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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2answers
97 views
What does small AC signal mean?
I'm taking an introductory electronics class, the first chapter is about amplifiers, controlled sources, gain, stuff like this. They mention "small AC signal" a few times but never explain what small ...
0
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4answers
108 views
Mathematical rigour in Signal and Systems
I'm an electronics engineering student with high inclination to analysis and pure mathematics ( abstract algebra/linear algebra ... ). I was just wondering if there was any book ( or any resource ) ...
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2answers
69 views
How to use electrically isolated weak signal for Arduino interrupt?
I'm trying to use the signal generator from a DSO Nano v2 to drive an Arduino interrupt for testing purposes. I have measured the output of the signal generator at approximately 13mA @ 2V DC.
I have ...
1
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2answers
48 views
Basic question on CRO usage
I have to measure signals using oscilloscope on all the four lines in following circuit. J1, and j5 are headers given by the manufacturer on the board (MACHX02 1200-ZE). I connected ground lead of the ...
0
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1answer
69 views
Should I use Magnet Wire as a conductor in this experiment?
I need to run a few wires from a HMC5883L compass sensor to a micro-controller to process the data. Can I use magnet wire to carry the signals from the sensor to the micro-controller or would the ...
6
votes
2answers
316 views
How does a signal travel down a telephone wire?
To get data to a computer the telephone wire must sent a signal but how does it do it ?
Does it use analogue or a digital signal?
How does it send the "1s" and "0s"?
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0answers
45 views
Zero-Padding seems to CHANGE FFT of signal! [closed]
I am having trouble with zero-padding. As I understand it, in theory, zero-padding in the time-domain should 'sinc-interpolate' the FFT of the signal in the frequency domain.
This would mean, that 1) ...
1
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1answer
85 views
Invert a 555 Astable Output Signal
I can't believe how much trouble I've had figuring out how to do such a simple thing.
I have a variable frequency, variably duty cycle 555 configuration in astable mode. I'm using a set of pots to ...
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2answers
67 views
Total Harmonic Distortion
If a specific project specification says "...amplifier must be linear such that the harmonic distortions are maintained below -40dB...", does that mean that a THD of -30dB would meet the requirements ...
1
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1answer
48 views
Optimizing signal voltage level for 5V device
Are there any benefits associated with using lower signal voltages?
For example, if a 5V device has an input high voltage level minimum of 2V, would running input signals at, say 3.3 vs 4.5 or 5v ...
-2
votes
0answers
36 views
Why would a 3G repeater stop working? [closed]
I recently purchased a 3G repeater identical to this one, for my dad's boss who moved into an area with horrible connectivity (both mobile and wired). The first few months the signal went from 1 or 2 ...
-2
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0answers
61 views
algorithm required for audio and video seperation [closed]
can anyone give me an algorithm to separate audio and video from a video signal having both audio and video part. I want to implement it using filters and make it work on matlab . Also any kind of ...
1
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1answer
135 views
Reading the frequency of an AC signal using an arduino
Basically I have a motor with a magnet spinning on the end. I have a sensor that produces an AC signal when the spinning magnet is placed next to it. It produces a voltage of ±300mV. I want to measure ...
0
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0answers
33 views
Simulating time variying multipath channel in matlab
I need to simulate a time variying multipath channel with a specific doppler frequency in matlab. How can I do that?
1
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1answer
51 views
Do I have to worry about backwards crosstalk with a 1 way bus?
I'm working on a DDR memory circuit, and I'm not sure how big an issue crosstalk is on the command/address bus. I've designed for crosstalk with the DQ/DQS and CLK lines because they are high ...
2
votes
2answers
125 views
I have to determine if the signal is linear, time-invariant, and/or causal
Here is my problem:
$$\frac{d^2y}{dt^2} + 5\frac{dy}{dt} + 8y(t) = \frac{dx}{dt} + 3x(t)$$
I have to prove if this system is homogeneous and additive in order for the function to be linear, but can ...
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1answer
41 views
A uniform scalar quantizer
I have a uniform scalar quantizer with M=4 levels of quantization, and a natural mapping from levels to bits of the 01000110111110 Frame. Is it possible that this ...
