# What Is the Y-Axis Scale That Transforms Sine Waves into Straight Lines?

• RandallB
In summary, your instructor is talking about a Triangular Wave that is used to plot a sine or cosine wave as a straight lined saw tooth pattern. This type of plot has a name, Fourier Analysis, and has been covered in class. There is also a Vertical Scale against the Horizontal Scale that causes a Sine Wave plotted with it to appear as a Triangular Wave. The type of plot or graph this would be called is not known to the interviewer.
RandallB
What would you call the scale on the Y axis that would plot a sine or cosine wave as a straight lined saw tooth pattern?

Is such a graphing style in use and does it have a name?
RB

The type of plot to which you are referring is called a Triangular Wave... has your instructor(s) talked about Fourier anaylsis?

Theelectricchild said:
The type of plot to which you are referring is called a Triangular Wave... has your instructor(s) talked about Fourier anaylsis?
The type of plot to which you are referring is called a Triangular Wave... has your instructor(s) talked about anaylsis?[/QUOTE]

I can see where Triangular Wave is a good description of what a saw tooth pattern looks like, (of course it's not really a Triangular Wave we are talking about a sine wave here). But did your instructor(s) give a name to the Vertical Scale against the 'angular' Horizontal Scale that causes a Sine Wave plotted with it to appear as a Triangular Wave? Or a name to the type of graph or plot this would be called?

Your not calling it a Fourier Graph or Fourier Plot are you?

I'm only assuming, but it seems to me it would only valid from -1 to +1, that is it would not be "scalable" for use with larger numbers (as a log graph is). Rather the data would need to be scaled to a max of 1.

RB

I've never heard of this type of scale, so I can't give you a name.

You are referring to $$y_{scaled}=\sin^{-1}{y_{real}}$$, correct?

Yes, in that case, it could not directly be expanded to y>1.

I know what your talking about, we looked at those kind of waves in E&M when doing voltage analysis in lab. The instructor called them triangle waves.

Moo Of Doom said:
I've never heard of this type of scale, so I can't give you a name.
You are referring to $$y_{scaled}=\sin^{-1}{y_{real}}$$, correct?
Yes, in that case, it could not directly be expanded to y>1.
Yes

I'll keep looking a bit but I'm guessing I'll have to create my own.
I'm thinking it would be helpful in ploting and comparing statistical results involving sin functions.
RB

I don't know if you're this far, but even using Matlab or Mathematica will allow you to make use of the following Fourier series for the triangular wave.

$$f(t)={\frac{8A}{\pi^2}}\sum_{n=1,3,5,...}^{\infty}[\frac{1}{n^2}sin(\frac{n\pi}{2})]sin(n{\omega_0}t)$$

Where A of course is referring to the amplitude.

Theelectricchild said:
I don't know if you're this far, but even using Matlab or Mathematica will allow you to make use of the following Fourier series for the triangular wave.
NO - I believe what your describing is a near infinite number of frequencies or waves to produce a triangular wave (Same kind of thing required for a square wave).

What I have is one wave of only one frequency. I’m just plotting it so that the PLOT is triangular by finding the appropriate Y axis scale.
Thus a Triangular plot here is not the same as a triangular wave.

There seems to be a lot of confusion here, so hopefully to clear things up:

He's not talking about infinitely many sine waves being added to make a triangle wave, he is asking about changing the scale of the y-axis to make a single sine wave appear to be a triangular wave. This is analogous to the way a log plot makes an exponential graph appear linear.

Explain!

## What is a straight line sin wave plot?

A straight line sin wave plot is a graph that displays a sinusoidal wave with a constant amplitude and frequency. It appears as a smooth, curved line that oscillates between positive and negative values.

## What is the equation for a straight line sin wave plot?

The equation for a straight line sin wave plot is y = A*sin(2πft + ϕ), where A is the amplitude, f is the frequency, t is the time, and ϕ is the phase angle.

## What does the amplitude represent in a straight line sin wave plot?

The amplitude in a straight line sin wave plot represents the maximum displacement of the wave from its equilibrium position. It is half the vertical distance between the top and bottom of the wave.

## How does changing the frequency affect a straight line sin wave plot?

The frequency in a straight line sin wave plot determines how quickly the wave oscillates. Increasing the frequency will result in a shorter wavelength and a faster oscillation, while decreasing the frequency will result in a longer wavelength and a slower oscillation.

## What is the purpose of using a straight line sin wave plot in scientific research?

Straight line sin wave plots are commonly used in scientific research to analyze and represent periodic data. They can be used to study various physical phenomena, such as sound waves, electrical signals, and oscillations. They also allow scientists to make predictions and identify patterns in data sets.

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