Television receiver including shading correction without deteriorating S/N ratio

Claim 1

A television receiver, comprising: image signal generating means for producing electron beams by supplying an image signal voltage directly to a cathode of a substantially flat screen cathode ray tube; brightness level detecting means for determining an input brightness of said image signal based upon an automatic brightness limiting (ABL) signal and for producing an inverted ABL voltage; parabolic signal combining means for producing a shading correction waveform by combining a horizontal parabolic wave signal and a vertical parabolic wave signal; and shading correction means for correcting brightness inequalities of an image formed on a fluorescent screen due to the screen flatness of said cathode ray tube by modulating said electron beams by varying a potential supplied to a first grid of said cathode ray tube in response to signals obtained by multiplying said inverted ABL voltage produced by said brightness level detecting means with said shading correction waveform produced by said parabolic signal combining means.