Questions tagged [harmonics]
Questions related to frequencies that are generated by mixing other fundamental frequencies.
138
questions
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2answers
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Harmonics in transformers
could you explain what it is that causes harmonics in transformers?
I've read that these are the reasons, but it still doesn't give me a proper explanation.
Saturation of the core
Magnetizing current
0
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0answers
26 views
Harmonic Balance works, transient does not work!
I have an oscillator circuit and the harmonic balance simulation shows there is oscillation in Vout:
However, when I run a transient analysis, the results are totally different and show there is no ...
1
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1answer
33 views
Can AC harmonic quantities be expressed as a sum of phasors of different frequencies without confusion?
https://www.electronics-tutorials.ws/accircuits/harmonics.html
The problem with AC harmonics is that each term has a different frequency, being a integer factor of the first frequency. I was wondering ...
0
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1answer
60 views
Why does wound rotor IM have the belt leakage but the squirrel cage rotor does not?
According to the description on page 159 of Prof. Lipo's book "Introduction to the AC Machine design":
It is important to mention that the harmonic leakage is important only for wound rotor ...
24
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4answers
2k views
Ceramic resonator changes and maintains frequency when touched
I'm experiencing a weird phenomenon with a ceramic resonator test circuit, where the frequency of its output can be changed by touching the circuit with my finger. The circuit would maintain this ...
0
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1answer
45 views
Switched capacitor sample and hold circuit as as mixer
I am trying to find out how important the "hold " level in a sample and hold down-conversion mixer is.
If the level is decreased, will it lead to any loss?
Out of these three subfigures, ...
0
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0answers
39 views
Harmonic analysis of an electrical circuit
I am having troubles trying to figure this out.
I have a complicated electrical circuit and I would like to compute the spectrum of some voltages of interest. Below is an example of what I want to do ...
0
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1answer
53 views
Does imposing an odd initial condition reduce spurs in MASH Delta-Sigma Modulators that has second order stages?
I've been reading about how fractional spurs can be reduced in a Digital MASH Delta Sigma Modulator (especially for application with a fractional-N PLL) by having the initial condition of the first ...
0
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3answers
59 views
Are harmonics always the peaks in the frequency response plot?
I would like to implement a certain type of audio alarm with 1 fundamental frequency and 4 harmonics.
The example frequency response of a qualified alarm on the spectrum analyzer is shown in the ...
3
votes
1answer
49 views
THD calculated with amplitude instead of RMS
I have a digitized sinewave, and want to determine the THD of this waveform.
This is the equation I am familiar with for calculating THD:
$$
THD=\frac{\sqrt{\sum_{n=2}^{\infty}V_{n_{rms}}^2}}{V_{fund_{...
0
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0answers
37 views
Single-phase thyristor full bridge rectifier vs three-phase thyristor full bridge rectifier
For Single-phase thyristor full bridge rectifier compared to a three-phase thyristor full bridge rectifier, with regards the input current harmonics, does the three- phase rectifier have an advantage ...
-1
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2answers
80 views
What is the physical meaning of reactive power in non-sinusoidal steady-state (with harmonics)?
In sinusoidal steady-state (linear loads, no harmonics), I understand what is reactive power \$Q = V_{\text{rms}} I_{\text{rms}} \sin{(\theta)}\$ where \$\theta = \theta_v - \theta_i\$: its absolute ...
2
votes
1answer
50 views
If interharmonics are defined for periodic signals, aren't interharmonics misleading?
Before explaining my question, I'm going to assume that 1) interharmonics, just like harmonics, are sinusoids; and 2) to analytically represent the interharmonics of a signal, we sum them to the ...
0
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0answers
29 views
Questions about class-F and Inverse class-F RF power amplifiers
I have few questions regarding class F/F-1 RF power amplifiers, i've read few textbooks but none satisfied my exact questions
Why class F/F-1 are sometimes classified in the textbooks as a switched ...
4
votes
1answer
118 views
When a signal has an interharmonic, is the signal periodic or non-periodic?
I have some questions regarding interharmonics. What I'm going to do is first ask just a few, and then as people answer them I would expand this post or create a new question.
Harmonics are sinusoids ...
0
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1answer
65 views
Why the power line interference harmonics appear gaussian?
I have a recorded signal from a data acquisition system.
I am getting this noise in my signal:
The picture shows the FFT of the signal. I checked the frequencies of the noise and they are 50 Hz apart ...
