Anti-Alias Filter Type Selection Guide

A variety of 8-pole filter types are available for the USBPGF, SCS, and AAF line of filter products from Alligator Technologies. Please use the information below to select the best filter for your application or contact Alligator Technologies for assistance.

FILTER TYPE	STRENGTH/WEAKNESS	APPLICATION
Cauer	Good passband flatness and low noise with sharpest attenuation slope; non-uniform group delay.	For frequency-domain applications requiring a minimal attenuation band; also useful in the time domain where signals are of a DC nature.
Bessel	Uniform group delay; lowest wideband noise; drooping amplitude response in the frequency domain; longest attenuation band.	For time-domain applications requiring minimum distortion of rapid changes such as an impulse.
Butterworth	Best passband flatness in the frequency domain and very low noise; non-uniform group delay although more uniform than Cauer filters and larger attenuation band then Cauer filters.	For frequency-domain applications requiring minimum noise or maximum passband flatness to 0.85Fc.
High-Speed Cauer	Similar to Cauer with lower noise as well as higher band width and higher stop-band rejection; non-uniform group delay but more uniform than standard Cauer.	Similar applications to Cauer, but with a need for a corner frequency higher than 50 kHz or a higher stopband rejection.
High-Speed Linear Phase	Highest maximum corner frequency; sharper roll-off than Bessel; reduced input/output voltage limits.	For highest-bandwidth applications, especially and especially useful in the time domain.