Finding RMS value of strange column function

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Homework Help Overview

The discussion revolves around finding the RMS value of a function described as a pulsed DC signal, with participants exploring the characteristics of the waveform and its implications for calculating the RMS value.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the relationship between the RMS value and the mean value, with some attempting to clarify the nature of the function and its graphical representation. Questions arise regarding the impact of varying signal levels on the RMS calculation.

Discussion Status

There is an ongoing exploration of the definitions and characteristics of the waveform, with some participants providing insights into the terminology and potential interpretations of the signal. Guidance has been offered regarding the calculation of the RMS value, but no consensus has been reached on the specifics of the function.

Contextual Notes

Participants note that the problem description lacks clarity regarding the functional form of the graph, which may affect the calculations and interpretations being discussed.

Twinflower
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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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