0
votes
2answers
37 views
Validity of superposition when summing powers from each harmonic
In Boylestad's Introductory Circuit Analysis 13th edition page 1176, there's an example about working out the total power dissipated by a circuit fed a nonsinusoidal signal. The signal is decomposed ...
0
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1answer
130 views
Oscillator circuit using comparator and opamps
All opamps are ideal and Rx = 2R in the figure. The comparator is a nonlinear block which operates as follows: if its input Va < 0, its output is +1V. If Va > 0, its output is -1V. To simplify ...
1
vote
2answers
44 views
how to tune wave to obtain a specific harmonic seriers
I wanted to know what is the relationship between a square wave and its harmonics, in other words can i change a square wave features (frequency, duty cycle etc) to obtained a desired fundamental ...
1
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1answer
36 views
Harmonic voltage source, how to calculate it
I have this scheme.
I have all the parameters:
L1=110 uH
C1=160 nF
C2=5 nF
Rt=1.2 kΩ
ω1=45290 rad/s
ω2=162089 rad/s
ω3=238366 rad/s
ω4=276982 rad/s
But I dont understand how to calculate the ...
0
votes
1answer
25 views
Is my thinking right for the simple harmonic circuit
If this is a simple harmonic circuit, then what is the \$X_C\$?
I know harmonic circuit means that there is no value in the imaginary part of the impendence or admittance, that is, \$Z_{th}=R+0j\$ or ...
17
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9answers
2k views
Why harmonic distortion and not at other frequencies?
Despite searching I can't seem to find the answer to this. In understanding harmonic distortion, one piece of the puzzle that is missing for me is:
- why does the distortion manifest at harmonic ...
1
vote
1answer
97 views
Relationship between harmonic's amplitude and square wave's Tr and Pw
I started reading this TI guide on high speed layout guidelines and had some question on the theory of clock signals (pages 2 and 3).
From the image below it's clear that the amplitude of the first ...
0
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0answers
25 views
Formula for calculating the MMF and its harmonics of n-Phase PMSM with integral slot winding (slot per pole per phase =1 & 2)?
Data\Prerequisites:
Integral slot winding full pitch winding
Slot per pole per phase = 1 and 2 (two different possibilities)
Number of phases : n = 3,4,5,6,7
Assume number of turns = N and current to ...
1
vote
3answers
114 views
Aperiod vs Period waveform Fourier Transform: How does nature understand which is the case?
Today I reviewed the theory behind the Fourier Transform, and I asked myself a question that I couldn't answer to in the process.
Theory: A periodic waveform has a Fourier series which can be seen ...
0
votes
1answer
65 views
Why exactly does peaking of magnetization current occur in a transformer?
Initially assuming that the input current is sinusoidal.
In a practical transformer, flux \$\phi\$ produced in the primary is not linearly proportional to the current \$I\$ through it. Due to ...
0
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0answers
76 views
Design an LC filter for a variable load
I'm working on a single phase inverter, and I'm trying to add an LC filter to get a nice sin curve with a THD < 5%.
My problem is that when I test some random values I can get I good THD, etc. But ...
0
votes
1answer
49 views
How Power measured by Meters is affected by Harmonics?
I want to know how energy meters (Electro-static or electronic) measure Energy (let's assume power, ignore time) when there are harmonics present.
I know what are harmonics, how are they generated ...
1
vote
1answer
88 views
Why is total harmonic distortion defined in the following manner?
So the total harmonic distortion is defined as
$$THD = \sqrt{\frac{V_{2}^2 + V_{3}^2 + V_{4}^2...+V_{n}^2}{V_{1}^2}}$$
which means Total harmonic distortion is defined as the square root of the ...
0
votes
0answers
45 views
Where should power factor correction and active harmonic filter connected?
After mains electricity meter, there is an isolation transformer (delta to star) and all load is connected to the secondary of the isolation transformer.
We plan to install a power factor correction ...
0
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0answers
147 views
Total Harmonics Distortion and DFT
I am trying to understand a design that would enable us to measure/determine the Total Harmonic Distortion.
Few key points:
The system is micrconcontroller (TI, C2000, dual-CPU) driven electronics
...
0
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0answers
146 views
RFI filter modeling in LTspice w/ triac
I have a few questions about modeling an RFI filter in LTspice with a triac-based dimmer circuit. I'm referencing the circuit described in Figure 11 in Triac Principles and Circuits -- Part 2 (Nuts &...
