Questions tagged [spectrum]
The spectrum tag has no summary.
94 questions
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Obtain phase spectrum from frequency/phase modulated signal
I have a homodyne rf setup in which I measure spectra by stepping frequency by frequency. The phase reference resets every time I change the signal frequency, so I can only measure the amplitude, but ...
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How can I use MATLAB to show that the Doppler effect destroys orthogonality of OFDM subcarriers?
I am trying to get a visual representation of how the Doppler effect destroys the orthogonality of the subcarrier and understand this effect.
I plotted three orthogonal subcarriers in MATLAB:
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Strange comb spectrum found during EMI precompliance
During near field testing I encountered this thing I've never seen neither on the wild nor on the book. The board has an STM32F107 with an 8MHz crystal and no ferrites or choke whatsoever (I'm ...
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How can I improve the estimation of the power spectral density (PSD) of a signal from an oscilloscope
I need to obtain the power spectral density (PSD) of a signal measured with an oscilloscope. The signal consists of a sinusoid with a DC component plus noise. I acquired data from the oscilloscope, ...
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On the understanding of signals from an IR detector coupled to a lock in amplifier
I have a CW laser which is modulated by an optical chopper rotating at 1kHz. The modulated CW beam struck a sample holder and the absorption signal is recorder via an Infrared Associates MCT detector. ...
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Spectrum Analyzer problem
I am seeing some strange behavior with my spectrum analyzer. It is a Tektronix RSA306B.
I have put a 50 Ω termination at the input of the spectrum analyzer and I am seeing a lot of spurious ...
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What two laws of harmonics are demonstrated here? [closed]
I clipped the top and bottom of a sine wave at exact reciprocal angles (73.73159173° to 106.2684083° and 253.73159173° to 286.2684083°) to prevent the creation of even (red) harmonics (by being ...
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FFT analysis in LTSpice is giving wrong results during partial execution of time domain simulation (Details in body)
In LTspice, while computing FFT using waveform window (View-> FFT), the results seems to be wrong if FFT is computed after partial execution of simulation ( eg: if simulation is paused in between)...
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Is it possible to to use same frequency band and same frequency blocks for two adjacent/near telecom circles
As shown in the Screen-Shot, TRAI (Telecom Regulatory authority of India) in the pre-auction recommendation manual to DoT(Department of telecommunication) mentions 770 MHz of the spectrum ( 35 MHz for ...
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Would a square waveform (or trapezoidal waveform) have frequency content lower than its fundamental frequency?
I was trying to understand the LC circuit response for the circuit given below.
(Note: fsw indicates the frequency of input square wave as in a buck converter)
As far as I know, for a linear circuit, ...
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Op-amp chopping principle in frequency domain to reduce offset voltage
I am trying to understang the chopping principle used in op-amps with help of this document (page 19 - 20.)
I understand that switch S1 (aka modulator M1) causes modulation with 1/2 duty cycle and it ...
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Confused with parameter definition of spectrometer
Regarding this spectrometer specs, what is meant by "spectral sampling resolution"`? It is give as 2.55 nm. And how is that different from spectral resolution? The term "spectral ...
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Why do we take 50 ohm resistance value for unit conversion in Spectrum View in the oscilloscopes?
While we change the unit in Spectrum View, why is it explicitly mentioned 50 ohm? Why don't we take the resistance value of 1 Mohm into account as well? Though we do have 1 Mohm as one of the ...
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Optical filters: What is the difference between Free Spectral Range (FSR) and the resolution based on (FWHM)
I have a question regarding the Free Spectral Range (FSR) and resolution based on (FWHM) of optical filters like based on Fabry-Perot-Interferometers.
As of now, I always thought of the resolution as ...
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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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