Two-oscillator scan stability

MANY are familiar with raster patterns, particularly the example seen on the face of television receivers. In order to present the most picture information with least bandwidth, such regular raster patterns are stabilized by synchronizing signals, derived by subdividing the frequency produced by a piezoelectric crystal stabilized oscillator. However, the simplicity of using an independent, stable oscillator for each of the vertical and horizontal deflection waves has been appealing. This was especially so for the extensive circuitry and subdivision needed to furnish the high-speed scans and quadruple interlace required when Avion-Alexandri carried out a U.S. Air Force RADC contract to pursue the experiments in electronic image processing done at the National Bureau of Standards.¹