Accession Number : AD0657477

Title :   A STUDY OF FACTORS AFFECTING OPERATION OF THE VG REMOTE PPI,

Corporate Author : JOHNS HOPKINS UNIV BALTIMORE MD PSYCHOLOGICAL LAB

Personal Author(s) : Garner,W. R.

Report Date : 15 AUG 1946

Pagination or Media Count : 38

Abstract : The following conclusions were drawn from the results of these experiments. Detectibility improves as the video gain of the VG is increased. In general, detectibility is better with a more positive CRT bias. There is, however, an optimal CRT bias for every video gain setting. Clipping of the video signal in the PPI adapter unit does not seriously harm detectibility, although there are other disadvantages to such clipping. Increasing the accelerating voltage on the CRT decreases detectibility slightly, and considerably darkens the tube face. The reflected light intensity has no effect on detectibiblity over a wide range of intensities, both above and below the intensity normally used. Detectibility is better with the opal viewing screen than with the paper viewing screen. Under the optimal operating conditions of the VG, detectibility is approximately 1 decibel poorer than on the VF remote PPI. The higher the average detectibility, the less is the variability in the detectibility scores. The higher the video gain, the less is the variability in the detectibility scores. The more positive the CRT bias, the less is the variability in the detectibility. The reflected light intensity is the only factor which has any effect on discriminability, and that effect is very small. Range discrimination on both the VF and VG is alike for pulse lengths greater than 3 microseconds. For pulse lengths less then 3 microseconds, range discrimination is very slightly better on the VF than on the VG. (Author)

Descriptors :   (*PLAN POSITION INDICATORS, OPERATION), RADAR EQUIPMENT, RADAR TARGETS, DETECTION, TARGET DISCRIMINATION, GAIN, VOLTAGE, SCREENS(DISPLAYS), CATHODE RAY TUBES, INTENSITY, VIDEO SIGNALS, PERFORMANCE(ENGINEERING), PERFORMANCE(HUMAN)

Subject Categories : Electrooptical and Optoelectronic Devices
      Active & Passive Radar Detection & Equipment
      Human Factors Engineering & Man Machine System

Distribution Statement : APPROVED FOR PUBLIC RELEASE