Simple FIR Digital Filters Improved highpass magnitude response can again be obtained y cascading several sections of the first-order highpass filter Alternately, a higher-order highpass filter of the form H()=∑ M-1 M 7=0 is obtained by replacing z with -z in the transfer function of a moving average filter Copyright C 2001, S K Mitra
Copyright © 2001, S. K. Mitra 16 Simple FIR Digital Filters • Improved highpass magnitude response can again be obtained by cascading several sections of the first-order highpass filter • Alternately, a higher-order highpass filter of the form is obtained by replacing z with in the transfer function of a moving average filter − z M n n n M H z z − − = = − 1 0 1 1 ( ) ( 1)
Simple FIR Digital Filters An application of the fir highpass filters is in moving-target-indicator (MTD radars In these radars, interfering signals, called clutters, are generated from fixed objects in the path of the radar beam The clutter, generated mainly from ground echoes and weather returns, has frequency components near zero frequency (dc) 17 Copyright C 2001, S K Mitra
Copyright © 2001, S. K. Mitra 17 Simple FIR Digital Filters • An application of the FIR highpass filters is in moving-target-indicator (MTI) radars • In these radars, interfering signals, called clutters, are generated from fixed objects in the path of the radar beam • The clutter, generated mainly from ground echoes and weather returns, has frequency components near zero frequency (dc)