What is Signal processing: Definition and 131 Discussions

Signal processing is an electrical engineering subfield that focuses on analysing, modifying, and synthesizing signals such as sound, images, and scientific measurements. Signal processing techniques can be used to improve transmission, storage efficiency and subjective quality and to also emphasize or detect components of interest in a measured signal.

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  1. J

    Find Function/Transform for signal that minimizes CV of data

    Warning...this requires scripting and iteration, and is not theoretical -- it is a real problem I haven't been able to solve, but I'm sure someone here can... :-) Data: each .csv file is a test recorded at a time interval of 7.5Hz and each file has 3 columns. The first column is time in...
  2. T

    Improving Torque Data Signal with Digital Filtering

    Hello, I have a three phase brushless motor and was trying to measure its torque and speed using a torque sensor. The motor will first go to its maximum speed which is about 6000RPM, then I applied a brake to decrease its velocity. Here is what I get as a result of data acquisition : The...
  3. P

    Can pocket FM radio output at 50kHz?

    I've recorded the output hiss from a small battery powered radio operating inside a metal tin. From related posts, I can say that the radio is effectively shielded from receiving any FM transmission, and the resultant hiss is thermal noise in the early stages of the receiver. I believe that...
  4. R

    How Can You Extract Specific Signals from a 2D Image Using Fourier Transform?

    Suppose 3 1D Signals x(t), y1(t) and y2(t) are given as x(t)=sin(40*pi*t); y1(t)=.5*sin(40*pi*t) and y2(t)=x(t)+y1(t). Left side =Right side Here,values of x(t)and y1(t)i.e.(Right side) are given and we get y2(t)(Left side).The plots of x(t),y1(t) and y2(t) are plotted below...
  5. R

    What Does the Fourier Decomposition of an Image Represent?

    Hello everyone have a look at this video of Fourier Decomposition of an image.also we know that Fourier series is given in the image as...
  6. R

    Why the Fourier transform is so important compared to other?

    I am engineering student and studying signal processing. The term Fourier transform comes in the discussion several times. There are many transforms like Laplace transform,Z transform,Wavelet transform.But as per my view ,Fourier transform is mostly used compared to others in general. My...
  7. R

    Is signal reconstruction possible using phase/magnitude only

    I am studying Fourier Transform and it's inverse. We get phase and magnitude of a signal from it's Fourier transform and reconstruct it back from both together(magnitude of signal +phase of signal) My question is that is it possible to reconstruct given signal back using it's phase only or...
  8. A

    How can I improve thresholding for real-time qrs detection?

    I am working my final year project on realtime qrs detection using pan tompkins algorithm, using matlab, i am facing problems in the thresholding part.needed help in this part. Thanks :)
  9. M

    Beginner's Guide to Compressed Sensing in Signal Processing

    I hope this is the right place for this post. I'm originally a physics student but my thesis supervisor assigned me a work in which the concept of compressed sensing (CS) becomes the underlying aspect. I have searched some sources online but, no good. I guess this is because this CS thing is...
  10. S

    Physics related career for Computer Science graduate?

    I hold an Engineering Degree with major in Computer Science and have 1.5 years experience as programmer. Being an Indian, I was pushed into Engineering and didn't know much about other career options back in 2008. Now I feel I should have taken up Physics. I abhor a mundane IT job. I wish to...
  11. B

    Signal processing in matlab, what is signal length ?

