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Questions tagged [signal]

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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Why is my Iphone signal generator not producing the desired results?

I have "Signal Gen" installed on my iphone. I am using a male-male aux cable and am trying to connect it to my multimeter. I have the signal generator set at -0.0dB running at 80.Hz. When I connect ...
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43 views

What is image and video signal ?

Signal is something that carries information. Usually, something is a pattern of variations of physical quantity that can be manipulated, stored, or transmitted by a physical processes. I am wondering ...
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35 views

How can I measure RSSI of an antenna with an Arduino? [on hold]

How can I measure RSSI (Received signal strength) of an antenna with an Arduino? Is it sensible to use ESP8266 with Arduino for this?
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using directional coupler to cancel common mode signal?

Reading this paper, and other ones by the same authors, I encountered the idea of rejecting the common mode signal (the large background) using a directional coupler. The second paper linked here ...
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55 views

FPGA/VHDL: Branching Input Signals

I was curious if it's possible, or if there is any harm, might be a better question, in branching an input signal within an FPGA design for multiple uses? What I was looking to do in my design is this:...
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1answer
45 views

Protect signal from noise in Arduino

I am trying to send a signal from the Arduino to a relay to open a switch. My problem is that my Arduino will be near the AC power lines. I searched for how to prevent the noise to ruin the signal ...
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1answer
59 views

Need help extracting line out signal from car radio

I'm trying to extract audio signal from my car stereo and use it as an input to my external amp. The place I want to get it from is marked in red in this picture: I used the IC31-34 pin12 to get the ...
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13 views

Find a particular TMSI during paging in GSM

I have read that Mobile Stations (phones) in a particular Location Area are paged using TMSI (mostly) during an incoming call. This paging signal is destined for all Mobile Stations. I would like to ...
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36 views

What is the signal-noise model of laser induced fluorescence?

The following image is an example of a fluorescence signal trace from the photomultiplier tube detector (PMT). Each spike represents one fluorescently labeled cell. This signal model is definitely ...
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1answer
40 views

Spectral analysis of spectrum analyzer

Using measures from a spectral analyzer, I am a bit confused on how to properly compare the power of each spectral line with the fourier coefficients (Parseval). Take this signal: Take it's spectrum:...
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2answers
84 views

Why are binary signals drawn continuous in time despite being a digital signal [on hold]

The conventional definiton of a Digital signal is as follows: A digital signal is a signal that is discrete in time and quantized in amplitude. Almost all resources (textbooks, online sources,etc) ...
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36 views

Isolate a digital signal that changes its amplitude

I have to isolate a digital signal that has the following characteristics: frequency: between 1 and 1000 Hz amplitude pk-pk: 12V offset: 0-6V With "offset" I mean the actual voltage may change from ...
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72 views

Rubidium standard mystery output?

I've been playing with a frequency counter (Racal 2202R) that has a built-in rubidium standard. It has two outputs, "Rb OUT 1" and "Rb OUT 2". I could not find any documentation at all, but the ...
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66 views

3.3v signal to drive 5v relay [duplicate]

I am reposting a question with more details, hope you will be kind enough to share you knowledge with me - I am currently playing around with a NodeMCU 1.0 - ESP8266 and having trouble switching on ...
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0answers
32 views

Question about time invariant systems

So, as per projectrhea Going x[n] -> System -> Delay results in what I would expect. However, going ...
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1answer
69 views

Wheel heading using PWM

I have a general question which im not sure how to implement. Suppose that a car is driving on a straight road and it starts doing some maneuver. Due to this maneuver the driver moves the wheel ...
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1answer
47 views

Understanding voltage drop in control cables

I recently worked on a project that involved a 300 feet cable run from one part of a building to another at our plant. Its a simple 120V circuit that originates in a control panel, travels 150 feet to ...
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8 views

The reason for signal not going back to LOW at high frequencies [migrated]

I have written a simple Arduino sketch, that shall produce a clock signal. Here is the code: ...
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2answers
61 views

What is the meaning of the difference between the Fourier transforms of a single pulse in these two cases?

