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

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3
votes
1answer
38 views

Electric field in coaxial cavity

I have a geometry as follows: This is a hollow metallic cylinder with a small metallic rod inside. The rod is connected to the bottom of the cylinder but is a bit shorter than the outer cylinder. ...
-2
votes
2answers
61 views

I need to predict values on a sinewave from the period and toatl of the sinewave see image [closed]

This image should show what I am trying to achive The period is 1 year with each x value been 1 week apart. The total of all Y values added together are 32000 but i want to predict each y value from ...
2
votes
2answers
65 views

What happens if a series of EM waves pass through an inductor?

An inductor takes an AC current and produces a magnetic field. An EM wave is made of an electric field, and magnetic field propagating through space, so can a series of EM waves passes through an ...
-2
votes
3answers
55 views

what is the reason behind the envelope shape in AM wave?

In an AM wave what is the reason behind shape of envelope? why does a mirror image of modulating wave appear below the axis as well?
-3
votes
2answers
118 views

Can a smartphone send directly a message to another smartphone 20 miles away? [duplicate]

According to this website, a typical cellphone has enough power to reach a cell tower up to 45 miles away So, can a smartphone send directly a message to another smartphone 20 miles away?
-4
votes
1answer
61 views

Why do smartphones need towers to send messages? [duplicate]

Why do smartphones need towers to send messages? Why can't they send messages directly to each other?
2
votes
0answers
135 views

Peculiar noise when observing a square wave

I'm using the following function generator: http://www.farnell.com/datasheets/499058.pdf?_ga=1.129729036.1263433037.1467971694 and a Tektronix TDS 1002B scope for some measurments. Most of the time I ...
0
votes
2answers
116 views

Can we feel sinusoid? [closed]

If we have a signal of 1 or 2Hz, can our skin receptors feel that sinewave, if that sinewave has aproppriate voltage level?
0
votes
0answers
34 views

XR2206 frequency stability problem

As you can see from the above pictures, the signal is moving to the left fast and with no frequency stability. Is there any problem with the diagram? It worked for 100 kHz but failed for anything ...
1
vote
2answers
41 views

Square wave filtering with d-flip flop

I have a square wave (1st line), I want to skip every odd impulse, and output every even one without change, as shown in the second line. Is this different from frequency division? What is the ...
0
votes
1answer
65 views

How to 'average' a sine wave of RMS values?

Lock-in amplifiers (Stanford Research Systems 830) display sine wave signals in RMS values SR830 Manual (page 3-3). One can use the internal buffer to rapidly measure a signal, storing up to 16000 ...
-2
votes
2answers
45 views

What is voltage input and voltage output?

I'm so confused about what these are. On a half wave rectification circuit this is labelled at the end with a wave coming out of it: I understand that this wave is just showing the half wave ...
0
votes
2answers
71 views

How do I determine the start and end of the wave?

I am facing a bit of a challenge in trying to understand basic concepts or terms within the signal world. I have a number of values retrieved from a sampled signal that is generated randomly for no ...
0
votes
1answer
85 views

Wien Bridge Oscillator with LM358

I am constructing 10kHz , 30kHz and 50kHz sine waves using wien bridge oscillator design with LM358 OP-Amp. I have a few problems with the circuits that i could not figure out. Thank you for all your ...
0
votes
2answers
78 views

Wave rectification

I'm just a bit confused about what is actually happening when a wave goes up and down. It's a graph of voltage vs. time, so therefore wouldn't that mean the voltage was going up and down constantly? ...
0
votes
1answer
71 views

full wave rectifier is not rectifying the wave properly

the following rectifier does not create a wave that is rectified evenly. according to the books this should work when using a centre-tap transformer. scales : (Y = 10ms/div) & (X = 5V / div) ...
0
votes
2answers
29 views

Determining the inital phase of a waveform

How could I determine the initial phase of the following sinusoids with these parameters only ? from what I can see , I know that B is leading C since the crest is behind the Y axis .. Therefore , B ...
0
votes
1answer
66 views

Triangular Wave Current input to a capactior, Voltage Response?

