Getting strange square root performance.
I'm using the ADAU1451 under Sigma 4.2 to square a couple of signals, add the squares, and then take the square root. Should be a simple task. The squaring is no problem at all, I simply drive both inputs of a multiplier like this:
See, the square of 3 is 9, just as I figured it would be.
But here is another static test using the 'basic' square root block. I tried the Precision an the Integer ones with about the same results. This gives me an unexpected number, as if the square root block has gain or something.
In this example I'd expect to see the number 1, not 16. Other inputs give correspondingly strange results. What is it that I don't understand about this? Thanks!
Audio Signal Processors
adau1451
SigmaDSP Audio Processors
Oh, never mind. I was using the 'integer' one all along. You know what they say about those square root blocks, "They all look the same."
While you were writing your reply I just tried the regular square root block and as you noted, it's working fine. You brought up a good point about blocks differing in a possibly important characteristic appearing identical in schematics. There's other examples, such as single and double precision filters. It can be problematic, especially when reviewing an old schematic whose construction is long forgotten (for me, a few days will do it...).
I've encountered that on several occasions, particularly when working on circuits started by others. Frequently I can 'fake' a Grow or Add Algorithm and have it tell me what it is. But with so many letters in our alphabet, one extra one to delineate the version of the part would sure help.
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