Questions tagged [wave]

May refer to an electromagnetic wave (such as a radio wave) or the PCB manufacturing process of wave soldering.

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69 views

What does this sine wave say exactly? [closed]

I am currently just trying to understand how sine waves function and what the readings they're giving mean. I have an example of a demodulated signal that I found and was wondering if anyone could ...
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37 views

A circularly polarized EM wave is perfectly absorbed by any interface?

According to the Fresnel equations, the effective reflectivity of an arbitrarily polarized electromagnetic wave is given as: $$ \Gamma = \frac{\Gamma_p + \Gamma_s}{2} , $$ where \$\Gamma_p\$ and \$\...
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2answers
145 views

Phase shift a square wave

I have an application where I would like to derive a secondary square wave from a primary one but with a continuously variable phase shift. I would like to know if this is possible to achieve in a ...
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4answers
118 views

What is waving in light? [closed]

I've been building an AM transmitter and it's generated a lot of questions. At the top is the electromagnetic wave. It may seem simple but I've yet to find an answer. As far as I know, light is made ...
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6answers
113 views

Why are transmitting antennas generally larger than receiving antennas?

The reasons I can think of are transmitting antenna has to be more directive also larger length will imply larger power and thus will help compensating for losses. But on contrary if receiving antenna ...
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2answers
86 views

Why does higher bitrate requires higher bandwith?

I try to understand this question since a while and I think I came to an understanding. But I need someone to confirm it. At first, I thought the bitrate was dependent on the frequency (more sines per ...
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1answer
37 views

Average amplitude and DC component

While I read my college book in signals, I got stuck with some basics: DC component is component of zero frequency. With no DC component, a signal has an average amplitude of zero, with a DC ...
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1answer
27 views

Do surface charges exist when EM wave gets reflected by dielectric boundary?

If both the materials on a boundary are dielectric then do surface charge exists. I was solving using pillbox it showed that there should be surface charge on boundary to satisfy change in normal ...
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0answers
56 views

Generating a sine wave

Hello so I thought I could use a VCO to generate a sine wave , but I didn't find anything that generates a sine wave with 500Khz. So then thought to use a microcontroller, like Atmel o Arduino, but it'...
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28 views

Polarization of an electromagnetic wave

How can I find polarization of an electric field as shown below? $$\vec E (0,0,0) = \vec a_x E_{0x}+\vec a_y + 2j \vec a_z \dfrac{V}{m} $$ The propagation of the wave is as shown below. $$ \vec a_n = \...
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1answer
26 views

Refractive index, wavenumber, and wave impedance of the PEC that a plane wave is normally incident on

I am trying to find the refractive index \$n_t\$, wavenumber \$k_t\$, and wave impedance \$\eta_t\$ of a perfect electric conducting medium t. Here is my work so far: The conductivity of the PEC is \$...
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9answers
5k views

If a square wave has infinite bandwidth, how can we see it on an oscilloscope?

If a square wave requires infinite bandwidth how can we display it on oscilloscopes? Link: Oscilloscope fundamentals.
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2answers
345 views

What is a guided mode?

I am currently reading my text, for my electromagnetics course, and we are discussing guided waves. The text casually mentions the term "guided modes", and never really defines what that ...
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1answer
89 views

LM358 waveform generator issue

I would like to generate a 30 kHz & 60 kHz sawtooth waveform using an LM358P operational amplifier per the following schematic. Theoretically, and in the simulation, the circuit should work ...
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1answer
76 views

Why only half the peak voltage in my half wave rectifier?

I built a simple half wave rectifier using a center tap transformer and a 1N4007 diode. I connected the 1N4007 diode to one of the live secondary wires of the transformer and measured the DC voltage ...
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3answers
111 views

How do a generate a clean, precise pulse wave electronically without jitter?

