In signal processing, group delay is the time delay of the amplitude envelopes of the various sinusoidal components of a signal through a device under test, and is a function of frequency for each component. Phase delay, in contrast, is the time delay of the phase as opposed to the time delay of the amplitude envelope.
All frequency components of a signal are delayed when passed through a device such as an amplifier, a loudspeaker, or propagating through space or a medium, such as air. This signal delay will be different for the various frequencies unless the device has the property of being linear phase. The delay variation means that signals consisting of multiple frequency components will suffer distortion because these components are not delayed by the same amount of time at the output of the device. This changes the shape of the signal in addition to any constant delay or scale change. A sufficiently large delay variation can cause problems such as poor fidelity in audio or intersymbol interference (ISI) in the demodulation of digital information from an analog carrier signal. High speed modems use adaptive equalizers to compensate for non-constant group delay.
For a device such as an amplifier or telecommunications system, group delay and phase delay are device performance properties that help to characterize time delay, which is the amount of time for the various frequency components of a signal to pass through the device from input to output. If this timing does not sufficiently meet certain requirements, the device will contribute to signal distortion. For example, sufficient amounts of distortion equates to poor fidelity in video or audio, or to a high bit-error rate in a digital bit stream.
Phase delay directly measures the device or system time delay of individual frequency components. For a modulated signal, which must be demodulated to recover the original signal intelligence, group delay must be used with the modulated signal to determine the time delay of the demodulated signal.
Discussed in this article is background theory on a device’s phase response property, from which the device’s phase delay and group delay properties can be calculated exactly. The article then goes on to illustrate the theory and use cases of these related device properties.
Homework Statement
Hi, I would like to generate a random delay time and value in testbench. This is what I did:
for(i=0;i<300;i=i+30)
begin
j = i + {$random} % (300 - i) // MIN + {$random} % (MAX - MIN )
#j b = {$random} %3;
#3ns b = 3'b000;
end
I want to generate random...
Hi, a friend and I were talking and a question came up about a delayed force.
It goes like this:
This is hypothetical obviously.
You have the sun and the Earth pulling on each other because of gravity. (The force of the pull between them does not matter, it just has to be equal.)
The sun and...
In this thread in another forum, I calculated the coordinate speed of light as measured by a distant observer. As far as I understand it, the length contraction in GR is only in the radial direction, right? None tangent, correct? The time delay of light found, though, trying different examples...
I've been experimenting for hours, and my LED still won't light correctly when this method is used, and the fluke 87 reads voltage on the circuit in a non-logical way. Can you help? Here's what I have set up when using an online calculator:
Time delay: 2000 milliseconds
Power supply: 15v...
I'm a rising junior and will very likely apply to physics graduate school during senior year, but I'm also thinking about applying for a Fulbright Scholarship or other programs that would be a year long and not necessarily involve physics. Everything I found when I searched this forum said...
Hello,
A project I am working on currently requires me to test how capacitors in our circuit react to change in Humidity. As expected, the experimental results suggest that capacitance goes up with increasing humidity, as the electric permitivitty of air surrounding capacitor increases...
Homework Statement
[See attached diagram]
I'm trying to design a circuit that connects to the input terminals of the noninverting input of this comparator circuit such that:
-The input to my circuit consists of a SPST switch and a 9 volt battery
-When the switch is thrown on, there would be a...
Homework Statement
I am trying to calculate the delay of the inverter.
Homework Equations
The Attempt at a Solution
I tried to build the circuit in LTspice, but seems like I couldn't get anything useful from the plot. So I am hope somebody good in LTspice take a look with this and hope they...
I would like to know if the transmission delay of pressure give a differential force on an object ? Example: an object in water, we put pressure with mass over water at right at t=0s. The pressure at right is faster on the right side than the left side (d1<d2). The object seems to move with a...
I'm taking my first two engineering courses in the fall, but I'm thinking I might hold off now until I transfer. I looked up my teachers on rateyourprofessor.com and they both have received pretty abysmal reviews. Is this maybe student's normal reactions to their first engineering courses, or is...
Folks,
I have a query regarding the attached circuit.
In order to design a rectifier, I was trying different structures.
So, I started with the attached circuit without delay elements.
I have used a cap at the NMOS, so that the cap will gets charged. But I don't want the cap to discharge...
Homework Statement
Im trying to model this in simulink. I am having a little trouble getting things to work. I need to create a variable delay model or basically implement a "flanger" effect.
Flange
A flange is an audio effect, which is achieved by combining two identical signals with...
Yes, it is about OPERA experiment, but it has nothing to do with neutrinos.
