Two-Rate Based Low-Complexity Variable Fractional-Delay FIR Filter Structures
| Autor: | Håkan Johansson, E. Hermanowicz |
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| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | IEEE Transactions on Circuits and Systems I: Regular Papers. 60:136-149 |
| ISSN: | 1558-0806 1549-8328 |
| DOI: | 10.1109/tcsi.2012.2215697 |
| Popis: | This paper considers two-rate based structures for variable fractional-delay (VFD) finite-length impulse response (FIR) filters. They are single-rate structures but derived through a two-rate approach. The basic structure considered hitherto utilizes a regular half-band (HB) linear-phase filter and the Farrow structure with linear-phase subfilters. Especially for wide-band specifications, this structure is computationally efficient because most of the overall arithmetic complexity is due to the HB filter which is common to all Farrow-structure subfilters. This paper extends and generalizes existing results. Firstly, frequency-response masking (FRM) HB filters are utilized which offer further complexity reductions. Secondly, both linear-phase and low-delay subfilters are treated and combined which offers trade-offs between the complexity, delay, and magnitude response overshoot which is typical for low-delay filters. Thirdly, the HB filter is replaced by a general filter which enables additional frequency-response constraints in the upper frequency band which normally is treated as a don't-care band. Wide-band design examples (90, 95, and 98% of the Nyquist band) reveal arithmetic complexity savings between some 20 and 85% compared with other structures, including infinite-length impulse response structures. Hence, the VFD filter structures proposed in this paper exhibit the lowest arithmetic complexity among all hitherto published VFD filter structures. |
| Databáze: | OpenAIRE |
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