FIR (IIR) filters does not mean it is a Non Recursive ( Recursive) Filter in Digital signal processing

Sometime even published books state something wrong linking FIR filter and Recursiveness.

Though FIR filters are majorly non recursive and IIR filters are majorly realized recursively, the two are not related in any way.

FIR digital systems in DSP simply means the impulse response of the Finite number of Input samples x(n) is a finite number of out samples y(n).
IIR digital systems on the contrary have impulse response which is not a finite set of samples.

Recursive systems are those in which the output y(n) is fed back as a loop as an input. If no output is fed back then it is non recursive.

The two definitions is not correlated and remains separate. FIR any day does not mean non recursive!

Here is an example where a simple FIR system is defined using both in a recursive and non recursive way.

Say FIR system is defined by the difference equation:
y(n) = x(n) + x(n-1)
this is a non recursive implementation

Now the same difference equation can be represented in a recursive fashion as shown below

y(n) = x(n) + x(n-1)

now:
            y(n-1) = x(n-1) + x(n-2)
      => x(n-1) = y(n-1) - x(n-2)

Substituting above , we get

y(n) = x(n) - x(n-2) + y(n-1)

where y(n-1) represents feed back. So This is a recursive implementation.
Hence watch out all DSP buffs!
  

Tip for all drivers! How to save yourself from a drowning car.

I think it is very important for everyone who drives to know this to save themselves and their loved ones in the car from drowning!

For whatever reason, if you happen to go off road into a water mass, be it pond, pool, ocean, river, lake, you need to know the basics to get yourself out safe and sound. Here are some basic tip to save yourself. You can of course Google for more!

1. Embrace yourself by putting your hands on the steering wheel just before you hit the water.

2. You got about 30 seconds before your electrical begin to fail. Use this time to open your window( Although counter intuitive this matters a lot), Remove you seat belt and then remove seat belts of your kids, then try and see if you can open the door preferably in that order.

3. Follow the bubbles to swim to surface.

4. Now in the event that you are unable to open your window before the car starts drowning, first thing to know is, forget about opening the car's door.The Pressure outside is far more than the pressure inside the car. You cannot open the door, unless you let the water from outside to fill the car inside. How do you do that. Break the window. Again, the wind shield is made to be strong, so thats not going to be your option. Your side windows are the key. Use a sharp object to Break the glass. Or there are tools out there that can help you effortlessly. Buy one for your car.

5. Key is not to panic. Break your glass, let the water gush in. Force your self  out with the water gushing inside or wait till all the water fills your car and open the door and leave.

Having said all this, the best tip one could ever give you regarding this is - Drive safe!

The secret behind the Eye Patch!

Apparently Pirates are not all dumb after all. They might have not showered for some time but that is not the point of this post anyways.

Ever wondered why these guys wear an eye patch. it is not always to cover their Cataract eye. It is just that one of the eyes serves as night vision. What more would a person living most of his life on board a ship want. Especially those days when there was no electricity? it is just that these guys have a patch on one eye which would be all closed on deck exposed to bright sunlight. When they wanted to go below the deck, they would swap their eye patch and use the current one as night vision as their Rods( eye optics) are not saturated with the sunlight above.

Slick huh! I was damn impressed.

Remove Startup Programs in Windows OS

It is all frustrating that to have all programs start up on windows startup. Here is a method to remove the some of the programs which automatically starts up and runs on windows startup.

Click on Windows
type msconfig in the run command line and press enter
In almost all the windows version you will find a tab for Startup in the next window that pops up.
Under this tab check/uncheck all programs you want or do not want to start on windows startup.
Click apply / ok.

Your software will not be slow the next time it boots up.