Video signal reproducing apparatus with electron beam scanning velocity modulation

摘要

In a video signal reproducing apparatus having a cathode ray tube in which at least one electron beam is made to scan a screen in line-scanning and vertical directions while the intensity of the beam is modulated to establish the brightness of a video picture to be displayed on the screen, and in which bright picture portions are represented by respective high level portions of a video signal defined between rising and falling edges extending from low level signal portions representing contiguous dark picture portions; a waveshaping circuit receives the video signal and acts thereon to provide a compensated video signal in which the width of each high level portion between the respective rising and falling edges is increased, the compensated video signal is employed to control the intensity of the electron beam, the rising and falling edges of each high level portion of the video signal are detected to provide a beam velocity modulation signal with respective positive and negative peaks by which the scanning velocity of the beam in the line-scanning direction is modulated, and the positions of such positive and negative peaks are shafted, relative to the corresponding peaks of a differentiation of the video signal, in the directions toward the adjacent low level signal portions of the compensated video signal.