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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29
votes
7answers
66k views

What exactly are harmonics and how do they “appear”?

From reading so many sources online, I still cannot grasp why a different waveforms have harmonics. For example: when designing a silly amplitude modulation (AM) circuit that puts a square wave from ...
1
vote
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 ...
18
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4answers
3k views

What is the function of a Fourier Series?

What is a Fourier Series? What it is used for?
1
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7answers
13k 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 ...
4
votes
3answers
4k views

What will I see in oscilloscope when attempting to analyze Bluetooth or Wi-Fi signals?

I would like to know what will show up if I put bluetooth or wifi carrier signal (2.4GHz family) in a say 50MHz oscilloscope? Am I going to see something like a rectangular block? And the only ...
14
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3answers
30k views

Changing a Signal's DC Offset

I have a square wave being generated from a waveform generator oscillating between 0 V and 5 V. The generator does not support negative DC offsets. I need to shift this signal down to be centered ...
2
votes
3answers
7k views

Square Wave Amplifier - 5VDC -> 13VDC

I want to have a square wave that goes from 0 VDC to 5VDC go through some sort of amplifier and that amplification takes that same wave ( at a frequency of 1200Hz but could also be adjusted later ) ...
-2
votes
2answers
212 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?
21
votes
3answers
55k views

How to read serial data from oscilloscope

I have a microcontroller (PICAXE 20X2) and a pot meter. I programmed the micro so that it sends any change of pot meter to serial port of PC. Obviously it is a 8bit ADC. Now the interesting thing for ...
7
votes
6answers
4k views

Why is “wavelength” used as a unit for the length of an antenna?

We often refer to antenna size relative to wavelength. For example: a 1/2 wave dipole is approximately half a wavelength long. Wavelength is the distance a radio wave travels during one cycle. (...
2
votes
3answers
6k views

Making a Triangle wave on LTSpice using LM741 opamp

I'm trying to get a 1kHz, 15V triangle wave on LTSpice. For that, I'm using the following design: So far, my Square Wave has the desired frequency and amplitude, but my triangle wave has a lower ...
5
votes
2answers
5k views

Why Periodic Signals has only integer frequencies but non-periodic does not?

Why does a periodic signal only has integer frequency values while a non-periodic one has all real numbers as frequency values? The frequency is just the number of times one full cycle has happened ...
4
votes
6answers
2k views

Why does more bandwidth guarantee high bit rate?

The definition of bandwidth is frequency range and it seems to be correct to say that higher bandwidth guarantees higher data rate. However, i do not understand why it does. Data rate depends on ...
4
votes
3answers
5k views

How does an swr meter directional coupler work?

How does the directional coupler in an swr meter work? How are the forward and reflected waves separated out from the standing wave on the feeder? I would like an answer in terms of sine (or cosine) ...
4
votes
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....
3
votes
2answers
5k views

QAM modulation - how data in different frequencies are laid out?

I know that QAM modulation uses a change in phase and amplitude to send data. But We use a series of frequency spaces as bandwidth to send data. However, we know that different frequencies oscillate ...
3
votes
2answers
63 views

Why does lumped discipline not hold as dimension approaches operating signal wavelength?

I'm studying some basic introduction to the lumped matter discipline on my own. I completely understand where the first two constraints come from (i.e. lumped matter can only interact through their ...
3
votes
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 ...
1
vote
1answer
7k views

How to make sawtooth wave from square or triangular wave?

I know it is easy to convert a square wave to a triangular wave by an integrator. I know also that they can be made out of Harmonics but I don't know how to make a sawtooth wave form. Having a ...
1
vote
2answers
479 views

Sine Oscillator - for audio frequency

I'm looking to create several sine waves on a single circuit. All must be under 20Khz frequency and each must be unique. Mostly it will be 5-10 frequencies needed. As I found - almost all crystal ...
0
votes
4answers
2k views

Amplify Square Wave with Simple Mofset Circuit

I am a hobbyist. I have a square wave being generated by a 5 volt Arduino. (I tried a 555 circuit but I couldn't get it at an exact square wave.) The Arduino square wave runs from about 2 or 3 volts ...
6
votes
2answers
2k views

How to generate 30Hz sine wave?

I'm building a voice ring modulator. Part of it involves a 30Hz carrier sine wave to modulate the voice with. Since I'm trying to build a portable device it will be DC powered, and since a function ...
3
votes
3answers
130 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
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2answers
3k views

Why does the length of an antenna, relative to the wavelength, matter?

I cannot understand following wikipedia illustration: It shows the antenna at right angles to the direction of travel of the EM wave. The wavelength is measured in the direction of travel. So why ...
1
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1answer
1k 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 ...
1
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3answers
4k views

What role does the capacitor play in an AM demodulating circuit? [closed]

The goal of this question. Demodulate the AM signal. (Please assume a diode demodulating AM radio of the most imaginable simplicity.) I am assuming an alternating current sine wave is coming into ...
1
vote
5answers
165 views

Making a square wave which has two different kinds of pulse width

I am going to make a square wave which has two different kinds of pulse width.At first,i think i can use the digital logic gate to finish it,however,after taking lots of time for trying,i still can't ...
0
votes
1answer
67 views

Two simulations are different. Mine V.S. Paper's

Paper Link : http://rincon-mora.gatech.edu/publicat/cnfs/new16_pzdamp.pdf After reading the Fig3 (Asymmetrically pre-damped piezoelectric charger),explanation of its process,i make a schematic(a.) ...
0
votes
1answer
137 views

Simulation is the same as my thinking,but different from the pape r(charging loop)

This question has already perplexed me for a long time ,after simulating it, the simulation is the same as my thinking,but different from the paper.So now i am confused who is right. There is energy ...