Signal Definition and 935 Threads

Looking at this datasheet: http://www.ti.com/lit/ds/symlink/lm386.pdf Most circuits near the bottom have a 250uF cap in line with the output. Would changing this cap affect the audio signal or would it just further smooth out the waveform?

Hi there, I want to modify a equation which is written for Singal to Noise Ratio. Now I want to change for logical interference. But I could not find any reliable source of explanation, " [FONT="Arial Black"]what is the relation between SNR/SINR and interference(Logical/Physical)?"

Homework Statement Find the average power of the signal, x_{1}(t) = 5cos(2\pi t + \frac{\pi}{10}) - 6sin(10t + \frac{\pi}{8}) Homework Equations The Attempt at a Solution P_{avg} = \frac{1}{T_{1}} \int_{0}^{T_{1}} 25dt + \frac{1}{T_{2}}\int_{0}^{T_{2}}36dt P_{avg} = 61...

Homework Statement S(t) = S(0)e^{-i \pi f_{o}t} e^{-t/T^{*}_{2}}, 0 \leq t < \infty S(t) = 0, t < 0 Show that the spectrum G(f) corresponding to this signal is given by: G(f) = S(0) { \frac{T^{*}_{2}}{ 1 + [2 \pi (f- f_{o} )T^{*}_{2}]^{2}} + \frac{i2 \pi (f- f_{o} )...

Hi everyone! I would like to analyze a biological signal for periodicities using a Fourier transform, i.e., I'd like to get a frequency distribution plot based on a long stretch of signal. Additionally, I would like to be able to mark the positions of certain frequencies within the signal that...

I've been trying to figure out how to get the signal to noise ratio of a completely multiple choice type exam. I can't do it and it's driving me nuts, so finally I found this website and decided I'd ask. :D Say you let your students take a multiple choice test and you are able to get all...

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...

Homework Statement 11. What kind of frequency components can be observed in the output if a linear system is excited by a symmetric square wave? 12. What kind of frequency components can be observed in the output if a non-linear system is excited by a symmetric square wave? Homework...

Homework Statement We're supposed to convolve the signal x[k] = u[k] - u[k-8] with its impulse response h[k] = sin(pi*k/4)*( u[k] - u[k-8] ) with the help of MATLAB. Homework Equations - The Attempt at a Solution The thing is that we don't know how to do this in MATLAB...

Turning FETs "off" in presence of AC signal at Drain or Source Hello, I have a very interesting problem that surprised me, and as of yet have not been able to find a solution for. I have two coupled coils. One is being driven by a pulses. The other coil has FET switches to switch the...

I'm trying to control the speed of a computer fan using the radio input from an RC transmitter/ reciever. The PWM output of the reciever is 1ms to 2ms high and 20ms low, so 10%-20% duty cycle. The computer fan requires a 30% to 100% duty cycle, at 25khz (about a 40uS pulse) I was thinking of...

I recently did an experiment where I had a T-type attenuator. It was connected to a 50 ohm load, and as such I used a function generator with an internal impedance of 50 ohms. Doing the correct calculations, I found the source and load impedance were matched to the attenuator at 50 ohms...

Suppose traffic is moving uniformly with a constant density $\rho_0$ when a traffic light turns red. At time $t = 0^+$, the initial density profile is then modeled according to the figure below. The resulting wave motion of the disturbance is governed by $$ \frac{\partial\rho}{\partial t} +...

periodicty -- Sampling of a periodic signal... I have a doubt..is a signal which is sampled from a periodic signal also periodic?if so then is there a relation beyween the time period of the two?

Hello, I'm having some issues with small-signal analysis of BJT differential amplifiers. Let's say I have this BJT differential pair and suppose that Q1 and Q2 perfectly match: http://i50.tinypic.com/14ahdgn.jpg Suppose a small differential input is applied and consider the small–signal...

Hello, I'm looking to amplify a very weak AC signal using op-amps. The problem I'm running into is that I can only operate using a +5V supply voltage, no negative voltages. My AC signal is about 5mV and I need it to be about +2.5V. The AC signal is initally DC baised and is at +3.5V, so I put a...

Hello, I'm studying BJTs and I have a doubt about deriving the output resistance in the small signal equivalent circuit. Let's consider the circuit below: To derive the output resistance, I'd write the following KCL: i_x = i_{rc} + i_c at this point, every example I've seen says R_o = R_c...

Hello All: This may be a repeat post - I looked at my history and did not see it. I am looking for a product ( finished/qualified) that takes a standard Analog signal ( 0-10V and/or 4-20mA) and converts to a PWM signal with fixed but settable; Frequency of ~ 100 to 5000hZ - possibly with a...

Homework Statement A Hertzian dipole at origin generates a signal in empty space which is detected at a wire loop with position vector; r=(50m)ez Homework Equations Signal is detected by changing magnetic field; B(t)=B0 sin(2∏ft)ex Show it is consistent with the Maxwell's solution to a plane...

Hello, I've been trying to find the answer to this question on the internet but no real luck so here goes: Imagine a signal My_signal which has two components, the actual signal A which is not constant over time and a noise component, we can call it N, where said noise component has a standard...

I have included a picture of what I would like to be able to make. I know that older phones operate on very specific MHz signals and that the newer ones are 2.4, or 5.8 GHz. I know there are scanners out there. But the purchase of one could be illegal, right? So why not make my own, to pick...

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...