    Homework Statement Use Matlab to construct a signal of length 2^13 = 8192 that contains only three frequencies: x=0.5*sin(2*pi*200*t)+0.2*sin(2*pi*455*t)-0.3*sin(2*pi*672*t) Compute and plot the absolute value of the DFT. What does the question mean by signal length and why is it expressed...
  12. TheDemx27

    Low Power Signal Processing -- Bouncing an RF signal off the Moon

    I'm doing a project that has been done many times before, bouncing a signal off the moon, but I'm trying to do it with low power. I'm told the expected S/N ratio is -30dB. The problem I'm trying to figure out is whether or not it is theoretically possible to pull out the signal out from the...
  13. A

    Best Way to Learn Introductory Signal Processing

    Hello PF'ers, Does anyone have insight on the best way to learn Signal Processing? I am new to the subject and feel totally lost in my course. Our professor has a teaching style that doesn't work for me. He isn't teaching from a textbook and the notes don't fully explain things. Successful...
  14. M

    Signal Processing energy conservation

    Homework Statement Two receivers, d=5 [meters] apart, are recording an air wave signal. The air wave travels in v=330 [m/sec] and coming from one side of the receivers. The air wave contains all the frequencies between 10 [Hz] and 200 [Hz]. a) If we sum up the recorded signal from the...
  15. A

    Digital signal processing, linear time invariant system,

    I really confused, I found in a book that the following system, y[n]= x[n+1]-x[n], is not causal! But from the definition of causality that the output y[n0] depends only on the input samples x[n] for n<=n0,,, So I think that this system is causal... If you agree with me please tell me that...
  16. J

    Signal Processing Vs Machine Learning as a career

    Hello, I have an undergraduate degree in EE and I have a passion for mathematics. I'm trying to decide if I should do a masters in signal processing or machine learning. What are the pros and cons of each given the way the industry is? (I live in Bangalore, the tech capital of India, where...
  17. N

    Calculating Optimal Weights for MVDR Signal Processing Gain

    Using a MVDR method for a uniformly spaced linear array of sensors, I calculated the optimal weights. The procesing gain is (SIR)out / (SIR)in . The value turned out complex. Is this possible/makes sense?
  18. N

    Digital signal processing - Pseudo Inverse Method

    Digital signal processing -- Pseudo Inverse Method Homework Statement The Attempt at a Solution (a) A =the matrix with [ .4 0 0 0 0 0 0 0 0 0 0 0; .7 .4 0 0 0 0 0 0 0 0 0; -.1 .7 .4 0 0 0 0 0 0 0 0;... all the way down to 0 0 0 0 0 0 0 0 0 0 -.1] so it is 11 x9 . w=[w0 w1 ... w8]'...
  19. J

    Digital signal processing - conjugate reciprocal of a complex number

    Digital signal processing -- conjugate reciprocal of a complex number what is the difference between conjugate of a complex number and conjugate reciprocal of a complex number i am asking with reference to z transform...Thanyou
  20. N

    Simplifying equations involving Dirac Delta (Analog Signal Processing)

    Homework Statement I'm specifically having trouble with taking the Fourier transform of f(t) in order to sketch F(w) and also to move on with the rest of the problem. Homework Equations f(t) = (5+rect(t/4))cos(60pi*t) mixed_signal = cos(60pi*t) The Attempt at a Solution I attempted to...
  21. dexterdev

    In signal processing , what do the term 'feature' means?

    In signal processing , what do the term 'feature' means? Feature extraction etc. For example, in audio signals what are the main features? -Devanand T
  22. B

    OC Signal Processing Textbook Recs Requested

    I was wondering if anyone can recommend me texts any or all of the following topics: - Signals and Systems - Digital Signal Processing - Digital Audio and Speech processing - Digital Image processing - Digital Video processing Would prefer if replies came from people who have perused through...
  23. T

    Definition issue frequency domain - Random Signal Processing

    Hello i have a question about Random Signal Processing and the frequency domain. If i understand correctly one cannot use the Fourier transform to represent a stochastic process in the frequency domain. What is therefore used is the Power Spectral Density: S_X(f)=F\{R_X(\tau)\} Were F...
  24. J

    Schools Signal Processing Graduate Schools

    I'm a junior electrical engineer at a NY state school I'm looking to get my masters in EE with a specialization in signal processing. What are the best graduate schools for this? Thanks
  25. M

