Digital filter

Basics :

Digital filter basics :
Filtering is the spacial part of digital signal processing. It can be remove unwanted part of the signal such as random noise Read more

Digital filter can be classified in several different groups but their are two major types of digital filter are to be FIR and IIR Read more

Filter design techniques :
1. The approximation of the specification using a causal discrete time system Read more

Advantages : 1.The digital filter are highly flexible 2. All data can be stored
Disadvantages : 1. Expensive 2. Harder to design Read more 

In the both of recursive ad non recursive (FIR and IIR filter) in DSP, the algorithm can be implementation is based on DFT or differential equation. Read more 

Digital filter applications :

1. Simulation/modeling  2. Noise suppression  3. Bandwidth limiting Read more 

FIR Filter :

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

Block diagram of FIR filter :
A discrete time fir filter of N number of order and the top part is an N stage delay line with N+1 taps to shown in figure. Each of unit delay is a Z-1 operator in the Z transform notation. Read more

FIR filter characteristics :
1.Can be adaptive 2. Unconditionally stable Read more 

Butterworth low pass filters design 
This type of response is called as butter-worth response because its main characteristics is that the pass-band maximally flat. That means there are no variations in the pass-band device. Read more

Advantages and disadvantages of FIR filters :
Advantages : 1. FIR filter are always stable 2. It is simple
Disadvantages : 1. Large storage requirements 2. Can not simulate prototype analog filter Read more

IIR Filter :


IIR filter basics :

IIR filter are one of the two primary types of digital filter. It is very important part of digital signal processing application Read more

1. IIR filter sometimes unstable 2. IIR filter has difficult to design Read more

IIR filter application :

1. Telecommunication  2. Clock recover in data communication Read more 

Advantages and disadvantages of bi-linear transformation method
Advantages : 1. The mapping is one to one 2. There is no aliasing effect
Disadvantages : 1. The mapping is non linear and because of this; frequency warping effect takes place Read more

IIR filter examples :
H(s) = 3 / (s+2) (s+3) with Ts = 0.1 sec Design the digital IIR filter using BLT. Read more 


Impulse invariant method example 
Step 1 : Analog frequency transfer function H(s) will be given. If it not given then obtain expression of H(s) from the given specification
Step 2 : If required H(s) by using fraction expansion Read more

Advantages and disadvantages of IIR filter 
Advantages : 1. Less memory requirement 2. Lower computational complexity
Disadvantages : 1. They are more susceptible to problem of line finite length arithmetic 2. They don't offer the computational advantages of FIR filter for multi-rate application Read more