Systems and methods for optical distance measurement

A system for measuring a distance to an object, the system comprising:

• a light emitter configured to emit an outbound light pulse;
• a light sensor configured to receive a returning light pulse reflected from the object and output an analog pulse signal representing the returning light pulse;
• a field-programmable gate array (FPGA) coupled to the light sensor, wherein the FPGA includes a plurality of delay units and a plurality of latches, wherein the delay units are sequentially coupled to each other, wherein each latch is coupled to a corresponding delay unit of the plurality of delay units, and wherein the FPGA is configured to—
• convert the analog pulse signal to a plurality of digital signal values, and
• generate a plurality of time measurements corresponding to the plurality of digital signal values by sampling each digital signal value, wherein a time resolution of the sampling is shorter than a clock period of the FPGA, and wherein sampling each digital signal value includes—
• transmitting the digital signal value sequentially along the plurality of delay units;
• determining a number of the plurality of latches that were triggered during a clock cycle of the FPGA, wherein each latch is configured to be latched in response to the corresponding delay unit receiving the digital signal value;
• and
• calculating a time measurement corresponding to the digital signal value based on the determined number;
• and
• a controller configured to calculate the distance to the object based on the plurality of digital signal values and the plurality of time measurements.