LSI Correlator

The LSI Correlator is a competitively priced digital correlator designed for real-time computation of auto- and cross-correlations and for photon counting of pulse streams arising from dynamic light scattering (DLS), diffusing wave spectroscopy (DWS), diffuse coherence spectroscopy (DCS) and fluorescence correlation spectroscopy (FCS) experiments.

This advanced hardware correlator implements both the multiple-tau and linear-tau digital correlation algorithms which allow spanning the largest lag-time range nowadays available. This makes our correlator suitable for particle sizing of both fast and slow dynamics samples. Our device is especially designed to offer the greatest flexibility, robustness, reliability, and platform portability. Its powerful hardware architecture makes the LSI Correlator a stand-alone device, suitable for further customization.

Correlation function generated by the LSI Digital Correlator based on a Dynamic Light Scattering Experiment.


Main Features

Multi-tau Auto- and Cross-Correlation: 16/8 multi-tau correlation scheme, covering lag-time axis spanning from 12.5 ns up to 3436 s by means of 322 channels, hence covering a time range of 13 orders of magnitude.

Programmable fastest lag-time: The LSI Correlator offers the possibility to choose the fastest lag-time of the averaged multi-tau correlation functions in order to reduce the statistical noise for signals that don’t need the fastest channels. Initial selectable lags are: 12.5 ns, 200 ns, 400 ns, 800 ns, 3200 ns.




Normalization: Both symmetric and compensated normalization are selectable. 296 monitor channels are available upon 322 total channels.

APIs: The LSI Correlator can be accessed through an application programming interface (API) available for Matlab, Communication: The LSI correlator transmits via USB 2.0 and Gigabit Ethernet for remote usage. Optional: Java, LabView, C, C++, C#, Python, etc.

Supported Operating Systems: Windows and Linux.

Software: The device is accompanied by a user friendly software for device control and advanced data-treatment when used as DLS correlator (CONTIN, Cumulant Analysis, Exponential Fitting). 

Linear Correlator Software: Starting at 0.4 µs to 12.5 µs sampling time with programmable lag time.

Detector Overload Protection: Our digital correlator implements a fast gating output that is triggered when the instantaneous count rate exceeds a user programmable threshold. This functionality is active even when not measuring and helps protecting expensive detectors from unexpected overloads.

Synchronization Clock Output: An output clock is available in case the user wants to synchronize the correlation function computation with the operation of other hardware parts in their setup.

Stable Operation:  The LSI Correlator comes with an external power supply for perfectly stable and reliable operation. It is able to recover from communication errors (e.g. host computer crashes, network outages, etc.) without the need to be reset.

Upgradable Firmware: The firmware of the LSI Correlator can be upgraded in few minutes by the user. This allows the end user to stay up-to-date with the latest features developend by the LS Instruments team.

Maximum Count Rate: 20 Mcps over 52 ms integration interval.
Standard count trace sampling time: ~ 52 ms

Size: The correlator in housed in protective aluminum housing of 6x12x12 cm.


Download detailed specification file:


Upcoming additional features

Linear Correlator Hardware: User selectable lag from 50 µs and multiples of 50 µs. The channel layout is user-programmable over 1024 user selectable lags to be chosen among more than 106 available channels.

Double Correlation Function: The correlator computes two independent correlation functions with identical structure (16/8 multi-tau)

Correlation scheme: 32/16



Hardware Digital Correlator

Volume discounts and tailored hardware configurations are available upon request. For more information, please contact .


The electronic hardware of the LSI Digital Correlator is available as OEM.