HowToDoIt

Despite its widespread, the development of digital IIR filters (Infinite impulse response), even in our time, a time of high technology, for many remains a mystery. From time to time I come across articles or videos about the principle of the IIR filters design. Becomes sad when looking at the next one “good explanation” I understand that thanks to just such a presentation of the material most students loose their hope to understand it. Many of my friends have practical skills in the design of IIR filters, but frequently they use such package as Matlab, to obtain the coefficients of an IIR filter, sometimes even without understanding its principle of work. If you do not fully understand a principle of work of a particular piece of code, you can not say with certainty about its reliability. Refreshing knowledge from the university, I decided to share them with you in form of the article developing digital IIR filter “from scratch”! ↓ Read the rest of this entry…

Again and again, this post for me is none other than the cry of my soul. I am struck by the fact that some things from everyday life used by us for granted. We believe even in lie. Take the formula, substitute the value and it works (so far, seems to be :). People, stop! “But all is working right!” – You might say. “Smart guy from the forum said that everything will work perfectly!”. Perhaps smart guy is right, but as the classic said “Do not trust anyone!”. Should you trust me? – It is really possible, but after rechecking. After all the task of the engineer not only to create something but also deeply understand the running process. As an example of “it should work!”, we will consider the recursive formula for the sine wave generation, which I have repeatedly seen on many websites and blogs dedicated to digital signal processing. Naturally, I checked this formula in practice and was really surprised by such simplicity. It really works! I was so amazed that could not resist and set out myself to understand the magic of the miracle formula. I was not very surprised when the clear and simple way of the formula deduction was not found in the network. Found a lot of absurdities, empirical and deductive methods and other “rubbish” but for myself – NOTHING. ↓ Read the rest of this entry…