6. 1 Concepts on Digital Filter Normalized specifications Maximum value of the magnitude (gain)is assumed to be unity or the minimum value of the +2 loss function is 0 dB pass band amo 20log gIo /+52dB band am-2010g0(1-2,) 0 25.dB Transition band Maximum passband 2021年12月5日2时7分 attenuation
2021年12月5日2时7分 6.1 Concepts on Digital Filter Maximum passband attenuation
6. 1 Concepts on Digital Filter o Maximum passband attenuation max 200g(1+82)dB For 8,<<1, as is typically the case, it can be shown C-20log10(1-26)2andB max 2021年12月5日2时7分
2021年12月5日2时7分 Maximum passband attenuation ( ) 2 max 10 = + 20log 1 dB For 1, p as is typically the case, it can be shown max 10 − − 20log 1 2 2 ( p p ) dB 6.1 Concepts on Digital Filter
6. 1 Concepts on Digital Filter o The passband and stopband edge frequencies, in most applications are specified in Hz, along with the sampling rate of the digital. Then, the normalized angular edge frequencies in radians are given by 2,2F 2丌FnT Q。2丌F 2丌FT 2021年12月5日2时7分
2021年12月5日2时7分 The passband and stopband edge frequencies, in most applications, are specified in Hz, along with the sampling rate of the digital. Then, the normalized angular edge frequencies in radians are given by 2 2 P P p P T T F F T F F = = = 2 2 S S S S T T F F T F F = = = 6.1 Concepts on Digital Filter
6. 1 Concepts on Digital Filter o Selection of the Filter Type o the second issue of interest is the selection of the digital filter type, that is, whether an IIR or an Fir digital filter is to be employed o The objective of digital filter design is to develop a causal transfer function H(z) meeting the frequency response specifications 2021年12月5日2时7分
2021年12月5日2时7分 ⚫ Selection of the Filter Type The second issue of interest is the selection of the digital filter type, that is, whether an IIR or an FIR digital filter is to be employed. The objective of digital filter design is to develop a causal transfer function H(z) meeting the frequency response specifications. 6.1 Concepts on Digital Filter
6. 1 Concepts on Digital Filter o For iir digital filter design the transfer function s a rational function of z-1 M P0+P12+p22+…+p d+d,z-1+dz-2+……+d,z Moreover, H(z) must be a stable transfer function, and for reduced computational complexity, it must be of lowest order n 2021年12月5日2时7分
2021年12月5日2时7分 For IIR digital filter design, the transfer function is a rational function of z-1 : ( ) 1 2 0 1 2 1 2 0 1 2 M M N N p p z p z p z H z d d z d z d z − − − − − − + + + + = + + + + Moreover, H(z) must be a stable transfer function, and for reduced computational complexity, it must be of lowest order N. 6.1 Concepts on Digital Filter