Event Timing (ET) technology has emerged from Institute of Electronics and Computer Sciences (IECS) of Latvia and has a very long history going back to 60ies and 70ties of the 20th century. Up to date the technology and methods have been constantly improved. The basics of ET technology are described below.
Innovative technology for high precision event timing
There is an important problem of combining high precision, high measurement rate and a reasonable price in designing high quality event timers. Traditional technologies for high-precision event timing do not provide solution to this problem.
To solve this problem in late 1990-s we offered a new technology based on digital signal processing (DSP) (see Fig. 1). The general idea of this technology is to generate a specific type of analog signal during the moment defined by an input event, digitise this signal and later perform its digital processing. When the processing is done in a necessary way, it leads to an estimate of the position of the analog signal on the time scale. The technology not only provides exceptional performance, but also leads to almost full replacement of highly specified hardware with typical capabilities of digital processing, therefore significantly reducing hardware costs.
Specific methods of event timing based on this approach mainly differ from best practices by analog signal generation and according digital processing algorithms. Our research is mainly focused on solving the following problem: to achieve best precision by using limited number of analog signal samples to increase measurement rate. Specifically, a recently developed method for measuring the time of event provides picosecond accuracy, using only four measurements of an analog signal.
If you wish to learn more about our technology, please leave a comment below or send us a message using the contact form.
Fig. 1: A time diagram, illustration the approach to event timing based on digital signal processing.
Methods for testing and specification of picosecond-precision event timers
At a time we are dealing with the problems of reliable testing of our event timers. The matter is that these timers provide extremely high precision, exact determining of which in commonly certified way is impossible or, at least, very difficult. For example, the common-used comparison method needs a reference instrument with much higher certified precision than the one used for our previous models.
There are only a few such instruments in the world and they are accessible only in exceptional cases. For this reason particular methods are being developed for reliable precision testing of our event timers in process of their prototyping and further manufacturing. In view of that there are two basic problems for research. The first is to clearly define the timer’s errors, specification of which can be really useful for practical applications (such as single-shot resolution, differential linearity, interval linearity, offset drift etc.). The second related problem is to develop the testing methods providing a reliable evaluation of these errors for any specific implementation of our event timers.
As for the testing methods, the main research task is to evaluate the precision parameters with sub- picosecond resolution and make that without applications of highly specialised test equipment. Mostly we are solving this task on the basis of statistical approach to the tests. In many respects the methods developed up to now confirm the mentioned requirements.
High-performance event timer system design
There is a whole line of our event timers developed and made on the basis of DSP approach to high-precision event timing. Over many years application area for our event timers is focused mainly on Satellite Laser Ranging (SLR) where high performance of measurement equipment is especially needed. In this area our R&D team closely collaborates with “International Laser Ranging Service” (ILRS) [http://ilrs.gsfc.nasa.gov/] that coordinates operation of the global network of SLR stations and related institutions. Specifically, about 30 units of our recent event timer and completed timing systems for SLR have been developed in years 2006-2008 on requests of the ILRS partners from various countries.
In line with development of our technology for event timing, we continuously are advancing the performance characteristics of our event timers. Specifically, the latest model A033-ET provides <4 ps single shot RMS resolution, combining it with the measurement at rate up to 25 MHz. This is twice as better that for the previous models.
In addition to SLR, other possible applications of Riga timing instruments also are being studied. In particular, the time-of-flight spectrometry is currently studied as a primary subject of interest for such applications.