Abstract: Large format TV tubes must produce a high peak brightness in order to be acceptable to the user. This results in a large beam current in bright areas of the picture and in a subsequent defocusing of the resulting spot on the display and in a loss of the sharpness of vertical and horizontal transitions. The apparent sharpness of a vertical transition is gained by modifying the deflection of the TV receiver such that, at vertical transitions, the line on the bright side of the transition is deflected away from the transition region. Advantageously, the amount of vertical scan modulation corresponds to a multi-level control signal and depends on the grey levels of the transition.

Abstract: Method and apparatus for deriving line and frame frequency synchronization signals from a received television signal which has a repeated sequence of a plurality of different digital words, each word being in a respective one of a plurality of lines, as synchronization signals. One of the digital words is recognized and a first signal indicative of the recognition of one of the digital words is generated. Another digital word is recognized and at least one further signal indicative of recognition of the respective further word is generated. The first and second signals are used to determine the sequence and timing of the first and further signals to, in turn, generate a signal indicative of synchronization signal detection. The initiation of receiver sync signals at the line and frame frequency is obtained in response to the signal produced as a result of the signal indicative of synchronization signal detection.