A measurement system includes a current source that is arranged to generate a current pulse to charge a capacitor as a function of an input clock signal. The accumulated charge on the capacitor is converted to a sample (e.g., resultant digital value) by an ADC (analog-to-digital converter). The samples can be aggregated as a distribution in order to estimate the jitter of the input clock signal. Variability of the measurement system can be minimized through calibrating the device-under-test at specific points of PVT (process, voltage, and temperature) conditions. A confidence metric such as a standard of deviation can be derived from the associated samples. The measurement system can be included on a substrate that includes the oscillator that generates the input clock signal.