- The bandwidth (BW) of the filter is the difference between the upper and lower cut-off frequencies
- Shape factor (ratio of BW measured at 6dB and 60 dB) determines how effectively signals are attenuated outside the passband
- Provides adjacent channel Selectivity depending on shape factor (i.e. the steepness of the skirt). Better than 2:1 shape factor desirable
- Typical BW of filters:
- CW 100 Hz – 300 Hz
- SSB 1.8 kHz – 2.4 kHz
- FM 12.5 kHz