Finding RMS value of strange column function

AI Thread Summary
The discussion focuses on calculating the RMS value of a given function, identified as a pulsed DC signal with a 25% duty cycle. The RMS value is derived from the equation involving the integral of the squared function, leading to the conclusion that the RMS value equals A/2. Participants clarify that the function's behavior varies when the signal ranges between +1 and -1 V, with the squared signal consistently equating to 1 V. There is also a mention of a misunderstanding regarding the function's description, which was initially referred to as a "strange column function." Ultimately, the conversation emphasizes the importance of accurately interpreting the waveform for correct RMS calculations.
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Homework Statement


This is the given function:
RMS.png



Homework Equations


The RMS equation goes like this:
<br /> \sqrt(\frac{\int(f(t)^2 dt)}{b - a})<br />


The Attempt at a Solution



The first part of the exercise was to find the mean value.
This is A/4.

The RMS value should be higher than the mean value, but I need the function to use the equation and I can't "see it" from the picture.
 
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RMS == the square root of the average of ( the square of the signal).

You are given a graph of the signal. On the same axes you can plot the signal squared, then determine the average of this. Then ...
 
Ah, thank you for putting it into perspective

RMS value = A/2
 
And it's not called a strange column function. It's called pulsed DC. Or 25% duty cycle switched DC. :smile:
 
duly noted ^^
 
And what happends if the "pulsed DC" varies between +1 and -1 V ? The signal squared = 1V anyhow (except for a few 0V periods)

rms2.png
 
Last edited:
Never mind. I got it :)

I made it too complicated at first
 
Then it's called a strange column function.

What you have sketched doesn't tally with your verbal description. For what you sketched, its RMS value will be equal to that of a 60% duty cycle switched DC, since a level of -1 contributes the same as does +1, in determining RMS value.
 
the second picture is another problem which I had to determine the mean and RMS value.

the problem description does not mention any DC or functional description of the graph
 
  • #10
You could call it a stepped waveform. Maybe a staircase.
 
  • #11
I'll keep that it mind, thanks :)
 

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