Signal Definition and 989 Threads

Please can someone explain the clear concept between large signal model and small signal models in BJT. Please explain what to assume in large signal and small signals problem solving wise and also the concept. Amongst vBE, VBE, vbe which is large signal?, small signal? and what we assume in...

Is exponential function e to the power x[t] stable? My book uses BIBO and says its stable but for -x[t] it says its not stable. Is my book wrong?

Traveling signal “paradox” Most relativity paradoxes are not true paradoxes they merely require some clarification about frame of references, stationary observer, etc… I hope some folk could help me clarify my “paradox” or point out where someone as already discussed this concept. We...

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...

Hi, this is part of an application note entitled "Low-Noise Amplifier Stability Concept to Practical Considerations" from Maxim. Could you help me with the question in the picture? Thanks. Source: http://www.maximintegrated.com/app-notes/index.mvp/id/1849...

I believe this is an error minimization problem so I am trying to solve the following equation Min((∑ ( (S(t) - A cos(b t + C)))^2 ) Where S(t) is the input signal, t is time and I will sum over t, A is the amplitude, b is radians per second (frequency), and C is the phase angle. I...

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?

Homework Statement Assume λ≠0. Also bypass capacitor is very large compared to coupling capacitor. a.) Draw the low frequency small signal equivalent and derive lower 3dB frequency formula. b.) Assuming transistor high frequency capacitances, draw the high frequency small signal equivalent and...

Homework Statement Homework Equations The ratio of the parameters \frac{E_1}{E_2} to find the gain (in dB), 10\timeslog10\frac{E_1}{E_2}. "To determine the gain factor in part 8, first think about what happens to the energy when you multiply the signal by a constant factor. Then use the...

What is signal to noise ratio ? And how do I calculate it with the wiener filter?

Hi, I seem to be having some issues going from state space representation of a system to signal flow graph representation. My troubles seem to be, if I have something like this \frac{d}{dt}x_{1}(t) = v_{1}(t) In state space representation I list functions to which the derivatives are as...

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]'...

In the usual BH model, evaporation ends in a final flare and the possibility has been studied that a class of gamma-ray bursts, the VERY SHORT ones (VSGRB) could represent final explosions of PRIMORDIAL black holes (PBH). http://inspirehep.net/record/901360?ln=en When quantum corrections are...

So here is my dilemma: We have our SR830 in a MOKE set-up. The modulation of the laser is with a chopper at approximataly 336 Hz. The reference signal is not being picked up by the SR830, but using the same cable the reference frequency is coming up on our oscilloscope. ie, plug the cable...

Homework Statement A noisy but slowly-shifting sensor signal is being filtered with a low-pass, finite impulse response filter. What is the mean delay and expected SNR boost (noise standard deviation of output compared to input) for two filter variations: N filter taps uniformly weighted...

Homework Statement We measured the time between a signal source, and it's reflection coming back through our probe after going through an open-ended coaxial cable. My teacher told us this: the cable has a polyethylene insulator between central wire and the grounding web, which has a...

Homework Statement Given the transmitting power of 0.1 mW and received noise of -100 dBm. Consider a signal which needs a SNR of 30 dB. Calculate the range for a signal of 0.5 MHz given that the damping for the signal is calculated as: L = 10 +8.0*f [dB/km] where f is the...

So far I have: V=Acarriersin(2∏Fcarriert) (1+Cmodsin(2∏F1t)+Cmodsin(2∏F2t)) which I think is pretty close to correct. Where: A is amplitude, F is freq, t is time, Cmodis the coefficient of modulation, i.e. 1=100% modulation. I can find plenty of websites offering 1-tone AM, but not 2 or more...

This is part of a solution to find the average of power consumption. In the solution, the boundary taken is from -T/2 to T/2. Can we integrate from 0 to T instead?

How is this done. Been reading about sputtering and DC sputtering is extremely simple. However, I'm not very experienced with RF circuitry so understanding exactly how to design that circuit confuses me a bit. Been reading about RF circuits but to generate an RF signal every method I find uses...

Homework Statement The output of a sensor which produces 10000 electrons is connected to parallel RC circuit with Resistance= 50 ohm, and the capacitance=10pF. Calculate the signal to noise ratio at temperature 300K. Homework Equations SNR= 10 log (power of signal/ power of noise) Or...

Hi I made a counter using Dflop in Ltspice. But when I am using the count bits as signal to other circuits the clock signal is getting distorted. Why is this happening? How can I overcome this problem? Thanks Salil

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

I am a beginner at electronics, and wanted to make a simple (non-audio) radio transmitter and reciever, with no inductor-capacitor resonator, since I don't understand it and I am not making an audio radio. Here is my transmitter, with the input wire to the BJT being the signal: Here is my...

Say x(n) = n for 0 <= n < 4 and 0 o.w. So X(W) = Sum n=-∞ to ∞ x(n) exp(-inw) = sum from n=0 to 3 nexp(-inw) = 0 + exp(-iw) + 2exp(-j2w) + 3 exp(-j3w) How would I graph F(W)? Also if the signal was continuous x(t) = t for the same interval X(W)= integral 0 to 4...

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...

