6.1 Concepts on Digital Filter For Fir filter design the transfer function is polynomial in z-1 H()=∑h(n)=n For reduced computational complexity, the degree n of H(z)must be as small as possible In addition if a linear phase is desired then the fir filter coefficients must satisfy the constraint h(n)=±hN-n 2021年1月27日1时46分
2021年1月27日1时46分 For FIR filter design, the transfer function is polynomial in z-1 : ( ) ( ) 0 N n n H z h n z− = = h n h N n ( ) = − For reduced computational complexity, the degree N of H(z) must be as small as possible. In addition, if a linear phase is desired, then the FIR filter coefficients must satisfy the constraint: 6.1 Concepts on Digital Filter
6.1 Concepts on Digital Filter o Advantages in using an fir filter >lt can be designed with exact linear phase >The filter structure is always stable with quantized filter coefficients 2021年1月27日1时46分
2021年1月27日1时46分 Advantages in using an FIR filter ➢It can be designed with exact linear phase. ➢The filter structure is always stable with quantized filter coefficients. 6.1 Concepts on Digital Filter
6.1 Concepts on Digital Filter o Disadvantages in using an fir filter >In the cases, the order noir of an FIR filter is considerably higher than the order Nur of an equivalent iIR filter meeting the same magnitude specification. It has been shown that for most practical filter specifications, the ratio Noir/nur is typically of the order of tens or more and, as a result, the IiR filter usually is computationally more efficient 2021年1月27日1时46分
2021年1月27日1时46分 Disadvantages in using an FIR filter ➢In the cases, the order NFIR of an FIR filter is considerably higher than the order NIIR of an equivalent IIR filter meeting the same magnitude specification. It has been shown that for most practical filter specifications, the ratio NFIR/NIIR is typically of the order of tens or more and, as a result, the IIR filter usually is computationally more efficient. 6.1 Concepts on Digital Filter
6.1 Concepts on Digital Filter o If the group delay of the iir filter is equalized by cascading it with an allpass equalizer, then the savings in computation may longer be that significant o In many applications, the linearity of the phase response of the digital filter is not an issue making the iir filter preferable because of the lower computational requirements 2021年1月27日1时46分
2021年1月27日1时46分 If the group delay of the IIR filter is equalized by cascading it with an allpass equalizer, then the savings in computation may longer be that significant. In many applications, the linearity of the phase response of the digital filter is not an issue, making the IIR filter preferable because of the lower computational requirements. 6.1 Concepts on Digital Filter
6. 1 Concepts on Digital Filter o Introduce of filter design o The approach to iir filter design based on the conversion of a prototype analog transfer function to a digital transfer function is widely used. Then the most common practice of IIR filter design is 2021年1月27日1时46分
2021年1月27日1时46分 6.1 Concepts on Digital Filter The approach to IIR filter design based on the conversion of a prototype analog transfer function to a digital transfer function is widely used. Then, the most common practice of IIR filter design is ⚫ Introduce of filter design