1
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0answers
67 views
how can i use “e” in MATLAB
is any other way to express this function so i can plot it in matlab over the range -1:.1:5?
continuous signal:
x(t) = 10e^(-3t)*u(t)
MATLAB does not recognized "e",
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1answer
67 views
State space representation in s-domain
I was supposed to find state space representation and its matrices of this system:
and I have no idea, how to do this. We were told not to transfer the system to time domain, but I can only do ...
4
votes
1answer
69 views
Is it possible to make a multi-display adapter as an independent project?
I've been looking at the Matrox DualHead2Go, which is essentially the best/easiest way to go about using dual monitors for a MacBook Pro. Some people suggest using a USB to VGA or HDMI - but obviously ...
0
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0answers
57 views
impedance mismatch and signal refletions
Below figure describes the setup
impedance mismatch ( the waveform on oscilloscope )
unknown behavior after adding a couple of resistors (to match impedance) in series between the laser driver ...
-3
votes
2answers
92 views
Free space model (wireless communications)
The received power at a given distance = 1km is 1nW .
Find the received power at a distance of 5km from the same transmitter , using the Free Space Model.
Suppose that frequency is 1800Mhz, ...
1
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2answers
90 views
How do I use T-Flip Flops to derive circuits - given the clock signal speed?
I've been trying to do my EE homework for several hours and cannot figure out how to do this stuff.. I've read through the chapter multiple times, searched YouTube and Google, and nothing seems to ...
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2answers
89 views
A simpler method or more descriptive answer to the Fourier Transform
I'm trying to do a CT Fourier Transform of these two signals
$$e^{-a(t-1)} \cdot u(t-1)$$
and
$$e^{-a(t-1)} \cdot u(t)$$
Where \$a\$ is any real number, and \$u(t)\$ is the unit step function.
My ...
0
votes
2answers
54 views
Common Mode Differential Analog Input
I'm using the LTC5598 IC for modulation. I am confused as to how to properly feed my BaseBand analog signal into the chip.
According to its datasheet:
The circuit is optimized for a common mode ...
4
votes
2answers
105 views
Returning Currents for two side boards and returning current questions
I have some questions these are I am not sure:
I have designed a board that has classical 2 side PCB design. Frequency is not a big issue for me but with ESD my CPU resets itself. (CPU clock 20 Mhz, ...
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5answers
410 views
How to Generate a square, sine, and triangle wave with DC input
I want to make a simple synthesizer as a start to audio electronics. I want to start with a simple square, triangle, and sine, which the user can vary the pitch.
Is there a simple circuit to do ...
0
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2answers
129 views
How to know the kind of filter from the transfer function [closed]
I got that system \$x_n \to x_n-x_{n-1}\$, so \$h_n=[.....,0,1,-1,0,...]\$, with \$h_0=1\$ and \$h_1=-1\$, so the transfer function given by:
$$H(\omega)=\sum_{i=-\infty}^{\infty} h_ne^{-jwn} = ...
1
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2answers
112 views
Attenuator noise figure and loss
My question is with regard to how attenuators effect noise. From what I understand
$$
\text{NF} = 10\log \left( \frac{S_{in}/N_{in}}{S_{out}/N_{out}} \right) = 10\log \left( L \frac{N_{out}}{N_{in}} ...
1
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2answers
47 views
Confusion with modulation/demodulation
I am following a book: Data communication and networking (Behrouz-Foruzan).
It says that modulation means building a bit stream from an analog signal. However as far as I understand it's the ...
3
votes
1answer
148 views
Is sending a signal over 433.92 Mhz blocked by plastic?
to be honoust: I never understood radiowaves; how I can receive radio in my house? Transferring a complete video through air from laptop to router? Never a clue.
So with that (lack of) knowledge my ...
2
votes
4answers
153 views
Measuring Signal Strength with a RF Circuit
Note: I'm primarly a 4th year Computer Science student, but I have also interest in electronics but I have very limited knowlege.
Is it possible to measure the signal quality or level of a RF ...
0
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1answer
79 views
Degradation of AC signals as inputs of inverter amplifier circuit
i recently, did a configuration of an inverter op amp model and i fed it with an analog signal of the form$$S(t)=2sin(1000t\pi)$$
As you may know, the general response of an inverter Op Amp (741), is ...
