Sunday, 23 April 2017

Expt - 8 Digital FIR Filter Design using Frequency Sampling

It as an alternative method for implementation of FIR Filter Design.
The desired frequency response Hd(w) is sampled at discrete values of frequency to obtain H(k). A factor of 2*pi has to be added every time a sign change occurs in the magnitude of H(k). 
The final output sequence is obtained by Inverse Discrete Fourier Transform (IDFT).

Hd(w)----------------H(k)------------------h(n).
         
       (By sampling)           (By IDFT)

        
The frequency sampling realization of filter is computationally more efficient mainly because the sample values are symmetric about k = N/2.

11 comments:

  1. it would be more efficient if simulation results will also attached

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  2. The frequency sampling realization of filter is computationally more efficient than the direct form realization as frequency sampling method eliminates the the co-efficient of H[k] which are zero.

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  3. The algorithm for FSM is well-explained.

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  4. alising may occur if nyquist criterion is not followed

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  5. Frequency sampling technique is one of the easiest methods for designing a FIR filter moreover it is computationally faster.

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  6. FSM is used in the cases where desired response in known.

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  7. It is computationally more efficient because coefficients of H[k] becomes zero for w greater than cut off frequency. Thus only non - zero values are to be taken into consideration while obtaining h(n)

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  8. DFT is used in FSM which involves computation at fixed values of frequency. Hence, it is preferred.

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  9. Easy and preferred method for designing FIR filter

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  10. Frequency sampling realization is computationally more efficient than direct form realization

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