Questions tagged [signal-processing]

the analysis, interpretation and manipulation of signals

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9 views

realtime software 90 degree phase shift a sinusoidal signal [migrated]

I would post this to stack overflow but it seems to me more like a signals and systems problem, which EE's thrive on. I need a realtime system implemented in software that can generate a sinusoid ...
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2answers
76 views

Why does a pole at high frequencies attenuates noise?

I am trying to understand the concept of realizability for an improper transfer function, and I am struggling to understand some concepts. I know that if I have an improper transfer function, for ...
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1answer
41 views

Differential input circuit design frequency issue?

The current design for this differential op amp scales down -/+ 10V 100kHz signal inputs to 0-3.3V for an ADC to properly read. Using a gain of .165, it adjusts -10 to 0 by adding a 1.65V offset, as ...
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1answer
36 views

Fractional Frequency Divider

let's consider a fractional frequency divider, which is defined (wikipedia) in the following way: A fractional-n frequency synthesizer can be constructed using two integer dividers, a divide-by-n ...
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0answers
14 views

Discrete Cosine Transform (DCT) Coefficient Distribution

I have two images : Original Image Binarized Image I have applied Discrete Cosine Transform to the two images by dividing the 256x256 image into 8x8 blocks. After, I want to compare their DCT ...
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2answers
48 views

Thermal Noise autocorrelation and time domain analysis

I have some doubts about the termal noise of a real resistor. The equivalent model of a noisy resistor is this one (here the reference): Here there is the model of a noisy resistive network: I ...
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1answer
40 views

How to find phase shift(angle) between two signals in simulink?

So I'm doing a delta wye transformer in simulink and phase shift between these two signals should be 30 degrees, but how to show that, or calculate it? And how to find angle of each signal?
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48 views

Why Do Pipeline ADCs have an “Overlap Bit”?

In pipeline ADCs, there is an amplifier after each stage that amplifiers the remainder of the previous stage by 2^(number of previous stage bits - 1). For example, if the flash ADC in the first stage ...
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34 views

How to transmit the data from the buffer filled with ADC values through DMA on STM32F7

I am currently trying to a sample a signal between 25-40kHz with three microphones to calculate the time difference. I'm having difficulites understanding what to do after the ADC is activated and ...
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1answer
54 views

Shifting an audio signal from 0 - 4V to -2 - 2V

I'd like to transmit an audio signal over a digital radio and I figured out I'd need an op-amp in an inverting configuration on the transmitting side to turn a -2V to 2V signal into a 0-4V one. That ...
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2answers
48 views

Signal fidelity from fiber optic crosstalk

I was watching a video about tapping fiber optic cables when it brought up some points from an early US govt document describing security concerns about fiber optic cables. The relevant part: ...
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1answer
223 views

How did the Telstar 525/405-line conversion system from 1962 work?

The Wikipedia article on the Telstar satellites from the early 1960s says that in order to facilitate transatlantic television signals (where the US had the 525-line (480 visible) NTSC system, and the ...
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2answers
47 views

Lock-in amplifiers, signal averaging and signal post-processing

I would like to know about what are the benefits of using a lock-in amplifier. I have read that they basically consist on multiplying a signal by a reference which switches the frequency to DC. Then ...
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1answer
30 views

Getting different impulse responses by solving with Laplace transform and plugging delta-dirac

If I know that the output of a system $$y(t) = 2e^{-3t} \cdot u(t)$$ and it's specified that the input is $$ x(t) = u(t) $$ I was trying to find the impulse response h(t). So I solved it using ...
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1answer
84 views

How can I calculate the amplitudes of this signal's harmonics?

How can I calculate the amplitude's of the harmonics? This signal is the voltage of a capacitor bank. There is a few amperes of current on the capacitors in form of PWM. On the signal the 200mV Jumps ...
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1answer
61 views

Resonant Radar — How aspect independent is it? [closed]

Resonant Radar: transmitting at a bandwidth that encapsulates nearly the natural resonance frequency of a reflective object in hopes of illuminating it upon return (higher amplitude.) I have read ...
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4answers
78 views

Rejection of particular frequency in a signal which contains many frequencies in its spectrum (fourier transform)

How does a filter know which frequency is to reject? Detail: A signal may contain a lot of frequencies. How could we surely say that the result of linear combination of the result of applying ...
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1answer
40 views

Purpose of divide-by-2 (or CLK/2) on a video pixel clock generator ICs

I've been looking into some video clock generator chips and almost all of them have a divide-by-2 or CLK/2 output pin (in addition to the normal CLK out). What would be the purpose or application for ...
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1answer
80 views

Does a program exist to draw logic signal waveform from csv data?

