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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25 views

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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Relation of sweep time and number of measurement points in Spectrum Analyzer

My configuration is as follows: RBW: 100 kHz Detector: MAXPEAK Frequency span: 1.1 GHz - 1.8 GHz Spectrum Analyzer: R&S FSV 30 I do not fully understand how the sweep time and number of points ...
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49 views

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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Why does Rigol DSA815-TG loses TG normalization?

I'm observing the following behavior of Rigol DSA815-TG spectrum analyzer. You turn on the device, enables tracking generator and uses TG->Normalize. Everything works just fine. But after 10 minutes ...
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44 views

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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44 views

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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33 views

Line Impedance Stabilization Network (LISN) ripple to measurement transfer function

While reading about LISNs, I was lost a bit. The CISPR limits are in dBμV, so they're voltages. But are these an image of the current following IN the DUT? Below you're see the LISN transfer ...
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37 views

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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91 views

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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165 views

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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51 views

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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“Trace Max Hold” function in spectrum analyzer

I have seen my professor doing a measurement with the spectrum analyzer in which he wanted to evaluate the frequency response of a bandpass filter. He used a signal generator in sweep mode from 1MHz ...
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71 views

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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152 views

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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71 views

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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76 views

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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113 views

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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120 views

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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562 views

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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148 views

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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108 views

Can I connect transmitter output to spectrum analyser input directly?

I have a spectrum analyser, that tolerates 30 dBm 50VDC signal on its input and has internal selectable attenuator up to 40 dB. Can I connect it directly (i. e. without any external attenuators) to ...
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265 views

Link between phase noise and linewidth for a oscillator?

I was googling for a formula to transform the dbc/Hz value given in data sheets for VNA, spectrum analyzers and VCO is often given in dBc/Hz with offset. Now looking up research papers about future ...
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94 views

Incoherence between oscilloscope and spectrum analyser

There seems to be an incoherence between what I see with my oscilloscope, and what I see with my spectrum analyser. I have a signal of about 1MHz (if I'm not wrong), 5mV, from an antenna, through ...
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81 views

Measurements using spectrum analyzer

I need to measure the following characteristics of a frequency synthesizer using a spectrum analyzer: Frequency range: 2.286 GHz to 2.346 GHz Output power: -2.5 dBm to 2.5 dBm SSB phase noise: ...
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203 views

THAT4315 audio analyzer - capacitors getting hot

I have designed a audio spectrum analyzer circuit with THAT4315 and a drivers for IN-13 bar graph nixie tube to visualize the signal level. To supply +-12V to the opamps, the Meanwell NSD15 module is ...
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100 views

NFC spectrum analysis, weird frequencies showing

I apologize for the picture quality, I did not have an opportunity to export the screenshots. I have a problem properly interpreting this signal. The subcarrier peak is visible but the data seems to ...
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Question related to two closely separated signals that need to be analyzed by a spectrum analyzer

Question The settings of a spectrum analyzer are given as following: Center Frequency = 1.89 GHz, RBW = 10 kHz, VBW = 10 kHz and Span = 50MHz. The Reference Level is set to -20 dBm and ...
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76 views

R&S Spectrum Analyzer Voltage Measurement Error

I just got FPC1000 spectrum analyzer that goes from 5 kHz to 1 GHz. I didn't had any spectrum analyzer experiences before this one so everything is very new to me. Among few things that I don't ...
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56 views

Dynamic range given the THD [Spectrum Analyzer]

Imagine that I have to measure the THD with an error less than 6%, given the first 40 harmonics. How do I know the dynamic range of the spectrum analyzer that I have to use?
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519 views

How to measure a 100 ohm differential signal on a spectrum analyzer?

I have a pair of 1.5V PCML differential signals coming out of an Altera Cyclone V GX FPGA, terminated on the FPGA in 100 ohms with common mode voltage = 0.65V (also provided on the chip). I need to ...
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73 views

Spectral analysis of spectrum analyzer

Using measures from a spectral analyzer, I am a bit confused on how to properly compare the power of each spectral line with the fourier coefficients (Parseval). Take this signal: Take it's spectrum:...
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1k views

Using a Spectrum Analyzer to measure VSWR

I need to measure the VSWR of a coaxial wire that has a length of 100 metres and a characteristic impedance of 50 ohms using a Spectrum Analyzer (I don't have a Network Analyzer). I found this website:...
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71 views

How to test an RF crystal oscillator performance integrated into a Cellular radio?

I have a couple of reference designs with 2 different crystal oscillators integrated into it. These are cellular radio and can generate standard LTE QAM signals out of it. But I do not have access to ...
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169 views

calibrating vector network analyzer with \$75\Omega \$ coax

I am new to electronics and I just began to use a vector notwork analyzer for some measurements. I calibrated my vector network analyzer with both ports connected to 50\$ \Omega \$ coax cables with ...
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956 views

How do I measure very low frequency noise?

I'd like to measure low-level noise in the 1 Hz to 100 kHz range, for example at the output of a LDO. For higher frequencies a spectrum analyzer would do the job, but most only go down to the MHz ...
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170 views

Is it not recommendable to use a spectrum analyzer in its limit frequencies?

Suppose we have a spectrum analyzer whose range of frequencies goes from \$x \ \mathrm{Hz}\$ to \$y \ \mathrm{Hz}\$. Is there any problem that could arise from measuring signals that are near those ...
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104 views

Harmonic mixing in spectrum analyzers

I'm having a pretty difficult time understanding how tuning works when using harmonics in spectrum analyzers. I'm reading about the topic from Keysight's AN 150. Question 1 The following plot is ...
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116 views

How do multiple mixing stages work in a spectrum analyzer?

I'm reading about spectrum analyzers from Keysight's AN 150. On page 12 they explain how multiple mixing stages are used to obtain narrower IF filters. The block diagram offered is the following one: ...
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94 views

Phase noise in spectrum analyzers

I'm reading about spectrum analyzers from Keysight's AN 150 and I have two questions regarding phase noise. The AN states: No oscillator is perfectly stable. Even though we may not be able to see ...
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2k views

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 ...
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103 views

What is difference between channel power and normal power plotted by a spectrum analyzer?

I want to measure the power received by an antenna from an energy source by plugging the antenna to a spectrum analyzer (SA). What makes me confused is that there are different kinds of power that I ...
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192 views

S-Parameters math confusion

S11 for marker 1 says -47.661 dB Two Questions 1st ..... What is | S11 | ^ 2 2nd Is this accurate ? g = 20 log_10(-47.661) dB
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How does tuning in a spectrum analyzer actually work?

I have a pretty basic doubt about how tuning works in spectrum analyzers. I'm reading about the topic from Keysight's AN 150. The problem arises in this paragraph in page 11: We need to pick an ...