What is Spectrum analyzer: Definition and 20 Discussions

A spectrum analyzer measures the magnitude of an input signal versus frequency within the full frequency range of the instrument. The primary use is to measure the power of the spectrum of known and unknown signals. The input signal that most common spectrum analyzers measure is electrical; however, spectral compositions of other signals, such as acoustic pressure waves and optical light waves, can be considered through the use of an appropriate transducer. Spectrum analyzers for other types of signals also exist, such as optical spectrum analyzers which use direct optical techniques such as a monochromator to make measurements.
By analyzing the spectra of electrical signals, dominant frequency, power, distortion, harmonics, bandwidth, and other spectral components of a signal can be observed that are not easily detectable in time domain waveforms. These parameters are useful in the characterization of electronic devices, such as wireless transmitters.
The display of a spectrum analyzer has frequency on the horizontal axis and the amplitude displayed on the vertical axis. To the casual observer, a spectrum analyzer looks like an oscilloscope and, in fact, some lab instruments can function either as an oscilloscope or a spectrum analyzer.

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  1. hagopbul

    I Can Ground Penetrating Radar Help Locate Earthquake Survivors?

    Hello : As the news coming from Syria and Turkey about earthquake devastation, is it possible to use ground penetrative radar or sound identification and wave frequency spectrum analysis to locate survivours ? The human sound are in the range of 20 kHz shouldnt we be able to use microphones...
  2. C

    I Optical spectrum analyzer related

    Can anyone explain why optical spectrum analyzer plots are in negative dB
  3. F

    DIY wideband antenna VSWR - beginner

    Dear forumers, I would like to do some RF measurements by using a spectrum analyzer or an SDR in the ~ 100mhz-6ghz range. I'm new to this and to the concepts in general and I would like to hear a few recommendations. I primarily interested here in how much it is acceptable to use a DIY...
  4. Q

    Network analyzer vs Spectrum analyzer

    I'm currently studying the network analyzer(NA) and spectrum analyzer(SA), and one thing makes me wonder; Would it be possible to 'mimick' a NA with a SA and a signal generator(SG)? Ofcourse some phase calculations may also be required, but from my naive understanding, if a NA sends various...
  5. P

    Spectrum Analyzer: Measuring Quiet Sound Frequency

    Homework Statement How can I measure the frequency of a really quiet sound. The software I have only measures the peak frequency (so not the frequency of the sound I want to measure which is lower f). Homework EquationsThe Attempt at a Solution
  6. U

    How does a spectrum analyzer measure Noise Spectral Density

    Hi, I'm a noob when is comes to these kinds of measurements on a spectrum analyzer. Take for example two LDOs: 1. http://www.analog.com/media/en/technical-documentation/data-sheets/ADM7154.pdf 2. http://www.ti.com/lit/ds/symlink/lp5907.pdf (see figure 17) They claim...
  7. S

    Understanding a sound spectrum analyzer output

    Hi, I am just trying to understand the output of a sound spectrum analyzer. There are three dimensions 1) Time 2) Frequency 3) Volume (db) I am confused about few things here: 1) How should I perceive the volume dimension here? 2) Why are the db values negative here and w.r.t what reference...
  8. zambadeos

    Accuracy of an Optical Spectrum Analyzer (OSA)

    Hey! I've a simple (and maybe stupid) question about the accuracy of an OSA. The datasheet report a level accuracy of 0.4 dB but this seems quite strange to me. Indeed level measurements are done in dBm thus, as long as dB measures a relative power, I assume that even the 0.4 dB are referred to...
  9. J

    Inductor's output power measurement using spectrum analyzer

    Hello! I have a question about measurement of spectrum analyzer. I made some inductor by lithography, evaporator, and lift-off process, and tried to measure using spectrum analyzer. (The probing was GSG type) I swept the frequency from 100MHz to 5Ghz, and output power was monitored by...
  10. S

    Calibration of HF Spectrum Analyzer

    Hey guys, Cannot seem to find the answer to my question within the Owners Manual for our high-frequency spectrum analyzer. When performing the 2-port calibration, it gives the option of testing in forward or reverse, which is a function of the test cable's orientation (male or female). Is it...
  11. M

    Unusual SNR in the guide of a Spectrum Analyzer

    If I posted in the wrong section, please feel free to move the thread in the correct one. Since this is my first post in the forum, I have yet to get a good grasp of it. With that said, let's begin! Prologue: SNR (Signal to Noise Ratio), sometimes indicated with S/N, is a very important...
  12. H

    Using a spectrum analyzer to find LC resonance?

    Hi everyone, I am using a signal generator in series with a RLC circuit, generating an AC signal at 1kHz. I have my probes connected across the resistor When I change the timescale the Fres bandwidth changes on the spectrum analyzer. At 1mS the resonant bandwidth is from 25kHz-50kHz At...
  13. M

    Spectrum Analyzer + PC: Interface & Contact Info

    Hi everyone, i want to operate spectrum analyzer by pc or laptop. Is there such interface of spectrum analyzer and pc possible? If yes, then how? Tell me the name and contact detail of person who have make such interface..
  14. D

    What kind of filters to use for audio LED spectrum analyzer?

    Hi, all I've been reading these forums for a while, and now that I have a question, I've finally decided to join. The question I have is school-related, but not really direct coursework since it's very open-ended. I am part of a group (in electronics class) that is building an LED...
  15. D

    Stereo oscilloscope and spectrum analyzer

    I need to implement a stereo oscilloscope and spectrum analyzer using C or matlab.. I am familiar with the basic commands regarding wav files in matlab. i also created a very simple music synthesizer. regarding the stereo oscilloscope, how do you get to display the sound wave in real time...
  16. M

    Light spectrum analyzer software

    Do you know some soft. which could analyze light spectrum(.jpg)?
  17. S

    LED Spectrum Analyzer schematics

    Hi, I am looking to build a basic spectrum analyzer (if that is what you would call it) out of some LED lights for a car stereo. Basically, I want about 8 - 10 bars (for different frequency bands), and I want them to jump up and down to the music, giving it a direct feed off of the car...
  18. M

    Spectrum Analyzer vs. Network Analyzer

    Hi all, I was wondering if someone could clarify what the difference is between a spectrum analyzer and a network analyzer. Thanks, Mike
  19. R

    How to Make a Spectrum Analyzer: Electrical Engineering Guide

    Im totally new to electrical engineering, and i would like to know how to make one (spectrum analyzer)?
  20. B

    Solving Issues with a Spectrum Analyzer for Discrete Signals

    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...