A signal is a stream of information in the form of a varying quantity. Usually in electronics, signals can be in the form of voltages, currents, or radiated electromagnetic fields.

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Reconstructing Clock for Serial Signal

Supposing I have a serial signal (example below) which is transmitted without an accompanying clock signal, I would like find a circuit (using discrete components / ICs, possibly an FPGA, but not a ...
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2answers
41 views

How does the function inside the rectangular function work?

I'm looking at a Signals and Systems problem, and the question asks to show the inverse fourier transform of \$f(w)=\operatorname{rect}(\frac{w-10}{2\pi})\$ is: ...
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55 views

Which serial protocol or encoding scheme does this scoreboard use?

I am trying to decode a signal stream coming from a Nevco scoreboard controller: Packets like this are sent every ~2.7 ms. I suspect it is some sort of UART signal because it is on the RX line of ...
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0answers
28 views

What is the purpose of pilot tones in ofdm, what is its physical significance and how it works? [on hold]

In OFDM packet we send pilot tones aswell but why and what it actually does how it is coded, where it is coded, basically want to know A to Z
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1answer
42 views

looking to capture an infared code

I am trying to get an infared signal being sent from an emitter (think along the lines of a remote control). I know I can use a fotoransistor on a breadboard to capture/detect the signal, but I have ...
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1answer
31 views

How much is the noise of a multiplexer for analog inputs?

I have 4 sensors, each have with two differential output (S- and S+) that I need to use in a differential amplifier (with a gain equals to 1000 in my case). The difference between S- and S+ is ...
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0answers
34 views

Use Earth and Ground Rods as Tip and Ring for a Modem

My co-worker and I recently tested this theory out with two Cermetek 1794A modems. Datasheet: http://www.cermetek.com/Catalog/High-Speed-Modems/DataSheet/CH1794A_607-0020.pdf Now first, we did two ...
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1answer
66 views

Mirroring (flipping) a voltage signal?

Which circuit can convert the input voltage signal to either output signal A or B as shown in the image below? Background info: {Update1:This is the signal from a Passive Infrared (PIR) Sensor ...
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1answer
39 views

output of a cascade system with known impulse responses

We have a system \$x(t) -> |h1(t)| -> |h2(t)| -> y(t)\$ and \$x(t)= e^{(-2t)}u(t)\$ and \$h_1(t) = h_2(t) = e^{(-2t)}u(t)\$ and we want to find the output \$y(t)\$ of the system. What I am ...
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2answers
47 views

system and properties of linearity,causality, time invariance, stability, invertibility

I have a system and I want to find which properties hold for this system $$ y(t) = \left.\begin{cases} x(t) & t \geq 1 \\ \\ 0 & -1 < t < 1 \\ \\ -x(t) & t \leq -1 \end{cases} ...
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2answers
95 views

Why does more bandwidth mean higher bit rate in digital transmission?

I understand that similar questions like this one have been asked before on this site, listed below. However, I am confused about the answers. If I explain what I think I understand, can somebody ...
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1answer
59 views

Power opamp 'floating' output

So I had to design an amplifier with a 'floating' output. (I don't know if floating is the right word, it's the direct translation from dutch.) See the picture below ( I drew it whilst sitting in the ...
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2answers
60 views

Simple RFID reader - AM demodulator not working

I'm currently working on building my own simple RFID reader. I've already build a small circuit in which my coil is fed from 5V current source or is connected to ground dewpending on the 125kHz square ...
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1answer
41 views

Amplitude spectra of cos product

I have the following signal: $$\cos(2\pi t) + \cos(2\pi t)*\cos(20\pi t)$$ How would I find the amplitude spectra of this? I know how to find the amplitude spectra of a signal of the form like so: ...
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1answer
72 views

Xilinx and VHDL · Why is this INOUT port undefined?

