Time cannot be created, but it can be measured by using common references. The oscillation of the cesium atom, or a pulsar, can be used in our lifespan, but neither one is steady forever. We can create 'instances' of time with tuning forks and electronic oscillators. By creating them we define them in terms of 'increments' of time. Those deemed to be laboratory grade become our reference devices for measuring time and frequency, the reciprocal of time.
Questions tagged [time]
216 questions
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What do I need to close an electrical circuit for a certain amount of time
I need something that closes an electrical circuit for a certain amount of time when it receives an electrical pulse.
In my case, two wires touch, even for a second, the device I need will supply power for 30 seconds to another device.
Someonation
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Wirelessly get the current date and time
I know there is a wireless signal all over the US (at least) sending out the current date and time. Some clocks use it so they don't need set, just not sure what its called. Is there a module or a circuit out there to listen to this to get the time…
Justin808
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Doppler pings from MH370 Inmarsat : how was the data processed?
Published news reports indicate Inmarsat used something similar to 'doppler shift' to analyze pings from flight MH370, concluding the plane was traveling south not north.
Any normal radio receiver would loose minor frequency shift early on in the…
Bryce
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Does the Epson RX8900 real time clock count the year "00" as a leap year?
The datasheets ambiguously say...
A leap year is set whenever the year value is a multiple of four (such as 04, 08, 12, 88, 92, or 96).
Is zero a multiple of four? This is more of a philosophical question than a specification. The shown series…
bigjosh
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Phase shift a data signal by about 200ns
It would be very nice to be able to insert a little "phase shift" circuit into a data line of mine to shift it by one clock - about 200ns - instead of doing it in software which will be difficult and break compatibility with other hardware which…
Thomas O
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Compute the total time required to take a photo
I'm in the computer sciences engineering field. For a project, I need to use a camera, take a photo, process it and take a decision and so on. It's a hard real time problem as we have timing constraints. Hence, I would like to compute the time…
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Are consumer systems able to measure nanosecond timings?
Following the theft of my brother's car (a modern Audi Q-something), I got interested in how contemporary cars are protected.
The authentication of the key to the car is dreadful (I work in information security and how certificates are handled is…
WoJ
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How to test if a discrete system is causal or non-causual?
I know like this might seem like a trivial question but I am a bit confused with it. Take for example the the system y=x(n-10). Initially I thought this system was noncausal because n-10 means that the graph of the signal would be shifting 10 units…
Andrew Schroeder
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