Signal Definition and 935 Threads

Hi there, I'm trying to design a positioning system that makes use of RSSI. When a wireless signal would propagate through a human body, the signal strength would be weaker than when it wouldn't have to overcome any obstacles. My question is: would this difference in signal strength be...

Hello, I am reading The Art of Electronics, and I have two specific questions regarding examples it has introduced. I am dealing with bipolar transistors the current chapter. I think my questions mostly stem from not understanding concepts. The text has introduced the technique of...

Hello everyone, I'm working on a project that requires me to demodulate an NTSC composite video signal into an RGB form. Despite having read a book and visited numerous websites detailing how this is performed, I am still confused. First, it seems that the colorburst signal is not in phase (or...

hello guys .. first of all , iam not sure that i should type this thread here . so excuse me for that in this problem i can understand the part until it's said that w=0 then x(t)=1, which is periodic for any value of T but i can't understand the part after that in the case of w is not equal...

I have a constant 100 uA square wave DC 10Hz signal that needs to have a pulse width of 50ms. I was reading up on using an electronic timer relay (recycle type) or a solid state relay controlled via PWM. I need some help choosing which route to take, or if there are better/easier ways to...

Also can we have an analog signal in alternating current?

I am very new to circuit design so any help is much appreciated. I need to design a signal generator that will output about 30V-40V peak to peak at 13MHz (sine wave) If the signal generator is not able to, then I need some kind of amplifier. So far I have looked into Hartley and Colpitts...

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...

Hi! Homework Statement a) Calculate and sketch amplitude spectrum of u(t), b) u(t) is input signal for linear time invariant system whose transfer function H(jw) is shown. Calculate output signal uo(t) Homework EquationsThe Attempt at a Solution I completed task a), I got...

Homework Statement The schematic shows a low-pass filter identical to the one you built in studio. This filter uses a 60 k resistor and a 250 pF capacitor, and the input signal is at 30 kHz. (1 pF=10−12 F)...

Hi! Here is my task: 1. Homework Statement Periodic signal is input signal for circuit (photo). a) Calculate and sketch amplitude spectrum of $$u(t+1ms)$$, b) Calculate participation (in percent) of DC component of power of total mean power of signal $$u(t)$$, c) Sketch power spectrum of...

Hi! 1. Homework Statement My task is to calculate amplitude and phase spectrum of this signal: Homework Equations My idea is to calculate complex Fourier series of this signal, $$f(t)=\sum_{n=-\infty}^{n=+\infty}Fne^{j\frac{2n\pi t}{T}},$$ where...

Hi :) I'm designing a research and need you guys's help :) It's an experiment to finding out what happens in our brain when we are stimulated by electricity. I have to collect the signals from brain, but not using EEG. (I already failed once...:'( ) I've been thinking about MEG, but it...

For an image, higher the dimensions of image ,more is the resolution of the image.But is there any relation present between sampling frequency and dimensions of image? Also, Whether the Number of samples presents in an image is equal to product of dimensions of image?

Homework Statement V(t) = [2t - 4] u(t) u(4 - t) I need to express this a sum of step and ramp functions. Homework Equations The Attempt at a Solution I have absolutely no idea how to proceed

Hi all, For my research I would like to create a high frequency high voltage signal. This signal should be in the order of 1kV-5kV with a frequency of around 10MHz. Can anyone help me with this? I'm not an electronic expert. I only have to apply the electric field, please note that I do not...

I know that in the pursuit of low noise amplifiers, the cooler the better, generally speaking. But when does it make sense to try and go through the work required to cool an amp? One of my passions is radio astronomy. I have a good collection of LNA's around of various types and an eight foot...

Hi, I am designing a channel switching all tube guitar amp that I have two channels and be able to switch between the two channels. For now, I am using mechanical relays for switching and it gives me a popping sound when I switch channel. So I want to design a muting circuit to mute out the...

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...

Homework Statement Express the following signal in terms of ramp, exponential, and parabolic functions, where t should be consistently shifted Homework Equations signal simplification techniques, not known to me The Attempt at a Solution It seems you can express this in terms of...

Hello! I want to induce a (weak) signal in a wire across the room from me. I was just wondering, how would I go about doing this if I couldn't touch the wire and couldn't modify the equipment to accept these signals BUT was close and in line of site of the wire?

When I sample a certain digital signal with increasing sampling frequency, the fast Fourier transform of the sampled signal becomes finer and finer. (the image follows) Previously I thought higher sampling frequency makes the sampled signal more similar to the original one, so the Fourier...

Hi, What I have been trying to achieve is learn about signal processing ,particularly filters. Newbie to DSP,so far! I have 2 signals with me.Voltage and current signals. Both are unfiltered. I have managed to filter out these two signals to remove most of the noise. Now,I want to find the...

Hello! I am a bassist in a rock band and I hace slight issue with trying to rig up this "this" http://www.newegg.com/Product/Product.aspx?Item=N82E16811992011 LED Controller to do its color changing awesomeness while pulsating with what is coming out of an output on my amp (which is a...

I don't see why not but is there any reason that i could not use these modules http://www.ebay.com/itm/121370353437?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649 to make a wireless link between this camera and screen...

