Questions tagged [harmonics]

Questions related to frequencies that are generated by mixing other fundamental frequencies.

20
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5answers
3k 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 ...
1
vote
0answers
64 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
votes
1answer
35 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
100 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 ...
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2answers
67 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
37 views

SMPS: Current Mode Control [Sub-Harmonic oscillation] - How to determine ramp when capacitor is unknown?

Currently I am working to charge an DC-link capacitor to prevend inrush currents. I want to charge the capacitor from 0 to 700V using with an Vin of 700V. I want to do this by using an SMPS and found ...
1
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0answers
41 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
68 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
votes
1answer
14 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
74 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....
0
votes
1answer
91 views

Generating a realistic sine wave in MATLAB

I'm working on a simulation on MATLAB and I need a realistic sine wave which has harmonics. So I know there would be harmonics at 2f,3f... but I am not sure how to determine their amplitude. I tried ...
0
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1answer
189 views

Harmonic resonance calculation in power-factor correction

Eaton's Power factor correction: a guide for the plant engineer states, Capacitors and transformers can create dangerous resonance conditions when capacitor banks are installed at the service ...
0
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1answer
41 views

If I use a CAT 2 10x probe does my DSO need to be CAT 2?

I need to measure the harmonic distortion on a solar inverter (power output). I need to buy all the equipment from scratch and was wondering if my DSO needs to be CAT 2 rated if I use a CAT2 10x probe....
0
votes
2answers
78 views

Filter harmonics in AC power line [closed]

I run a Toshiba Digital copier machine in my shop and the machine started showing error codes related to power issues a few days ago. This happens randomly during daytime. There were no problems at ...
0
votes
1answer
56 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 ...
4
votes
2answers
462 views

Why is this the maximum dynamic range in a spectrum analyzer?

In Keysight's popular AN 150 there is a plot of noise and harmonics amplitudes versus the level of the input signal at the mixer (page 57). It's stated there that the maximum n-th dynamic range is ...
0
votes
1answer
182 views

How do I calculate THD in proteus?

I know how to plot the Fourier transform, but is there a more precise way to measure the total harmonic distortion? I have this graph: As you see, there's only one distinguishable component at 1 kHz ...
3
votes
1answer
446 views

Symmetric vs Asymmetric PWM

I am working on Control of Power Converters, I was reading TI's piccolo DSP ePWM guide and came across symmetric vs asymmetric PWM, I have a good basic understanding about converters, DSP and all. ...
0
votes
2answers
301 views

Are ripples and harmonics the same thing?

I started working on the "Direct Power Control of Grid Connected Voltage Source Converters", everywhere in the literature, authors state that one of the major drawbacks of this control technique is ...
2
votes
2answers
74 views

Switching mode power supply for Power Line Communication

For a Powerline Communication device that uses the frequency band 42 to 89 kHz. I need to choose a power supply that will not add noise in the powerline and kill my communication band. There are two ...
0
votes
2answers
482 views

Why is neutral required in three phase charging of Electric vehicles?

Talking about both three-phase AC as well as DC fast charging (wherein 3 phase AC is converted to DC) in EVs, I think that the 3-phase rectifier represents a balanced 'load'. Therefore I want to know ...
1
vote
1answer
202 views

Total harmonic distortion (THD) of a circuit

Where \$V_{sin}\$ is sinusoidal with frequency \$f_{1} = 1 kHz\$. The THD is defined as the sum of the power of all harmonics (except the fundamental) divided by the power of the fundamental harmonic....
0
votes
0answers
648 views

Power factor and Harmonics associated with Electric Vehicle charging

What is the power factor associated with (typical) DC fast chargers and onboard chargers in electrical vehicles? Also, how much is the harmonic content (especially triple-N harmonics) associated with ...
0
votes
1answer
74 views

For induction motors, would one expect harmonics to be different between Delta and Y stator windings?

Given two induction motors with the only difference being that one is wound delta, the other Y, would I expect to see a different behavior if the source is a three phase voltage with harmonics?
1
vote
1answer
508 views

How to design filter for inverter for following cases?

I am going to make two pure sine inverters for collage project. Both inverter uses 24V battery as DC voltage source. Switched to ~360Vdc and ~180Vd by boost converter accordingly. Both then switched ...
0
votes
3answers
64 views

meaning of having harmonic on special signal

my question maybe seems very simple but, I'm not familiar with the answer of that; what is the meaning of harmonic of the signal exactly? I know the harmonics of the signal are signals whoes ...
0
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4answers
196 views

what causes voltage harmonics

People keep telling me that Nonlinear loads causes current harmonics and when i ask them about what causes voltage harmonics, they tell me wherever there is current harmonics there is voltage ...
0
votes
1answer
343 views

LVDS clock signal EMI

I am working on a project in which we have an an i.MX53 to driving an LCD through the LVDS connector and we fail the required EMC criteria. There are multiple peaks at 40 MHz intervals (starting at ...
0
votes
0answers
33 views

Very low network impedance close to 13th harmonic frequency

I carried out a frequency scan of an electrical network model with a proposed 220kV transmission line. Addition of this line lowered the system impedance to very low value (to 3 Ohms) at 13th harmonic ...
1
vote
0answers
56 views

irritation in LTspice

I have written some measurement commands in LTSpice to calculate the weighted harmonic distortion (PWHD) .meas a1n INTEG (I(Lgra)*cos(2*n*180*fg*time)) .meas an PARAM a1n*2*fg .... (if somebody ...
1
vote
1answer
558 views

Export error log values from LTspice

I have used .meas expressions to calculate harmonic values in LTSpice. The problem is that these are now in the error log and I cannot export them. Is there a way to export error log values in a .csv ...
1
vote
1answer
114 views

Is my laptop charger is working as harmonic filter and absorbing harmonics?

