FIR filter basics

Digital filter is very important in digital signal processing. As mentioned in the introduction, the filter has basically two uses: separation and signal restoration. One of the most popular filters knows as FIR filter, whose impulse response is of the finite period, as a result of it settles to zero in finite time. FIR filter is the most popular kind of filters can execute in software and these filter can be continuous time, analog or digital and discrete time.

What does FIR mean?

FIR filter stands for finite impulse response filter, It is a digital filter used in digital signal processing application. FIR filter can be easily designed to be in the linear phase.

In this filtering, if you put in an impulse, that is, a single "1" sample followed by many "0" samples, zeroes will come out after the "1" sample so has made its way through the delay line of the filter.

FIR filter is to simple to implement it is one type of advantages of FIR filters. One of the most digital signal processor the FIR calculation can be implemented, learn or done by looping a single instruction.

FIR filter sometimes has the disadvantages that they require more memory or calculation to achieve a given filter response characteristics.

Compared to IIR filter, FIR filter offers the following advantages :
  • They are simple to implement, the FIR calculation can be done by looping a single instruction.
  • They have desireable numeric properties. IIR filter can cause significant problems due to the use of feedback, but FIR filters without feedback can usually be implemented using fewer bits, and the designer has a fewer practical problem to solve related to non-ideal arithmetic.
  • They can be implemented using fractional arithmetic.
  • They can be easily be designed to be linear phase. 
  • They are suited to multi-rate applications.