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Altera_Forum
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13 years ago

LPM_mult : dynamic reduction with signed number

Hello, I’m using a very simple setup configuration with quartus 2 and cyclone III : full scale analog signal - - > CAN 14 bit -- > DAC 14 bit : OK no distortion After that I add a LPM_m...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

After many tests , and pratical results , the solution :

LPM_Mult with signed binary.

Input A [13..0] Input B [13..0]. Keep output with defined width [27..0]

But!! need to use : [26..13] to have the same range on output DAC.

It works :-)

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I suggest to play around with a pocket calculator to understand the problem and possible solutions. To get exact factor 1 multiply, you need an extra bit in scaling factor.

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