Chebyshev Stopbands for CIC Decimation Filters
and CIC-Implemented Array Tapers in 1D and 2D
J. O. Coleman
The stopbands of a cascaded integrator-comb (CIC)
decimation filter are ordinarily very narrow, as each
results from a single multiple zero. Here response
sharpening with a Chebyshev polynomial, using a
previously reported CIC variant, separates each such
multiple zero into an equiripple stopband. By trading
unneeded depth at stopband center for improved depth
at the stopband edge, the latter depth improves by
some 6(N-1) dB in an Nth-order system. Increased
computational complexity is modest: a few low-speed
additions and multiplications by small integer
coefficients that can often be chosen as powers of
two. Alternatively, parameters can be configured to
replace the many small stopbands with one large one,
and this is demonstrated here with example
spatial-processing CIC designs that create pencil
beams for 1D and 2D receive antenna arrays.
Just before (11) the right side of the "approximately equal to"
operation should be inverted.
- ONLINE VERSIONS:
authors' two-column preprint,
unofficial (767 Kbytes)
abstract page in IEEE Xplore.
- Appears in vol. 59, no. 12, Dec. 2012 of the IEEE Transactions on Circuits and Systems
I: Regular Papers.
- DATE OF ENTRY: