Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [signal-processing]

the analysis, interpretation and manipulation of signals

Signal processing is an area of systems engineering, electrical engineering and applied mathematics that deals with operations on or analysis of analog as well as digitized signals, representing time-varying or spatially varying physical quantities. Signals of interest can include sound, electromagnetic radiation, images, and sensor readings, for example biological measurements such as electrocardiograms, control system signals, telecommunication transmission signals, and many others. (source)

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How to make a peak detector circuit

I wasn't able to find a good guide on this and I only recently discover electronics for myself so have a little knowledge. I was able to find something like what I need Article How does the circuit operate? It's simple: the input signal charges the…
a_vasilkov
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Frequency locking for averaging resampling

Background I've done a long one-shot measurement of a periodic signal by an oscilloscope. Thus, I've captured around 250 periods of a signal. The signal itself is a pseudo-random binary sequence at the output of a low-pass filter. Here is how a tiny…
skobls
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LF-RFID demodulation

I'm trying to read a LF (low frequency) RFID transponder, it works in the following manner: It uses load modulation, the receiver (the base station) generates the carrier and the transponder modulates it using magnetic coupling (like a electrical…
Daniel
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Why does the amplitude of a filtered signal decrease when higher order FIR filter is used?

I am having a signal of frequency range 0-2 Hz. I want to remove baseline wandering (very low frequency drift) for which I found the cut off frequency — 0.0245 Hz — and a FIR filter of order 91. The output signal has no baseline but the amplitude of…
Jyothi Jain
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Peak detector and LM324 not working

Trying to make second circuit. Here is my outputs (source: cs608722.vk.me) In1+ connected to ground, OUT1 blue and after diode red In1+ signal red and Out2 blue (source: cs608722.vk.me) Why cap charges if there is no signal.. Capacitor is…
a_vasilkov
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Why multiply by cos(pi/4)

I'm building a circuit to monitor AC current for my house and I have run into a need (in software) to multiply the max ADC value for a given sampling by 0.707 to scale the reading to obtain the correct amperage. There is a subsequent scaling…
Chris Swanson
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Is there a way to calculate the Fourier transform of a Hilbert transform system?

Assume we have an LTI system with impulse response $$ \frac{1}{\pi t} $$. Is there a way to calculate its Fourier transform to get the frequency response? I know that its classical Fourier transform is not defined since this function is not…
FreeZe
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DTV Data from IEEE 802.22 Meeting in May 2006

I am currently working on some signal sensing algorithms. In various papers I have come across the reference to DTV signal data that they used for their simulations, amongst others: Reference number 21 They led me to this web page, which seems to be…
Fabian
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Is the system y[n] = x[n] + x[n-1] invertible?

Is the system y[n] = x[n] + x[n-1] invertible? If yes, what's the value of x[n]? If no, could you please introduce a counter example? I couldn't find any counter example so I assumed the system is invertible and then tried to generate x[n] in terms…
Moustafa Elsayed
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Taylor approximation

Suppose we're given the position \$x\$ , velocity \$\dot{x}\$ , and acceleration \$\ddot{x}\$ at \$t_1 \$. We need to approximate the position \$x\$ at \$t_2\$. In below picture, I understand how \$x_1\$ represents the vertical black length,…
AgentS
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Passive Peak Detection for microvolt input

Hello I am trying to find a peak detection circuit that is as passive as possible (ideally no battery needed) that takes an input signal of around 700 microvolts pk-pk. All of the passive peak detector circuits that I have found use diodes making…
Samuel
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Should digital-to-analogue converter produce analogue signal?

Here is the question. (My inquiry is at the bottom of this page about the shape of the graph.) The ADC (analogue-to-digital converter) samples the analogue signal at a frequency of 5.0 kHz. Each sample from the ADC is a four-bit digital number…
anonymous
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Signal processing to demodulate LF RFID

I'm trying to read a LF (low frequency) RFID transponder. The carrier frequency is 125kHz and the base band signal has a 20kHz bandwidth. The modulation is in load modulation, a kind of AM modulation. I'm using the following approach to process the…
Daniel
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detecting the period of signal

I want to find the period of a signal. On searching on the net, I found that the power spectrum density (PSD) can give an estimate of period, by finding the highest peak in the spectrum. However, there are many methods to estimate PSD. Some of the…
Jyothi Jain
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What does a shift in time domain do to the phase in frequency domain?

Suppose \$y_k = x_{(k-m)}\$, i.e. \$x\$ is a time shifted version of \$y\$. Then the Z transform of \$y\$ is \$z^{-m}X(z)\$. What does multiplying by \$z^{-m}\$ mean in terms of the phase response of \$X\$ for a negative shift? A positive shift?
Daniel B.
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