| 摘要 |
A continuous wave pseudonoise radar system which employs a large word rate to avoid spillover and other noise. Spillover is the electromagnetic energy that is transmitted from the transmitting antenna directly to the receiving antenna. In other words, the spillover is not reflected from the target. The word frequency is thus made higher than the highest expected doppler. The high word rate would normally cause an ambiguous range indication because the word wavelength would be less than twice the maximum expected target range. However, this problem is solved by the use of coarse and fine range indicators. It is an outstanding feature of this invention that the coarse range is obtained by changing the transmitter bit rate. The difference between transmitter and receiver bit frequencies is then integrated over a selected period. The definite integral is directly proportional to range. However, the range turns out to be a function of the transmitter bit frequency only at the integral limits. Rapid loosely controlled frequency shifts can thus be made to detect accurately the range of supersonic targets.
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