Characteristics of Equiangular Velocity Spiral Scanning Television

Abstract

Resolution and other fundamental characteristics of equi-angular-velocity and constant-line-velocity spiral scanning television systems are compared, and the development of the system as well as the results of the measurement of an experimental spiral scanning closed circuit television system is discussed.
In the experimental system, the scanning beam moves with an equiangular velocity from the periphery of the picture screen towards the center and the spacing between the contiguous scanning lines is fixed.
A 1-inch vidicon tube in the camera and an 8-inch CRT in the monitor are employed, and the pair of deflection coils for each tube are made to have almost the same inductance.
It is found by the measurement that the tangential resolution, i. e. the resolution along the direction of beam scanning, in the central portion of the screen is about 350 lines when the video transmission bandwidth is limited to 900 kHz.