What is Square wave: Definition and 78 Discussions

A square wave is a non-sinusoidal periodic waveform in which the amplitude alternates at a steady frequency between fixed minimum and maximum values, with the same duration at minimum and maximum. In an ideal square wave, the transitions between minimum and maximum are instantaneous.
The square wave is a special case of a pulse wave which allows arbitrary durations at minimum and maximum. The ratio of the high period to the total period of a pulse wave is called the duty cycle. A true square wave has a 50% duty cycle (equal high and low periods).
Square waves are often encountered in electronics and signal processing, particularly digital electronics and digital signal processing. Its stochastic counterpart is a two-state trajectory.

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  1. L

    Square wave spectral components

    Why does a square wave contain only odd harmonics of the fundamental? If the even harmonics are low, how low are they. What happens to the even harmonics.
  2. T

    Expected power of a square wave

    Homework Statement What is the expected power of the first three frequency components of a square wave with an amplitude of 0.2V? Homework Equations None that I know of :( The Attempt at a Solution I'm not sure where to start with this since it seems to give me so little...
  3. O

    Trying to simulate a square wave. NOT WORKING

    For my extra credit project i am building a simple square wave osc i am trying to simulate the schematics in Multism, a program i just learned today. Here are the original schematics: more info on the circuit is found http://www.circuitstoday.com/square-wave-generator-using-ua-741"...
  4. T

    High speed sine wave to square wave converter

    Hi guys, I need to convert a sine wave to square wave, sine wave is running at about 1.5 GHz, so I had an idea of using comparator, but I am afraid that most of the conventional op-amps can't support my speed requirement. Any advice and reference circuits please.
  5. C

    Interference at Odd vs Even Harmonics: Is the Square Wave Really Square?

    If I look at the Fourier transform of the square wave signal, the peaks are at the odd multiples. In the device that I am working on, I would expect the interference at the odd harmonics of the center frequency. But I see the interference at even harmonics. When is this possible? (Only if...
  6. R

    Removing a DC Offset from a Square Wave Signal

    Suppose you want to look at a square wave signal riding on top of a large DC bias. This seems like it should be simple, but I was thinking about this today and I don't know how to do it. Normally, one would remove a DC offset with a high-pass filter (or just a capacitor). However, with a...
  7. F

    MATLAB Adding noise to a Square wave in Matlab

    Hi, I've got a square wave: x = square(2*pi*10*t); with time vector: t=0:0.001:2; I've also got a random noise signal: r=randn(1,10000); I want to add the noise signal to the square wave, but I can't add them because they aren't of the same dimensions. I know I can use awgn(x,snr) but I...
  8. G

    Can a Square Wave at 500 kHz and 2.5 kV Be Achieved?

    I've been told that a square wave at this speed and > 1 kV P-P won't happen, but I need one, and our lab has plenty of funding. Is this possible? Commercially available? If 500 kHz is out of the question, what about 100 kHz? Any information is appreciated--I don't know **** about electronics :(
  9. F

    Odd Square Wave Behavior in Lab Experiment

    So the other day in a lab my group was working with a signal and some noise and the signal we got was a bit interesting... Essentially we were using a white noise with 0.5 Vpp and a 1kHz square wave with the 10 times the amplitude (5V) running them through a 741 op-amp summing amplifier. We...
  10. X

    Help with fourier transform for special square wave

    I know how to describe a square wave with Fourier analysis, but what if I'm looking for a square wave with "peaks" that are longer than the "valleys." For example, from f(x)=1 {from 0 to 2}, f(x)=-1 {from 2 to 3}, f(x)=1 {from 3 to 5}, f(x)=-1 {from 5 to 6}... and so on in a periodic fashion...
  11. J

    Sine wave resonance using square wave input

    Hello All, I have been doing a few basic experiments with coils lately and I am trying to figure out the simplest way to drive a coil at its natural resonant frequency so that I can get the Q as high as possible. My only problem is that I don't have a sine wave generator that I can use. I...
  12. D

    Fourier Series Representation of a Square Wave using only cosine terms.

    Hello, I am attempting a past exam paper in preparation for an upcoming exam. The past exam papers do not come with answers and I'm a little unsure as to whether I'm doing all of the questions correctly and would like some feedback if I'm going wrong somewhere. Any help is greatly appreciated...
  13. Topher925

    How to remove 60Hz noise from square wave?

