Teledyne LeCroy DFP2 - Digital Filter Package 2 - Manual (Page 7)

DFP2 Option
923134 Rev A ISSUED: June 2013 5
Kinds of Filters 1
Low-pass Filter Low-pass filters are useful for eliminating accumulated
high-frequency noise and interference, and for
canceling high-frequency background noise.
Sample applications are in datacom,
telecommunications, and disk drive and optical
recording analysis for accurate RF signal detection.
Band 1: Pass Band — DC to top of the transition
region; signal passes unattenuated.
Band 2: Transition Region — edge frequency to edge
frequency plus width; increasing attenuation.
Band 3: Stop Band — above end of transition region;
signal is highly attenuated.
High-pass Filter High-pass filters are useful for eliminating DC and low-
frequency components. Sample applications include
Disk Drive and Optical Recording analysis (emulation
of the SLICING function).
Band 1: Stop Band — DC to bottom of the transition
region; highly attenuated.
Band 2: Transition Region — edge frequency minus
width to edge frequency; decreasing attenuation.
Band 3: Pass Band — above edge frequency; signal
passes unattenuated.
1 1. Filters are optimal FIR filters of less than 2001 taps, according to the Parks-MacLellan algorithm described in Digital
Filter Design and Implementation by Parks and Burrus, John Wiley & Sons, Inc., 1987, and then adjusted by windowing
the start and end 20% with a raised cosine for improved time domain characteristics and better ultimate rejection in the
frequency domain, slightly increasing 1
st stop-band ripple height.