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Altera_Forum
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15 years ago

Round or truncate? 截取和舍入对滤波器输出精度影响？

turncat and rounding on the accuracy of the filter output? designing filter with Fpga, there are two output modes, turncut and rounding. What effect on accuracy on Both methods have? Is t...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

If you look at Dave's posts after mine, you will see very good description of both noise and dc bias for various truncation algorithms. The case of direct truncation leads to truncation error of up to 1 LSB. Other cases lead to 0.5 LSB error. The actual error power will then depend on probaility issues and can be modelled same as quantisation noise of ADC sampling.

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http://www.ovro.caltech.edu/~dwh/correlator/pdf/esc-100paper_hawkins.pdf (http://www.ovro.caltech.edu/%7edwh/correlator/pdf/esc-100paper_hawkins.pdf)

http://www.ovro.caltech.edu/~dwh/correlator/pdf/esc-100slides_hawkins.pdf (http://www.ovro.caltech.edu/%7edwh/correlator/pdf/esc-100slides_hawkins.pdf)

Look at p40 and p41 of the slides for examples of truncation noise and the different rounding methods available in MATLAB. The figures show the bias involved in all methods; and that convergent is the rounding method to select.

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