In texts the Fourier transform of a single pulse is explained as below: They always create the pulse from -T to T, and they always show the sinc function symmetric around the origin. But in reality ...
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56 views

Confusion with Nyquist theorem when sampling cosines versus sines

I'm having different results when sampling a cosine wave versus sine wave at different scenarios. I used MATLAB to plot waveforms. I will try to give some examples to make clear where I'm stuck at. ...
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1answer
52 views

Single tone signal generation at microwave frequency with best phase noise and spurious performance

What is the best way to generate a single tone signal with best phase noise and spurious performance? Is frequency multiplication the best way? single stage multiplication or multi stage ...
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2answers
44 views

Confusion between analog & digital signal and modem

Telephone wire is a lowpass chaneel so the process looks like below. (Maybe right?) Voice(analog signal) → Sampling(digial data) → Coding(digial signal) → transmit There's no need to convert digital ...
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2answers
33 views

Signals and Systems - Taking Integral of Unit Step Function

I am a taking signals and systems course and my professor posted the solutions to our latest homework and I am trying to understand one of the steps. Below is the solution. Bracketed in red is what I ...
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1answer
60 views

Find a sinusoid in a sensor data

I am collecting raw data from a radar sensor using source code from the manufacturing company to allow me to plot data. I am looking for a repetitive movement that would be considered sinusoidal. ...
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3answers
137 views

Methods for confirming on both sides that a signal was received in one direction

Say there are two devices (A & B) that talk to each other (full duplex). For the sake of this example, let's say the medium is RF (wireless). If device A sends a message to device B, what ...
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1answer
50 views

Pseudobipolar signal example - Analog Devices AD7682

What is a pseudobipolar signal? I read this word in the datasheet below: http://www.analog.com/media/en/technical-documentation/data-sheets/AD7682_7689.pdf Can you show me an example with a plot ...
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1answer
47 views

Would a bridge rectifier allow to detect µs-scale pulses of either polarity

The incoming signal is ground-referenced and consists of short (a few µs each) pulses at >150V. The signal is at ground potential the rest of the time (the "duty cycle" is low), and is of low ...
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2answers
60 views

Proper convention for schematic component pin input/output arrows

In a schematic, if a designer chooses to use arrows on pins of a component, should they always point in the direction of current, or in the "perceived direction" of the signal? Or this a made-up ...
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2answers
54 views

Do I need to consider RF power splitters for signal <1kHz?

I need to tap a signal on a BNC cord to record it with a Labjack ADC. The signal is very low frequency, as the FFT shows. I was planning on using an RF power splitter to add a line to the Labjack. ...
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1answer
38 views

Are these two ways of doing equivalent?

I have two signals sampled at, say, 256 Hz. I want to make the difference between these two signals and downsample them, say until 32 Hz. Is it rigourously the same (in term of final result) to make ...
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2answers
70 views

Does a splitter still reduce signal if only 1 of its ports is used?

I'm using a Wilson Electronics signal amplification system to try to get phone signal in my house. I'm going to attempt using a coaxial splitter like this one to split the amplified signal to multiple ...
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1answer
33 views

Higher Voltage = Improved Signal Strength

I'm using a reed switch to detect the state of my garage door. It's connected to an ESP8266 via twisted cables of 1.5m and each line has a pull-up as the signal floats too much otherwise. Well it ...
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2answers
371 views

PWM, PAM, PCM sine generation and usage confusion

I am confused about something fundamental regarding PWM, PAM and PCM. I am going to be using a speaker's driver analogy to explain my point. As far as I know motors use PWM for power input, I don't ...
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1answer
123 views

RS485 minimum node spacing - 3 x RS485 device on PCB

I would like to ask something about RS485 minimum node spacing which is described in (Page 5) TI Design guide I would like to create device which consists from 3 existing RS485 devices. My plan was ...
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2answers
162 views

How can I determine the order of filter?

