Questions tagged [spectrum-analyzer]

Spectrum analyzers display the amplitude of an input signal versus frequency. Typically the frequency extends along the X-axis and the amplitude extends up the Y-axis of the display. They are used to measure the spectrum of an unknown signal within the frequency range of the particular analyzer being used. Sometimes their name is prefixed by the broad frequency range they cover, hence terms such as Audio / RF / Optical spectrum analyzer.

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Can anyone explain this high-frequency "alien voodoo black magic"?

I was casually watching Mike tear down a spectrum analyser (13:30 is the relevant part, 16:50 is the awesome part), and he came across what he aptly described as "weird messed up alien voodoo black magic stuff": As a layman, I can only nod in…
Polynomial
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Where do overtones in a 555 generated square wave come from?

I have built a 555 oscillator and connected it to a speaker. Using an oscilloscope I adjusted the 555 to generate a 2.5kHz square wave. I then held a microphone up to the speaker and fed the input into a spectrum analyser. What I expected to see was…
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Oscilloscope with FFT or a Spectrum Analyzer?

Could someone explain to me please which applications demand one or the other and why? As far as I have read it's all about the 'dB'; is that true? And why? At first I can see Digital Storage Oscilloscopes (DSO) with FFT function and Spectrum…
mFeinstein
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What happened to all of the Dynamic Signal Analyzers?

Decades back there were at least half a dozen instrumentation companies offering Dynamic Signal Analyzers (DSA's). Not Spectrum Analyzers, but rather Dynamic Signal Analyzers. The main differences being dual or multiple channel input and frequency…
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Measuring signal with of nanosecond pulse width with a spectrum analyser?

I'm looking to measure the signal width of electronic signals (device under test, DUT). The problem is that these signals have a quite short pulse width which would require me to use a GHz oscilloscope which I don't have (and can not afford at the…
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resolution bandwidth

I have the following trivial question: I have acquired a noise spectrum with a resolution bandwidth of \$124\mathrm{Hz}\$. I would like to convert it to \$\mathrm{V/\sqrt{Hz}}\$. Shall I simply multiply or divide the signal by…
user222401
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Why do spectrum analyzers use envelope detectors?

Spectrum analyzers can usually be represented by the following block diagram: Before entering the video filter, the signal passes through an envelope detector. What I don't understand is why this is done. As far as I understand, the envelope…
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Audio spectrum analysis: PC Software vs Hardware Spectrum Analyzer

I need to do some audio spectrum analysis (basically, listening to a machine and tell if it is properly calibrated). I will record the sound it makes with a microphone (it sounds differently if it is calibrated correctly than if it is not), and then…
Nicholas
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Reading S2P Files - What Does Each Column Represent

I'm having a hard time reading s2p files. For an example say that I am measuring the parameters of a 2-port network (port 1 and port 2). What do each columns represent? I can tell that the first column represents the frequency, but what about the…
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What power is measured by a spectrum analyzer?

Is the signal level that is shown in a spectrum analyzer power of the signal being measured. If yes then what power is it: average power, true power or peak power? Also when using a power meter for measurement of power, what is difference in its…
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What does sequences like 1-3, 1-10, 1-3-10 etc in a spectrum analyzer mean?

I have read in a paper explaining spectrum analyzer basic 'When selecting the RBW(resolution BW), there is usually a 1-10 or a 1-3-10 sequence of RBWs available. More RBWs are better because this allows choosing just enough resolution to make the…
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Understanding EGSM-900 (LTE 8 band) electromagnetic spectrum

I am trying to fully understand the physical layer of the GSM standard. For doing that I am looking at the E-GSM-900 band (mostly used in Europe). In my country these frequencies has been assigned to the network operators as follow: Table headers:…
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Observing effect of household appliances on powerline communication

I had been recently working on Powerline communication modems (PLC). I put two PLC modems at different parts of my home and observed the data transfer rate between them. However, I observed that when I turned on an appliance in a home, I could see…
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Connecting a spectrum analyzer without DC block

I have seen many spectrum analyzers with the warning on the RF input port: “!!! Avoid electrostatic discharge and DC voltage !!!”. Out of precaution I always connected my signal source with a DC block but now I find the DC block filters my signal…
divB
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Why do spectrum analyzers generate X-Rays

Most, if not all, old HP spectrum analyzers say X-Rays generated in this intsr are sufficiently screened Why do they generate x-rays at all. The HP 8565E I am looking at can only measure up to 50 GHz so I have trouble seeing why it would have such…
Brian Carlton
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