The attenuation characteristics of the filter are defined by:
•Low and high attenuation frequencies: The attenuation frequencies are set by the Attenuation Frequency (Low) and Attenuation Frequency (High) parameters. The values you enter indicate the frequency at which the specified attenuation level is reached.
•Low and high attenuation levels: The attenuation levels are set by the Attenuation (Low) and Attenuation (High) parameters. The values you enter indicate the amount by which you desire to suppress the level. An attenuation level of 100 equals a magnitude of 1/100.
For example, a Band Pass filter with band edges specified at 100 and 1000, an attenuation level of 10, and attenuation frequencies of 20 (low) and 100 (high) means that the filter gain is 0.1 at 80 and 0.05 at 1100. The epsilon (ε) is a measure of the attenuation level reached by the filter’s magnitude characteristics at the critical frequency. Attenuation level at the critical frequency is given by:
The ripple is the attenuation level at the critical frequency. Defining the epsilon completely defines the ripple.