Appreciate if somebody could explain the difference between “Envelope Peak” and “Envelope Peak Accurate”.
It pretty much is like the name says. "Peak Accurate" is measuring the peak values much more accurately but the trade off is processing time. It is more processor intensive. So we give you the choice based on your application. Some places you really require high accuracy but other places it is not important. Sometimes a smaller program size is the most important.
I'll slightly add to Dave's response.
There was an inconsistency that happened when users utilized a tone with a frequency being an integer divider of the sample rate. Say FS/4. Using this sine tone (or any constantly repeating, periodic signal) may cause samples to be consistently aligned to a lower value than the actual peak of the signal (refer to the traditional sampling theory explanation); It will then cause an incorrect peak value reading. To avoid this, we derive a couple of phase shifted variations of the signal to ensure that the peak value is ALWAYS the real, measured and perceived value of the signal.
In reality, music never behaves as a sine wave, its also none periodic and therefore I would say that it's safe to use the "none accurate" version of the algorithm for audio purpose since it will yield the same results. For purists and those that not only deal with random signal (such as music), the accurate version is a safer bet.
All this can be very easily understood by using a sine tone generating FS/4 and then feeding the result to both envelopes. You will see that the accurate version will not pump while the other one will.
As the sampling rate increases compared to the measured signal, this problem doesn't exhibit itself.
What's your application?
Thanks to both of you.
I was intrigued because besides the double of size in Dsp memory cannot measure any difference in my application.
By the way, exponential decay will be a very useful upgrade.
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