This is my first study about signal analysing. I'm very confused about filter order. My problem is how can I know whether its 4-th order, 12-th order, or 2nd order like the book says so? I'd like to ...
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1answer
50 views

Pass a signal in low-level entities and update it back in top-level entity in VHDL

I have tried a lot to pass a signal that is in a top-level entity, to a low-level entity as an in-port and do some operations on that signal and let the changes happen to the main signal. Here i just ...
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1answer
49 views

RF Combiner Losses

I'm having a hard time understanding what is actually achievable with an RF combiner. Let's consider this scenario, here port 1 of the RF combiner has a sinusoid at f1=100Hz and port 2 has a sinusoid ...
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1answer
45 views

RF signal generator, spectrum analyzer measurement questions

I want to test the attenuation characteristics of an RF filter I’ve built into a project, but do not have any experience using RF signal generators or spectrum analyzers. In all of the videos I have ...
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1answer
49 views

Longest Usable Wires for Low Voltage DC

I have a question that I am curious about. I am designing an IoT device from my microcontroller. My question is how far can jumper wire (standard solid-core copper wire) go before it loses significant ...
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1answer
46 views

How to use a signal from one function generator to gate another signal from another function generator?

I have 2 function generators with me and each is outputting its own signal. The first one is a 100kHz square signal and the second one is a 10MHz sine signal. What I want to do is use the first signal ...
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2answers
121 views

A confusion between dB and dBVrms

dB is always power ratio and we can write it in terms of voltage ratio. Imagine Vx = Vs*sin(wt) where Vs is the amplitude. In the case of dBVrms the Vref is 1V rms. So: dBVrms = 20*log10(Vs/sqrt(2))...
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2answers
48 views

Period Measurement

I am reading a book about the measurement in communications. There are a lot of information about how to measure frequency and period of signals. OK, i have understood that we should measure the ...
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0answers
70 views

signal generator and clock synchronization with FPGA

I am just a beginner in electronics, so please bear with me. I am using a signal generator to get two channel output which are then fed to a FPGA based Mojo. The mojo is then connected to a computer ...
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2answers
95 views

Long distance button

I have always had problems with my wireless doorbell solution. Since my driveway is around 50m (160ft) the signal is never quite strong enough to trigger the bell all the times. So I was thinking ...
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42 views

Calculation of strain using fiber sensor

I'm going to use that fiber sensor for straing measurments https://www.smartfibres.com/products/smartfbg I would like to know the signal processing procedures. My approach is to do FFT with window ...
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1answer
58 views

Method for Sending Multiple (16) Channels of Duty Cycle Modulated Signal over Medium-Long Distance

Problem What is the best method or industry standard solution for transmitting multiple channels (13 signal, 3 ground) of duty cycled modulated signals up to 25 feet. The data will be transmitted by ...
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2answers
116 views

How does an electrical speaker determine amplitude and frequency? [closed]

So, I know that a DAC converts coded binary signals into analog signals, but what sort of thing determines the pitch and amplitude of the outgoing sound? Does the DAC use a clock for frequency and ...
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1answer
35 views

Ion-selective electrode: high input impedance to measure the voltage

I read that an ion-selective electrode has an high impedance (\$100 \, M\Omega\$) and that it's necessary a high input impedance to measure the electrode voltage. I'd like to understand the above ...
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45 views

STM32L4 drive voltage randomly(?) too low

Not really sure where to even begin with this one. Last night when I turned everything off, the STM32L432 Nucleo board I've been working with drives high to 3V. When I turned it on this morning--no ...
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57 views

where to separate a whole Analog to digital chain into two PCBs

I wanted to ask this question in ADC vendor's forum, but I realized this is a general signal question. So, put is here. My question is "where is the best place to separate a whole Analog to digital ...