Signal Definition and 935 Threads

  1. P

    2.4GHz radio signal through small gaps

    For an engineering project I am trying to place a 2.4GHz RFID tag inside a resin casting of a large seaside pebble. However since the resin is less dense than a real pebble, I need to add some mass of metal (since is is much denser) to the resin before it sets. It is crucial for the casting to...
  2. M

    Z-transform for a signal with an unknown sampling rate

    Homework Statement Given a ramp function x(t) = t*heaviside(t) with the known z-transform ( z / (z-1)^2 ). If the time-domain signal has been delayed by 2 seconds, then sampled with an unknown sampling rate (T). How could I get the z-transform (one-sided) for the discrete signal, for any values...
  3. K

    Plot signal from list of data in MATLAB

    I want to load a .mat file which contain 500 column of data in it and plot the signal out through the GUI using .m file. Can anyone help me on the code?
  4. M

    Transmit Digital Signal using Analog Modulation?

    Hello, I know that you send digital signals using ASK, FSK, PSK modulation. I was wondering though if it was possible to send that same digital signal using FM or AM modulation? If not, I was wondering if anybody knew of any popular ASK or FSK modulation IC's? Thanks!
  5. B

    Generate 3MHz Signal from 9V DC Voltage

    Sir, I want to convert a 9 V dc voltage into a 7 V AC Voltage at a frequency of 3 MHz. Please help me on this. How can I do that?
  6. S

    How to test whether a signal is periodic or not?

    Hi all, let's say I have generated some discrete data as a function of time. And when I plot it, it looks like that it is periodic. Is there any scientific way to check whether or not the discrete data is really periodic? And determine the period, if possible? Many thanks.
  7. M

    Pressure Signal Processing: Integration, Differentiation, RMS, Smoothing

    I want to ask how to process a pressure signal so that the signals can be smoothed / linearized, e.g. integrate, differentiate, rms, additive smoothing?
  8. N

    Signal to interference ratio for CDMA

    Hi, I am doing a project on communications engineering. I've done some background reading on CDMA and spread spectrum technologies such as Direct Sequence and Frequency Hopping. My project supervisor has asked me to find out the equation for the signal to interference ratio of CDMA systems...
  9. J

    How Does Gradient Direction Affect NMR Signal Characteristics?

    Suppose that you obtain a one dimension magnetic resonance image from two water-filled cubic shaped containers arranged as shown below. This diagram is a cross-section of the cubic containers in the x-y plane. figure description: -one of cube's is 2 cm wide, the other is 1 cm wide, and...
  10. L

    Decaying signal resonator power

    I am measuring the reflected power of a resonator for potential wireless applications. I'm pulsing the resonator with a 10.64GHz (resonate freq) pulsed waveform (10ns pulse width, 200ns period). Use an oscilloscope, it's easy to see the reflected pulse - with a maximum voltage just after the...
  11. E

    Career Opportunities in Signal Processing and Machine Learning

    Hi all, I'm considering doing a masters in either signal processing or machine learning. I have a bachelor's in electrical and electronic engineering, and have a bit of experience (internships mostly) in both industry and research. I was wondering if there are a lot of career opportunities...
  12. W

    Using a computer as a signal generator

    Hello. I am trying to build a version of a Chladni plate, which is a device that uses a modified speaker assembly to mechanically resonate a dish containing salt or some other powder. When the input signal reaches the resonant frequency of the plate, crazy patterns start to appear in the salt...
  13. S

    How Do Random Signals Differ from Random Processes?

    What is the difference between Random Signal and Random Process? A random process does not necessarily imply and ensemble of random signals. Is this correct? M
  14. M

    MATLAB: output the frequency components of a DTMF signal

    Homework Statement I badly needed an urgent help in Matlab. I have to create a Matlab function (M-File) that will output the low (flow) and high (fhigh) frequency components of a DTMF signal given the numeric symbol (x) (* and # not included). I don't even know where to start since...
  15. P

    How Fast Does an Electric Signal Travel in Different Wires Compared to Light?

    What is the speed of propagation of an electric pulse compared to the speed of light: - In a normal copper wire. - In a superconductive wire.
  16. Z

    Learn How to Sketch a Signal with Step-by-Step Instructions

    Sketch the following signal u(t-3)-2u(t-8)+u(t-5) if it was u(t-3)+u(t-5) I'd be able to sketch it, but the 2u(t-8) is confusing me help me :( I can draw the first part u(t-3) how do I add the second to the graph and then the third
  17. B

    Fourier transform same as signal.

