Half-band filter
A half-band filter is a finite impulse response (FIR) low-pass filter that reduces the maximum bandwidth of sampled data by a factor of 2 (one octave). When multiple octaves of reduction are needed, a cascade of half-band filters is common. And when the goal is downsampling, each half-band filter needs to compute only half as many output samples as input samples. In digital signal processing, half-band filters are widely used for their efficiency in multi-rate applications.
It follows from the filter's definition that its transition region, or skirt, can be centered at frequency where is the input sample-rate. That makes it possible to design a FIR filter whose every other coefficient is zero, and whose non-zero coefficients are symmetrical about the center of the impulse response. (See Finite impulse response § Window design method) Both of those properties can be used to improve efficiency of the implementation.[1][2]
References
- ↑ Venosa, Elettra; harris, fredric j.; Palmieri, Francesco A. N. (2011-10-17). Software Radio: Sampling Rate Selection, Design and Synchronization. New York: Springer. pp. 91-93. ISBN 9781461401124. https://archive.org/details/softwareradiosam00veno_250.
- ↑ Meyer-Baese, Uwe (2007-11-14). "5.4.1". Digital Signal Processing with Field Programmable Gate Arrays (3 ed.). New York: Springer. p. 274. ISBN 978-3540726128. https://archive.org/details/digitalsignalpro00umey.
Further reading
- Lyons, Richard G. (2010-11-11). Understanding Digital Signal Processing (3 ed.). Prentiss-Hall. ISBN 978-0137027415.
- https://www.dsprelated.com/showarticle/1113.php
 |  |
