A new design of interpolator for Time to Digital Converter

We propose an alternative approach for time interpolation of (Time to Digital Convertor)TDC in which a saw-tooth wave is generated instead of using sinusoidal wave in [10]. The proposed method avoids floating number operation for runtime as well as lowers the temperature variation caused by analog passive components. Since the differential portion of two projected signals is amplified, the wider range of time interval can be measured while preserving a few picoseconds resolution. Compared with the conventional analog interpolation, the proposed method using saw-tooth wave overcomes the drawbacks of conventional analog interpolation TDC by reducing the dependency on passive components which are sensitive to environment and operational conditions. It provides high repeatability and linearity property within a wide range of operation with high resolution of measurement. With the aid of proposed interpolation circuit, a practical TDC and its embedded measurement system are expected to be implemented. The experiment results demonstrate its feasibility and effectiveness for practical usage with a simple and low cost implementation.