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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1answer
43 views

how to reduce signal noises

I am trying generate guided waves on simple metallic plate through piezo-ceramic material, I place two piezo on the surface of the plate at the different location and through Arbitrary pulse generator,...
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1answer
48 views

Conceptual question about Frii's equation

That's a pretty basic one but for some reason I am stuck now: Suppose I have a transmitter that transmits Ptx=4W_EIRP with an ideal, omni-directional antenna. The power applied to the antenna ...
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4answers
75 views

Average of flipped square wave

So I need to find what will be the average of a flipped square wave. I know that the high amplitude is 15V and the low amplitude is -9V and the average of the original signal is 2V. What will be the ...
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2answers
206 views

Propagation 'speed' of EM waves in air versus through conductive material

This paper I was reading said: "At a high level, the propagation speed of EM waves through conductive materials is SLOWER than their speed in air". Don't conductive materials intrinsically have less ...
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3answers
346 views

Why phase is the position of the waveform relative to time 0

I was reading a book which says: Phase describes the position of the waveform relative to time 0. It indicates the status of the first cycle. and below is a picture I am a little bit ...
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1answer
53 views

Cut-off frequency in ideal waveguides

it is known that in an ideal waveguide (with a perfect electric conductor and with non-dispersive and non-conductive dielectric) there is a cut-off frequency, for each mode, such that for higher ...
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0answers
69 views

Analogy to explain why an antenna must be (in order) size of wavelength

An antenna has to be sized on the order of the wavelength because we want waves to form. Waves mean, very roughly speaking, different "state" (current, voltage, water level, ...) at different ...
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2answers
328 views

Distance requirements in antenna arrays?

Antenna array is a broad term and it encompasses at least the following concepts: MIMO or massive MIMO: for spatial multiplexing beamforming: increasing the SNR (at transmitter or receiver) by ...
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2answers
132 views

Wave Propagation in Transmission Lines

let's consider this image (from AAC book, see here) The author wanted to show that a transmission line propagates not only voltage and current waves, but also an electromagnetic wave in the space ...
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1answer
45 views

Antenna's resistance: meaning and evaluation

When I studied elementary antenna's theory, I saw that the resistance (for simplicity let's consider only the resistive terms) of an antenna Ra is made of: 1) a parasitic resistance Rl, which causes ...
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2answers
140 views

Square wave generator won't work

I'm trying to generate a square wave at 21kHz (+13V,0V) using this schematic: I used formulas and this website to find the correct values for my components but it doesn't seem to work on Simetrix. ...
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1answer
96 views

Does a pcb as patch antenna isolate itself?

I'm currently working on a prototype patch antenna for UHF. Since I'm out of copper at the moment, I used empty PCB's as base material (don't mind the PCB in between, it's only a spacer): So now my ...
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2answers
100 views

1v square wave generator

I'm trying to create a square wave form from a single AA battery, say 1v. I came across an IC which is essentially a low voltage 555 timer: Semtech SX8122 however it is marked obsolete. I would like ...
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1answer
342 views

How to generate a controlled frequency sine wave using a microcontroller like PIC18F4550?

I'm designing a phonic wheel emulator. I have a PIC18F4550 and the following power supplies: +5V, -5V, 12V. I need to geneate a sine waves from frequencies near 500Hz up to approximately 8kHz. The ...
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1answer
69 views

Magnetic Monopoles and Magnetic Current Densities

I see that in electronic engineering the Maxwell equations are written with also some terms which represent the magnetic charge and the magnetic current densities. I was told they are inserted only to ...
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1answer
15 views

Voltage/Current waves on N port networks

I have a doubt about the sign convention for waves in an N port network. Consider for instance the following 2-port network: How should I fix the directions of voltage and current to calculate powers?...
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1answer
248 views

Quarter-wave impedance transformer working principle

consider the following scheme: A transmission line of length lambda/4 has been put before the load ZL in order to get an impedance matching. But, I do not understand how it works. Precisely, by the ...
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1answer
83 views

