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Altera_Forum
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14 years ago

FIR Megafunction Signed (Fractional) Binary only?

I am using Quartus II 11.0. It looks like the FIR filter Megafunction supports only Signed Binary or Signed Fractional Binary. As far as I understand, this means that the MSB is the sign bit, a...
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Altera_Forum
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14 years ago

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Both are 2's compliment. Signed fractional binary format results in the same hardware implementation as signed binary format, the binary point is conceptual only.

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I buy that numerically it doesn't matter whether the integers are fractional or not (and I don't know why the GUI gives the option). But it seems that the signed binary representation is the same as sign-magnitude (http://en.wikipedia.org/wiki/signed_number_representations#sign-and-magnitude_method) representation, and not the same as two's-complement (http://en.wikipedia.org/wiki/two%27s_complement). The manual isn't very clear on this.