The light pulses with runtime measurements require a precise and robust clock system with a time reference. An external crystal oscillator is used for realizing the time reference. A phase-locked loop is used to generate an approximate frequency of 4GHz with a corresponding geometrical resolution of 7.5 cm.
The ADC (Analog to Digital converter) clock signal is used in delay with a resulting clock signal. A programmable divider is used for reducing the highest system frequency where a clock signal is used for the digital part, ADC (Analog to Digital Converter), and the laser pulse are triggered.
Since the components can be positioned far away on the chip, clock signals with a vast network are generated.
However, buffering of signal and wiring that is necessary to cause phases difference to occur in clock paths but it is seen as errors in the measurement of the runtime.