    I have an amplification circuit where I am essentially reading a somewhat deformed square wave and I am having a lot of trouble with 60Hz noise from the walls being superimposed on my signal. The signal of interest goes from 5v - 0v, has a period of about 60ms, and I need it to be relatively...
  14. E

    Synthesised Sine wave VS Modified Square Wave inverters

    I am to contrast the difference between modified square wave, and synthesized sine wave inverter outputs. Am I to understand, that a modified square wave output is like a square wave, but the transtion to current flow in the other direction is delayed some at the zero point. This is to give...
  15. J

    Square Wave Frequency Doubler using Op-Amps

    Hello All, Here is my challenge. I have an idea to build a square wave frequency doubler circuit using nothing but op-amps. The idea is to make a circuit that can exactly double the frequency of a 50% duty cycle square wave input of variable frequency, and produce a 50% duty square wave of...
  16. X

    Frequency of the square wave were chosen too high?

    What would the pattern look like if the frequency of the square wave were chosen too high? and too low?
  17. L

    Optimized Create 1kHz Square Wave Oscillator in Multisim

    Homework Statement The assignment is to create a square wave oscillator using an op-amp in Multisim. The wave's frequency should be 1 kHz and the duty cycle 60%. Homework Equations f = 1 / (R*C) R1 < R R1 < Rf I guess. The Attempt at a Solution Here's what I've done...
  18. S

    High Frequency Square Wave Generator: 500 MHz, 2 Channels

    Greetings, Sorry to bother you with such a trivial question, but I'm looking for a high frequency (>500 MHz) 2 channels square wave generator. Do you know any material (not too expensive if possible) that would match these specifications? Many thanks!
  19. R

    Square Wave Generator: Design Help for Senior Project

    im working on my senior design project and was looking for some help in designing a square wave generator that outputs a 32khz, 5Vpp square wave. i found a site that shows a circuit http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/square.html but when i connect the circuit for some...
  20. A

    Building a Basic Square Wave Oscillator: A Beginner's Guide

    Hi, I promise I did search for this before posting what I thought would have been something which had been answered before. Can anyone tell me how to build a simple square wave oscillator? Do I need a differentiator to get the straight vertical lines? I'd appreciate any help anyone could...
  21. K

    Troubleshooting an Odd Square Wave Oscillator: A Scientist's Analysis

    I found a schematic from the internet that was claimed to generate a square waveform at a decent frequency. I built the thing but it doesn't seem to work at all. I'll attach a picture of the schematic. Could you tell me what's wrong with it and if there is any other relatively easy way to make...
  22. B

    Applying a square wave (from 0 to 5V) on a RC circuit

    Hi, I am working with capacitor now and I have this question. I am applying a square wave (from 0 to 5V) on a RC circuit. At the output ( at the resistor) I get a positive and negative values? why is that ? I am suspecting the fact that the capacitor create a phase difference of -90...
  23. B

    Harmonics of a Square Wave

    Harmonics of a Square Wave... Homework Statement A 200kHz square wave with a fundamental frequency amplitude of 15V. Find amplitude of the third harmonic. Homework Equations This is what I do not know. I know this is a Fourier transform problem but just don't know what to do with...
  24. cepheid

    Sampling: Multiplication by Square Wave

    We are considering a system in which the input signal x(t) is multiplied by a periodic square wave s(t) in order to produce an output w(t). The input signal is band limited with |X(j\omega)| = 0 \ \ \textrm{for} \ \ |\omega| \geq \omega_M , where \omega_M is the bandwidth. We are supposed...
  25. G

    MATLAB Reducing Noise from Matlab Generated Square Wave - SNR 0dB

    I posted the details of myquestions earlier but no help. Maybe I need to rephrase it. I basically generated a square wave and added noise to it using Matlab. The question is how do I design a filter to reduce as much noise as possible to retain most of the square wave. The SNR is OdB...
  26. Z

    Build a filter that will accept a 200hz square wave

    i need to build a filter that will accept a 200hz square wave that will remove all harmonics other than the fundamental. there also needs to be an option to pass or block the dc value in the circuit. i understand the how to make the filter, but not the part about how i would have an option with...
  27. M

    How to Design an Oscillator for Producing Square and Triangular Waves

    I have a question as to how to design an oscillator that will produce a wave such as the one I have attached. It is a square wave, but with changing times, first half wave with time 20ms, and second half wave with 5ms. Also, how could i make this oscillator then produce a triangular wave.
  28. M

    Comparing Data from Rotary Arm Sensor to Theoretical Square Wave

    I have collected 5000 points of data from a sensor on a rotary arm (which I was trying to control to move with a position time graph that follows the pattern of a square wave) My question is, once I've plotted the graph in excel, how can I overlay a perfect (theoretical) square wave to show...
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