16.2. Fundamentals of Low-Pass Filters
The most simple low-pass filter is the passive RC low-pass network shown in Fig. 16.2.
Its transfer function is
where the complex frequency variable, s = jω + σ, allows for any time variable signals. For pure sine waves, the damping constant, σ, becomes zero and s = jω.
For a normalized presentation of the transfer function, s is referred to the filter's corner frequency, or −3 dB frequency, ωC, and has these relationships:
With the corner frequency of the low-pass in Fig. 16.2 ...