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

Homework Statement First of all, I have to calculate power spectral density S(jw) of this signal: It looks something like that: t>=0 Homework Equations The Attempt at a Solution It seems to me, that I can't use this standart formula: So.. I see that there is signal...

There is an example for the radio signal for Twin Paradox from the book "Classical Dynamics of Particle and Systems, Thornton, Marion". Refer "1.jpeg", example 14.5, it said that "However, Frank continues to receive a signal every 3 years for the 8 years it takes the last signal Mary sends when...

Fourier transform of RF signal with a "prism"? We can use a prism to decompose visible light into components of different frequencies. This is a Fourier transform by nature. For an ideal prism, the energy is conserved in the process. How about RF signals? There is no fundamental difference...

Hi, This is not a homework, just a problem that I can't figure out. Please help. Assuming that I have a low pass filter with cutting frequency, fc and a signal with many different frequencies (with some below fc and some above fc) is applied to the input of the filter. As we know, the...

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...

When I do MRI, after I send the Pulse radio, I get signal. There longitudinal magnetic and Transverse magnetic , their signal is shared or that two separate signals which are received with the antenna and create an image?

Homework Statement Make a sketch of the spectrum of the signal defined by: x(t) = \sum_{k = -3}^{3}\frac{1}{1+j\pi k}e^{j4\pi kt} Use polar notation for the phasors on the plot, and sketch the frequency axis in Hz. Homework Equations The Attempt at a Solution a_{k} =...

Homework Statement What (complete) set of sampling and filtering parameters would you choose to record a signal from a high speed pressure sensor if you wanted to accurately determine its power spectrum below 35 kHz with a resolution of 0.5 Hz? Homework Equations frequency resolution =...

Homework Statement A binary encoded signal with a bit-rate of Rb = 112 kbps is now encoded using polar NRZ baseband encoding and then modulated using binary FSK with a carrier frequency spacing of 10 kHz. What is the bandwidth required to transmit this modulated signal? a.132 kHz b.224...

Hey guys, So I'm working on a project currently being built off of a cheap commercial Quad-copter (Syma X1) as it's base platform. Just as a little background I am trying to make it so that it is not controlled by a remote (that is pushing knobs and levers up and down to control it) but by EMG...

Hello, I'm trying to interface an Infineon TLE4263-2ES voltage regulator with a external watchdog figure. The microcontroller is from the Freescale S12G family. My question is kind of gereic, in a way. When I'm sending a pulse signal to the voltage regulator from the micro, at what frequency...

Dear, I assume that a signal S is expressed as S = a*S1 + b*S2, where a, b are weight constant, and S1, S2 are the different signals. In addition, S1, S2 have similar distribution such as Gaussian or Laplacian distribution, and theirs pdf is p_S1 and p_S2. In the above...

Dear, I assume that a signal S is expressed as S = a*S1 + b*S2, where a, b are weight constant, and S1, S2 are the different signals. In addition, S1, S2 have similar distribution such as Gaussian or Laplacian distribution, and theirs pdf is p_S1 and p_S2. In the above assumption...

Hello, This is my first post; so first of all, let me thank all of you for starting and running such a good forum that provides lot of help and insight into various engineering problems. As to my brief introduction, I am an IT professional with educational background in (Mechanical)...

I would like to take an incoming signal (digital or analog), invert it, and send it to an antenna. What is a simple high-level approach to this?

Homework Statement For a phasor V(x) = 8 + 4j find the sinusoidal signal that it represents if the frequency is 50 Hz? Homework Equations The Attempt at a Solution sqrt(64+16)=8.944sin(50t) so clearly this is not correct?

Hi, I have the following question: A signal x(t) which is band-limited to 10kHz is sampled with a sampling frequency of 20kHz. The DFT (Discrete Fourier Transform) of N= 1000 samples of x(n) is then computed. To what analogue frequency does the index k=120 respond to? I'm trying to...

Need help understanding the "signal" wire. My servo, http://www.allelectronics.com/make-a-store/item/DCS-110/STANDARD-RACING-SERVO/1.html Not sure if this servo requires AC or DC power. What I really want to understand is the signal wire; specifically how changing the input value either...

large signal current gain hFE = (IC - ICBO)/(IB + ICBO) and small signal current gain hfe = IC/IB 1. what is the difference between these two. 2. why can't we use large signal current gain in small signal currents?? 3. i have these notes on page 57 (page 1 on pdf) paragraph 2 of these...

Hi everyone, at my university (Computer engineering) we are studying the small signal model, but i didn't understand the practical application, i mean, why and when should it be used ? For example at home i usually make electronics circuits, so i wanted to know how can i use the small signal...

Hello all, I am trying to model a received laser signal, x(t), reflected off a moving target. I am currently trying to model for both frequency change due to Doppler shifting as well as a time-varying phase shift, θ(t), due to the continuous change in distance from the target. My current...

Homework Statement Spaceship is ##\scriptsize100m## long in its proper coordinate system and is moving relative to Earth. Astronaut sends a light signal from the rear part of the spaceship towards the front part. It seems to an observer on Earth, that a light signal needed ##\scriptsize 0.57\mu...

Hi, I am curious to know if there any passive (or simple active) methods to convert a very coherent signal into an incoherent one? I suppose I would need to find a way to chirp the signal and a non-linear medium might be one method. Any ideas? Thanks narra