Patents Patent 14358

Latvian Patent No.14358 “Calibration method for time-to-code interpolation converter” Inventors: J.Artjuhs, V.Bespaļko, J.Buls, A.Mezeriņš. Owner: Institute of Electronics and Computer Science. Published: 20.05.2011.

Invention is related to time-to-code interpolating conversion of event instants when the direct reading of a clock counter is combined with an interpolation that performs measurement of the fractional part of the period T0 of the clock pulse signal, which corresponds to the time interval between the event instant and the next following clock pulse. The instability of the interpolator characteristics represents a problem, which can be reduced by an interpolator calibration done prior to measurements. A specific sequence of input pulses representing event instants is measured to perform the calibration. The fractional parts of the period T0, which are resulted from each input pulse, are converted into interpolation codes. The frequencies of realizations of every code are counted. The interpolation transfer function as time versus code characteristic is estimated by sequential adding of these frequencies. The specific calibration sequence is such that the interpolated fractional parts of non-synchronism are evenly distributed within interval [0, T0]. Therefore the offered method makes it possible to determine the real transfer function of the interpolator so as to perform the necessary correction of the interpolation results. That significantly improves the interpolation precision and also allows to considerably simplify the interpolator circuitry.