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- Two FFT blocks of different sizes exhibit problem

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Altera_Forum

Honored Contributor I

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05-18-2015
01:42 PM

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Two FFT blocks of different sizes exhibit problem

Design has FFT blocks of different sizes sizes. Finding incorrect results unless the sizes are the same. I am using version 13 DSP Builder, and have not synthesized the design, but have simulated the design with Simulink. If I make the FFT sizes the same, which isn't what I want to do, then I can get correct results. I am thinking that there are shared resources between the two FFT blocks, making a ***conflict*** when I use two different FFT parameterized links.

I will try to obtain a more recent DSP builder to see if the problem goes away, but I don't have too much hope for this, but will let you know if I succeed with a more recent DSP builder version. It would be nice if the MATLAB Simulink S-fuctions were open source, because I cannot determine what is causing the conflict. Thanks, Jamie_ctLink Copied

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Altera_Forum

Honored Contributor I

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05-20-2015
02:42 PM

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Altera_Forum

Honored Contributor I

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05-26-2015
01:49 PM

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Altera_Forum

Honored Contributor I

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06-02-2015
04:21 PM

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Thanks, sharkster.

This confirms my suspicions, about not using model references. I am getting good results with subsystems now using the fixed point FFT libraries. Learning the hard way! Jamie_ctTopic Options

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