Aspects of the disclosure provide for an apparatus comprising a time-to-digital converter (TDC) and a processor coupled to the TDC. In some examples, the TDC may be configured to receive a signal and generate a measurement result indicating a time between start and stop events of the signal. The processor may be configured to receive the measurement result, compare the measurement result to a target value, and determine a non-linearity model configured to correct a variance of the measurement result from the target value.