Automotive - Adaptive Cruise Control
A client, who is major European automotive system company, has developed an adaptive cruise control system which utilizes 2 ASICs designed by Swindon Silicon Systems Ltd.
The system uses a swept Gunn diode oscillator operating in the 77GHz band to produce 3 radar beams each scanning for targets in the road ahead. The reflected signal from a target when demodulated produces an image in the spectrum ranging from 1KHz up to 120KHz which corresponds directly to distance from a particular target. Extensive signal processing of the data ensures the overall integrity of the system.
One of the SSSL ASICs is used in a low phase noise frequency locked loop, which accurately controls the swept Gunn oscillator frequency. The ASIC uses a bipolar technology and operates with -36dBm input levels at input frequencies up to 1.2GHz. The main features of the ASIC are a low noise amplifier and divider, highly linear frequency discriminator with automatic calibration and a Gunn driver loop control amplifier.
The second ASIC uses the same bipolar technology and provides a very accurately shaped gain filter characteristic to pre-distort the target demodulated spectrum, before converting to the digital domain using an A/D converter. This increases the dynamic range of the system for the subsequent digital signal processing.