I'm using Xilinx ISE 13.1 x64 WebPack for a college assignment and I'm implementing a BCT for the sake of it. It's a Binary Coded Ternary. Like a BCD, but with only three digits (0, 1 and 2), to ...
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2answers
259 views

How exactly does this shift-register work? - Fairchild 74HC589

I'm using a PISO shift-register, specifically the Fairchild Semiconductor 74HC589. I got the jist of the workings of a generic shift-register via the very useful animated GIF in Wikipedia link above, ...
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4answers
122 views

Waveform generation with opamp

I need to design a circuit that generates the voltage waveform shown in the Figure 1 when an input voltage is applied as shown in Figure 2. Figure 1 and Figure 2 are in the second link below. Only ...
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2answers
53 views

Create a fake depth encoder signal on a surface system?

I am trying to create a test box which will do away with the actual depth encoder as it is awkward to have out all the time the encoder is similar to this: ...
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2answers
47 views

Why does a nonlinear system cause inter-modulation?

Can someone answer or point to a link explaining why a nonlinear system causes harmonics. According to Wikipedia ... non-linear systems generate harmonics, meaning that if the input of a ...
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3answers
104 views

How to calculate maximum allowable signal swing at the collector? [on hold]

How to calculate maximum allowable signal swing at the collector? How does change in beta value change the swing at both ends?
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2answers
58 views

How to get the phase response of an arbitrary LTI system?

If I have a frequency response (of a discrete-time system) composed of several complex exponentials such as $$H(e^{j\omega}) = A_0 + A_1 e^{-j\omega } + A_2 e^{-j\omega t 2} + A_3 e^{-j\omega 3} + ...
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2answers
389 views

How to go about turning on/off a coffee machine with an Arduino?

I have a coffee machine that has one button. When this button is pressed, the coffee machine will do its thing and automatically shut off after a certain period of time. I need to use a signal from ...
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1answer
55 views

Standing Wave Ratio(SWR) Measurement

I'm trying to find a way to measure SWR digitally. Generally SWR is measured with analogue equipments and it is not practical on self designed PCB. I did not find so much resource on how to do it ...
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2answers
61 views

Door phone audio signal to pc soundcard

I need to interface door phone system to a pc soundcard to listen and talk to the external unit. The door phone to interface is an as yc/200 of BPT and its a classic analog 4+n wires Door phone ...
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4answers
102 views

Simple broadband RF generator [closed]

How to make a generator of RF signal which have multiple signal outputs ? Details: ...
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0answers
57 views

Forming Nyquist Plot from magnitude and phase transfer function graphs?

So the solution is present above, but I'm having issues understanding the Nyquist Plot. So here's what I know from the magnitude and phase graphs: At \$\omega = 0\$, \$G = |\infty|\$ At \$\omega ...
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2answers
71 views

Signal distribution, buffers, rise times and EMC

I am designing a DSP based audio mixer. There are 4 AD/DA converters (AD1939 and AD1974) and a DSP (OMAP L138), which is on a carrier module. I am distributing the frame clock (48kHz) and the bit ...
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1answer
55 views

How to perform FFT for I(real) & Q(imaginary) arrays?

I have two arrays namely I & Q, each array contains 1024 points. Now I'm trying to perform FFT using Cooley Tukey algorithm. According to the picture above, the number of input points are ...
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1answer
56 views

Barker code autocorrelation

How do you auto correlate the following Barker code? I tried to use the formula on Wikipedia's page but it did not make sense to me. +1, +1, -1, +1
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3answers
101 views

Circuit to Detect Floating Signal Line

I have a few external input probes on a device I'm making which are connected to an ADC. Is there an electrical (i.e. non-mechanical) method of detecting whether the ADC input is ...
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2answers
125 views

Combine two audio signals

I'm currently building an in-car alert system using a Raspberry Pi. My car has an AUX port (3.5mm jack) which I currently use with my phone - to play music. I wish to be able to play music, and play ...
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53 views

Shielded cable vs. unshielded in underwater environment

I know basic electromagnetic theory very well and understand why this works but I'm not sure about one thing regarding usage of coaxial (shielded) cable vs. unshielded (normal conductor) cable when ...
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3answers
61 views

Is it possible to have a continuous quantized signal or a discrete infinite precision signal?