I am trying to build a simple pulse generator circuit for electrophysiological stimulation purposes. It seems to be surprisingly difficult to generate a square/ pulse waveform where the pulses have ...
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0answers
103 views

Building a triangle wave generator using two LM358 with single supply operation

I am trying to build a triangle wave generator with the following specifications: The triangular wave must oscillate between V_max=7.2 V ,V_min=1.6 V Duty cycle = 0.5 ±1% Frequency, f_osc= 8.5 kHz ±5%...
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5answers
324 views

How is digital data represented in analog waves? [closed]

This question is simply coming from an intrigued teenager, so if it has any flaws, I'm sorry for the inconvenience. To my knowledge, when digital data is transmitted wirelessly, it is first encoded ...
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3answers
115 views

TV remote mystery

My TV remote has this hole. The hole exists for the propagation of the EM waves coming from inside the remote correct? I guess plastic would absorb those EM waves and we don't want that to happen. ...
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3answers
142 views

How fast is DC current/voltage?

The standard way to calculate the speed of information (current/voltage, EM wave) through a dielectric medium (like PTFE or fiber) is to determine the relative dielectric constant, and compute the ...
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1answer
45 views

Synchronizing sine waves from solar panel and grid electricity [closed]

I am new to the field of solar panel. I would like to install and use the electricity produced by the solar panels (through inverter) directly on the appliance, e.g. a fridge. In case of cloudy sky, I ...
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0answers
40 views

Calculate output power of sine and triangular wave

What is the mathematical expression to calculate the power dissipated by a load crossed by two separate electrical signals representing two specific mathematical functions knowing: Load resistance ...
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2answers
75 views

Radio Waves propagation (Intuitive Understanding of Wave propagation)

I have few similar questions regarding Radio waves communication particularly FM and AM type of Radio wave communication. Please bear with the naivety of the questions. Questions: Radio waves in FM ...
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5answers
2k views

How can a DC spark create EM waves?

I have a question please about sparks used in the early history of radio. I have read the similar questions but I still need your help please. I have learned from sources such as https://neurophysics....
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2answers
94 views

Precision amplitude 600kHz square wave generator

I'm looking for a circuit that creates a precision amplitude square wave of 600kHz (50% duty cycle). The amplitude of the square wave needs to be 3Vpk-pk +/-10mV, but can be DC offset. The output of ...
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2answers
167 views

With so much radio signalling occurring simultaneously (TV, Cellphone, Radio, etc.), how does our atmosphere keep them separated and avoid disruption? [closed]

I know this question has been asked before, but I still don’t completely understand. I understand that different stations are given different frequencies, but waves are able to interfere with each ...
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2answers
138 views

Best waveform for Radar

I was wondering what would be the best waveform to generate for a phased array short range imaging radar? Square, sine, etc. Also what frequency would be best to operate at for the carrier wave given ...
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5answers
156 views

Create electromagnetic waves using Lc tank circuit

Electromagnetic waves are produced by the motion of a dipole and suppose we have top and bottom points then the negative and positive charges must oscillate between those 2 points. However an LC ...
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2answers
94 views

Is it possible to generate a sine wave formula using values from an array?

so we have an Arduino code which includes an array, is it possible to make those array disappear [in the code] and instead formulate a sine wave formula for those [array] to make the output in sine ...
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1answer
31 views

What is the phase of the impedance at each point on a resonant center fed half wave dipole?

Everyone knows that for an ideal center fed half wave dipole operated at resonance, the impedance at the center is 73 + j0 ohms. The impedance at any point on the antenna is determined by the ratio of ...
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2answers
58 views

power waves and scattering matrix

I have some doubts about the concept of power waves used in the description of the scattering matrix of an N-port component. In particular, I was wondering what is the most general and correct ...
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0answers
16 views

Difference Amplifier to retrieve sine wave

I have built the following summing amplifier circuit from a Fourier approximation of x(t)= 0.143 + 4/π ∑((sin⁡(2π(2k-1)ft)/(2k-1)). I am now trying to retrieve a sine wave from the output of the ...
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1answer
35 views

Friis transmission equation: how do I consider power loss along other directions?

