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Altera_Forum's avatar
Altera_Forum
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15 years ago

Larger multipliers are faster?!

I'm designing some IIR filters in a Cyclone III, so I had a quick look to see how fast I could get a large multiplier to run. I used lpm_mult, with a latency of 2, and optimized for speed (latency 2 ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

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I'm designing some IIR filters in a Cyclone III, so I had a quick look to see how fast I could get a large multiplier to run. I used lpm_mult, with a latency of 2, and optimized for speed (latency 2 seemed to be fastest).

I got a 48x48 running at 148 MHz, and a 64x64 running at 202 MHz. This is quite counter-intuitive to me. What am I missing?

Thansk

Pete

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Hi Pete,

can you post your projects ? I tried the multiplier, but my larger mult is slower ( as expected )

Kind regards

GPK