I am simulating a cap. When i give a triangular current input to a capacitor, I see an increase in voltage for both rising and falling side of current signal. why is this happening? For a rising ramp ...
0
votes
2answers
73 views

High-current capable, high precision sine wave

I'm actually asking 2 questions - one about sine wave generation and another about high rate / precision voltage measurement. I'm working on a project where we have to generate a sine wave on top of ...
1
vote
6answers
588 views

What is the best way to get a sine wave from a square wave?

I have square waves of different frequencies (1KHz to 20KHz), and I need to convert them to a sine wave of the corresponding fundamental frequency. A RC ladder Low-pass filter was the first thing ...
1
vote
2answers
48 views

Medical Ultrasonography Phased Array Beamforming

Medical ultrasonography equipment images the interior of the body by reflecting ultrasonic sound waves off of discontinuities between internal tissues / organs. I did some reading about this ...
-1
votes
2answers
142 views

Ways to voltage shift a wave down to ground

Say I have a wave signal that is always above ground, that is, the signal is positively clamped to the ground. (EDIT: from an input of a helpful user, I now know this should be called "negatively ...
-6
votes
2answers
78 views

How electromagnetic waves works, how they are created and how thay transform to electric signal? [closed]

Few days I am trying to learn more about electromagnetic waves, induction, electromagnetic spectrum... And how it's connected. Here is what I understand now: There is a lot of electromagnetic waves ...
1
vote
1answer
75 views

Digital potentiometer as INA129 gain

I'm working on a waveform generator for which I'm using the DDS AD9833 chip to generate sine signals and triangular signals. I'm trying to amplify these waves since the AD9833 output is 600mVpp and I ...
-2
votes
1answer
306 views

How to calculate R and C for AM Demodulation envelope detection?

How can I calculate the value of \$R\$ and \$C\$ for an AM envelope detection circuit. Knowing that the carrier wave is \$20\mathrm{KHz}\$, \$1\mathrm{Vpp}\$ sine wave, and the message signal is a \$...
0
votes
1answer
304 views

Designing audio player - low-pass filter, DAC

I'm building audio (wave) player on some microcontroller. I will have external 16-bit DAC and I wonder if that's enough? I mean, is low-pass filter really needed? (I know what it does and why you ...
1
vote
1answer
82 views

Convert PWM to 3-level voltage

I want to convert a generated PWM by a microcontroller to a 3-level voltage. [] the maximum output voltage range is between -5 to 5 or -10 to 10 volts. Another point that may well be considered is ...
-1
votes
2answers
49 views

How to solve Power Density Function?

How to solve this problem: A radio receiver needs $$ 1 \textrm{ nW/}\textrm{m}^2 $$ of power density function, how far away from a 1-watt point source will it continue to work?
2
votes
1answer
143 views

Why do we not use both E and B fields for a receiving antenna?

An antenna is an electrical device which converts electric power into radio waves and vice versa we all know this. In transmission, a radio transmitter supplies an electric current oscillating at ...
1
vote
1answer
74 views

“Drawing” signals with antenna

Can you produce max waves, adding them, creating massive spikes like it showed in this video with water, but with multi antennas. Can you do this with electromagnetic wave in air with some complex ...
2
votes
1answer
290 views

Square generator 1KHz to 1MHz with 1KHz precision

I would like to make a square wave generator which will output a signal with amplitude X voltages and frequency between 1KHz to 1MHz, with the precision of 1KHz (for example: 785kHz, 926kHz, 999kHz, ...
0
votes
5answers
491 views

Wavelength in real life

How to understand term wavelength of radio wave in real life. What this column 'Wavelength range' means to us in real life? I theoretically understand what it is (distance between two successive ...
6
votes
1answer
165 views

Why does EM radiation travel much further than the magnetic field of an equivalent power electromagnet?

If both fall of as 1/r^2 from the source then why can radio waves travel around the world and still be picked up easily at the right frequency but the field from a powerful electromagnet can not?
2
votes
1answer
320 views

How tuning of particular FM signal is done?

I have a transistor radio which has facility to play FM radio channels between 88MHz to 108MHz frequencies. Now,consider a situation ,there are five FM stations which I can hear in my city 91.1MHz,93....
2
votes
2answers
169 views

What are values of fundamental frequency and the harmonics for the below signal g(t)?