    M.Sc in Electrical Engineering: Signal Processing

    Hi All, Since I myself hate reading long posts I will cut to the chase. I graduate in June with a B.Sc in electrical engineering and am hoping to go for graduate studies. During the last four years I took courses in almost all areas of electrical engineering. The only field I liked AND...
  26. N

    Signal processing approach to stydy the brain

    I have sought information about different approaches(fields) to neuroscience and how they differ in terms of understanding how the brain works. I'm interested to learn more about neurobiophysics, computational neuroscience and engineering perspectives. In engineering especially about brain...
  27. H

    Basic questions about signal processing and fourier analysis

    1)A note consists of a fundamental frequency and the multiples of that frequency called harmonics. Peak frequency means that one that contributes most to the note. Is the fundamental frequency always the peak frequency? Since the frequencies die out very quickly as the value of n increases...
  28. C

    Signal processing in the nervous system?

    How does body motion control occur? For example, walking on high heels during a strong wind is pretty hard. There is a compressible fluid flow across the body, the center of mass is changing all the time, you have to balance on a tiny surface area, sensor data from the skin, eyes, ears, etc...
  29. J

    Help with Signal Processing Homework

    Homework Statement 1. We need to design a low pass analog filter using anyone of the MATLAB routines: buttap,cheb1ap, cheb2ap,ellipap. Find analog filter's poles, zeros, and gain. Which would be the best to use and why? 2. Design a digital IIR from the analog filter with the following specs ...
  30. M

    Signal Processing Help: 3rd + 1st Order Nonlinear Device Multiplier

    Homework Statement http://i.imgur.com/01AUp.png Homework Equations The Attempt at a Solution Having some problems with this question, using a third + first order nonlinear device to make a multiplier. I'm fine with using a second order, but this one is stumping me. So, I...
  31. C

    Signal Processing: Up and Down Sampling

    Homework Statement Does the upsampling and downsampling have any effect on the amplitude? consider the following X(e^jw) Homework Equations what will be the amplitude of the signals? do they remain 1 or are they to be divided/multiplied by L/M, L being upsampling factor and M...
  32. X

    Introductory Systems and Signal Processing resources?

    I don't have an explicit problem to be answered per se, but what can I do about my signals processing course? We're only into our 4th week of school, and already my professor has had several lectures on Fourier Transforms. I am lost. Besides basic calculus, trig, and complex number theory...
  33. S

    Gravitational wave data analysis. More of Signal processing techniques

    I am using the matched filtering technique to extract the data from a heavy noise background in the process of detection of gravitational waves. I calculate the correlation between the experimental data and a theoretical template. I have been told that the maximum of the correlation function...
  34. A

    Engineering Control and signal processing engineer

    I want to what is the actual job of a Control and signal processing engineer. And does he/she has any kind of job type in power plants or energy supplies? hope to get an answer as soon as possible. Airer
  35. B

    Question about signal processing devices

    Since signal processing electronics rely on a constant DC power supply with a supply current that can only be converted into a fluctuating DC current by the switching devices of the circuitry, does an AC input signal coming from a microphone or wireless receiver need to be converted into a...
  36. U

    Is there any cosmological research field concerning signal processing?

    Hi, everyone~ I have a BS in EE, and I want to be a researcher in cosmology or astronomy. To accomplish that I have to get a PHD in such areas. But my major in college was mainly about signal processing and networks. So, I'm wondering if there is any PHD program in cosmology or astronomy that...
  37. C

    How Do You Determine if a System is Causal and Distinguish Between FIR and IIR?