When converting an analog signal to the digital domain I understand that one does two things. An analog signal is continuous and must be sampled in to discrete time segments (Discretization) The ...
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2answers
99 views

Xbee-Arduino serial input (outliers problem)

I have an Xbee configured as receiver and Arduino (standalone w/ atmega328p chip) connected together. The RSSI pin of the Xbee is connected to one of the Arduino Board PWM pin. I used the PulseIn to ...
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2answers
216 views

Signal jammer vs scrambler [closed]

From what I understand, both of these things inhibit electronic devices from communicating with each other. A scrambler does this by altering the signals sent out by the transmitter device in such a ...
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1answer
87 views

(Arduino Uno) Wrong Input on Pin 2 even though it's not really connected

I'm new to Arduino and I have following problem: I tried to control a servo with two buttons (left, right) and it worked perfectly. But today I tried to do the same but with some additional LED ...
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1answer
89 views

How is signal strength calculated?

How is the signal strength calculated in case of cell phones ? How will the signal strength be calculated in case of WiFi networks ? I am not certain if the question I am asking is the same as QoS ...
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1answer
50 views

Linearity and time invariance

If the input of an unknown system is shown by: \$x(t)= u(t)-u(t-1)\$ which results in the following output: \$y(t)=u(t)-u(t-3/2)\$ then what can be said about the linearity and time invariance of ...
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1answer
199 views

How to get RSSI of Bluetooth, specfically HC-05

We purchased a Bluetooth device EGBT-045MS in hope that we will be able to get its RSSI. Do you have any idea how to do this?
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1answer
83 views

How can the signal strength of an RF signal be measured?

I am a graduating ECE student and we are currently making our project study. Our group would like to make a proximity indicator. Initially, we planned to use Radio Frequency for this. The idea was to ...
3
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5answers
273 views

Does the fundamental frequency affect the bit rate on a wire?

This is from the book Computer Networks by Tennenbaum: The bandwidth is still the width of the band of frequencies that are passed, and the information that can be carried depends only on this ...
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0answers
72 views

Why more bandwidth means more bit rate per second? [duplicate]

According to this link ( and some other sources I have found ) more bandwidth on a wire means more bit rates per second... Can someone try to explain why this is so as simple as possible? This is ...
0
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1answer
55 views

How to find Amplitude of a Signal in Simulink

I have a com port object sampling at 0.01 seconds a stream of data. The 'data' is a signal from an accelerometer with a sinusoidal shape. I need to do math operations on the amplitude of this signal. ...
3
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2answers
110 views

Clalculating effective value of square waveform

I need to calculate the effective value of this signal: I dont know how to calculate this. Iknow how to calculate the effective value of well known waveforms like square, sin, ..., but this is a ...
3
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2answers
137 views

Sampling Theorem

$$x(t) = \frac{sin(2000\pi t)}{\pi t}cos(1000\pi t)$$ is sampled with sampling period \$T_{s} = \frac{1}{8000}\$, to obtain the sampled signal \$x_{p}(t)=x(t)p(t)\$, where \$p(t)= \sum_{n = ...
3
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3answers
557 views

How to Calculate the average of a Square Wave?

I could not figure how to calculate the average of a square wave. Consider a square wave of +5V from time 0 to 6 sec and -3V from 6 to 10 sec. On integrating from time 0 to 6 the average: 3.0V On ...
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2answers
94 views

What component to use for audio signal switching?

I'm looking to build a guitar pedal switcher based on a Raspberry Pi or Arduino (have not yet decided, but I have an unused Raspberry around and I lean towards that). Anyway, digital logic. Now, I ...
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1answer
111 views

How to drive a video signal (of any kind) to a CRT monitor? What's the protocol, interface, standard, convention, etc.? [closed]

Say I am going to develop a video displaying computer componenet (call it a TTL chip, GPU, whatever). There has to be some basics on how to communicate with the monitor, or how to make sure the data ...
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4answers
150 views

Is this a valid sinusoid?

The given image is from first edition of this book To me the first sinusoid seems valid, in sense that values can be computed at different points. However, in the case of second sinusoid I fail so ...
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1answer
112 views

Connecting phone using copper power wires

I want to install a video door phone (intercom) in my home, for this I have done a pre-wiring of 4 individual copper wires (normally used for home electricity) and the total length of wires is about ...