We know that a Fourier series formula for any signal $s(t)$ is given as $$\frac {a_0} 2 + \sum \limits _{m=1} ^\infty (a_m \cos \frac {2 \pi m t} T + b_m \sin \frac {2 \pi m t} T)$$ Here,as we see ...
2
votes
3answers
91 views

Fundamental property of an EM wave

Imagine there's an electromagnetic wave propagating in vacuum with a frequency \$f\$ and wavelength \$\lambda\$. Its speed is \$c\approx3\cdot10^8{{m}\over{s}}=f\cdot\lambda\$. Now, the wave has to ...
1
vote
0answers
74 views

perfect square wave cannot be played back

If I produce a square-wave by creating a sine wave first and then doing, if x >= 0 return 1, else return -1 this produces a "perfect" square wave(python code). Like this the audio signal cannot even ...
-1
votes
1answer
166 views

permittivity and conductivity vs. attenuation [closed]

Is there any direct relationship between permittivity of a medium and attenuation of an EM wave? What about conductivity vs attenuation? edit: Ok for instance an EM wave traveling in sea water. I ...
0
votes
2answers
150 views

+5 to 0v square wave from a 12vdc supply

I need to build a simple 0 to +5v square wave from a 13vdc (automobile) supply. The frequency of the output needs to be based on a 1vac input signal. I believe it can be done with a handful of ...
1
vote
1answer
89 views

Confused regarding standing waves on transmission line

I am currently learning about transmission lines form an online book hosted by a website called “All About Circuits”. If anyone is interested, the particular chapter I am currently reading can be ...
1
vote
3answers
269 views

Dipole antenna VS. coil for RF transmission or recieving

Correct me if I am wrong, but all RF light waves are created via a changing electric and magnetic field. But when looking at all kinds of radios and RF circuits, this light wave is always made with a ...
0
votes
3answers
265 views

Using half wave rectifier for low power applications

Im trying to make a low power application feeding it from a 9vAC, source, i have been reading that i can use a half wave instead of a full wave rectifier, i already did the circuit and been doing ...
0
votes
1answer
187 views

Triangle Wave Generation

What would be the best way to generate a triangle wave that can operate at 250kHz @ 4V peak-to-peak? I have tried the following circuit: However, the best I could obtain was a 4mV peak to peak ...
0
votes
2answers
87 views

Measuring the dampening sinusoidal wave of a simple LC Tank circuit?

I've been trying to do the simplest of things...measure the decaying sinusoidal wave of a LC Tank circuit on a breadboard. I've created an "inductor" out of a coil of copper wire I wrapped around a ...
1
vote
1answer
264 views

Get triangular wave on pspice

I designed a integrator op-amp on pspice. I want to get triangular waves for output and square waves for input. Input is OK, but I can't get triangular waves. What is wrong, should I use a second ...
2
votes
1answer
77 views

Measure propagation velocity through finite transmission line

I'm currently trying generate a wave in a circuit but am running into the issue of figuring out exactly how to measure the propagation velocity. The circuit diagram is below L1=L2=L3, C1=C2=C3, R1=R2=...
-4
votes
1answer
348 views

How to encode and decode electromagnetic waves in binary? [closed]

If I am not wrong the electromagnetic waves can be produced by opening and closing an electric circuit. (Tell me if I am wrong) Let's say we want to send an electromagnetic wave that has the ...
1
vote
1answer
41 views

EM wave polarization check

I am trying to recall the quick way to check the EM polarization theoretically, I mean if I have a wave described as (ssume capital letters are vectorial fields) \begin{equation} \ E = E_o *exp(j* \...
0
votes
1answer
76 views

How deep can I bury a 1 MHz transmitter

So in designing a deep underground sensor network, my team wants to use a 1 MHz radio, but we cannot determine a way to model the soil, so as to calculate how deep i can bury a radio for showing proof ...
0
votes
1answer
285 views

Are all antennas traveling wave antennas?

I've been reading a lot about traveling and standing waves, and I am right now reading about traveling wave antennas, to my understanding ALL antennas should be traveling wave antennas, but this is ...