    I have a couple of questions about the theory about how to tell whether a system is casual and FIR or IIR. First point is about a casual system. Is it true that all FIR systems are casual? How can you tell if an IIR system is casual? I am I correct in thinking that a FIR system only has a...
  38. S

    Solving FFT Signal Processing Problem for Complex Time Signal

    Hi, I have a complex time signal x(t)=X1*exp(i*∅)+X2*exp(i*2*∅). On converting to frequency domain, i expect frequency components at ω and twice of ω (when ∅=ω*t). FFT gives the desired frequencies, but the amplitudes don't correspond to X1 and X2. I understand that this is due to the phase...
  39. P

    Difference between RF and Signal Processing Filters?

    I've designed both types of filters for years and can't really explain the difference in clear simple terms. I'm hoping somebody here can help me out with that. First, some working terminology: RF filter - a filter with a controlled input and output impedance, usually 50 ohms, to match the...
  40. wukunlin

    Recommended Books for Self-Study in Signal Processing

    Is there any recommended books for signal processing for self study? Or like a reference book covering most fields? my final bachelor year has been filled with prescribed papers but I'm thinking I will need to be familiar with signal processing. At the moment I am looking "Digital Signal...
  41. D

    Queries on Signal Processing - Cross Correlation

    I'm new to the field of signal processing and currently reading a paper which it uses cross-correlation of two signals for detecting some machine failures. But I'm confused with the complex conjugate in the equations. Take equation from wikipedia as example: (f\star g)(t)\equiv \int_{-\infty...
  42. W

    EE/Math electives for signal processing

    Hey, I'm an EE undergrad looking to tentatively specialize in signal processing. My relevant background includes a course in signals/systems, introductory feedback control (using Nise), analog communication systems (using Haykin), introductory probability, the usual Calc I-IV sequence, linear...
  43. C

    Intermediate Frequency vs Baseband Signal Processing

    In the digital communication class I took, people talk about how to do detection and processing at the baseband. But from what I read, it seems that many systems do the signal processing at some intermediate frequency without mixing it all the way back to baseband. My questions are why and how...
  44. F

    Is a Degree in Engineering Required for a Career in Signal Processing?

    Hi, I'm doing ICT (telecommunications) engineering and have enjoyed subjects which involved signal theory (using matlab, Fourier transform, modulation, filters etc). Just wondering if there is a job where I can use the theory/maths that I learned in these subjects?
  45. J

    Engineering Electronic engineering technology and signal processing

    hello I am in the final year of my electronics engineering technology program and I've really developed an interest in subjects such as analog and digital signal processing, filters, amplifiers, etc. are there jobs in these areas for people at my level? I've been doing some job searching and...
  46. M

    Question about deconvolution of signals (digital signal processing)

    I have a set of discrete data that I have performed multiple Gaussian smoothing filters on to act as a low-pass filter. What I have come up with is something like this: http://i51.tinypic.com/152kieg.jpg I'm using findpeaks() in matlab, and a peak that I want is being taken over by the...
  47. F

    Signal Processing: Questions Answered

    Hello, Recently I've been very interested into going into signal processing. I have a couple questions... 1) Exactly how much math do you need? Do you need anything past PDE's? 2) How are job prospects for this field? 3) Are you required to do any hands-on stuff? (e.g. build...
  48. S

    Signal Processing mathematics books ?(laplace, fourier )

    Hello, Can you suggest me some good Math books about Fourier laplace transforms, convolution, transfert functions and stuff ? Because all I have right now is some crapy math notes and an electricity book that doesn't mention anything about math theory. I tried google but I really don't...
  49. 1

    Signal Processing and Mathematica (filters)

    Mathematica problem: Filter: H(jw)=(3.84+5 (j w))/(5+j (1.11 w^2)) Bandwidth where: |H|>1/Sqrt[2]*Hmax Calculate the bandwidht Tips or solution would be much appriciated Thanks
  50. M

    A/D Signal Processing: Sampling Frequency & Quantization

    Hello, I'd like to know the relation between the sampling frequency and the quantization. If the sampling frequency is 200KHz, and the analog signal ahs a maximum frequency of 80KHz, How many bits will the qantization be done to have a 6Mb/s bitrate?
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