A STUDY OF FACTORS AFFECTING OPERATION OF THE VG REMOTE PPI,
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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 15, 1946
- Accession Number
- AD0657477
Entities
People
- W. R. Garner
Organizations
- Johns Hopkins University