Time Tagger Ultra (TTU) and Time Tagger X (TTX) utilize a USB 3 interface, allowing a maximum transfer rate of approximately 80 MTags/s . On the other hand, Time Tagger 20 (TT20) uses a USB 2 interface, which limits the maximum transfer rate to about 9 MTags/s . It is worth noting that the transfer rates depend on many different variables, e.g., CPU performance, workload from other running processes, power and performance settings, etc. The results mentioned above can only be achieved using a high-performance CPU with minimal workload from other applications running on the same computer.
The maximum transfer rate achievable with your system can be measured using the transfer_rate.py and/or maximum_transfer_rate.m scripts in Python and Matlab, respectively. These scripts can be found in the example section of the installation folder.
In a series of tests conducted using the top-performance CPU AMD Ryzen 9 5950X 16-Core 3.40GHz with only essential processes running in the background, we were able to measure a maximum transfer rate of approximately 82 MTags/s for the TTU and TTX, and 9.2 MTags/s for the TT20. If your laptop has an “Ultra-Low Power” CPU (denoted by a U at the end of the CPU model, such as the AMD Ryzen 7 PRO 4750U or Intel i7-1365U), it is crucial to connect your laptop to a power source when acquiring data. Otherwise, you may experience a reduction of up to 30% in the transfer rate.
These results suggest that CPU performance is more significant in limiting the maximum rate than USB 3, provided everything is set up correctly. You can find additional information on how to set up your Time Tagger connection to the PC to maximize the data transfer rate in the Data Transfer section of this documentation. Moreover, you can refer to the dedicated section to learn more about the PC requirements to maximize the transfer rate.
For very particular applications where an extremely high transfer rate is required, the TTX supports qSFP+ (SFP+) FPGA link to the Time Tagger, which enables data transfer of up to 1200 MTag/s (300 MTag/s) in the form of raw data blocks encapsulated into Ethernet frames. This is mainly meant for communication to custom external FPGA designs but can also be accessed by a PC with a qSFP+ adaptor. You can find an in-depth guide on how to set a TTX to FPGA connection in our documentation .