Moving target indicator device

A small cathode-ray device has been investigated as a moving target indicator. Using terms defined by IRE the device may be described as an electrical-signal storage tube having a relatively high static decay rate of predetermined value. In its present form the tube has a nominal diameter of one inch, a length of six (6) inches, and uses magnetic deflection and focus. Operation depends upon the electrical characteristics of a continuous dielectric layer, which is scanned by a narrow beam of low-energy electrons. A wide range of repetition rates can be accommodated by appropriate choice of dielectric relaxation time, and by adjustment of operating conditions. Several modes of operation are possible, adapting the device to frame-to-frame cancellation, or Area MTI, as well as to line-to-line cancellation, the function commonly performed by delay lines and their associated circuitry. Besides the obvious advantage of small space requirement, this tube promises to outperform other storage tubes and delay lines in certain other respects. Resolution is not limited by mesh structure at the storage surface as in the barrier grid storage tube. The interval of time between sweeps is not restricted to a single value as in a delay line. Cancellation ratios in excess of 40 db have been measured at TV scanning rates and at typical radar repetition rates. Theoretical and practical considerations are discussed and examples of presently-achieved performance are presented.