| 摘要 |
PURPOSE:To attain double density effect by changing a vertical focus independently of horizontal focus so as to apply loose vertical focus at non-interlacing and bury the space between horizontal lines in a pseudo way. CONSTITUTION:A vertical deflection signal is fed to the base of a transistor (Tr) Tr1 and a Tr2 amplifies the said signal. In order to change the vertical focus at interlacing and non-interlacing, a switch 50 is connected to a bias terminal B of the Tr2 and the switch 50 and resistors r8, r9, r10 change the bias voltage. When the vertical deflection signal VN+,N- in waveform diagram is a waveform at normal focusing (at interlacing), a mean value VFN of both signals is a focus voltage, and it is changed into a focus voltage VFN, as a waveform shown in broken lines at a non-interlacing so as not to change the deflection sensitivity of the signals VN+', VN-' while keeping the voltage difference of both the signals. Thus, the space between the horizontal lines is buried in a pseudo way at the non-interlacing.
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