Rat Race (Hybrid 180°) Scattering Matrix

why the S matrix of a rat race is the following one? Which is the reasoning for determining it?
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1answer
121 views

Radar and Standing Waves

I have a doubt about the working principle of a simple Radar. Consider a stationary object, which does not move with respect to our transmitter. We send an electromagnetic wave to it, and it will ...
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0answers
21 views

Conductance curve for SPUDT with only one peak

I am trying to reproduce the results obtained by Morgan in his book on surface acoustic waves using the RAM model to analyze a DART kind IDT (p.270). In his book the curve he gets is double-peaked ...
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1answer
69 views

How to transmit a signal to a point [closed]

I have a signal generator (Digital Dual Channel Funktion Signal Generator) and want to generate two signals (530 and 550 Khz signal) and want to transmit these generated signals to the points on a ...
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1answer
161 views

Peak Detector with Reset

I'm trying to make a N.Peak Detector with reset functions. I've tried various modification to the classic peak detector without any success. What I'm trying to accomplish is: Detect the negative peak ...
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1answer
130 views

Triangular wave amplification

I've made a triangular wave by ICL8038 and it works perfectly at 15kHz with 15Vpp. I need to drive a 4 ohm load by that triangular wave. Could you please show me a solution/circuit to do that?
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1answer
29 views

Directional Coupler Terminals

I have a basic question about directional couplers. In this scheme each port is represented by one wire. What does it mean? The other terminal of each port is GND for all?
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3answers
683 views

How to produce sawtooth waveform from square waveform?

I have a question pertaining the changing of square waveform to sawtooth waveform using OpAmp. Following the picture below, I have to create a sawtooth waveform from a square waveform. It seems that ...
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2answers
90 views

I need an equation to calculate the time for a power percentage of a half cycle sine wave into a resistive load

I need to calculate the time a thyristor/triac needs to be on for a desired percentage of full power of each half cycle of the AC line input. On for the full half cycle will give me 100%. On for 1/2 ...
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3answers
603 views

How Much Current is Usually Used with IR Transmitting LEDs, in Remote Controls?

If you take various Remote Controls from your home, such as for a TV, Audio System, TV Box, etc, and measure the current that is supplied to the IR LED in the remote, what would be common current ...
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1answer
36 views

TOA distance resolution

As far as I could understand, TOA systems, abstractly, work by measuring the time it took the wave to transfer from a transmitter to a receiver and multiplying it by the speed of the wave in the ...
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1answer
53 views

Alternating Voltage

Is AC the same as an alternating voltage ?
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0answers
439 views

How to make a piezo speaker louder with 5V?

I have connected a tiny piezo pc speaker (https://sktechworks.ca/wp-content/uploads/2017/11/Speaker.jpg) to an arduino and used to tone command to play a simple melody in repeat (square wave only ...
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1answer
127 views

Cut-Off Sinusoid or Sinuosoid?? - Standing Voltage Waves on Transmission Lines

My textbook shows two diagrams that appear to contradict each other to me. Each depict the magnitude of the standing voltage waves on a transmission line. The first, fig 2-14, shows a sinusoid bounded ...
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4answers
158 views

Sinusoids represented using Euler's formula notation, confusion

EM plane waves are represented using the equation (ignoring amplitude) $$E(x,t) = e^{j (wt - kx)}$$ They are also represented in this form: $$E(x,t) = \cos(wt - kx)$$ I want to get the electric ...
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1answer
210 views

Generating square wave using NXP LPC1768?

I am reading a book that teaches about programming the LPC1768. I have the following exercise here: Using any digital output pin, write a program which outputs a square wave, by switching the output ...
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1answer
195 views

How to generate a high energy electromagnetic wave? Using high voltage or high current?

