| Visual Cue
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Narration
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| Slide 1
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Welcome to the spoken tutorial on feedback diagram creation using Xfig
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| Slide 2
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In the spoken tutorial on block diagram creation,
We created the diagram shown here
We will refer to it as the blocks tutorial
Please master the blocks tutorial before starting the current one
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| Slide 3
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In this tutorial, we will explain how to create block diagrams of the type shown on this page
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| Slide 4
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I shall use Xfig, version 3.2, patch level 5
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| Slide 5
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We will begin with block.fig created in the blocks tutorial
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| Slide 6
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Let us go to Xfig
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| Open file
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Let us choose the file, then open.
In the entry box, we can enter “block” and press open.
Or double click on “block.fig”.
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| Save file
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Using the “save as” option on “file”, we will save this figure as feedback.
We now have the file feedback.fig
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| Click Grid Mode
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Let us put the grids on by clicking on the “grids”
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| Scroll bar
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The scroll bar on the right can be used to move the canvas up or down.
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| Top right
Scroll bar
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The role of each mouse button is shown on the top right hand side.
This role depends on the activity.
To illustrate this, let me take the mouse to the vertical “scroll bar”.
Observe the comment next to the left button.
I cannot move the mouse to show this.
It is because, the role of the buttons will change if I move the cursor away from the scroll bar.
The “left button” moves the canvas up and the “right button” moves it down.
Instead of clicking the left or right button, we can also click the “centre button”, hold and drag the canvas up or down.
In a similar way, you can move the canvas to the right or left, using the “scroll bar” on the top.
I will now move the box to the centre by clicking the “middle button”, holding and dragging the canvas to the centre.
As I release the mouse, the box gets moved to the centre.
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Let us now create the feedback diagram starting from this block.
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| Select copy
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Let us copy this box.
Click on the box and select it.
Move the mouse to the new location and click.
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| Click text
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Let us now put some text.
Let us click the “Text box”, indicated by T, from the left hand side panel.
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| Text size
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Let us choose the size of the text.
Move the mouse to the value box and enter 16.
Click “Set”.
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| Text just
Click
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Let us click the “Text Just” button in the attributes panel.
Let us choose centre alignment.
Let us click at the centre of the first box.
Sorry, I did not choose the correct position.
I will click at a different location to move the cursor away.
I will then click at the correct position.
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| Enter text
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Let us now type the text “Control” and click the mouse.
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We would now want to enter some more lines with arrows.
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| Polyline
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Let us choose the “polyline button”
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| Arrow Mode
Arrow Type
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Let us select the “Arrow Mode” button from the attributes panel and select the second option.
Let us click the “Arrow Type” button and an arrow head.
Let us click at the point where we want the line to start.
Let us move the mouse to the end point of the desired line. Let us now click there with “middle mouse button”.
The line is created with an arrow.
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| Put circle
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I want to place a circle.
Let us choose the “circle on the left” from the “left hand side panel”.
We will place it to the left of the first box.
Click the mouse. As I move the mouse, the circle becomes larger.
When we get the right size, let us click the mouse button.
Oops, the circle is larger than what I wanted.
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| Edit
Delete
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I can undo this operation, using the edit button at the top.
We can also delete this object, using the Delete button on the left hand panel.
Let us do that now.
A skeleton with cross hairs appears.
All key points of all objects also appear.
Move the cross hairs to a key point that indicates the circle and click.
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| Wrong delete
Zoom
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In case a wrong object is deleted, no need to panic.
You can undo it: Click the “edit” button, hold, go to “Undo” and release the mouse.
If some objects are closely placed, you may have difficulty in choosing them.
You can solve this through the “zoom” feature.
Click the “View” button on the top left hand side, hold and choose one of the zoom options.
Let me release the mouse at “Zoom to fit the canvas”.
Now it is easy to discriminate between the objects.
Let me delete the circle now.
Let me unzoom.
I will move the diagram to the centre with the use of scroll buttons.
I do not like to leave “delete” symbol on, because I can accidentally delete something else.
I can change this by choosing any other button.
Let me choose the left circle.
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| Circle
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Let me redraw the circle
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I want to put another line from this line.
For this, we will first put a “dot” on the line.
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| Library
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Let us click the “library” on the left hand side panel.
The library is indicated by a stack of books.
A “dialog window” opens.
Next to the library, it says “None Loaded”.
Let us click and hold.
A list of available libraries appears.
Move the mouse to the “Logic library” and release it.
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| Small dot
Place dot
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Let us choose the “small dot” by double clicking on it.
The “dialog window” gets closed.
We see a cross hair, along with the chosen small dot.
Let us place the dot on the line by clicking.
The cursor and the small dot show up once again, suggesting that we can place it at some other location also.
We do not want to place the dot at any other place.
Let us close it by clicking the right button of the mouse.
The right button does an “undo” operation.
In this case, dot selection has been removed.
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Let us draw a line from this dot to the circle.
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| Polyline
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Let us select the polyline.
Notice that the previous selections of “arrow mode” and “arrow type” have been remembered.
Within a session, Xfig remembers the parameter values.
Click at the dot. Move the mouse to the bottom and click.
Now turn the mouse to the left, until at the bottom of the circle.
Click.
Move the mouse to the circle and now click the “middle mouse button”.
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| Line
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Let us draw another line, to the left of the circle.
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| File save
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Let us now save this figure using the “file button” at the top left hand corner of Xfig and choosing “save”.
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| File export
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Let us now export the file.
Let us click the “file” button once again and choose “export”.
Let us choose “language” and then “PDF”.
We get the file “feedback.pdf”.
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| Open block.pdf
on terminal
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Let us open this file through the command “open feedback.pdf”.
We now have the block diagram that we wanted.
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We have completed our objective.
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| Slide 9
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We have an assignment for you
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Substitute blocks with different ones.
Try out operations, such as, rotate and flip.
View the file feedback.fig in an editor, and identify different components.
Using the library, create entirely different block diagrams.
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| Slide 10
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Spoken Tutorial is a part of the Talk to a Teacher project Supported by the National Mission on Education through ICT (NMEICT), MHRD, Government of India.
More information on this mission is available at
http://spoken-tutorial.org/NMEICT-Intro
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| Slide 12
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We welcome your participation and also your feedback.
This is Kannan Moudgalya signing off. Thanks for joining. Goodbye.
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