bin size
bin size jitter, FWHM, RMS, quantization error
Please note: A meaningful assessment of the practical resolution of TDCs requires careful inspection of the technical specifications of the devices in use. For instance, a nominal digital resolution of 1 ps is effectively irrelevant if additional jitter sources dominate the measurement process, leading to an actual timing inaccuracy on the order of 50 ps.
Explanation: In time-to-digital converters, the bin size is the unit of quantization for time measurements.
Our TDCs are not implemented on FPGA platforms, but are realized using dedicated ASICs that ensure a controlled and highly uniform bin size. Consequently, residual jitter contributions are substantially smaller than the inherent quantization error. For short time intervals, the measurement uncertainty is therefore predominantly governed by the bin size.
Under these conditions, the maximum error approaches approximately half a bin, the root mean square (RMS) error amounts to about 0.8 bins, and the full width at half maximum (FWHM) corresponds to roughly 2 bins.
The cycle-to-cycle jitter of cronologic TDCs is much lower than their bin size. Therefore you can expect an RMS error below half the bin size for your measurements. (© cronologic GMBH & Co. KG)