    Hi friends, I was looking for signals which will have themselves as the Fourier transform. Few of them are given below. \frac{1}{\sqrt{2\pi}}e^{-\frac{t^2}{2}}\longrightarrow e^{-\frac{\omega^2}{2}} \sum_{k=-\infty}^{\infty}\delta(t-kT)\longrightarrow...
  18. S

    Cleaning Up Signal Distortion Using FFT: Devising an Effective Method

    Homework Statement hello! i'm given a signal h(t) = v(t)*g(t) where g(t) is a distortion/noise that got added and has a very low frequency compared to v(t) i need to devise a method to clean up g(t) The Attempt at a Solution i'm thinking of to do the fft on the signal h(t)...
  19. S

    FFT Signal Processing to Clean Up Distortion/Noise

    hello! i'm given a signal h(t) = v(t)*g(t) where g(t) is a distortion/noise that got added and has a very low frequency compared to v(t) i need to devise a method to clean up g(t) i'm thinking of to do the fft on the signal h(t), and remove the lower frequencies and do the inverse...
  20. J

    MATLAB Solving Signal x(n) with DFT in MATLAB

    hi everyone, I need help in a project.I have a signal x(n)=(0.5^n)*u(n). i want to find the DFT of the signal for N1=50,N2=20,N3=11 and then the reconstruction of the signal. I don't know anything about MATLAB and i don't have any idea how i'll do this. My problem is the code so if someone can...
  21. S

    IR led signal distance,Omron PLC reset

    Hi, I have 2 questions here and hope some experts can answer them. Question 1: How to improve the signal distance of the IR led?What parameters in the datasheet that we should look into? I have purchased few IR leds but all of them can't shoot more than 3 metres. I noticed increasing...
  22. S

    AC+DC signal equation=> Then Filter AC signal= output only DC signal visible

    Dear friends, I would like to know how can I remove an AC signal from a signal which is combination of AC+DC. AC signal 60V/50Hz DC=50V. Please suggest me a C code or any algoritham or a filter which can remove AC signal completely and I should be able to see only DC...
  23. S

    Height affecting wireless signal

    Hello. I went to get a new router because I finally decided to get wireless. I got a Linksys WRT120N which supposedly has a decent range, according to the sellsman. On my apartment the router is about ten meters and has a couple walls between it and the computer. The computer receives really...
  24. S

    Hypothetical question on signal propagation

    If you connected a DC or AC source to the end of an single, infinitely long, straight wire suspended in free space (separated from anything), would propagation occur along the line?
  25. B

    What is the Energy of a Signal with Rectangular Components?

    Homework Statement Given two constants, A and B, what is the energy of the following signal? f(t) = A*rect(t) + B*rect(t-0.5) Homework Equations E_f = \int_{-\infty}^{\infty} |f(t)|^2 The Attempt at a Solution E_f = \int_{-\infty}^{\infty} [A*rect(t) + B*rect(t-0.5)]^2 dt =...
  26. E

    Audio Signal Processing: changing spectrum directly

    Hi all, I'm having some trouble understanding the consequences of directly changing the frequencies in the spectrum of an audio signal. Let me give you an example: Let's say I have some audio signal, which I convert to a spectrum (in LabView, using a direct cosine transform (to avoid...
  27. M

    What is the fundamental period of 3cos(1.3PiN) - 4sin(0.5piN + 0.5Pi)?

    Hi all, First post here for me. 1. Problem Statement Find the fundamental period of: 3cos(1.3PiN) - 4sin(0.5piN +0.5Pi) 2. Relevant equations: T = 2PI / w 3. My attempt: Not sure how to proceed. By themselves the fundamentals period would be: 3cos(1.3PiN) w = 1.3Pi...
  28. M

    Low Signal Amplification: OP-07 & LM324 Preamp

    Do opamps amplify lineary down to very low signals like a few microvolts, the OP-07 for eg. I have an LM324 in moving coil phono preamp and the + input in which the AC coupled signal is going to is also connected to the + supply(6v) thru a 100K resistor. Is this to bias the opamp input because...
  29. K

    What can be a signal sweep used form?

    So I have access to a signal generator and a spectrum analyzer and one of the SG functions is to generate a sweep. Let's say the frequency starts from 50 MHz and goes up to 100 MHz, the amplitude can also be a sweep from one value to another The thing is what applications can that feature...
  30. D

    Why an antenna cannot receive analogue baseband signal of 0-4000Hz?

    Modulation is the process of impressing an information bearing signal to a carrier for effective transmission over a long distance. example Am and FM used in radio transmission Analogue baseband signals of 0-4000Hz are shifted to 60-64Khz range. Communication systems often do not carry...
  31. N

    Average power of sinusoidal signal

    Homework Statement Question: Consider the sinusoidal signal: A*cos(\omegat + \phi) Determine the average power Homework Equations This is my first real attempt in signals and I am really confused with the question... I guess my question would be am I suppose to take the P = lim as t->...
  32. A

    How Do You Calculate the Average Power of a Non-Periodic Signal?

    Hi, I'm wondering how do we calculate the average Power of a random (non-periodic) signal. I know how to do it if the signal is periodic, but with a non-correlated Gaussian signal I'm a bit lost. Can anyone shed some light? Thanks,
  33. W

    How to Block a Wireless Router Signal: Help Needed

    i am new , so i am not sure if this is the rite place. my Question i want to show my students how to block the signal coming from a wireless router. Pl help!? i have tried wrapping the antenna with aluminium foil and putting the whole modem in an aluminium container, none of...
  34. J

    Analog Signal Loop/Switch Control?

