cronologic xTDC4 TDC time to digital converter zoomed image


Our common start time to digital converter

A classic common-start TDC featuring 4 stop channels with a bin size of 13ps.
High precision

High precision

The occurring cycle-to-cycle jitter of the xTDC4-PCIe is much lower than the bin size of 13ps. Therefore you can expect an RMS error below 7ps for your measurements.


The threshold discriminators can handle positive and negative threshold settings with configurable level. This allows you to use the xTDC4-PCIe with a wide range of detectors or constant fraction discriminators (CFD).
TiGer timing generator

TiGer timing generator

All inputs can also be used to output periodic pulse patterns for controlling external devices. The exact timing of the generated pulses is measured by the TDC.

The xTDC4-PCIe time interval analyzer is based on a classic common-start architecture yielding high data throughput. In a common-start scenario, the arrival times of pulses on the "stop"-inputs are measured relative to a signal on the "start"-input. The xTDC4-PCIe is ideally suited for a multitude of time-of-flight applications such as TOF mass spectrometry (TOF-MS), time-correlated single photon counting (TCSPC), and LIDAR.

The xTDC4-PCIe's four-stop channels allow, for example, to use segmented detectors or measure pulses from a single detector channel at multiple thresholds to obtain rudimentary pulse height information. Such features are beneficial in many TOF-MS applications and LIDAR light detection and ranging. Fluorescence lifetime imaging microscopes (FLIM) benefit strongly from the high timing resolution of the xTDC4-PCIe.

The integration of an xTDC4-PCIe time interval meter into your data acquisition application is easy! The board provides a stream of simple data structures as a ring buffer, containing a list of relative time stamps for all stop events.

cronologic will support you with drivers for Windows and Linux.



(fluorescence-lifetime imaging microscopy)
The decay time of an excited fluorophore is typically in the range of a few nanoseconds. In fluorescence lifetime imaging the exponential decay of a sample is determined requiring a timing resolution in the picosecond regime.


also known as: LIDAR, LiDAR, and LADAR, "light detection and ranging", "laser imaging, detection, and ranging", "3-D laser scanning", "LIDAR mapping", "airborne laser scanning", ALS
LIDAR Systems emit ultraviolet, visible, or near-infrared light to image objects and measuring the time-of-flight (TOF) of reflected photons. Such systems are used for object detection and tracking in many different fields, ranging from archaeology to agriculture, autonomous vehicles and robots etc.


optical time-domain reflectometry, optical time-domain reflectometer, remote fiber testing
In optical time-domain reflectometry the time of the reflections is determined from the reflection loss by measuring from the same end of the fiber how much light returns via the Rayleigh backscatter or is being reflected from individual locations along the fiber.

TOF mass spectrometry

TOF- & MASS- spectroscopy detectors, TOFMS
In many TOFMS units cronologic TDCs are used to measure precisely the arrival of single ions. From the arrival time, the ion’s time-of-flight is deduced, from which the mass-to-charge ratio of the detected particle can be determined.

Time Domain Reflectometry

TDR, distance-to-fault, DTF
TDR (Time Domain Reflectometry) is an electronic measurement method that measures reflections along a conductor. It belongs to the category of Distance-to-Fault (DTF) measurements. TDR measurements provide meaningful information about the broadband behavior of transmission systems.

Time-Correlated Single Photon Counting

TCSPC, photon counting, time-correlated single photon counting, detection of individual photons, single-photon detectors (SPD), photosensors
Whether in astrophysics, materials science, quantum information science, quantum encryption, medical imaging, DNA sequencing or in fiber-optic communication: Single-photon detectors (SPD) provide a timing signal from which, for example, fluorescence lifetimes of excited matter can be deduced.

atomic clocks comparisons

two-way satellite time and frequency transfer, TWSTFT, coupling of atomic clocks
We are quite proud that our time to digital converters resolve so accurately that they are suitable for comparing atomic clocks.

phase shift measurements

frequency and phase shift measurements, phase-noise-analyzers
In phase measurements the phase of an incident signal is compared to the phase of a device's response signal. With increasing frequency, such phase shift measurements become more challenging. cronologic TDCs provide many features which help to address this difficult task.

quantum research

Quantum research affects many areas of modern science: quantum cryptography, quantum information science, quantum encryption, quantum key distribution (QKD), quantum electro dynamics (QED), quantum computing etc.
Quantum phenomena such as superposition, uncertainty, and entanglement are studied in quantum research with the goal that they can be safely fabricated when needed and made useful in various disciplines.


- Data

Optimized for
common start
1start & 4stop channels @13 ps
5x LEMO 00
13 ps
5 ns
parameter dependent
48 MHits/s
218 µs default, 14 ms extended
yes / no
PCIe x1
50 ppb on board
TDC channels @ bin size
Additional inputs
Bin size
Double pulse resolution
Dead time between groups
Readout rate
Common start/stop
Number of boards that can be synced
Readout interface
Time base
Linux support available
low cost
Currently there are no Downloads available for this product.

Product Brief xTDC4
User Manual xTDC4
xTDC4 driver v1.2.0.exe for Windows 7/8
xTDC4 driver v1.4.2.exe for Windows 10 & 11
get support for your Linux distribution