A CMOS Receiver-TDC Chip Set for Accurate Pulsed TOF Laser Ranging

An integrated receiver-time-to-digital converter (TDC) chip set is developed for pulsed time-of-flight (TOF) laser rangefinding. The receiver detects the current pulse from the optical detector and produces a timing mark for the TDC. The receiver uses time mode walk error compensation scheme achieving <+/- 2.5-mm residual timing-walk error within a dynamic range of similar to 1:40 000. The multichannel TDC measures the time position, width, and rise time of the echo pulses simultaneously with similar to 10-ps precision. Both chips are manufactured in 0.35-mu m complementary metal-oxide-semiconductor (CMOS) technology. The functionality of the chip set was demonstrated in a laser radar platform using 12 W and 3-ns optical pulses produced by a laser diode (LD). Measurement accuracy of similar to +/- 3 mm was achieved with noncooperative targets at a distance range of a few tens of meters within an amplitude range of received echoes of 1:40 000.