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2answers
76 views
How to choose and design a waveform generator such that it generates signals of mentioned rms voltage, Vi and of frequency f given below?
Type: Sinusoidal
Vi = 35 mV
f = 30 kHz
4
votes
1answer
71 views
How do I connect a signal shield to minimise noise from close proximity AC
In my proposed application, I will have approximately 30 RS-485 nodes configured in 3 chains spaced ~1m apart. There is a need to pass through 240v L-N-E, +5v, A, B, GND in each node. The physical ...
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1answer
353 views
Amplitude and phase spectrum in MATLAB
I have a little problem with the subject Theory of signal. We were told to make amplitude and phase spectrum of cosinus in MATLAB, but we don't have results nor materials from our teachers, so we have ...
1
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1answer
220 views
Estimating a sinc period and width of a rectangular pulse
For a rectangular pulse that has as a fourier transform of a sinc function like so:
How can I estimate its sinc period in the frequency domain and compute the width of the rectangular pulse in the ...
2
votes
2answers
160 views
How does Fourier series apply to signals?
I have the complex form of Fourier serie:
It says that an and bn are real numbers, while c is a complex number. I need Fourier serie to represent an electrical signal that should transmit bits. ...
3
votes
3answers
183 views
Why a high number of harmonics means a lower bitrate?
I am studying on a book (I'm still at basics) and I haven't understood why a signal with a lower number of harmonics implies a low bit rate. I have this figure:
It clearly shows how a signal with ...
18
votes
4answers
847 views
Do you recognise this signal?
The story for this signal is the following. I've bought an NAD C 356BEE amplifier with an integrated MDC DAC module. It has optical and USB input. The optical is OK, but if I connect the DAC to my ...
-2
votes
2answers
132 views
What amplifier circuit to use for a wheatstone bridge force transducer [closed]
I would like to amplify the signal from a force transducer which can measure load from 0-1500g. The object i am using is less than 1 gram. I would need an operational amplifier. I would like to know ...
-2
votes
2answers
107 views
A step function, \$u(t)=1\$, for \$t \gt 0\$. What is the value of \$u(0)\$?
What is the value of \$u(t)\$ for \$t=0\$?
we know,
\$u(t)=1\$, for \$t \gt 0\$
\$u(t)=0\$, for \$t \lt 0\$
3
votes
2answers
91 views
How do we plot \$u(t−τ)\$
When analyzing simple circuits to understand the theory of their operation, we often make use of the Heaviside step function, \$u(t)\$.
When we calculate a convolution integral, we must understand ...
-2
votes
2answers
157 views
Ultra low power Micro Wireless Audio Transmitter/Reciever [closed]
I'm am trying to send a signal from a device to a receiver. The signal would need to travel through walls/an enclosed area up to at least 150'. The signal would have to be powered by two AAA ...
0
votes
1answer
140 views
Book recommendation on “signals and systems” [closed]
I'm looking for book recommendation on "signals and systems" that will cover all the topics mentioned in the following list
Signals and Systems:
Linear time invariant systems:
impulse response,
...
0
votes
1answer
80 views
Orthogonal Frequency Division Multiplexing - calculate what frequencies are orthogonal?
So, I work at an ISP that uses wireless and DSL.
Something that keeps coming up is something called OFDM. It's used by some of our wireless solutions, and I understand (or at least think I ...
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votes
1answer
109 views
A zero mean random signal is uniformly distributed between limits –a and a and its mean square value is equal to its variance
A zero mean random signal is uniformly distributed between limits –a and a and its mean square value is equal to its variance. ...
0
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1answer
246 views
Arduino beacon for IR Seeker v2 (Mindstorms NXT Sensor) - Pulse IR at 38Khz Carrier and 1200 Frequency
I hate to ask a question like this, that is kinda just like "give me the code" but seriously. I've tried reading up on it everywhere, and I just don't seem to get a thing of having both a carrier ...
1
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1answer
77 views
3
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1answer
72 views
2-Channel Relay Question
I recently purchased this signal relay board.
When Input 1 and Input 2 are at 3.3VDC, both D1 and D2 illuminate.
Here is my set up,
+3.3VDC for IN1 as well as a separate +3.3VDC for IN2. For VCC we ...
