3.3 Low-Pass RC Filter (contd.)
The physical intrepretation of these relations is straightforward.
As you increase the frequency w,
the amplitude of the voltage signal appearing at the output terminals
falls with respect to the input signal. It also becomes delayed,
the angle of the delay increasing with frequency.
It is common to represent the ampltitude response of a circuit
in terms of decibels (dB). In general, decibels are given by taking the logarithm
(base 10) of a power ratio and multiplying the result by 10, i.e.
deciBels = 10 log10 ( Power / Reference power )
Since power is proportional to voltage squared, we have in this case
deciBels = 10 log10 | Vout / Vin |2