OptoScope’s outstanding measurement accuracy

Extremely small temporal jitter

Due to fluctuations in the sweep voltage, for technical reasons a dispersion of the temporal shift occurs when capturing images for measurement purposes with streak cameras. When several images are overlaid, this temporal shift then results in an overall image whose temporal resolution is reduced by the shift. These measurement errors are specified at 20 psec in streak cameras for images captured in rapid succession. The systems supplied by Optronis improve on this value and deliver a jitter of typically 5 psec. In single image mode – in other words, images in slow succession – this jitter can again be worked out using a software algorithm.
The term jitter describes the variation or timing displacement of a high-frequency digital signal. To understand this better, jitter can also be described as a “pulse tremor”. With a jitter, the variation may lie in the pulse frequency, in the amplitude or in the phase of the signal pulse. For images captured in rapid sequence, this can lead to a deterioration in time resolution. The temporal jitter of a sweep unit depends on the type and quality of the electronic circuit which creates the sweep.

Extremely small temporal jitter
This involves the established process with avalanche-effect transistors. The process is very popular as it gives a very rapidly executed reference impulse of high voltage which is directly available for the sweep. The advantage of the process is the simplicity of its implementation. The disadvantage is the avalanche breakdown, the time of which cannot be predicted. This occurs typically with a temporal jitter of approx. 20 psec. For its TSU11-10 camera, Optronis takes a different approach. Here, a top quality intensifier saturation system is used which converts the incoming trigger signal into a fast ramp of superior quality. As the function of the intensifier is purely analog, this results in a high level of precision repeatability and/or an extremely small temporal jitter.

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