Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

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.

A signal is a stream of information in the form of a varying quantity.

The use of signals is what differentiates electronics from power electric systems: in electronics the electricity is used as a carrier for signals, in order to transmit and process information.

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In a USB cable, is it OK to swap the D+ and D- wires?

I heard that D+ and D- are differential signals, does it matter if I swap them when connecting a USB device to the computer?
Yan King Yin
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Can a radio transmitter somehow detect the number of receivers in its area?

During conversation, a colleague proposed that over-the-air television and radio broadcasters can determine the number of viewers or listeners based on the "load" on their signal. This seems to me like total bupkis, but he's piqued my curiosity and…
ghaberek
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Why put a resistor in series with signal line?

A lot of times in circuits I see a resistor placed in series in a signal line and sometimes even in series with an MCU's VDD line. Is the intention of this to smooth out noise in the line? How is this different from using a small cap, like a .1µF to…
PICyourBrain
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What exactly are harmonics and how do they "appear"?

From reading so many sources online, I still cannot grasp why a different waveforms have harmonics. For example: when designing a silly amplitude modulation (AM) circuit that puts a square wave from a microcontroller in to an antenna, how are…
John Quinn
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Is it possible to receive information if the received power is below the noise floor?

This relates to my previous question, which I think I have asked in the wrong way: How to insert background EM noise into pathloss equation? I wasn't really interested in detectability of the signal, and I have phrased that question very…
David K.
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How termination resistors work; what happens if I use lower values?

I am going to try to interface low-speed 8bit DDR2 chip to FPGA, and I've got some questions crucial to make it work :-) Is that correct that the idea of termination resistor is to sink most of the signal to GND, so that only small part of it…
BarsMonster
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In which direction do electric signals flow?

We know that electrons move from the negative to positive terminal, and that holes flow in the conventional direction of current - from the positive to negative terminal. I've always assumed that this means that electric signals travel in the…
slebetman
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How does data travel inside a wire?

I know this is a very basic question but the answers returned by google are way too complicated for me to understand. I am not asking about modulation here. What I want to know is what exactly is carrying the data. Please let me explain my…
Sunshine
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Difference between bit rate and baud rate and its origins?

Everyone seems to have different definitions everywhere I look. According to my lecturer: \$ R_{bit} = \frac{bits}{time} \$ \$ R_{baud} = \frac{data}{time} \$ According to manufacturers : \$ R_{bit} = \frac{data}{time} \$ \$ R_{baud} =…
Psi
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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 PC with USB, then it makes clicking/popping noise…
csadam
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transmitting 5v signal over a long cable

I'm seeking for help here as I need a reliable answer to this. I need to get an input signal (low frequency 5v digital pulse), to a micro-controller from a (proximity) sensor situated in a distance from the control board. I'll itemize the important…
Codenamed SC
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Why does a female-female coupler break the USB-C standard?

I'm working on a project which uses a PCBA which basically acts as a USB-C extension. It has 2 USB-C receptacles (female) connectors. The mapping between the two receptacles is one to one. The pair of D+ and D- are shorted (meaning both orientation…
Frenetique
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What generates the clock signal in a fast CPU and how does it work?

Often, for integrated circuits, a quartz crystal is used to generate the clock signal. However, this only reaches speeds in MHz. What component, or what circuit, generates signals up to 5 GHz like in computer processors? How is it possible to…
Markinson
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Why are flip-flops usually triggered on the rising edge of the clock?

Usually in digital design, we deal with flip-flops that are triggered on a 0-to-1 clock signal transition (positive-edge triggered) as opposed to on a 1-to-0 transition (negative-edge triggered). I have been aware of this convention since my first…
travisbartley
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How do receivers decode multiple GPS signals on the same carrier frequency?

I'm currently researching GPS signals and am trying to fully understand the path of a signal from satellite to receiver. I understand that mixed into the GPS signal is a C/A code as well as a PRN which aids in the process of CDMA that the receiver…
Justanothermatt
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