Archive for January, 2012

Digital filters :advantages disadvantages and uses and esign

January 18th, 2012 Remo No comments

Digital filter advantages
This type fof filter has the greater accuracy.Dital filters are comparatevity cheaper  than the digital filter.The ease of data storage is one of the main advantages of the digital fiters.Implementatipon ofsophisticated algorithm implementation is also very good for the the use of digital filters.Digital filter allows to use of sophisticated algorithm implementation.
Now what is the application of the VLF signals?What we can do in digital filter is that we can process very low frequency signals –signals which cannot be done with the analog filters.

Next we discuss what are the limitation of digital filters.
There is no doubt that digitals filters make the system more complex than the anlog filters.A/D and D/A converters are very much necessary for the application.Beacuse our real world is an anlog one.
For high frequency signals we need to sample as twice of the frequency in concern so because of nyquest criteria.So forhigh frequecy signals samplig frequency becomes a too large which may be a limitation for the A/D converters.

In digital filter the power consumption is more than the anlog filters.
Applications of digital filters:
Digital filters play a major role in thye filed of echo cancellation in telephone networks.In modems ,line repeaters ,channel multiplexing,video conferencing  digital filter has a major role in many application areas of modern days.
In the filed of consumer electronics Tv,radio mp3 player and many song or voice modifiaction applications there are many digital filters are applide.
I image processing application s also digital filters are used.Digital filters are also used iin image compression ,enhancement imeage analysis and recognistion of image s.
Speech processing is a field where digital filters are used .In military application  in radar signal processing the digital filter is an is an essential part.Sonar signal processing is also a place where digital signal processing and use of digital filters are used.
For secure and navigation  digital filters are also used.
Designing digital filters:
How to design a digital filter.Digital filter design is a very important topic in the filed of  digital signal processing.
Design of digital filter is very challenging in the filed of digital filter design.How the digital filters are classified ?
Digital filters are classified based on the fact that how they respond to a unit impulse.

IIR filter:
They are actually the digital counterpart of the analog filters.Thisn this type of filter uses feedback.This filters requires less resources than the FIR filters.

Now what are the problems of high order IIR filters?

The high order IIR filters have or may have problems with the instability,overflow for arith \matic operation.So in this IIR filter require carefulll design to avoid the problems of IIR filters in high order.

How o build a stalker:khitish problem solution 2012

January 18th, 2012 Remo No comments

A simple robot based on khitish criteria.
A robotics contest to be held on khitish at IIT kharagpur.
How to build a line follower robot with another robot following the line follower  robot in another surface.
So if another robot has to follow the robot1 (which is a line folower robot).The another robot  which is follwoing the robot-1 can be any robot but must not be a robot which is not controlled manually.
It should be autonomous and follwing the robot-1 autonomously.
Now robot -1 is following a  a white line in the black surface.In the black surface the robot -1 is moving  and following the white path. Now robot-2 has to follow that path but in  a different surface. The surface may be at te  top of the robot-1 surface.Robot-1 and robot-2 will communicate among each other via wired ln link or wireless link. 
So the probable solution for that is is as follows:
So how we proceed to design such a systems whare robot 2 is following the robot-1 ?
The basic task first just construct the line follower robot. The line follower robot is a well exposed area.there are many good documets about the creation of the line follower robot is given  2 such places i know is here .

///// give line follower robot links

Now after the line follower robot construction is over then we need to optimise the performance of the line follwer robot as in the following way.
Now how we optimize the performance of the line folllower robot?
How the performance can be optimized that is one of the main crutial task.
So for that reason what we need to do ?
When ever a small turning etc done in the robot-1 that should be  recorded.
NOTE: recorded in this sense means that suppose a 20 degree right turn is made by the robot-1 due to the  white  path nature on the black surface.So if there is a 20 degree turn for the  white line in the black  surface.Then the line follower robot(robot-1)also  have to do a 20 degree turn on the right side.So this information that robot-1 has made a 20 degree right turn is to be passed to robot-2 which is following the robot-1. So the line follwoing robot-1 has to  send the info that 20 degree right turn has made.
How robot-2 is send a signal that 20  degree right turn is made,Say the microcontroller used in robot-1  is responsible for turning at right i mean 
give signal to turn at the right side  by the amoun of 20 degree .

Now question is how to turn a small car at right side??
Answer is: stop the front right motor and rotate the front left motor so that 20 degree turning can be done.
Say for example:A  1/2 rotation of the left front wheel motor make a total 20 degree rotation, so that is recorded( i mean 1/2 rotation).
So that is recorded and send to follower robot-2.Now the follower robot will receive that the info turn right and rotate left front wheel 1/2 rotation.
So this way robot 2 can exactly follow the path of robot 1.
If anybody want the full details of this how to do ??
just join the forum,before joining te forum you can email me .After you email me  and after that i will create the forum account for you,where you can get free suggesstion for that.
I can also supply te the things like circuit digram free with suggesstions. 7 professionals are ready to give you the answers.
So must join the forum and ask others to join the forum.