Difference between revisions of "Precision"
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| + | == Precision in the context of manipulation with actuators == | ||
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| + | {{todo|elaborate}} | ||
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| + | == Precision in the context of measurements with sensors == | ||
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| + | '''Precision:'''<br> | ||
| + | * The narrowness of the random distribution in the (nowadays digital and discrete) measurement readout. | ||
| + | * Not(!) the possibly present random distribution in the "real" value. | ||
| + | |||
| + | '''Resolution:''' | ||
| + | * The size of the steps of the measurement readout (no further sub-steps). | ||
| + | * In case precision is far lower than resolution a one step difference is pretty meaningless. | ||
| + | * The unit of resolution is: readable steps per unit of measurement quantity | ||
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| + | Precision (of single measurements) can never exceed (be finer than) resolution. | ||
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| + | === Lowering bandwith to increase resolution and precision === | ||
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| + | By taking many measurements and averaging them out precision can be improved. | ||
| + | Measuring this way takes more time so the maximum frequency of measurements (bandwidth) gets lower. This is why noise in measurement readouts falls/(rises) with falling/(rising) bandwidth. | ||
| + | |||
| + | In case of manual averaging over many sub measurements at some point | ||
| + | precision hits the resolution limit. Quite a bit before that happens one should start to store the averaged values with a higher resolution. While the new precision must still be higher than the new resolution (fundamental law), the new higher precision (harbored in the new higher resolution) '''can''' exceed the old resolution. | ||
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| + | '''The continuum:'''<br> | ||
| + | Even a single measurement takes finite time. So it can be seen as an average | ||
| + | over many much shorter sub measurements with much lower precision each. | ||
| + | Higher bandwidth <=> more noise. | ||
| + | |||
| + | This is related to the heisenberg uncertainty principle. | ||
== External links == | == External links == | ||
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* noise; standard deviation; bandwith | * noise; standard deviation; bandwith | ||
| + | ---- | ||
| + | * [https://en.wikipedia.org/wiki/Metrology Metrology] | ||
Revision as of 19:14, 8 August 2017
Contents
Precision in the context of manipulation with actuators
(TODO: elaborate)
Precision in the context of measurements with sensors
Precision:
- The narrowness of the random distribution in the (nowadays digital and discrete) measurement readout.
- Not(!) the possibly present random distribution in the "real" value.
Resolution:
- The size of the steps of the measurement readout (no further sub-steps).
- In case precision is far lower than resolution a one step difference is pretty meaningless.
- The unit of resolution is: readable steps per unit of measurement quantity
Precision (of single measurements) can never exceed (be finer than) resolution.
Lowering bandwith to increase resolution and precision
By taking many measurements and averaging them out precision can be improved. Measuring this way takes more time so the maximum frequency of measurements (bandwidth) gets lower. This is why noise in measurement readouts falls/(rises) with falling/(rising) bandwidth.
In case of manual averaging over many sub measurements at some point precision hits the resolution limit. Quite a bit before that happens one should start to store the averaged values with a higher resolution. While the new precision must still be higher than the new resolution (fundamental law), the new higher precision (harbored in the new higher resolution) can exceed the old resolution.
The continuum:
Even a single measurement takes finite time. So it can be seen as an average
over many much shorter sub measurements with much lower precision each.
Higher bandwidth <=> more noise.
This is related to the heisenberg uncertainty principle.
External links
Wikipedia
- en: Accuracy_and_precision => validity ~ seldom: Exactness
(accuracy ~ seldom: correctness ~ ISO: trueness)
de: Richtigkeit & Präzision => Genauigkeit ~ selten: Exaktheit ~ selten: Validität
(Richtigkeit ~ selten: Akkuratheit)
- Random and systematic errors:
Observational_error; Errors_and_residuals;
de: Zufällige Abweichung & Systematische_Abweichung => Messabweichung
- noise; standard deviation; bandwith
