somewhere in one of the scales to display a vertical double arrow and keep pressing to zoom in.

    Alt click to zoom out.

Zooming in a Selection

Shift click and drag the mouse over a portion of one of the scales. The selection will turn grey.

  • To increase or descrease the size of the segment – zoom out or zoom in – leftwards or righwards, click and drag one of the borders of the red rectangle .

  • To reset the general view double click on one of the scales.

Browsing the Representation

To move the selected segment :

  • click on one of the scales to display the double arrow and drag the mouse leftwards or rightwards.

  • Shift click in the rectangle to display a triangular pointer and drag the mouse leftwards or rightwards.

Browsing and Zooming

To move the temporal segment and zoom in or out simultaneously : rotate the mouse.

Amplitude or Frequency Zoom

These manipulations are the same as the previous ones, with a few differences.

Zooming Around a Given Value and Browsing the Representation

  • To zoom around a given value :

    1. click somewhere on on the waveform amplitude scale or on the sonogram frequency scale

    2. scroll the mouse to the right to zoom in, or to the left to zoom out.

  • You can scroll the mouse up or down to move the waveform simultaneously.

  • To move the waveform only, you need to zoom in first a little, then scroll the mouse up or down, or use the scrollbar.

Fast Zoom Upward/Downward

To increase the speed of the zoom, keep pressing on the amplitude scale.

  • If you click in the upper part of the scale, the waveform will move upwards, towards the negative amplitude values.

  • If you click in the lower part of the scale, the waveform will move upwards, towards the positive amplitude values.

Alt click to zoom out.

Zooming In a Selection

To zoom in a precise region from the values of the scale, Shift click and drag the mouse over a portion of the frequency scale. The selection will turn grey.

Zooming In or Out a Region/Full Scale

Zoom In

To zoom directly in a time/frequency or time/amplitude region,

  1. select the zoom tool in the palette – press S

  2. click and drag a region in the waveform or in the sonogram.

Zooming Out/Full Scale

  • Alt click to zoom out

  • Double click to reset the maximum scale.

Temporal Location

Zooming Around the Cursor Position

Use the Window/Zoom Time In-Out or the corresponding Cmd + = or - shortcut.

Zooming Aroung a Fixed Point

  • Click somewhere on one of the temporal scale and scroll the mouse up or down to zoom in or out.

  • Click somewhere in one of the scales to display a vertical double arrow and keep pressing to zoom in.

    Alt click to zoom out.

Temporal Selection

Creating a Selection

Shift click and drag the mouse over a portion of one of the scales. The selection will turn grey.

To increase or descrease the size of the segment – zoom out or zoom in – leftwards or righwards, click and drag one of its borders .

To reset the general view double click on one of the scales.

Zoom
Browsing the Representation

To move the selected segment :

  • click on one of the scales to display the double arrow and drag the mouse leftwards or rightwards.

  • Shift click in the rectangle to display a triangular pointer and drag the mouse leftwards or rightwards.

To move the temporal segment and zoom in or out simultaneously : rotate the mouse.

Instantaneous Spectrum

All the manipulations described here apply to the instantaneous spectrum as well.

Instantaneous Spectrum and Sonogram

A sonogram analysis must have been executed in order to display the instantaneous spectrum.

Amplitude and Frequency Domain

The instantaneous spectrum can be manipulated independently from the other representations in the amplitude domain.

All manipulations related to the frequency domain will also affect the sonogram.

Examples

Zooming and Browsing a Spectrum
Zooming and Browsing the Amplitude of a Waveform

Frequency Zoom

Scales

The default scale of the sonogram goes from 0 to 7KHz. It can reach half the value of the sampling rate, or Nyquist frequency – 22.05 KHz for 44.1 KHz for instance.

The default value of amplitude "positive" or "negative" peaks is equal to 0 dB, and the default value of the rest position – central axis – is equal to -60 dB. In the waveform representation zone, peaks are equal to +1 or -1. The rest position is equal to 0.

Zooming Around a Given Value and Browsing the Representation

  • To zoom around a given value :

    1. click somewhere on on the waveform amplitude scale or on the sonogram frequency scale

    2. scroll the mouse to the right to zoom in, or to the left to zoom out.

  • You can scroll the mouse up or down to move the waveform simultaneously.

  • To move the waveform only, you need to zoom in first a little, then scroll the mouse up or down, or use the scrollbar.

Fast Zoom Upward/Downward

To increase the speed of the zoom, keep pressing on the amplitude scale.

  • If you click in the upper part of the scale, the waveform will move upwards, towards the negative amplitude values.

  • If you click in the lower part of the sclae, the waveform will move upwards, towards the positive amplitude values.

Alt click to zoom out.

Zooming In or Out a Region

Zooming In a Given Amplitude or Frequency Region

To zoom in a precise region from the values of the scale, Shift click and drag the mouse over a portion of the frequency scale. The selection will turn grey.

To zoom directly in a time/frequency or time/amplitude region,

  1. select the zoom tool in the palette – press S

  2. click and drag a region in the waveform or in the sonogram.

Press Alt and click to zoom out, or double click to reset the representation to the maximum range of the scale.

Zooming Between 0 and 4000 Hz.
Zooming Between 0 and 4000 Hz.
General View
The sonogram, before and after the double click.
The sonogram, before and after the double click.

To get a general view of the whole waveform or scale, double click on a scale.

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