Many LC Filter designs that
involve extremely sharp cut-offs cannot be synthesized. With
this in mind, Allen Avionics utilizes a special computer
aided design program that transforms this type of filter
into a flat delay device. Bu utilizing the proper delay
sections, it is practical in many cases to achieve a delay
flatness of 3% of the nominal delay over the passband. A
group of these very unusual Sharp Cut-off Lowpass Delay
Equalized Filters are offered by Allen Avionics as
Built Lowpass filters detailed elsewhere on these pages.
These filters have never been tabulated by anyone before and
their excellent specifications make them very desireable for
use as Anti-Aliasing filters in D/A or A/D digital systems.
Four shape factors are offered
in this series. Each one is designed to offer the best in
cut-off and delay flatness.
After learning about the
different types of filters, you have to know the important
information that has to be specified when you order a custom
filter. Allen Avionics provides an easy to use, step by step
filter order specification form with our catalog and here on
our web site that will guide you in the design of a custom
filter. The form covers all the filter types and allows you
to match your needs with our products. All the parameters
like cut-off, shape factor, impedance, size and termination
type are easily defined. If your requirements cannot be met
with the order form and the standard filter tabulations on
our catalog and web pages, our technical sales staff is
ready to assist you.