I do not understand a basic concept about Friis transmision equation between two antennas: where Dt and Dr are the antenna directivities (with respect to an isotropic radiator) of the transmitting ...
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1answer
57 views

Far field radiation and spherical waves

I have a basic doubt about electromagnetic waves emitted by a certain source. Depending on the shape and on the physical properties of the antenna, its electromagnetic waves may have different ...
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1answer
79 views

Separating odd and even pulses in a pulse train

How would one go about separating odd and even pulses in a pulse train and displaying them using LED indicators? A schematic would be of great help.
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0answers
44 views

How to half frequency of triangle wave

I wanted to know if there is a method/circuit to half the frequency of a triangle wave, in the same way a flip flop can be used to half the frequency of a square wave. Any help would be appreciated ...
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1answer
74 views

I'm having issue getting thick tin-lead 63/37 solder on Alloy 42 lead frame

I'm using Kester 2235 flux and using robotic solder dip so heights are static. I'm measuring thicknesses using x-ray fluorescence, they keep coming up very low. Should I be using an initial scavenge ...
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1answer
51 views

Does anyone know how can I deduce this formula for frequency from this sawtooth generator?

[ I know that this formula is correct, but I'm not sure how can I deduce it. Can anyone help me? Thanks in advance!
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2answers
127 views

Scope says 59.9 Hz .. yet I can't measure turntable speed

I needed to measure a turntable's number of revolutions per minute, but didn't have any incandescent lamps around. So I rigged an LED to an ESP8266 SOC and programmed it with delays to output a 60hz ...
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4answers
137 views

how to find the frequency of this nonperiodic composite signal?

I'm new to electrical engineering, sorry if my question sound dumb. Below is a nonperiodic composite signal plot: As you can see this is a nonperiodic composite signal in 1s and I know that if the ...
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3answers
90 views

Is the amplitude of a sine wave increasing or decreasing in this phase?

I'm new to electrical signal, sorry if my question sounds dumb. Below is a picture from my text book: It says a sine wave with a phase of 0° starts at time 0 with a zero amplitude. The amplitude is ...
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0answers
25 views

How do you model acoustic waves underwater that are generated by an Nd:YAG laser?

In this paper on page 84 they show the following experimental setup: The array of receiver hydrophones are set up to record sound pressure waves sent by the transmitter hydrophones. In Figure 6....
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4answers
157 views

How to demonstrate mathematically the conditions of reflection in transmission line?

We are all taught about transmission lines and its associates -- characteristic impedance, reflection, standing wave, etc. It is well known what happens when a transmission line is terminated with ...
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3answers
66 views

Spherical waves in far field region

in my antennas book (I do not put its reference because it is not in english) it is written that, at high distance from the source, the electromagnetic field radiated by it is a spherical wave. This ...
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0answers
27 views

Radiation pattern and propagation direction

I have a basic doubt about how to read a radiation pattern. Let's consider precisely the power pattern: it represents how the power is distributed along all directions in space. For instance, this ...
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1answer
34 views

Elliptical polarization and waveguides

It is known that a generic harmonic electric field which propagages in free space has an elliptical polarization (if you want to read the proof, look at this, slides 72 - 99). My question is: what ...
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0answers
42 views

What are the chain reaction that create the electromagnetic wave?

From my very limited knowledge I know that an electromagnetic wave is created by some chain reaction of accelarating/oscillating electric and magnetic waves, I also know about how the electromagnetic ...
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3answers
220 views

Why should signals in circuits propagate much slower than the speed of light?

I've read a couple of other topics (such as this one and this one) about the lumped circuit abstraction requiring that signal timescales (i.e. the period of the highest frequency signal component) be ...
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2answers
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Why are E and B field in phase in far-field electromagnetic wave propagation?

I am very frustrated with the fact that the E and B field of an EM wave are in phase in the far-field case. Before I get into this question I am letting you know that I already read this link related ...
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2answers
64 views

Why/How alternating currents through coaxial cable do not interfere with each other?

I know that cable TV use coaxial cable with alternating current frequencies varying from 5 MHz to 750 MHz. Why/How a alternating current of, for example, 5 MHz , 10 MHz, 20 MHz, 100 MHz, 300 MHz, 500 ...

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