Can someone try to explain how is it technically possible that faulty connection could be responsible for additional signal delay? I understand it can make the signal unreadable, but delayed by 60 ns?
Main reason I...
If it is : I would love someone to explain to me how it affect the redshift of galaxies.
If it is not : I will toss it in the pseudoscience box and not think about it again
Thank you
Guacamolewarrior
Delay Circuit with "Logical-Quality" Output?
Hi,
First of all, hello everyone (my first post here)!
I need to make a delay circuit for my car, but I need the transition time of the output voltage to be quick, because I will use the voltage to activate a power MOSFET transitor, which will...
I have a solenoid that is controlled by a PLC. I want to know what the delay time is from the time the PLC sends the signal to engage the solenoid to the time the solenoid is fully engaged. The time will be very short (milliseconds), but I need to know what the delay time is to within 5ms...
Homework Statement
Show that the group delay of an LTI discrete-time system characterized by a frequency response H(e^{j\omega}) can be expressed as
\tau(\omega)= Re\left\{\frac{j\frac{dH(e^{j\omega}}{d\omega}}{H(e^{j\omega}}\right\} .
Homework Equations
The...
A water glass (10 cm diameter at the top, 6 cm diameter at the bottom, 20 cm in height) is being filled at a rate of 50 cm^3/min. Find the rate of change of the height of the water after 5 seconds.
V=1/3(3.14) r^2h
I'm a little unsure how to approach this problem for two reasons. A) The glass...
For fun, I'm writing a simple special relativity simulator with a much smaller speed of light so that relativistic effects are clear even at low speeds. I already have time dilation and speed of light delay working. However, right now, the speed of light does NOT always appear to be the same for...
How much data could be theoretically and realistically stored in a hypothetical system consisting of a delay line loopback in the form of a long looped fiber optic cable?
My father and I were just having a conversation. The scenario he presented to me was this;
There are 2 ropes fixed on 3 points, like so:
A--------------B------------------------------------------------------------------------C
The distance of AB is approximately 10 meters, while BC is...
My grasp of physics is limited, however, I am an engineer, thus I am asking for other's assistance in understanding how to delay the annihilation of a virtual particle pair.
Most literature I've read, indicates a virtual particle pair is "real" if only briefly.
QUESTION: How long is...
If we where to make a wireless phone call to a planet 1 light year away the lag/time delay would be 1 year.
They would have to wait 1 year to hear what we say today.
But if we used a long (long is an understatement) piece of wire connecting the 2 phones, what kind of delay would there be...
How is comparator prop delay significant?
It's just delay, isn't it. Input occurs at say, t secs, output will occur at t+x secs.
I am looking for a high speed comparator, I don't understand why manufacturer's classify speed based on propagation delay. Isn't rise time the factor that decides...
Homework Statement
I am working on a project for my cosmology course. I need to determine the Hubble constant from time delay in a gravitational lens. We are using QSO 0957+561 for our data. My question is how do I determine the relevant distances Dl, Ds? I have Dls already. The...
Hi everyone,
First time posting, sorry if this is in the wrong format or wrong place. For a project in a cosmology course I need to find the Hubble constant from from time delay in a gravitational lens. the one we are using is QSO 0957+561. My question is how to I find the time delay from...
Homework Statement
Electrical pulses travel at about half of light speed through coax cables. Determine the pulse delay time for a cable with a length of 20 feet.
Homework Equations
The Attempt at a Solution
I don't think this question is very hard, but I can't find any...
[PLAIN]http://img96.imageshack.us/img96/7816/12530747.jpg
Hopefully this will post successfully...
Erm its the first part I'm not sure on, after that it's easy. I'm just not understanding the wording.
I need to work out the effective green time during the cycle
Im trying to design a circuit that will delay the turning on of a light.
I have three bulbs, one should turn on as soon as power is applied, the next should turn on in X amount of time after the first, and the final light should turn on in X amount of time after the second.
Basically like this...
Ulcerous delay of "The Hobbit"!
Yet another damn delay!
Now, it is Peter Jackson who has developed a stomach ulcer.
I want that film to be made NOW! :grumpy:
http://www.theonering.net/torwp/2011/01/26/41910-sir-peter-jacksons-stomach-ulcer-scare/
http://www.statesman.com/blogs/content/shared-gen/blogs/austin/politics/entries/2011/01/10/delay_appears_in_court.html?cxntcid=breaking_news
If we started sending more politicians to jail, perhaps they'd be more honest.
Hello,
I know that time dilates while approaching the event horizon of a black hole, but explanations failed to make me understand HOW MUCH of each phenomena causes this as an object approaches the EH.
