Time Scale Expansion and G(0) in a 50 Nanosecond Real Time Digital Correlator
In order to have twice scale expansion of the correlation function during a real time measurement in our 96 channel Malvern correlator, we have devised the following modifications to be used in the scaling mode of operation (crosscorrelation of the signal with its scaled version): in the first group of 8 channels the correlator is operated with a short sampling time (ST) equal to T 1 and scale level s 1 . For the following 64 channels the ST and the scale level can be expanded by a factor S 1 adjustable between 2 and 16. The channels therefore run with T 2 = S 1 · T 1 and s 2 = S 1 · s 1 . In the last 24 channels there is a second expansion S 2 , therefore T 3 = S 1 · S 2 · T 1 and s 3 = S 1 · S 2 · s 1 . The first group gives in an expanded scale the behavior of the correlation for small delay times, in the intermediate group the main part of the relaxation is observed, whereas the dying away to g (2) (∞) can be followed in the last group. In each of the three groups the correlator forms the following sums
KeywordsCorrelation Function Photon Correlation Spectroscopy Scale Level Shift Register Real Time Measurement
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