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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Ultra low current pulse generator (for BLE module interrupt)

At the moment I'm working on a project with at BLE-module. This module is based on the CC2541 from TI. I want the BLE-module to permanently transmit a signal. This module has two modes: a level- and ...
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39 views

FPGA with integrated operational amplifiers?

Do you know of any FPGA/CPLD chip with embedded op-amps and ADCs? Or maybe another way to amplify weak signals ( <1mV) inside an FPGA, without using external op-amps (simulation using DDA maybe)? ...
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1answer
45 views

Adding two signals and finding the RMS and Peak to peak value of the output signal

I would like to start by saying I have been solving exercise related to Op amps and how to find RMS values and Peak to peak values. But I got stuck on this exercise. Basically, two signals has to be ...
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1answer
40 views

How does a cable tone-and-probe kit work?

A useful tool for someone installing electrical cabling of any sort can be a Tone and Probe Tool: it allows one to find individual leads among a possibly hundreds in a cable trunk, without having to ...
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1answer
41 views

Maximum signal data rate

I have a frequency signal range from 25 Khz to 35 Khz. I know that the the minimum signal sampling to assure reconstruction of the signal from the samples is 70 Khz. Would it be correct to assume ...
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2answers
40 views

Which characteristics of a Radio signal are involved to be selected by radio receiver? [duplicate]

the radio antennas receives millions of signals. how our radio selects the appropriate signal as it's input? which characteristics of the signal are involved for this selection.
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1answer
36 views

Relationship between frequency and other signal characteristics

as a signal travels through the air it loses it's energy. when the energy of a signal gets low what happens to frequency, amplitude and other characteristics of that signal? does frequency decrease ...
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1answer
31 views

Calculate transfer function given 3dB point?

I'm not sure the relationship between transfer function from the 3dB point. The transfer function should give the gain, and I suppose when we put in the frequency at the 3dB point, the transfer ...
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2answers
29 views

first Mini dsp Project using matlab and books

i have basic knowledge of matlab and took signal and system course. i want to do project like below. but dont know filter on matlab. are there any books i can learn fft commands etc.(dft, ...
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1answer
19 views

What is the LCCDE equation of this block diagram

I cant find the LCCDE equation of this system ı try to reduce but thing will get compliceted
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1answer
40 views

İs this system is a LTI or not ?

I have a F system and a input of this system is e x(n) = e^iπn/4 and output is y(n)=cos(πn/4) So is the F system is LTI or it would be ? I try to using addivity and Homogeneity but I cant do it
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46 views

What does it mean for a voltage to be attenuated by X dB [duplicate]

Say that a signal is passing through a medium, and in the middle of it, the amplitude of that signal drops by 90%, in this case I would just say that the media attenuates the amplitude by X factor. ...
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1answer
51 views

For a first order system, what type of response to a sine wave?

If I put a sine wave through a first order system and reconstruct it with some type of weighting (equal or not), how should the response come out? Should the response follow the original sine wave ...
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1answer
31 views

A circuit to prevent parasitic powering of FT232RL by MCU, will it work?

In a previous question I asked how to prevent the MCU TX pin (3.3V when idle) from powering an FT232RL Usb to Serial chip via the TX line: Preventing parasitic powering of FT232RL by ATMega328P I ...
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2answers
392 views

Split TV signal to make a video wall

I'm working on this project for University. We are generating visuals by sending audio signals from the computer to an old tv. Left channel to TV's Vertical, right channel to TV's horizontal. We send ...
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2answers
48 views

Find the power spectral density?

