| DSP Blockset | |
Specifying Classical Discrete-Time Filter Parameters. For both the Digital FIR Filter Design and Digital IIR Filter Design blocks, frequency parameters are normalized to half the sample frequency, so the cutoff or band edge frequencies are always in the range [0 1]. The magnitude frequency response is normalized to 1 (0 dB).
The FIR filters are real, symmetric, linear phase filters; Type I for even filter orders and Type II for odd filter orders. Cutoff frequencies are defined as the frequencies where the magnitude response drops to -6 dB below the passband level (one half the passband gain). Band edge frequencies are defined as the left or right edges of a transition region between bands.
The following four sections provide several examples of how cutoff and band edge parameters are used to specify FIR filter responses:
The final section, Discrete-Time IIR Filters, illustrates how cutoff and band edge parameters are used to specify an IIR filter response.
| | Design Parameters of Classical Discrete-Time Filters | Lowpass and Highpass Discrete-Time FIR Filters | |