I am about generating an electromagnetic wave which should be powerful enough. So I should manipulate its electric field and magnetic field simultaneously. As far as I know E amplitude depends on the ...
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1answer
70 views

How can I turn off automatically, say after a fixed number of cycles, a 555 in astable mode?

I looked at the answer to "How to turn a 555 in astable mode into a decaying square wave" but this is really for an input to a speaker. I want the input to go into a counter to count the number of ...
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1answer
52 views

A wave generator of 64db max and an omnidirectional antenna of 3.2db what db can have max?

I have this wave amplifier of 64db max and an omnidirectional antenna of 3.2db and I have to transmit a sine wave of 82Mhz, are they suitable for me? What is the maximum gain I can get? I need at ...
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2answers
80 views

Effect of wall location for guided wave attenuation

Pardon my ignorance here if this has already been answered. I'm not fully familiar with the English terminology here so my searches came up empty. If there is any keyword I’m missing or I’m not using ...
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1answer
67 views

Is it possible to generate user-defined signal using an android phone?

Is it possible to generate an electronic wave signal using an android phone? (Theorically) For example by customizing the firmware can I produce some signals like \$ f(t)=2 \sin 3.2×10^9t+3\cos 5×10^...
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1answer
50 views

wave propagation ( pict) [closed]

Can someone explain to me what is a meaning of the starred items in this picture?
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1answer
86 views

Why does this “square wave” have what seems to be a charging action on it's leading edge?

I'm trying to produce a basic square wave output across a resistor from an ATMega328P Xplained mini. VCC is 5 V. Setup: Code: (Stuff with DDC/PORTB is just to control the onboard LED) ...
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1answer
122 views

The wavelength region of the IR sensor

I was reading an article that explains the Infrared sensor until I came to the wavelength region's section, which has been mentioned as the following: The infrared waves typically have wavelengths ...
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1answer
435 views

10MHz Sine Wave Generator

I have been looking for some time for a good design for a ~10MHz sine wave generator, with variable frequency from about 5-20MHz. The max required peak to peak amplitude is 10V. Many suggestions on ...
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3answers
98 views

Is a modern radio wave broadcasting station a very fast spark gap transmitter?

In a spark gap transmitter, is that a "real" radio wave that is produced? I know you can hear it on an AM radio, if you are close to the gap, but is it a radio wave the same as from a radio station? ...
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1answer
62 views

Electromagnetic wave equation for GPS waves

Recently, I came across a source which stated the model of a GPS L1 wave was: My question is, how was this equation derived?
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1answer
238 views

Calculate radiation power of an antenna in respect to a given antenna radiation pattern and a given angle

I work on a program that simulates the wave propagation of high frequency electromagnetic waves (2.4 or 5 GHz Bands) in 3D. I use a ray launching approach, where the emitted rays approximate the ...
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69 views

Why does the solution to the wave equation define two directions?

I've been studying transmission lines recently and I'm struggling to reconcile my intuition with the derivations. Take the form of the general solution to the wave equation given on this page antenna ...
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1answer
445 views

How to flicker high-power LEDs with precise square or sine wave?

I need some advice regarding a setup with high-power LEDs I am currently working on. My aim: I have a set of 6 high power LEDs (http://www.roithner-laser.com/datasheets/led_highsingle/apg2c3-530.pdf) ...
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1answer
222 views

EHF RF Transmitter and Receiver

We are working on a blood glucose meter that will measure BG readings through radio waves with a frequency between 60-70 GHz. That range is necessary to allow penetration through the tissue and we ...
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1answer
385 views

Length of the dipole antenna

I know it is really stupid question, but I can’t understand. I have a picture with dipole antenna (different length). If I have the current distribution along the length, that it is easy to determine ...
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1answer
107 views

Confusion about what EM fields really look like, and how that relates to data transmission, waveguides etc

After a discussion at work a few days ago, I realized I don't have a very good understanding of what RF energy is truly like. I've always thought, via physics and EE classes, that all EM waves (...