I don't understand how the graph of H(w) is used to find the equation for H(150) and H(200.)
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1answer
57 views

Limiting small signals to one direction (ideally with passive components)

My setup is as following: I use a Y-Cable for splitting an audio signal to two devices (boxes and earphones). The headphones have quite big speakers so they act also like a microphone - feeding back ...
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1answer
68 views

Why does USB signaling to microcontrollers need resistors

I'm currently trying to make a USB device with the ATMega16U2. On page 187 of the datasheet, there are unspecified resistors between the USB port and the pins of the microcontroller The Arduino Uno ...
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1answer
40 views

How can I combine my knowledge of signal processing with electromagnetic physics? [closed]

Now at University I've learnt both signal processing and electromagnetics, I am curious as to how these two areas can be combined into one. For example, in signal processing you are required to find ...
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1answer
47 views

When is a system's frequency response symmetric?

When is the frequency response of an LTI system symmetric, i.e. which property does it need to satisfy? Does it have to do with the system being causal (I believe this means that h(n) = 0 for n < ...
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1answer
27 views

DDC112 Analog to Digital converter

In DDC112 Analog to Digital converter, its mentioned that its suitable for Low-level current output devices, such as photosensors, and can be directly connected to its inputs. But to increase analog ...
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1answer
32 views

Is there any repeater with power amplifier?

I installed sensor module connected with controller. Those are connected with 6-wire cable, and it consists of 2-wire power(5V & GND), 4-wire signals(0~5V analog). First time, I thought distance ...
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1answer
63 views

How electric signal is converted to more powerful electricity

First a little disclaimer: I've a newbie question which is simple, but somehow I can't explain it to myself. I'm interested in how electrical signals can trigger let's say a movement, which requires ...
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1answer
55 views

Line-of-Sight method of simple code transmitting for outdoors

I'm trying to determine the best way to do this. Basically I'm trying to design a system that would transmit a signal containing a simple code to allow the receiver to identify the source device. It ...
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2answers
40 views

RF Combiner Hardware

I have say, 4 170 MHz signals coming in on 4 BNC cables. I would like to add these signals together. Is there a name for a piece of hardware that does this? Are there any special considerations I ...
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2answers
82 views

How do I drop 19VDC from a 0-60VDC source to get an accurate linear 0-48VDC signal

I've been using the Stack Exchange website for years, but never asked or answered a question, so first I'd like to say thank you for all of the help over the years. On to the problem: I want to ...
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40 views

Voltage at some point on a transmission line (a power distribution line in this case)

I am interested in knowing the instantaneous DC voltage (ball park) at a capacitor bank on a power distribution line at the instant I interrupt the circuit some distance away. If I interrupt the ...
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5answers
116 views

Why do we need transforms (Fourier, Laplace, Z and wavelet etc.) for a signal to analyse?

Why do we need transforms (Fourier, Laplace, Z and wavelet etc.) for a signal to analyse? Is it necessary for practical calculations and analysis?
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1answer
35 views

Choosing the right sampling frequency for WLAN 802.11ac signal (BW : 80 MHz)?

I’ve got a WLAN 802.11ac signal & it’s bandwidth is 80MHz, now I would like to know the ideal sampling frequency for this signal. As per the nyquist theorem , the sampling frequency could be 160 ...
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2answers
294 views

Area under Dirac Delta function

What is the difference of the area calculation for the Dirac delta function when using different limits of integration? $$\int_{-\infty}^{\infty}\delta(x)dx = 1$$ but ...
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1answer
37 views

exam problem finding impulse response from a given system? [closed]

I search but i did't find useful way to answer it please how to get the impulse response from a given given system
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1answer
143 views

Why it has used BPSK modulation after OFDM?

I am quite new to OFDM modulation. I am reading this from a tutorial. In one of its parts, for showing amplitude variation of the OFDM signals, there is a graph that has used 8 sub-carriers and BPSK ...
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1answer
155 views

Comparison of Series and Parallel LC Filters for Noise Reduction

Since there are two basic types of LC circuits that can be used for passing/blocking signals, I'd like to know the differences when using series or parallel LC circuits for noise at a known frequency. ...
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1answer
94 views

When is impedance matching necessary? Isn't it much less efficient on all other aspects?