I can see how the satellite has enough power to broadcast to the phone, but it's perplexing to me how the phone has enough power to broadcast to the satellite, especially when it comes to these small modern satellite phones. They don't seem to even be aiming the signal. Just from my...

For a school project I need to be able to shift the phase of a 100 kHz sine wave by 90 degrees (either positive or negative). I have tried several passive integrators and differentiators, both with poor results. I have also tried using an op-amp integrator and differentiator, but in both cases...

I am just a beginner so if I am asking in the wrong forum please move it to the more relevant one. From my understanding, electromagnetic waves are what carry audio signals and dependent on the conductor, this speed varies. I have read coxial will carry at about 2/3 speed of light, and...

Homework Statement Evaluate (simplify) the following expression: y(t) = ∫0∞ e2(t + 2τ)δ(t + τ)dτ =Homework Equations Shortcut signal expression techniques, integration of an exponential signal and impulse signal, other techniques that are probably unknown to me The Attempt at a Solution...

Hi . I am modeling a sodium steam generator in Octave. I build a set of differential equations and solve them with Octave DAE solver. My model works just fine. Now i would like to start implementing controls but I am quite confused with P conroler output signal and with what it actually...

Relativistic frequency shift of satellite signal Homework Statement An Earth satellite used in the Global Positioning System moves in a circular orbit with period 11 h 58 min. (a) Determine the radius of its orbit. (b) Determine its speed. (c) The satellite contains an oscillator producing...

Homework Statement A communication satellite is orbiting 36 000 km above Earth’s surface. Two cities, 3500 km apart are transmitting to and receiving signals from each other. Find the time required to transmit a signal from one city to the other. They are equidistant from the satellite. h...

Hello everyone! I am generating a signal as a function of time. This is an irregular signal generated by using the superposition principle and random phase. Thus I actually have already all the frequency components of the signal. And from the frequency components I know that there is also a...

Given N sampled points, using the FFT we can get the Fourier transform of those N points Xk. With N/2 the Nyquist frequency and X0 the DC value. Using the inverse we can then get back the original function we just measured. However if we would like more points then just the N we have measured...

Homework Statement Find the output signal for an amplifier with transfer characteristic: vO = 10-10-11e40*vi output bias of 5V input bias of 0.673 V and an input signal of 1 mV superimposed on the bias Homework Equations vO = bias out + signal out vI = bias in + signal in The...

Homework Statement I need some help with the following problem (from an old exam): A 16-bit single-ramp ADC has a sampling interval of T=1 μs and an input voltage range of 0 to 10V. Since for this ADC the input must be positive, its design includes a fixed DC input of 5 V upon which...

So I have a pair of headsets, turtle beaches, that require a usb power for the amplifier. Now I thought the amplifier was just to combine the two outputs of game audio and chat audio, but do headsets like turtle beaches need a more powerful signal than just headphone level. I ask this because I...

Hello! I am attempting to do an FFT on a signal e^(jω+nδω)t, where t is constant and for n=0:N-1. This signal starts off at ω when n =0 and then increments in steps of δω until it reaches the final frequency ω+(N-1)δω. Performing an FFT on this signal will put me in the time domain so my...

I know that a differential amplifier is used to effectively subtract one voltage signal from another (and amplify). However, are there any devices or techniques that can be used to electronically divide two voltage signals? Thank you

Hello, From an offset zener diode breakdown circuit, I have collected a set of bytes from an ADC. The values distribute normally as integers between 0 and 1024 with a mean of 512. I would like to use the data to create a set of random integers that distribute uniformly. So far, I have...

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...

My electrical engineering teacher had us do a research project, and i decided to do my on the effects of polarized electric fields and antennas. I was reading that RHCP signals have no effect on LHCP antenna receivers. When i sent my paper to my teacher, he told me that i had to prove this...

Hi all, I would like to make a switch for an AC signal (on off ,ie, high impedance and low impedance). The switch should have less than 1 ohmn impedance. The signal can range from 1-100Khz and the signal will be 50Vrms. I tried to use mosfets, but they do not block the signal completely...

Hi all, my task is to measure the charge time of an RC circuit with a counter using FPGA, once the cap is charged, i must discharge it again for next input. Idea is to discharge it with a signal from FPGA, but what sort of circuit would allow this without discharging the cap prematurely...

i am working on ultrasound sensors. At the receiving end i have 2 MHz signal of 80 mVp-p. i need to amplify it at-least by 10 times. Pleases suggest me an appropriate method. Additionally, i need to know if normal opamps work in 2 MHz signal? if not, are separate ICs available for that...

I have a 3 rad/s sine wave that I am sampling every 2 seconds. The slow sampling has created an alias of -0.14 rad/s. I have plotted this over the top of the original continuous time signal, please see attachment. My problem is that I only want to plot the first period of the discrete signal...

I was reading about noise and noise voltage/root hertz here - http://www.stanford.edu/class/me220/data/lectures/lect02/Noise_writeup.pdf What exactly is mean square. why do we need Mean square. How do we know time average of noise voltage is zero?

So,I got this vector of input data in Matlab,which is vector of approx 1x25000 length. I have frequency responce function attained by different estimators (H1,H2,Arx). Anyway,my FRF is also a vector of 1x129 length. Those two are different sized vectors.How should I find the output data...

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?