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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Is it ordinary that near-field probes do not detect EM noise?

Last week we did a pre-certification test with a device and it failed. Description of the device: It is powered from Li-ion battery. It integrates a BQ24090DGQT which is a Li-ion battery charger, the ...
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Signal Dimensions in Simulink

I'm using R2022a, in Simulink I can not find the Display tab to access Signals & Ports>Signal Dimensions. Could someone point me in the right direction please?. Also, in the figure below the ...
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Calibrating a VNA

I am using the Siglent SSA3032A-R spectrum analyser which has a Vector Network Analyser (VNA). Before measuring the impedance of an antenna under test so that I can match this antenna, I have to ...
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What is the loss of the test antenna connected to the spectrum analyser?

I am testing the gain and radiation pattern of some PCB antennas and have a Siglent SSA-3032X-R spectrum analyser connected to a Tekbox Biconical TBMA1 measurement antenna. The test set up and antenna ...
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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 ...
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HP 8568B J1 Connector identification

Can anyone identify these 4 individual RF connectors? I think it's some sort of RP-SMB, but it could be something more foreign. I would need to buy 4 cables to connect up the spectrum analyzer. ...
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Converting dB vs frequency to V/sqrt(Hz)/ frequency

I have taken noise data with a spectrum analyzer. Unfortunately, it doesn't seem able to plot the noise in the units of V/Sqrt(Hz) over frequency (Hz). What I have acquired instead is dB vs frequency. ...
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Approach to determine EMI frequencies in another factory

We produce AC-powered devices that connect to PC via USB. One of which was recently shipped to a factory (which is located in another country) in an environment with high enough EMI to make our device ...
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Frequency converter for spectrum analysis

I have an oscilloscope/spectrum analyzer that has a maximum sampling frequency of 20MHz and I would like to analyze the spectrum of a higher frequency band (also 20MHz wide) for example 90-110MHZ to ...
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Spectrum Analyzer Parameter Meaning

I have been working on an RF project and wanted to know the RF noise floor present in the lab. I connected the Lora Antenna to the spectrum analyzer as shown in the image below and set the Marker at ...
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What's the name of this spectrum analyser input connector (Agilent E4402B)?

Here's a photograph of the input connector and one of the attachments that came with it (which is this unknown connector to SMA converter).
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AGC circuit for a spectrum analyzer - seeking recomendations

I want to build a spectrum analyzer for my car stereo. 5 bands, left & right channels represented individually, 20 LEDS per band using cascading LM3915s per band and channel. (Yes, 20 LM3915s, 200 ...
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How to estimate SNR on a spectrum analyser

In the picture, the spectrum analyser shows 1kHz has about -5dB and noise between -40dB and -60dB (I'll just pick a value somewhere in the middle, or -50dB). So the SNR according to the equation: $$ ...
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Passive Probe With Spectrum Analyzer

Is it possible to use a regular passive oscilloscope probe with a spectrum analyzer? If not, what are possible choices of probes to use?
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Understanding RF spectrum of SMPS power supply

I have a (third-party) device that has failed EMI testing, and have been asked to investigate the cause and fix the issues. The device is an automobile accessory, and has 12 V DC power input. ...
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What causes the small peak at the start of the spectrum in a spectrum analyzer?

There is a "DC" peak that is at the start of the spectrum. I'm studying the differences between superheterodyne and FFT spectrum analyzers and I'm wondering if the peak is caused by the same ...
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Is there as way to verify a spectrum analyzer setup?

I just finished setting up my spectrum analyzer and I would like to ensure that everything is as accurate as possible. I was thinking of getting some kind of RF transmitter that transmits at a ...
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how to determine max peak of switching regulator in frequency domain (radiated emission)

I want to know how do I determine what should be the switching regulator peak in frequency domain(Radiated emission) , and where should I measure (Output or on inductor , capacitor). Lets do below ...
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Plasma damage to body cells

Can exposure to plasma or energy from Tesla home windings damage the body's cells? More generally, will the plasma or energy from the Tesla coil ionize?
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Understanding Output From DFT

I should preface this by saying I'm a novice at all of this: I'm designing a system (using a stand-alone FPGA board combined with an ADC that offloads data to a GPU) that is supposed to look for high ...
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Real World Small Signal AC Analysis

As stated in this question: Antiresonance of multiple parallel decoupling capacitors: use same value or multiple values? I have been curious to the real-world effects of different capacitors and their ...
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If I have a signal that switches between 5MHz and 4MHz faster than the sample rate of the ADC on a spectrum analyzer

Basically, what happens if your signal is switching between frequencies faster than the sample rate of the ADC in the spectrum analyzer? I have been curious as to what would happen in this case, would ...
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Why does the peak power change with the spectrum analyzer's span?