I understand that discontinuities of the physical properties of conductors create reflections much like dioptres reflect a bit of light, but : in which cases does impedance matching become ...
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26 views

How is 802.11 (Wifi) received signal strength (RSS) measured and reported to software?

I have looked around for a while now to find an answer to this question, but answers I find do not fully answer my question. I found this response interesting from another question on this site. ...
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2answers
59 views

Systems and signals - integration with dirac's function and step function

I'm taking the introductory course to systems and signals and the mathematics of integration using the step function and Dirac's function and For the first integral, I just don't know how to ...
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1answer
54 views

Replace Electret Microphone With Arduino Output

I have the following circuit for a simple FM transmitter. I want to replace the electret microphone with a simple tone generated by an Arduino (or equivalent) that will be broadcast over FM radio. ...
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2answers
123 views

Is it possible to amplify near zero signals?

Is there an amplifier has an ability to amplify any signal down to -500 dBm? If there is not, can it be possible? If it is not possible, what is the weakest ever signal that can be amplified?
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1answer
38 views

Determining whether piecewise function y[n] = {x[n] if n even, -x[n] if n odd} is time invariant

$$ y[n] = \begin{cases} x[n], & \text{if }n\text{ is even} \\ -x[n], & \text{if }n\text{ is odd} \end{cases} $$ My usual way of solving time invariance problems is to do this: $$y[n-m] = ...
2
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1answer
65 views

Finding the Power developed by the Nominal Frequency in FM

Question The sinusoidal signal \$f(t) = \cos(2 \pi f_m t)\$ is applied to the input of an FM system. The corresponding modulation signal output for \$f_m = 1kHz\$, is $$Q(t)=100 \cos(2 ...
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1answer
74 views

VHDL internal signal assignment

I am new to VHDL and tried to implement a simple example from a book, what represents a 2bit register and the testbench. Compiling the files works well, and signals the stimulate the register (reset, ...
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1answer
52 views

How to get BPSK data from I/Q signal

I am using AD8347(0.8 GHz to 2.7 GHz Direct Conversion Quadrature Demodulator) to demodulate a BPSK modulated carrier wave. There is no intermediate frequency used. By feeding the signal into this ...
2
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1answer
109 views

Difference between SINR SNR

I am bit confused between these two terms. I understand SINR is signal to interference+ noise ratio and SNR is signal to noise but isn't interference noise too? Then why have he segregated these two ...
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1answer
65 views

Complex numbers manipulation

I have a complex number s of the form s=[1/sqrt(NN\$_{t})] e^{j\phi_{k}}\$ S\$_{o}\$ is another complex number. It is given that |s-s\$ _{o}\$|<= \$\epsilon\$ where 0< \$\epsilon\$< 2 It ...
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1answer
72 views

Use of Audio Tranformers in Amplification

I came across this ckt to make a wireless ear phones using Infrared Signals from IR LEDs. I am unable to understand the use of Audio Transformer here to amplify the audio signal, instead OpAmps would ...
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0answers
42 views

Linear time invariant system transfer function is known - calculate output signal

Here is my task: 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) ...
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1answer
52 views

Sync filter in a lock-in amplifier

I've got two questions: What does a sync filter in a lock-in amplifier? What are pros and cons of using it?
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3answers
165 views

Sin signal from PWM

I wrote a program in order to use Pulse Width Modulation to simulate a sinusoidal signal. Added a low pass filter to get rid of the noise and the traces of it being a discrete signal. Added a half ...
2
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1answer
58 views

Radar maths I and Q components

I have just started work with radars. I read that incoming signal in case of Doppler radar is frequency shifted. On adding it to original signal we get Doppler shift. But we don't do it directly. ...
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1answer
92 views

Making Device to Send Data to Smartphones: 100m range, 1kb/s bandwidth, low power

What I want to make: A device that immediately sends a notification if the device incurs a moment of high acceleration. The notification needs to denote the acceleration. There is no guarantee that ...