Shape factor of filter

Shape factor (SF): The shape factor of a filter is typically the ratio of the stopband bandwidth(BW) to the 3 dB bandwidth. It is a measure of the steepness of the filter skirt. For example if the 40 dB BW is 40 MHz and the 3 dB BW is 10 MHz, the shape factor will be 40/10=4.

1. What is the ideal shape factor?
2. What is the selectivity of a filter?
3. What is the Q of a filter?
4. What is 60 dB bandwidth?

What is the ideal shape factor?

A shape factor equal to one usually represents an ideal case or maximum symmetry, such as a circle, sphere, square or cube.

What is the selectivity of a filter?

Shape factor is a common figure of merit for a related term, selectivity. For an RF filter selectivity tells us how much of the total bandwidth will be used by transition bands. The smaller the transition bands the smaller any necessary guard bands can be and less of the bandwidth is wasted in this way.

What is the Q of a filter?

The factor is known as Q (quality factor). The higher the Q, the better the filter; the lower the losses, the closer the filter is to being perfect.

What is 60 dB bandwidth?

BW at 60 dB = 10 kHz.