Consider a continuous wave signal being displayed on a spectrum analyzer at f=5GHz. It's a single peak. When I put marker on the peak it shows me the peak measured power. Now when I decrease the span ...
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Characterizing a capacitor

I have a capacitor for which I would like to get the output impedance as a function of the frequency. I would like to get something like this: For this I have a spectrum analyzer with an output which ...
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Workflow to test the quality of XLR microphone cables, and have a quantitative measure of this quality

I have more than 10 XLR microphone cables from different manufacturers (some of them quite cheap, some of them more expensive), and as I often do recordings (with condenser microphones) of music / ...
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Spectrum intensity varies depending on the frequency span

I am trying to measure the noise of a photo detector at different frequencies, using an RF spectrum analyzer. The measurement range was spanning from 10 Hz to 20 MHz. To cover not only the higher ...
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Input Attenuation and Intermodulation Products

I am measuring intermodulation using spectrum analyzer. How does the input attenuation affect the power of intermodulation products?
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Enhance sensivity of my magnetic field measuring setup

I have the following magnetic field measuring setup: Picoscope 2204A 16m wounded up bell wire connected to tip and ground clip as search coil antenna Now I want to enhance the sensivity for 50Hz to ...
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DC filter for a spectrum analyser - cut off frequency

Most of the available spectrum snalysers do not want a DC component to their 50 ohm input. But how low should the cutoff frequency be? Also which parameters indicates that clearly in the datasheets? ...
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Power Spectral Density units

I am trying to compare power spectral density values (obtained from dsp.SpectrumAnalyzer) with PSD values obtained from hardware which has a VSA. MATLAB's documentation says that " The power spectral ...
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Calculate power of an LTE Signal

I am looking for the formula to convert the power level of an OFDM RF signal to an absolute power level. For example if I have my typical rectangular RF spectrum and the bandwidth of the signal is ...
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Higher IF can cause clock jitters?

I was reading about Intermediate Frequency on Wikipedia, and it says that if the IF is too high, it can cause clock jitters. This is the first time I hear about this, and I cannot find any references ...
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What is the noise figure of a signal generator?

I'm wondering what's the noise figure or the overall noise contribution of typical signal generators? For example, if there is a test system with a signal generator that outputs 3 dBm signal (50 ohms),...
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How to measure -170 dB GPS signal with spectrum analyzer

I'm looking for a way to measure noise signals (probably MCU harmonics) that affect the performance of my GPS receiver (Ubox sam-m8q-0-10). Can anyone point me to the right direction? I own a ...
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Need Help Trouble Shooting A HP 8559A Spectrum Analyzer

I recently acquired an HP 8559A spectrum analyzer however instead of the HP182T display it was supposed to have it shipped with an HP180C display. I am unable to get the display to output a signal (I ...
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Infrared Sensor for drug detection [closed]

I saw that there has been a push to make a drug detector that can identify cannabis since it has been legalized. I was looking at mouser.com and found this ir sensor: https://www.mouser.com/...
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FFT in oscilloscope measuring Frequency spectrum

I am using a Keysight InfiniiVision MSOX3054T Scope having Bandwidth of 500MHz and Sampling rate of 5Gsa/s. I am learning to use the FFT Option in the scope. Below is the waveform I captured of my ...
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Length to make magnetic loop antenna/probe for 1.6GHz?

I'm making a near-field probe to to search for GNSS (GLONASS) blocking signals on my PCB. According to http://www.eryptick.net/unisold/loop.html the wire length for a loop should be 1/3 the ...
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Understanding the behaviour of a spectrum analyzer

I performed in the lab some experiments regarding a spectrum analyzer and I have a few questions about its behaviour. The analyzer used was this one At first I had to determine the spectrum of a 4kHz ...
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What's the reference dB level in spectrum analyser

I am using a Spectrum analyser. Measuring the 248kHz buck switching frequency and its harmonics in my board. I have set the frequency range from 200kHz and 1MHz. Using a near field H-Probe When I ...
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Voltage Measurement through Spectrum Analyzer

I have done some measurements with a Spectrum Analyzer of a square wave of 100kHz and amplitude equal to 1V. The resulting power spectral density is here shown: The highest peaks represent the odd ...
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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 ...
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Total thermal noise of a photodetector connected to a spectrum analyzer

I connected a photodetector to a spectrum analyzer (SA) and observed the signal (i.e. noise) on the SA when there is no light hitting the detector. I noticed that when I set a low spectral resolution ...
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Spectrum Analyzer Sweep Times Sub 1-ms vs. EMI Test Receivers?

I've got a Rigol DSA 832 and I have a client design that sends out a 1ms message every 100ms. The original protocol was a 1ms message every 6 seconds, which was darn near impossible to capture on ...
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Spurious signals around LO feedthrough in HP 8591A spectrum analyzer?

I am troubleshooting my HP 8591A spectrum analyzer. It is fully functioning, except for these spurious signals around the 0 Hz feedthrough. This noise is only within 15 MHz of DC. Where should I look ...
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Spectrum Analysis

I am working on a project where I need to measure the power density in milliwatts per centimeter squared (mW/cm²) from several different transmitting smart phone models. But the spectrum analyzer I ...
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What is the difference between residual phase noise and absolute phase noise?

Studying the characteristics of an oscillator with a phase noise analyzer, but I don't quite understand the difference between absolute and residual noise. Any help would be greatly appreciated
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How do I compute the average power from the PSD plot attached?

I want to calculate the average Power from the Power spectral density plot I have here. Any help would be greatly appreciated.
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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 ...
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Two details about phase noise have been confusing me for a long time. Hope to be resolved

Just like FLOYD M. GARDNER said in the PhaseLock Techniques, 3rd Edition: "In light of that success in spectrum analyzers, a practitioner’s answer to the question above is: The spectrum of phase noise ...
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