Solving Issues with a Spectrum Analyzer for Discrete Signals

In summary, the individual is having trouble obtaining the correct Fourier transforms for a wave obtained using a microphone. They have tried various methods, including using the real and complex components, but have not had success. They are seeking help and are recommended to consult "Numerical Recipes in C", specifically chapter 12 on Fourier transforms and power spectra.
  • #1
bogdan
191
0
I tried to obtain the spectrum of a discrete signal and I had some problems...
If I compute on a PC the discrete Fourier transform (FFT or DFT) I obtain valid Fourier transforms (the same Excel computes...)...
...but how do I analyze a wave obtained using a microphone ? I don't get the same results professional programs do...I tried using as the "intensity" of a frequency the magnitude...I tried using the real component...the complex one...but still no good...
Can you help ?
 
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  • #2
How about
intensity(f) = [squ](R2(f)+I2(f))
where R is the real component, and I is the imaginary one.
 
  • #3
You're looking for what is called the "power spectrum." The book "Numerical Recipes in C" is the best place to look (as usual!).

It's available in its entirety, free of charge, at http://www.nr.com

Chapter 12 deals with Fourier transforms and power spectra.

- Warren
 

1. What is a spectrum analyzer for discrete signals?

A spectrum analyzer for discrete signals is a scientific instrument used to analyze the frequency components of a discrete signal. It displays the amplitude of each frequency component in a signal, allowing for the identification of any issues or anomalies.

2. How does a spectrum analyzer work?

A spectrum analyzer works by taking a signal and converting it into a frequency spectrum. It does this by using a series of filters and detectors to measure the amplitude of each frequency component in the signal. The results are then displayed on a graph, known as a frequency spectrum.

3. What are some common issues that can be identified using a spectrum analyzer for discrete signals?

Some common issues that can be identified using a spectrum analyzer for discrete signals include noise interference, signal distortion, harmonics, and frequency drift. These issues can affect the quality and accuracy of a signal and can be detected and resolved using a spectrum analyzer.

4. How can a spectrum analyzer help in solving these issues?

A spectrum analyzer provides a visual representation of the frequency components of a signal, allowing for the identification of any anomalies or irregularities. By analyzing the frequency spectrum, engineers and scientists can determine the root cause of the issue and make adjustments to improve the signal quality.

5. What are some tips for using a spectrum analyzer for discrete signals?

Some tips for using a spectrum analyzer for discrete signals include setting the appropriate resolution bandwidth, using the correct detector type, and understanding the frequency range of the signal. It is also important to have a good understanding of the instrument itself, including its features and limitations.

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