Assuming that I want to collect several seconds of activity of digital signal on multiple pins of a device, one way is to create a simple FPGA design that buffers all that information and then ...
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1answer
19 views

Which are the physical factors that determine the maximum transportable resolution of a cable (for instance: HDMI)?

Which are the physical and electrical factors that determine that an old generation HDMI can transport for instance 1080p resolution, while a new HDMI (2.0) arrives at 4k? Is it due to a different ...
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2answers
53 views

What does it mean by input and output impedance in a signal generator?

I have a Lock-In amplifier that can generate sinusoidal signals up to 1.5V peak. There is an output port and input port, and I can obviously fix the frequency or amplitude of the signal I am sending ...
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5answers
134 views

Sampling theorem clarifications

whenever the sampling theorem was explained to me, a situation of this kind was proposed to me. If we look at the previous image we will see that the condition to avoid spectral aliasing is that we ...
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2answers
66 views

Can Decimation be used to improve the SNR of a signal?

While researching SNR improvement techniques, I came across many techniques, mostly the application of digital filters and windowing. Shortly, I read an article that said that performing decimation ...
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2answers
104 views

Is it easier to implement sigma delta modulator in FPGA by filter or state space model?

Sigma delta modulation is extensively used in quantization to reduce quantization noise. In the literature one can see different architecture for example python-deltasigma to implement a modulator. ...
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31 views

Changing an AC Signal with a MAX9926

We are using a MAX9926 in Adaptive mode to detect zero crossing of a crank signal. Its mode cannot be changed (PCBs made) however we have a particular use case where the signal presented is as ...
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1answer
25 views

Gaussian Channel: Capacity and Explanation

Let's consider a gaussian communication channel, which is represented through this scheme: Starting by this assumption it is possible to prove that the channel capacity is equal to The computation ...
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1answer
73 views

Effect of zeroes in stability

I thought earlier that zeros have no direct effect on stability but when I read the below article of Wikipedia where it said under the heading "Effect of poles and zeros " It says that adding zeros ...
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1answer
68 views

Opposite of the ideal notch filter

I know that the ideal notch filter passes all frequencies but one, but is there a filter that passes only one frequency and blocks all others? What is do you call such a filter and what is it used for ...
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0answers
28 views

Difference in output between digital codec and analog filter

I'm working on a project which deals with filtering audio signals with a Low Pass Filter and amplifying the output. Currently, we are solving this using the TLV320AIC3111 audio codec by Texas ...
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4answers
151 views

Is there a data transfer limit for virtual serial ports

I want to record 5/10 seconds of audio using an electret microphone and an STM32 nucleo development board and send it to my computer in real-time to be processed. I'm a beginner so I'm sure I'm making ...
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1answer
42 views

how to reduce signal noises

I am trying generate guided waves on simple metallic plate through piezo-ceramic material, I place two piezo on the surface of the plate at the different location and through Arbitrary pulse generator,...
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0answers
41 views

Voltage Measurement through Spectrum Analyzer

I have done some measurements with a Spectrum Analyzer of a square wave of 100kHz and amplitude equal to 1V. The resulting power spectral density is here shown: The highest peaks represent the odd ...
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33 views

Finding gains from the summing different phases signals

I have four signal which are the same frequency and different phases. It is possible to think S1=1kHz sine,0 degree S2=1kHz sine,30 degree shifted S3=1kHz sine,60 degree shifted S4=1kHz sine,90 degree ...
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1answer
38 views

Fourier Series of Convolution of Periodic and and Aperiodic Signals?

The impulse response of an LTI system is aperiodic and I pass in a periodic signal. Now I need to find the Fourier series representation of the output. Since Convolution in time domain is ...
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3answers
207 views

Why does an optical drive use laser light?

