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oscilloscope

An oscilloscope is an electronic measuring instrument that displays physical quantities in amplitude and waveform as a function of time on an oscilloscope screen. The underlying display function is amplitude-related in the vertical axis and time-related in the horizontal axis: y = f(x).

Since both display axes are calibrated, the signal amplitude can be determined at any time on the basis of the vertical deflection. Provided that a time reference is created so that the oscillogram always starts at the same time at the left edge of the screen. This time reference is the trigger. The trigger is an electronic circuit that triggers the time deflection to a precisely defined and adjustable reference level. The trigger signal is generated in a comparator in which the input voltage is compared with an adjustable threshold value and when the level is equal, the trigger pulse triggers the signal for the time axis, the horizontal display plane.

Oscilloscope display with time and level axis

Oscilloscope display with time and level axis

Characteristic values of oscilloscopes

The most important criterion for oscilloscopes is their bandwidth, and from this the inherent rise time. There is a direct relationship between the two, which is caused by the low-pass behavior. The mathematical relationship between the two is approximately rise time x bandwidth = 0.35. If, for example, an oscilloscope has a bandwidth of 500 MHz, then the self rise time is calculated as 0.7 ns. The oscilloscope will therefore always display pulses with a rise time shorter than 0.7 ns with the inherent rise time.

Block diagram of an analog oscilloscope

Block diagram of an analog oscilloscope

Since signals in nature and technology do not necessarily occur periodically, there are storage oscilloscopes and digital oscilloscopes( DSO) for non-periodic and uniquely occurring signals. The latter dominate oscilloscope technology thanks to powerful A/D converters and fast memories. Another oscilloscope development is the mixed- domain osc illoscope( MDO) with which time- and frequency-related measurements can be performed simultaneously.

Informations:
Englisch: oscilloscope
Updated at: 27.08.2012
#Words: 309
Links: measuring instrument, amplitude, display, signal, trigger
Translations: DE
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