Year: 2009
Ing. Petr Pánek, Ph.D.
All the high resolution timing devices are based on time interpolation. It results from our previous work that a surface acoustic filter can be used as an extremely precise time interpolator. We analyzed the nonlinear effects in this time interpolator. The analysis shows that the nonlinear distortion in the interpolator circuits causes a deterministic measurement error . The dependence of this error on time of the measured events can be expressed as a sparse Fourier series thus it usually oscillates very quickly in comparison to the clock period. The theoretical model is in good agreement with experiments carried out on our experimental two-channel timing system. Using highly linear amplifiers in the time interpolator and adjusting the filter excitation level to the optimum, we have achieved the interpolation nonlinearity below 0.2 ps. The overall single-shot precision of the experimental timing device is 0.9 ps rms in each channel, which is up to our knowlegde the best ever achieved in the world.
