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wind_sensor:wind_sensor_documentation [2015/12/01 10:59] daisygreen [Implementing Code] |
wind_sensor:wind_sensor_documentation [2021/09/19 21:59] (current) |
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| - squaring a function in time {x(t) -> x(t)<sup>2</sup>} is convolution in frequency domain {X(f) -> X(f)∗X(f)}. Also, sound is a real base band signal, so there for it is a low passed signal which is symmetrical around 0. (Squaring is similar to taking the absolute value. Either method could work) | - squaring a function in time {x(t) -> x(t)<sup>2</sup>} is convolution in frequency domain {X(f) -> X(f)∗X(f)}. Also, sound is a real base band signal, so there for it is a low passed signal which is symmetrical around 0. (Squaring is similar to taking the absolute value. Either method could work) | ||
| - A convolution between the same signal will be symmetrical and have it's peak in the middle. In this case it is at 0, and X(0) is the DC part which is the total energy in the signal. | - A convolution between the same signal will be symmetrical and have it's peak in the middle. In this case it is at 0, and X(0) is the DC part which is the total energy in the signal. | ||
| - | - You can find the frequency scaling depending on your sampling frequency. If sampling frequency is ω<sub>s</sub>, the frequency vector for the fft would go from -ω<sub>s</sub>/2 to ω<sub>s</sub>. | + | - You can find the frequency scaling depending on your sampling frequency. If sampling frequency is ω<sub>s</sub>, the frequency vector for the fft would go from -ω<sub>s</sub>/2 to ω<sub>s</sub>/2. |
| {{:wind_sensor:untitled2.png?nolink&400|}} | {{:wind_sensor:untitled2.png?nolink&400|}} | ||
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| Notice if you don't chose a value N large enough, the output of the mean of the last N samples will very large, an example is shown below. | Notice if you don't chose a value N large enough, the output of the mean of the last N samples will very large, an example is shown below. | ||
| - | </code>% Test on how the N parameter makes a difference in find the moving average | + | <code> |
| + | % Test on how the N parameter makes a difference in find the moving average | ||
| clc;clear;close all; % clears all | clc;clear;close all; % clears all | ||