Digital Filter And Its Advantages and Disadvantages!

In quest to design a digital filter, it is important to follow a step by step guideline from specification to implementation. Each option of the design process is open for all designers. Most digital signals process experts apply some digital filter theory especially reflecting the considerable research effort, approximation for finding useful method of calculating filter coefficient.

What is digital filter?

It is a network or a precise system by which we can change the wave shape, amplitude, phase, frequency and other characteristics of the signal in a desired manner. The main objectives of using the filter in digital signal processing are to improve the signal quality by reducing noise, to extract or to combine the desired portion of the signal. Basically in signal processing technology, it is an algorithm which is implemented in software and hardware to generate digital output signal from the input signal obviously in a desired manner. It performs on a routine filtering algorithm representing some variables, numbers or digitized analog signals on specific hardware or software.

There are few steps in real time digital filter with analog input. First, band limiter limits the analog signal in order to periodic sample and convert into series of binary sample. Second, a processor is used to process these input sequences into output sequences with some sorts of computational mathematical algorithm. After that, the processed signal converts in analog signal reducing some unwanted components.


  • It has linear phase response.
  • Thermal and environmental variation cannot change the performance.
  • It is so-called adaptive filter because the frequency response can be possible to adjust automatically with implementation of programmable processor.
  • It is possible to filter several input sequences without any hardware replication.
  • All data can be stored
  • It has repeatable performance unit to unit.
  • Due to its operating level is at low frequency, it is used where the use of analog system is impractical.


  • In reality, the signal bandwidth of the digital sequence is much lower than the analog sequence. Signal processing speed is one of the key factors of calculating the total device performance. Actually the speed operation totally depends on the number of the arithmetic operation in the processor.
  • Finite word-length effect, which results quantizing noise and round-off noise, is another major drawback during computation.
  • It needs much longer time to design and develop the digital sequences though it can be used on other tasks or applications once developed. Ordinarily good support of computer aided design can convert them into a enjoyable tasks.

Source by Alamgir Mahmud