| Popis: |
A 500‐kHz 360° mechanically scanned portable sonar with PPI display is described. The underwater unit [21 (d) × 35 (h) cm] has a rotating assembly which accomodates two transducers, a transmitting array with a − 3‐dB beam of 1.4° by 27° and a receiving array of 2.7° by 27°. The surface control and display unit [44(w)times;32(h)×4(d) cm] incorporates a standard television format 9‐in. display and all controls. Although the sonar is of conventional Ping and Listen analog design, the microprocessor controlled 256×256 digital display with eight grey levels has considerable advantages over long persistance equivalents typically used in sonata of this type. For example, there can be no blooming or picture fade, display manipulations and expansions can be readily achieved and the output can be recorded on a standard video recorder. Critical to the system design is its ease of operation and interpretation by unskilled operators, leading to a number of new sonar users. Therefore among the applications are civil en... |
