Xfig/C2/Feedback-control-diagram/English-timed

Time	Narration
00:00	Welcome to the spoken tutorial on feedback diagram creation using Xfig.
00:07	In the spoken tutorial on block diagram creation, we created the diagram shown here.
00:14	We will refer to it as the blocks tutorial.
00:18	Please master the blocks tutorial before starting the current one.
00:22	In this tutorial, we will explain how to create block diagrams of the type shown on this page.
00:31	I shall use Xfig version 3.2, patch level 5.
00:37	We will begin with "block.fig" created in the blocks tutorial.
00:43	Let us go to Xfig.
00:47	Let us choose the File, then Open.
00:52	In the entry box, we can enter "block" and press Open. Or double-click on “block.fig”.
01:04	Using the Save as option on File, we will save this figure as "feedback".
01:24	We now have the file "feedback.fig".
01:28	Let us put the grids on by clicking on the Grids.
01:34	The scroll bar on the right can be used to move the canvas up or down.
01:41	The role of each mouse button is shown on the top right hand side.
01:46	This role depends on the activity.
01:49	To illustrate this, let me take the mouse to the vertical scroll bar.
01:55	Observe the comment next to the left button.
01:59	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.
02:08	The left-button moves the canvas up and the right-button moves it down.
02:17	Instead of clicking the left or right button, we can also click the centre button, hold and drag the canvas up or down.
02:31	In a similar way, you can move the canvas to the right or left, using the scroll bar on the top. Left, right..
02:44	I will now move the box to the centre by clicking the middle button, holding and dragging the canvas to the centre.
02:57	As I release the mouse, the box gets moved to the centre.
03:03	Let us now create the feedback diagram starting from this block.
03:08	Let us copy this box.
03:13	Click on the box and select it.
03:16	Move the mouse to the new location and click.
03:27	Let us now put some text.
03:29	Let us click the text-box, indicated by T, from the left hand side panel.
03:37	Let us choose the size of the text.
03:43	Move the mouse to the value-box and enter 16.
03:51	Click Set.
03:53	Let us click the Text Just button in the attributes panel.
04:02	Let us choose the centre alignment.
04:05	Let us click at the centre of the first box.
04:11	Sorry, I did not choose the correct position.
04:15	I will click at a different location to move the cursor away.
04:19	I will then click at the correct position.
04:27	Let us now type the text “Control” and click the mouse.
04:35	We would now want to enter some more lines with arrows.
04:40	Let us choose the POLYLINE button.
04:43	Let us select the Arrow Mode button from the attributes panel and select the second option.
04:53	Let us click the Arrow Type button and an arrow head.
05:00	Let us click at the point where we want the line to start.
05:08	Let us move the mouse to the end point of the desired line.
05:14	Let us now click there with middle mouse button.
05:20	The line is created with an arrow.
05:25	I want to place a circle.
05:27	Let us choose the circle on the left from the left hand side panel.
05:33	We will place it to the left of the first box.
05:37	Click the mouse. As I move the mouse, the circle becomes bigger.
05:47	When we get the right size, let us release the mouse button.
05:54	Oops, the circle is larger than what I wanted.
05:57	I can undo this operation, using the Edit button at the top.
06:02	We can also delete this object, using the Delete button on the left hand panel.
06:10	Let us do that now.
06:14	A skeleton with cross hairs appears.
06:18	All key points of all objects also appear.
06:22	Move the cross hairs to a key point that indicates the circle and click.
06:32	In case a wrong object is deleted, no need to panic.
06:35	You can undo it: Click the Edit button, hold, go to Undo and release the mouse.
06:44	If some objects are closely placed, you may have difficulty in choosing them.
06:49	You can solve this through the zoom feature.
06:55	Click the View button on the top left hand side, hold and choose one of the zoom options.
07:00	Let me release the mouse at Zoom to fit the canvas.
07:04	Now it is easy to discriminate between the objects.
07:08	Let me delete the circle now.
07:12	Let me unzoom.
07:20	I will move the diagram to the centre with the use of scroll buttons.
07:35	I do not like to leave the delete symbol on because I can accidentally delete something else.
07:41	I can change this by choosing any other button.
07:44	Let me choose the left circle.
07:47	Let me redraw the circle.
08:00	I want to put another line from this line.
08:04	For this, we will first put a dot on the line.
08:07	Let us click the Library, on the left hand side panel.
08:11	The Library is indicated by a stack of books.
08:15	A dialog window opens.
08:17	Next to the Library, it says "None Loaded".
08:20	Let us click and hold.
08:22	A list of available libraries appears.
08:25	Move the mouse to the 'Logic' library and release the mouse.
08:31	Let us choose the small dot by double clicking on it.
08:36	The dialog window gets closed.
08:38	We see a cross hair along with the chosen small dot.
08:42	Let us place the dot on the line by clicking.
08:51	The cursor and the small dot show up once again, suggesting that we can place it at some other location also.
08:57	We do not want to place the dot at any other place.
09:00	Let us close it by clicking the right button of the mouse.
09:05	The right button does an undo operation.
09:08	In this case, dot selection has been removed.
09:10	Let us draw a line from this dot to the circle.
09:15	Let us select the Polyline.
09:18	Notice that the previous selections of Arrow Mode and Arrow Type have been remembered.
09:24	Within a session, Xfig remembers the parameter values.
09:28	Click at the dot.
09:34	Move the mouse to the bottom and click.
09:41	Now turn the mouse to the left, until at the bottom of the circle. Click.
09:47	Move the mouse to the circle and now click the middle mouse button.
09:54	Let us draw another line, to the left of the circle, by copying.
10:08	Let us now save this figure using the File button at the top left hand corner of Xfig and choosing Save.
10:19	Let us now Export the file.
10:22	Let us click the File button once again and choose Export.
10:30	Let us choose Language and then PDF.
10:36	We get the file "feedback.pdf".
10:43	Let us open this file through the command open feedback.pdf.
10:56	We now have the block diagram that we wanted.
11:00	We have completed our objective.
11:04	We have an assignment for you.
11:08	Substitute the blocks with different objects.
11:13	Try out operations such as rotate and flip.
11:19	View the file "feedback.fig" in an editor and identify different components.
11:25	Using the Library, create entirely different block diagrams.
11:32	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.
11:44	More information on this mission is available at:http://spoken-tutorial.org/NMEICT-Intro
11:53	We welcome your participation and also your feedback.
11:57	This is Kannan Moudgalya, signing off. Thanks for joining. Goodbye.

Contributors and Content Editors

Nancyvarkey, Sandhya.np14