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Flex400R is the highest speed real time digital correlator.
Three modes of operations.
- One auto or cross correlation function.
- Dual correlation functions. (two auto, one auto one cross, or two cross correlation
functions)
- Quad auto correlation functions.
Flex400R in single correlation mode specifications:
- Auto/cross correlations.
- 9.97 ns minimum sample in single correlation mode
- 288 real time channels in single correlation mode.
- Delay time range: 9.97ns to 1 hour in multiple tau channel layout.
- Input signal: standard TTL pulses.
- Two BNC connectors
- Easy to use FlexWindows software and software for Windows NT 4.0 and Windows95/98
libraries included.
Multiple tau channel layout ( sample time denoted at T, data width W) single mode:
- First 16 channels: T = 9.97ns, W = 1 bits, delay times T to 16*T;
- Second 8 channels: T = 2*9.97ns, W = 2 bits, delay times 9*T to 16*T
- Third 8 channels: T = 4*9.97ns, W = 3 bits, delay times 9*T to 16*T;
- Fourth 8 channels: T = 8*9.97ns, W = 4 bits, delay times 9*T to 16*T;
- Sample time doubles every 8 channels and data width increment 1 bit to prevent overflow.
- The longest delay time is about one hour.
Intensity limits:
Flex400R is designed with sufficient hardware resource to prevent overflow at any
reasonable intensities. However, in extreme situations, clipping and overflow could
happen.
The intensity in single mode limits are following:
- Maximum intensity integrated over 9.97 ns: 100 MHz. Clipping will occur if the
input intensity exceeds the maximum.
- Maximum intensity integrated over 100 ms: 28.28MHz. Overflow will happen if the
maximum is exceeded.
Flex400R in dual correlation mode specifications:
- Two auto, one auto one cross, or two cross correlation functions simultaneously.
- 100ns Minimum sample time.
- 2x272 real time channels.
- Delay time range: 100 ns to 1 hour in multiple tau channel layout.
Multiple tau channel layout ( sample time denoted at T, data width W) dual mode:
- First 16 channels: T = 100ns, W = 3 bits, delay times T to 16*T;
- Second 8 channels: T = 2*100ns, W = 4 bits, delay times 9*T to 16*T
- Third 8 channels: T = 4*100ns, W = 5 bits, delay times 9*T to 16*T;
- Fourth 8 channels: T = 8*100ns, W = 6 bits, delay times 9*T to 16*T;
- Sample time doubles every 8 channels and data width increment 1 bit to prevent overflow.
- The longest delay time is about one hour.
Intensity limits:
The intensity in dual mode limits are following:
- Maximum intensity integrated over 100 ns: 70 MHz. Clipping will occur if the input
intensity exceeds the maximum.
- Maximum intensity integrated over 200ms: 20 MHz. Overflow will happen if the
maximum is exceeded.
Flex400R in Quad auto correlation mode specifications:
- Four auto correlation functions simultaneously.
- 800ns Minimum sample time.
- 4x256 minimum sample time.
- Delay time range: 800 ns to 1 hour in multiple tau channel layout.
Multiple tau channel layout ( sample time denoted at T, data width W) Quad mode:
- First 16 channels: T = 800ns, W = 3 bits, delay times T to 16*T;
- Second 8 channels: T = 2*800ns, W = 4 bits, delay times 9*T to 16*T
- Third 8 channels: T = 4*800ns, W = 5 bits, delay times 9*T to 16*T;
- Fourth 8 channels: T = 8*800ns, W = 6 bits, delay times 9*T to 16*T;
- Sample time doubles every 8 channels and data width increment 1 bit to prevent overflow.
- The longest delay time is about one hour.
Intensity limits:
The intensity in Quad mode limits are following:
- Maximum intensity integrated over 800 ns: 8.75 MHz. Clipping will occur if the
input intensity exceeds the maximum.
More about multiple tau theory.
Multiple tau theory was invented by Klaus Schätzel. The following papers discuss
the theory and the advantage of the multiple tau scheme.
- Klaus Schätzel. Single Photon Correlation Techniques. Dynamic Light
Scattering: The method and some applications, Edit by Wyn Brown, Clarendon Press, Oxford,
P 76, 1993.
- Klaus Schätzel et. Noise on Multiple-Tau Photon Correlation Data.
SPIE Vol. 1430, P109, Photon Correlation Spectroscopy: Multicomponent Systems,
1991.
- Klaus Schätzel. New Concept in Correlator Design. Inst. Phys. Conf. Ser. No.
77, P175, 1985.
- Klaus Schätzel et. Photon Correlation Measurements at Large Lag
Times. Journal of Modern Optics, Vol. 35, No. 4, P711, 1988.
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