    Analog Signal Loop/Switch Control? Hello fine people of this board. I have been working on a custom project here for a year or two and I'm stumped at this point. I am working with 16 analog sensor/signal loops (16 ins and 16 outs). There would be 2 main signal inputs, and 2 signal outputs...
  35. M

    Identifying & Synchronizing Signal Phase for 60 Hz Cancellation

    Signal phase To cancel out 60 hz from my signal source(dynamic mic) I need to use an instrumention amp with another 60 hz source. How would I make the generated 60 hz have the same phase as the noise 60 hz?? and also do both signals have to be the same amplitude for this to work well?
  36. B

    Signal Frequency: Are Frequencies Always Present?

    signal frequency! suppose we have a signal varying randomly in amplitude with time...when we plot the frequency responce of this signal , we get a bandwidth of frequencies...My question is ' are all these frequencies present at all times??', or 'at any time , say t=to , only one of these...
  37. M

    Improve SNR Microphone Amplifier: Opamp Tips

    What are some ways to improve signal to noise ratio for a microphone amplifier, beyond getting low noise components. My amplifier is a single opamp.
  38. J

    Understanding Signal Distortion & Phase Shift w/ Resistor/Capacitor Circuits

    Statement: Capacitance and inductance in a circuit allow different frequencies to travel with differing degrees of attenuation and phase shift. This causes the received signal to be different from the signal sent. Question: With low and high pass filters, we can control what kind of signal...
  39. 0

    Signal that is a sine wave plus an offset

    I have a signal that is a sine wave plus an offset. I would like to measure the dc component and possibly also subtract it from the signal later. The signal is very slow (10th of Herz) and the offset changes on the order of minutes. I thought it should be possible to get a time average with an...
  40. B

    Is a Career in Digital Signal Processing Right for You?

    Career in DSP! I am doing b.e electrical and electronics from bits-pilani , india. I have just completed my second year. I had a course on signal and systems(fourier, laplace, sampling etc.) in my fourth semester.It has aroused my interest in dsp field. Can anyone here guide me on how to...
  41. S

    Signal Addition: Beginner FAQs | Learn About Signal Sum

    I am just a beginner in Signals and systems... In signal addition when we add two signals for example u(t) and u(-t), we are supposed to just add the values of both the signals at each and every point to get the sum,right? so in the case of u(t)+u(-t), what will be the sum value at t=0? Is it...
  42. N

    Fourier transform of tent signal

    Hello, I'm having an issue with a given problem. Homework Statement Using Parseval's Equation find the energy of the signal z(t)=\frac{4}{4+t^{2}} Homework Equations The book solves that problem by using the tent signal CTFT and duality property (i.e ). However that properly...
  43. C

    [VB6] Loudness of the microphone input signal.

    I am trying to create a program that would register it in a variable, when loudness of the microphone input signal exceeds some level for some amount of time. IS there a VB6 command that can allow me to measure the loudness of the input sound signal? Not on the sound card input. I have a...
  44. R

    Data collection - noisy signal - how much noise is acceptable?

    I'm collecting voltage data, and I need a resolution of at least .05mV, which I think I can provide over the range of voltages with my inexpensive A/D board. The problem is, the signal fluctuates maybe 1mV up and down, and so I get a noisy signal. I've tried running a low-pass filter through it...
  45. H

    Derivative of a signal: is it right?

    Hi everyone! I was trying to solve an old exercise but in a different way. It asks to find the signal x(t) given the graphs of |X(f)| and arg[X(f)]. Please refer to the attachment. My stategy this time is as follows: 1) find D(f) by deriving |X(f)| 2) antitransform D(f) and get d(t) 3)...
  46. T

    Limits of pitch and time resolution in signal analysis (FFT/SFTF)

    With DFT/FFT/SFTF or similar Fourier transforms, there's always a trade off between frequency and time resolution. It's like the 'uncertainty principle' for signal analysis. I have a few questions regarding this: 1: With a theoretical infinitely fast processor, is it possible to obtain...
  47. R

    Will Magnets interfere with Electric Signal?

    I have a standard 8P8C modular jack (RJ45) and the small clip has broken off. Instead of cutting it off and re-wiring a new one I was interested to find out if I could attach magnets (how I will attach them is not important at this time) to the connector and have the magnets provide the...
  48. T

    Best way to superimpose an AC small signal on a DC power signal

    I'm trying to design a system that will source DC power while transmitting a high impedance sourced AC signal superimposed onto this power signal. I'm sure this has been done in many applications, but I'm new to it. Currently I'm trying to use a basic adder circuit with an opamp to superimpose...
  49. RonL

    What Could Be Causing Inconsistent Wireless Signal Strength?

    Installed a D-Link DIR-655 Router for my wireless network. The network consist of 3 desktop computers, 3 laptops, and 1 Blu-ray (netflix setup). The only problem is that one laptop has a signal strength that varies from (the high) that I have seen, 38Mbps down to 1Mbps. The trend seems to...
  50. B

    FPGA VHDL tristate buffer for ram inout signal

    First off, this is not school related as my semester just ended and I've just been playing around with my fpga. My problem is that I'm trying to write to the ram module then read from it. I understand a little of the tristate buffer and inout signal but we didn't really go over this in class...
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