China
Africa
Explore chapters and articles related to this topic
Digital Filters
Published in Jerry C. Whitaker, Microelectronics, 2018
Jonathon A. Chambers, Sawasd Tantaratana, Bruce W. Bomar
There are sever always to prevent overflow oscillations in fixed-point filter realizations. The most obvious is to scale the filter calculations so as to render overflow impossible. However, this may unacceptably restrict the filter dynamic range. Another method is to force completed sums-of-products to saturate at ±1, rather than overflowing (Ritzerfeld, 1989). It is important to saturate only the completed sum, since intermediate overflows in two’s complement arithmetic do not affect the accuracy of the final result. Most fixed-point digital signal processors provide for automatic saturation of completed sums if their saturation arithmetic feature is enabled. Yet another way to avoid overflow oscillations is to use a filter structure for which any internal filter transient is guaranteed to decay to zero (Mills, Mullis, and Roberts, 1978). Such structures are desirable anyway, since they tend to have low roundoff noise and be insensitive to coefficient quantization (Barnes, 1979).
Finite Wordlength Effects
Published in Vijay K. Madisetti, The Digital Signal Processing Handbook, 2017
There are several ways to prevent overflow oscillations in fixed-point filter realizations. The most obvious is to scale the filter calculations so as to render overflow impossible. However, this may unacceptably restrict the filter dynamic range. Another method is to force completed sums-of-products to saturate at ±1, rather than overflowing [18,19]. It is important to saturate only the completed sum, since intermediate overflows in two’s complement arithmetic do not affect the accuracy of the final result. Most fixed-point digital signal processors provide for automatic saturation of completed sums if their saturation arithmetic feature is enabled. Yet another way to avoid overflow oscillations is to use a filter structure for which any internal filter transient is guaranteed to decay to zero [20]. Such structures are desirable anyway, since they tend to have low roundoff noise and be insensitive to coefficient quantization [21].
Accurate Computation of Vocal Tract Filter Parameters Using a Hybrid Genetic Algorithm
Published in Applied Artificial Intelligence, 2019
Mathew Mithra Noel, Venkataraman Muthiah-Nakarajan, Ruban Nersisson
In particular, if the pole values are close to unity the system can have limit cycles, adversely affecting the settling time. These problems are alleviated to some extent by doing saturation arithmetic in which the added value reaches a maximum or minimum and does not overflow or underflow as the case may be (Proakis and Manolakis 2003). Saturation arithmetic, however, makes the system non-linear because of the clipping. The remedy for this problem is to scale the signal or system parameters so that the chances of entry into the non-linear region is avoided (Proakis and Manolakis 2003). Since downscaling signal size will be detrimental to the SNR (signal-to-noise ratio), the usual practice is to minimize the size of the poles. In this work, the penalty forces the poles to be bounded above by a magnitude of 0.9. Thus, the problems of finite precision are dealt with automatically.