0
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3answers
219 views
approximation of a digital signal using the harmonic
I'm new to EE, still struggling in understanding some basic concepts. I'm reading a book which says about approximation:
To make the shape of the analog signal look more like that of a digital signal,...
1
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0answers
42 views
How is voltage induced in Yd transformer without neutral connection sinusoidal?
Thia is regarding bank of 3 single-phase transformers having star connected primary with isolated neutral and delta connected secondary.
I know that for bank of 3 single phase transformer core flux ...
0
votes
1answer
52 views
Calculation of active power using two waveforms with harmonics
I came up with the following example on a textbook I was given.
Let's suppose we have an R-L load. I want to calculate the active power P when the voltage and the current applied on the load are ...
1
vote
1answer
364 views
RMS value of fundamental harmonic vs RMS of third harmonic
If we have a periodic signal (square wave) with amplitude of 100V. Then what would the RMS value of the fundamental harmonic be compared to the RMS value of the third harmonic?
After some suggestion ...
0
votes
1answer
89 views
Finding a Fourier series of a Burst Fired sine wave having consecutive 2 cycles on & 2 cycles off?
I have been trying to find the solution of the following problem but with no luck.
I have a system that generates a waveform of sinusoidal type with the only difference being that this wave has 2 ...
0
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1answer
37 views
Harmonics modelling in electrical machines
I am currently working with a permanent magnet synchronous machine and I am trying to model the harmonics caused by magnetic saturation, dead time, and non linearities of the frequency inverter.
It ...
0
votes
1answer
58 views
Spectral lines vs Envelope of PWM wave
On the wiki page of 'Duty Cycle' there is a nice animation that shows the frequency spectrum of PWM wave as its duty cycle is modulated from 0 to 100%.
The animation shows the 'spectral lines' as ...
1
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0answers
59 views
Interpretation of IEC 61000-3-6 (Assessment of emission limits for the connection of distorting installations to MV, HV and EHV power systems)
Based on the installation I want to calculate the acceptable current harmonics related to my installation. IEC 61000-3-6 says:
For each customer only a fraction of the global emission limits GhMV+...
1
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2answers
2k views
How to Size Line Reactors and Understanding Reactor Specifications
I've got a 600 VAC, 75 HP VFD that I want to place line and load reactors in series with. Usually, I find charts like this that give me a horsepower table to follow as they are the easiest to use. ...
20
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5answers
4k views
Why is only the fundamental frequency component said to give useful power?
In most books it's said that the harmonic content in an AC line does not transfer power (just the fundamental frequency does), but no explanation. It seems intuitive, but why is that true?
Edit:
In ...
2
votes
1answer
186 views
Why only odd harmonics after signal is amplified? *Plots inside*
Why do I get only odd harmonics appearing? This not only happens at saturation of the transfer curve, but also in the linear portion of the curve.
I make an input signal and the power of this will ...
0
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3answers
317 views
Harmonic detection using lock-in amplifier
Can a third harmonic of a signal be detected using a lock-in amplifier under the same parameters fixed for collecting the fundamental or the parameters needs to be adjusted.Here by parameters I mean ...
0
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2answers
363 views
Calculating Total Harmonic Distortion using only the first harmonic
I have an assignment for a class where I have to calculate the thd of a signal using MATLAB.
I think I have a pretty good understanding of how this should be done, however, my professor instructed ...
0
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2answers
125 views
Harmonics in power system [closed]
I have seen in some text books that power converters produce harmonics in power systems.
How do power converters inject harmonics in a power system?
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0answers
42 views
Sideband Production
I am trying to understand exactly how sidebands are made. I've seen the math, but I'm looking for more of a component-level understanding of how they are made and what properties of the mixer ...
1
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0answers
153 views
What factors cause the harmonic distortion in ADC at high signal amplitudes?
I have been studying about the ADC's SNR vs amplitude relation. A sample curve is shown below:
I am interested in the region rounded (orange) of the gray curve. At that region, we expect to see ...
0
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1answer
17 views
how to avoid harmonic on intrrupt for proximity sensor in NodeMcu
i have 5v IR proximity sensor for measuring pulse output attached in NodeMCu
using intrrupt pin but it gets a random counter on the harmonic environment.
it is working fine in Normal situation what ...
0
votes
3answers
220 views
Tektronix function generator THD
I am confused by the datasheet of the AFG3021C: https://www.tek.com/link-click-count?nid=75006&url=https%3A//download.tek.com/datasheet/AFG3000C-Arbitrary-Function-Generator-Datasheet-75W282817....