For Loop Circuit -- calculate the nth derivative of the signal I'm trying to design a circuit that differentiate a signal using a differentiating amplifier. What I want to do is to calculate the nth derivative of the signal based on a count I specify. How can I apply the same amplifier to the...

Homework Statement Hi , The problem is how to analysis this signal in terms of time segments to understnd the characteristics/pattern of this signal Homework Equations There is no relevant equtions The Attempt at a Solution I have tried to use : RMS Wavlet FFT But which...

Hello All, I am a graduate student conducting a shallow subsurface geophysics study over closed landfill cells and have run into a bit of a problem with my data collection. I have ran traverses spaced 10 m apart running E to W across cells with all traverse lines ran twice using two...

Hi ! I want to amplify the output of my hall effect current transducer ( CSLA2CD ). The output of my hall effect sensor is 15.6mVac. And I used a dual rail op - amp to amplify this small ac voltage which the gain is 101 ( as shown in the schematic below ). I tried to simulate using multisim...

Why sine wave is the basic building block signal to make other signals? Not any other wave. -Devanand T

Homework Statement Using trig identities from a calculus book or other, write out the results to the following modulations. State which frequencies exist in the signal s(t). Homework Equations a) s(t) = Acos(2∏f₁t) * Bcos(2∏f₂t)The Attempt at a Solution cos(s) * cos(t) = cos (s + t)/2 + cos (s...

Hello all. I have produced a square wave with a given frequency (period of about 0.5 seconds). I am trying to match the phase of the square wave with a periodic pulse of the same frequency. I can detect when I have acheved the phase difference between them of zero but I need a way to...

Hey guys, If I wanted to go about generating just a plain noise signal (don't care what the signal consist of), at a certain frequency (say 10 MHz) what is the best way to go about doing that? If possible I would really like to use a microprocessor or ARM processor (due to the higher...

Hi, I have an issue I hope you guys will help me solve. I need to re-create a problem seen on Rail equipment where high voltage spikes are affecting equipment (resistive load) normally running on 600VDC. I thought about using a simple RC circuit to produce the spikes over the 600VDC...

"Quantum measurement predictions are consistent with relativity for macroscopic observations, but there is no consensus on how to explain this consistency in fundamental terms. The prevailing assumption is that the relativistic structure of spacetime should provide the framework for any...

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

how a step function has frequency content in it? thanks

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...

Signal flow graph, describing a RC circuit? Hi, guys. This is my first post on this forum! I'm trying to understand this example in my textbook. The current and voltage equations are: where G=1/R, Z(s)=1/Cs, and I1(s)=I1 Then the text says the following signal flow graph can be obtained: And...

This is actually a continuation of another thread here: https://www.physicsforums.com/showthread.php?t=618868 I don't want to hijack that thread. But that thread make me think about how the signal travel. Let's consider a pcb trace on top of a ground plane...which is microstrip. EM wave...

power -- what is the use of calculating power and energy of signal? what is the use of calculating power and energy of signal? advanced thanks

I have a solar energy system at my home. It basically uses an inverter that converts DC from the solar panels to AC that is phase-locked to the service from our electric company, then adds the two together to feed the home. There are two meters – one to measure the energy produced from solar...

I want to use a length of steel pipe as a communication medium. The pipe is about 20 feet long and the idea is to send some sort of signal along it that can be detected at the far end. I've had various ideas including using acoustic signals, or using the steel as an electrical conductor but I...

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...

hi gang, got a friend who lifes relatively close to a 1407kHz (multi kW) AM broadcast transmitter he has a ~ 50metre run of 75 Ohm coax between a security camera and the recording/viewing equip. The 1407 kHz is getting into the system and causing the usual herringbone pattern on the displayed...

I'm not sure if this is the right place to post this, but I'm trying to write a python script that takes a noisy multi frequency signal, transforms it to frequency space, windows it there with a gaussian, then transforms it back to time space. Here is what I wrote: Fs=1000 #sampling...

I'm trying to write a python script that takes a noisy multi frequency signal, transforms it to frequency space, windows it there with a gaussian, then transforms it back to time space. Here is what I wrote: Fs=1000 #sampling frequency fo=120 #center of gaussian sigma=0.01...

I'd like to preface by saying that I'm not excellent at physics, so I"m still trying to figure this out. I know that when you have an internet connection you have multiple "channels" open to deliver data. The same with audio wires. I was listening to a podcast and they were talking about the new...

Hi all! Quick question. If a Nyquist sampling rate in a signal is 2f, what lower frequencies can be represented without aliasing? I assume you could have frequencies which have only even number of samples in their wave length, or maybe in half of their wave length. Am I wrong? If someone can...

I have a device (fNIRS, though knowledge of fNIRS probably isn't necessary to help) which produces very noisy signals and a noise reference. The noisy signal consists of a combination of a desired signal, and a noise signal, which is a scalar and phase shift of the noise reference. However, I'm...

Homework Statement Consider the circuit shown below. A Q-point value for IC between a minimum of 4 mA and a maximum of 5 mA is required. Assume constant resistor values, and suppose that b ranges from 100 to 300. It is desired that RB have the largest possible value while meeting the other...

Hi, I need a little help trying to determine the possibility of incorporating touch and motion sensor technology in material like rubber, plastic or glass. My question is as follows: Is it possible to incorporate touch and motion sensor technology in material like rubber, plastic or glass...

Hello there I am sorry if this sounds silly or out dated i want to ask anyone, how can i model the mathematical representation from music signal(time domain). lets say i recorded the signal from guitar through my music production software and print screen that signal as shown here...