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Rms value of a signal having more than two frequencies
ksr
post Mar 16 2012, 05:36
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Hi guys,

I want to know how to calculate from a pcm file the following things...

1. Rms value of a signal when it is having single frequency and also multiple frequencies .
2. Rms value of harmonic components of a signal when it is having single frequency and also multiple frequencies .
3 Rms value of noise..

By using above values i want to calculate SNR, THD , THD+N.

Thanks in Advance
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Porcus
post Mar 17 2012, 14:29
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I was under the impression that what electrical engineers call 'RMS power', is -- assuming constant Ohmian resistance load -- just average of square voltage. Then the RMS of a unit-amplitude sine, is the average of the sin^2, which is 1/2. Or have I gotten it wrong?

In that case, white noise sure as hell doesn't have zero RMS power. (The problem is rather, does it posess any such figure at all. Measurability.)


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Speedskater
post Mar 17 2012, 16:08
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QUOTE (Porcus @ Mar 17 2012, 09:29) *
I was under the impression that what electrical engineers call 'RMS power', is --

I know that most of us have heard it a thousand time but:

Power is power, "RMS" is not part of power. The "RMS" is associated with the voltage (or maybe current) measurement used to determine power. Now sometimes the label "RMS Power" is used to show that real power is being discussed rather than "peak power" or "instantaneous power".


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