A comparison between pulse and frequency-modulation echo-ranging systems

摘要

A general theory of the operation of frequency-modulation systems has been developed which can be applied to either Asdic or Radar, and the information obtained from such a system is compared with that from a conventional pulse system and a multipulse system. It is shown that the frequency-modulation system lends itself to more variations in the design parameters (such as range resolution, bandwidth of transmission, rate of information at the display) than the pulse system; but the system using the greatest bandwidth will give the best echo/background ratio. Where the echo/background ratio is not the all important factor, the frequency-modulation system can be rate than a pulse system. designed to provide a higher information