Determine Y of New Coordinate with -6 db/octave Slope on Log Plot

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In summary, the conversation discusses the location of a new coordinate on a logarithmic plot with a slope of -6 dB/octave from an initial point of (10^2, 100). The y-axis represents decibels and the x-axis is in log form. The second coordinate is (10^3, ?) and the conversation considers how to determine the y location, concluding with the understanding that a slope of -20 dB/decade would result in coordinates of (10^3, 80) and (10^4, 60). The correct coordinates for a slope of -12 would be (10^3, 80) and (10^4, 60).
  • #1
Dustinsfl
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On a log plot in the x axis, if I have a slope of -6 db/octave from 100db, what would be the location of the new coordinate?

So the y-axis is db and the x-axis is in log.

First coordinate is \((10^2, 100)\) then a slope of -6. The second coordinate is \((10^3, ?)\)?

How does one determine the y location?
 
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  • #2
dwsmith said:
On a log plot in the x axis, if I have a slope of -6 db/octave from 100db, what would be the location of the new coordinate?

So the y-axis is db and the x-axis is in log.

First coordinate is \((10^2, 100)\) then a slope of -6. The second coordinate is \((10^3, ?)\)?

How does one determine the y location?

A slope of - 6 dB/octave is equivalent to a slope of -20 dB/decade...

Kind regards

$\chi$ $\sigma$
 
  • #3
chisigma said:
A slope of - 6 dB/octave is equivalent to a slope of -20 dB/decade...

Kind regards

$\chi$ $\sigma$

Then \((10^3, 80)\), and if I had a slope of -12 following, it would be \((10^4, 40)\), correct?
 
  • #4
dwsmith said:
Then \((10^3, 80)\), and if I had a slope of -12 following, it would be \((10^4, 40)\), correct?...

Not exactly... $\displaystyle (10^{3}, 80\ \text{dB})$ is correct and -20 dB\decade means $\displaystyle (10^{4}, 60\ \text{dB})$, $\displaystyle (10^{5}, 40\ \text{dB})$, etc...

Kind regards

$\chi$ $\sigma$
 
  • #5
chisigma said:
Not exactly... $\displaystyle (10^{3}, 80\ \text{dB})$ is correct and -20 dB\decade means $\displaystyle (10^{4}, 60\ \text{dB})$, $\displaystyle (10^{5}, 40\ \text{dB})$, etc...

Kind regards

$\chi$ $\sigma$

You said -6 is -20 so wouldn't -12 be -40?
 

FAQ: Determine Y of New Coordinate with -6 db/octave Slope on Log Plot

What is a -6 db/octave slope on a log plot?

A -6 db/octave slope on a log plot is a measure of the decrease in amplitude or power per octave on a logarithmic scale. It indicates the rate at which the signal decreases as the frequency increases.

How is the Y value determined on a log plot with a -6 db/octave slope?

The Y value on a log plot with a -6 db/octave slope is determined by using the logarithmic scale to plot the signal's amplitude or power at different frequencies. The -6 db/octave slope indicates that the amplitude or power decreases by 6 decibels for every octave increase in frequency.

What is the importance of determining the Y value on a log plot with a -6 db/octave slope?

Determining the Y value on a log plot with a -6 db/octave slope is important because it allows for the accurate representation and measurement of signals with different frequencies. It also helps in understanding the behavior and characteristics of the signal, such as its roll-off rate.

How is the -6 db/octave slope calculated on a log plot?

The -6 db/octave slope on a log plot is calculated by dividing the change in amplitude or power by the change in frequency on a logarithmic scale. This can also be expressed as a ratio of 6:1, indicating a decrease of 6 decibels for every octave increase in frequency.

Can the -6 db/octave slope be changed on a log plot?

Yes, the -6 db/octave slope on a log plot can be changed by adjusting the filter or amplifier used to produce the signal. Different slopes can be achieved by using different types of filters, such as high-pass or low-pass filters, or by adjusting the gain of the amplifier. The slope can also be changed by altering the frequency range being plotted on the log scale.

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