| 摘要 |
<p>An automatic alarm system for use with either seaborne or airborne radar systems is triggered when an object is encountered within a predetermined radius of the receiver. The circular video display (R) is divided into separate regions for object identification (Z1, Z2, Z3). The smallest central region (23) is identified as the critical region, within which any object must trigger the optical or acoustic alarm. The analogue video signal received is quantised by comparison with a threshold level to produce a square wave pulse train. The signals are sampled over a predetermined period. A correlator determines whether or not a warning signal is to be generated. The system distinguishes between a genuine radar and interference signals.</p> |
