An Integrated Laser Radar Receiver Channel Utilizing a Time-Domain Walk Error Compensation Scheme

An integrated receiver channel for a pulsed time-of-flight (TOF) laser rangefinder has been designed and fabricated in a 0.35-μm SiGe BiCMOS process. The receiver channel generates a timing mark for the TDC by means of a leading-edge timing discriminator that detects the crossover of the received pulse with respect to a set reference level. The walk error generated by the amplitude variation is compensated in the time domain on the basis of the measured dependence of the walk on the length of the received pulse. The measurement accuracy is ±15 ps with compensation within a dynamic range of 1:100000, and the single-shot precision and power consumption are 120 ps for a minimum detectable signal of ~1 μA and 115 mW, respectively.