On the one hand there is photon delay due to gravity acceleration approaching the speed of...
Can someone please tell about the Dayton 2A562 Time Delay Relay.
Does it wait 3 to 60 seconds before powering on, or does it wait 3 to 60 and then power off?
I am looking for something that will run for 3 to 60 seconds and then shut off.
thanks
Hi,
Just wondering if anyone could give me a few pointers in the right direction for this... thanks!
Homework Statement
Incredibly long problem statement so I'll summarise and ask more about the concept:
I have a Plant and Controller set up in the form of a usual control system. The...
Hi ;)
I'm new on the forum
I have a question in fluid mechanics:
A tube of length 1500 meters has water inside at 1 bar of pressure.
A time t=0s we put 100 bars of pressure in a side close to the left end of the tube. The pressure will be at the other side at time t=1s because it's the speed...
Homework Statement
A plane is moving at 600m/s with respect to the ground. According to clocks on the ground, how much time would it take so that the plane's clock is delayed by 2 microseconds? Homework Equations
Lorentz transformations.The Attempt at a Solution
Let O be a reference frame on...
Hello all,
During the course of a calculation I was doing for my research, I derived a delay integral equation of the form
g(x) = \int_0^1 dy K(y,x)g(x-y)
where K(x,y) is a known, but somewhat ugly, kernel that has a (1-y^2)^{-1/2} singularity, but is integrable such that \int_0^1 dy...
Homework Statement
The symbol z = e^(iw) is called the delay operator. Explain why (in terms of the phasor) z^(-k) corresponds to a delay of k sampling intervals.
The Attempt at a Solution
We really have only discussed how to manipulate the filter equations, not really waht teh delay...
Hello,
I'm looking for some help with a (hopefully) simple EE question regarding a DC circuit. I'm a chemical engineer and it's been a while since elec/mag physics for me :-) Here goes:
In my life outside engineering, I run a small ambulance service. Our ambulance has a rather annoying...
A lighter topic than we usually do here, but...
http://www.usatoday.com/travel/flights/2010-03-24-us-airways-delay-rule-exemption_N.htm?loc=interstitialskip
The argument is three-fold:
1. Tarmac delays due to the weather are not our fault.
2. Tarmac delays in Philly due to overcrowding of...
its a long post i for the question i ultimately ask i know, but i would really appreciate some advice. I t
recently graduated, and have been applying to phds but I have been finding that the thought of commiting to a phd doesn't excite me at present. genuinely think that if i get an offer i...
hi all,
I have a problem using the MATLAB dde23 solver to evaluate the delayed HR model:
dx/dt = y(t) - a*x(t)^3 + b*x(t)^2 - z(t) + e (x(t-tau) - x(t))
dy/dt = c - d*x(t)^2 - y(t)
dz/dt = r [ s*(x(t) - xo) - z(t)]
how could I set the history values (-tau<t<0)?
it is...
Here is convolution:
c[k]= (0.5)^k * delta(k-1)
What do I do about delta(k-1)?
I know if it is c[k]= (0.5)^k * delta(k), then it just equal (0.5)^k
But what do I do with delta(k-1)?
Hi,
I'm trying to take this Sellmeier equation,
n^2 (λ)=1+ (B_1 λ^2)/(λ^2-C_1 )+(B_2 λ^2)/(λ^2-C_2 )+(B_3 λ^2)/(λ^2-C_3 )
for which i have several sets of constants for prospective glasses, and convert it into a group delay dispersion graph, with axes of fs^2 vs wavelength.
How do i...
Hi there PF. I was wondering if there was a C++ command that delayed a command being run for a certain period of time. I'm trying to make a program that outputs the lyrics to a song at the right times.
In Cadence we built a CMOS inverter. I made a transient response graph showing the input and output voltage waveforms. We're supposed to measure rise delay and fall delay of the output voltage. How do I do this? I heard from someone else that it's where the graphs cross 1.5V, but I'm still...
right... i need to make a programmable digital delay circuit that can delay a pulse by a few nanoseconds. sorry if any of the following info is vague, I am only an apprentice and i have taken this on as a college project, but the poduct will be used at work in a calibration lab, but i am not too...
Here's something I've been wondering about for some time.
How long does it take a cell to produce a string of amino acids?
More spesific: The duration between the DNa beginning to make the RNA string and the string of amino acids being delivered?
Here is an excerpt from Wikipedia
The Shapiro time delay effect, or gravitational time delay effect, is one of the four classic solar system tests of general relativity. Radar signals passing near a massive object take slightly longer to travel to a target and longer to return (as measured by...