Integrated Solutions for Timing Jitter Measurement.

摘要

In this thesis we present two integrated solutions suitable for measuring the timing jitter of digital signals in SoCs and data acquisition systems (mainly sampling ADCs). The presented methods are also suitable for time measurement in a variety of timing-based metrological applications.;The second method consist of an ADC-based jitter measurement technique in which the jittery signal assumes the role of sampling clock. The novelty in this technique is that it supports arbitrary analog inputs to the ADC as measurement vehicle. The proposed measurement system comprises, in addition to the sampling ADC, an independent back-end digital system to extract jitter timing information. A very important feature of such a digital system is that the jitter-induced magnitude error in each output sample of the ADC is first measured before extracting its associated timing information. Jitter characteristics of the sampling clock are extracted with high accuracy. Indeed, as demonstrated in this thesis, even for an input signal to the ADC with a bandwidth as small as 4.61 MHz, the jitter distribution of a 12.5 MHz sampling clock is extracted with an accuracy of about 3.25 ps.;The first method is based on the amplification of the time difference to be measured using a time amplifier (TAMP). The result of the amplification is subsequently digitized using a low resolution time-to-digital converter (TDC). The amplifier is based on the principle of virtual charge sharing that allows for continuous, monotonic and symmetric time transfer characteristics. Given its analog nature, the time amplifier has linearity issues in addition to being prone to temperature and process variations and uncertainties. To address these problems, a measurement and calibration method that consists of a dual TAMP arrangement is used to deduce the measured timing quantities without a priori knowledge of the gain of the amplifiers. Also, an empirical and more direct calibration technique suitable for a single-amplifier-based measurement system is presented. In this thesis we implement an amplifier with a measured gain of 228 s/s feeding a TDC of 78 ps of resolution resulting in a timing measurement system of 342.1 fs of nominal resolution.