Let us consider the example of an ideal low-pass filter of normalized gain and whose frequency is in relation to cut-off frequency (see Figure 4.1).
With an ideal filter, transmission is total in the passband and the stopband.
We write x as the normalized frequency in relation to the cut-off frequency:
NOTE.– x is also called the normalized angular frequency in relation to the cut-off angular frequency:
Obtaining the transfer function of the filter H(j2πf) from the transfer function of the normalized low-pass filter H(jx) follows the frequency transformation summarized in Table 4.1.
|Obtaining a filter||Transformation carried out from the transfer function of the normalized low-pass filter|
|High-pass with ...|