The bandwidth of a circuit is given by the difference between the maximum and minimum frequencies, where the impedance isn´t less than 70,7% of the maximum value.
The bandwidth, as shown in the figure below, depends on the frequency and also the merit figure (Q).
Formula 1
Bw = f / Q
Where:
Bw is the bandwidth in hertz (Hz)
f is the central or resonant frequency in hertz (Hz)
Q is the merit figure or factor Q
Application Example:
Calculate the bandwidth of a resonant circuit operating at a frequency of 1 MHz with a merit figure of 200.
Data:
f = 1 MHz = 1 000 000 Hz
Q= 200
Bw = ?
Using formula 1:
Bw = 1.000.000 / 200
Bw = 5.000 Hz or 5 kHz