I have a square wave backup inverter (UPS). Whenever the power goes out, UPS turns on but all the fans run with noise and humming sound. I know it is because of square wave and harmonics. But when I ...
0
votes
0answers
414 views

Why is the chording angle 30 degrees, in a practical alternator?

So far what i have understood... Chording angle in Synchronous Generator/ Alternator is introduced to tackle the problem of harmonics that couldn't be taken care of during the design either in - ...
0
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1answer
229 views

How to control switching of mosfet in PFC boost rectifier using PI controller?

My aim is to reduce THD in the supply current and I wanna use a simple PI controller for that, to make the inductor current more sinusoidal and at the same time keep the output voltage of the ...
0
votes
2answers
567 views

High voltage square wave drives induction motor

This is the problem, i'm designing a water pump's universal drive (3 HP Max) controlled by Arduino, so my first vision is to convert 220VAC/50Hz to DC, Then reduce the voltage by DC-DC chopper circuit,...
5
votes
2answers
3k views

50/60Hz Noise Harmonics

I want to wirelessly communicate over low frequencies (<1kHz), and I noticed during some tests that 60Hz noise is showing up a bit at 180Hz (3rd harmonic), and also slightly at 300Hz (5th harmonic):...
1
vote
1answer
141 views

For Brushless DC Motors would one expect harmonics to be different between Delta and Y stator windings?

Given two 3-phase brushless DC motors with the only difference being that one is wound delta, the other Y with center grounded, would I expect to see high frequency voltage-current harmonics to be ...
0
votes
0answers
164 views

Is it true that inductors filter current harmonics and Capacitors filter voltage harmonics in SMPS?

In switch mode power supply applications, it is true that inductors filter current harmonics and Capacitors filter voltage harmonics? Is it true that in most applications we use LC filters due to the ...
0
votes
1answer
234 views

AD9850 Harmonics at Lower Frequencies

I am wanting to use the AD9850 for a particular application to generate sine wave signals in the 100Hz to 5kHz range. I've purchased a AD9850 module from ebay which just looks like the standard ones ...
0
votes
1answer
73 views

Suppress Certain Overtones In A Musical Instrument's Sound Wave

So, just like the title suggests, my college professor and I are trying to suppress certain overtones of an instrument's sound. I have a microphone hooked up to an oscilloscope, and I'm using the ...
0
votes
3answers
367 views

Mixer spurs and IF output filters

I'm designing a simple diode ring mixer for down-conversion from 1.5G to 200k. I want a band-pass LC pi-filter on the mixer IF output. I've designed the filter for 50R source and load impedance by ...
3
votes
1answer
528 views

Long lines: whether or not to treat PCB traces as RF lines

My setup: 53 x 28 mm PCB, uC will run somewhere between 1 MHz and 8MHz. Dual layer PCB design. From the info I gathered on this site it seems there are two aspects to consider in deciding how to ...
0
votes
4answers
1k views

LCR circuit with squarewave input: Why does the output take a decreasing amplitude through each cycle?

I understand a square-wave will be made up of a sum of sine waves in the form $$\frac{1}{n}sin(nf_0)$$ So when a squarewave is input to a LCR circut designed to be a bandpass filter, it will ...
0
votes
1answer
76 views

Harmonic simulation of microwave power amplifiers

I am working on microwave power amplifier design for 2.45 GHz, 300 W using LDMOS (part no.:MHT1004N). I am using Agilent's ADS for the simulations. I want to know what exactly is harmonic balance ...
2
votes
3answers
917 views

FFT Using Pic Microcontroller [closed]

Good Evening, I am fairly unfamiliar with DSP and want to engage in a project. I wish to perform a FFT on the source current going into a non-linear load and observe its harmonic content on an LCD. ...
2
votes
2answers
901 views

Understanding harmonics of different Amplifier Circuits (A,AB,AB w/OP-Amp)

I have been test the circuits for amplifiers and got somewhat stuck in understanding the results for the FFT's harmonics. With a standard type B I was able to get this graph for the harmonics for ...
1
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1answer
274 views

Why is harmonic voltage flowing to the source

In non-linear loads, Current Harmonic Distortions are created, which in turn creates voltage harmonic distortion that are said to flow from the load to the source ( system ). My understanding of ...
0
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3answers
92 views

Some Problems in a power amplifier circuit with THS3091

Recently, I designed a power amplifier circuit with THS3091. The schematic diagram and PCB of the circuit are just the same as the layout example of the datasheet of THS3091 in page 39. But some ...
0
votes
1answer
160 views

What is the rule of the Vdc regulation in a shunt active filter

I understood very well the principals of harmonics identification in an shunt active filter ( PQ theory : Akagi & al for example), but what i don't understand is why do we care about regulating ...
3
votes
4answers
4k views

Why are there no “even” harmonics in AC machines?

Why are there no "even" harmonics in AC machines? In Chapman's book, he says it's because of symmetry of the flux density wave but I don't get it...