Nowadays, lasers are cheap, but back in the day when CDs were first introduced, they were expensive. What is the reason for using a laser instead of a normal light source in optical drives?
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2answers
73 views

Matlab code to derive the overall difference equation relating two systems

Using Matlab, I am trying to: Get the overall difference equation relating to z[n] to x[n] and check if z[n] = x[n] is a valid solution to the overall difference equation I have two signals given ...
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1answer
53 views

CDMA basic working principle

I find it hard to find on the internet a simplified explanation of the principle of operation of the CDMA system. Could you give me an example of how it works and how a receiver can correctly identify ...
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1answer
69 views

Final Value Theorem yielding the wrong result?

C1 has an impedance of 1/0.1s Ohm in S-domain. Its impedance together with R1's is 100/(10s+10) Ohm The transfer function is: $$\frac{V_2}{V_1}=\frac{5}{\frac{100}{10s+10}+5}=\frac{50s+50}{50s+150}$$ ...
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150 views

Modulate/demodulate 125khz signal to 433Mhz transmitter module (2.5Ghz carrier)

I am trying to implement a project which consists of two circuits. Circuit A receives a 125khz AM signal and modulates it to 433Mhz CC1101 which then uses 2.4Ghz carrier to send at longer distance. ...
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1answer
201 views

RMS value of fundamental harmonic vs RMS of third harmonic

If we have a periodic signal (square wave) with amplitude of 100V. Then what would the RMS value of the fundamental harmonic be compared to the RMS value of the third harmonic? After some suggestion ...
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2answers
56 views

Difference between four matrices of state space?

I already know that there are two common types of representations used for mathematical modelling. One is transfer function and the other is state space. When dealing with state space representation, ...
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1answer
32 views

What are the appropriate pulse width and PRF for a pulsed Doppler sensor

I have a raw k-band transceiver, radar-based 24 GHz, motion detector, IPM-165. and here is the datasheet: https://www.innosent.de/fileadmin/media/dokumente/DATASHEETS_2016/Datenblatt_IPM-165_V8....
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1answer
50 views

Confusion regarding step responses of integrator and differentiator?

I am using matlab to study about step response of integrator and also of differentiator using transfer function modelling technique But i have two confusion, one in case of integrator is that step ...
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1answer
161 views

Spikes in raw acceleration data from AC motor

I have an MCU with an accelerometer, tightly mounted onto an AC motor inside a production hall. Once an hour, it collects 1 sec. (Sample rate is 5000) of acceleration data for the motor and saves it. ...
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1answer
73 views

How to determine value of t when plotting a signal

I'm trying to implement this model inatlab: I know that Ri = 2 and Si = -0.05+3j, ignore n(t). I want to plot the signal in time response, this is what I got so far: ...
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1answer
39 views

How to obtain SNR when we have the samples of a non-DC noisy signal in practice? [closed]

This may sound a naive question but I couldn't find an example. Let me begin with what I know about SNR and where I am confused. Lets say I have a DC like signal with some random noise on it and I ...
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2answers
62 views

Determine the output signal given the input and inpulse response

It's been a while since I've worked these types of problems, but I've been working out the following problem for a while now and can't figure out a few details: And here is the solution: ...
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2answers
129 views

Potential hardware solutions to detecting which string/fret is being played on a guitar? [closed]

I'm aiming to translate sounds played from the guitar to guitar tabs (accurately). I've had a look at solutions for detecting which string is being plucked: Detect string plucking in electric bass ...
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3answers
72 views

Measuring veloctiy by detecting objects with an analog sensor

I have a sensor (DRV425) which outputs an analog voltage. The voltage level changes to a lower voltage when the sensor pass an object. Please take a look at the screenshot. It shows the output signal ...
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36 views

Sum of a piecewise defined discrete in time function

I have to make the sum from \$-\infty\$ to \$\infty\$ of the next function (\$k\in \mathbb{Z}\$): \$x[n]=\left\{\begin{matrix} 3 &, &n=3k \\ 0 &, &c.c \end{matrix}\right.\$ for ...

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